Retinal detachment in dogs. Eye diseases in dogs Who treated retinal detachment in dogs

The retina is the thinnest inner layer of the eye that is sensitive to light. Retinal detachment involves the separation of the retina from the choroid. The reason for this may be either genetics or some serious illness. The disease is treatable, but we must remember that in advanced cases it can lead to complete blindness.

Symptoms and types

Dogs with a detached retina may show signs of complete or partial vision loss. The iris is often dilated and there may be no reaction to light.

Causes

Retinal detachment can occur in any dog, regardless of breed or age. however, it is noted that Older animals are most susceptible to the disease. In some dogs, detachment occurs due to congenital defects. If retinal detachment occurs in both eyes, this may be a sign of a serious disease, such as glaucoma. A possible cause of the disease can also be exposure of your pet to toxic substances.

High blood pressure (hypertension) is considered one of the risk factors. Other metabolic causes of retinal detachment may include hyperthyroidism characterized by increased activity of the thyroid gland, hyperproteinemia - increased protein levels in the blood, as well as hypoxia, that is, low oxygen content in the tissues of the body. In addition to these conditions, possible causes include eye trauma, ocular neoplasia (intraocular tumor), and inflammation of the blood vessels inside and outside the eye.

Diagnostics

In addition to examining the eye, laboratory blood tests are necessary to identify the possible disease that caused the detachment.

Treatment

Treatment is prescribed depending on the cause and severity of the disease. There are methods of retinal engraftment using surgery, as well as methods for regenerating retinal tissue. If surgery is not necessary, then treatment will be aimed at eliminating the cause of the detachment and will be carried out with the help of medications.

During the postoperative period, try to limit your pet's physical activity. Possible complications associated with retinal detachment can cause blindness, clouding of the lens of the eye (cataract), glaucoma, and chronic eye pain. For timely diagnosis of these conditions, it is necessary to regularly show the dog to the veterinarian.

In cases where retinal grafting is not possible and the dog is at risk of complete blindness, your veterinarian will teach you the necessary skills to care for a blind animal.

Prevention

Unfortunately, there are no measures to prevent retinal detachment.

Cataract, glaucoma, retinal detachment

All these diseases are quite common in dogs, especially older ones. Cataract is accompanied by clouding of the lens; externally, the disease is expressed in clouding of the eye, which acquires a matte gray-bluish, light gray or milky gray color. There are no discharge or other symptoms of conjunctivitis and keratitis.

In addition to old age, the cause of cataract formation can be diabetes, toxicosis and trauma. Treatment boils down to instillation of vita-iodurol-triphosadadenine, viceine and vitamin preparations into the eye, 1-2 drops 2-3 times a day. Therapy is long-term and only slows down the development of the disease.

Cataract

Surgeries on the lens for cataracts in dogs are possible, but are rarely used in practice.

Glaucoma is characterized by a constant or periodic increase in intraocular pressure from 30 (normal) to 70 mm Hg. Art. The most common type of glaucoma in dogs is secondary (in addition to this type of disease, congenital and primary glaucoma is also found). The causes of the disease are quite varied: deep keratitis, displacement or swelling of the lens, hemorrhages in the vitreous body and anterior chamber of the eye, as well as contusions of the eye and penetrating wounds from trauma.

The disease is expressed by clouding of the lens, atrophy of the iris, and sometimes changes in the shape of the pupils. The dog's eyes are cloudy, gray-blue in color; when palpated, the eyeball is compacted and enlarged in size. When treating glaucoma, the drug method is primarily used, and only if this does not give visible results, surgery is used. Increased intraocular pressure in dogs can be cured by instilling a 1% solution of pilocarpine 5-6 times a day, as well as GLP with the same drug once a day. A solution of phosphakol at a concentration of 0.02% is also used 2-3 times a day.

Treatment of glaucoma should be started in a timely manner to avoid complications, the most dangerous of which is hemorrhages in the space between the choroid and the retina and, as a consequence, its detachment.

In addition to complications with glaucoma, retinal detachment can be caused by trauma, atrophy of the vitreous, or large accumulation of exudate in the chambers of the eye. With this disease, the animal’s vision suddenly deteriorates greatly, up to the onset of blindness, the pupils dilate, and there is no reaction to light with a rapid change in its intensity. The final diagnosis is made by a veterinarian when examining the dog's fundus.

With a complete retinal detachment, it is not possible to cure a dog: the dog becomes completely blind. Partial detachment can be treated with subconjunctival injections of 0.1-0.2 ml of hydrocortisone with novocaine every 3-4 days. At the same time, 0.3-0.5 ml of dexazone is administered daily. Atropine at a concentration of 1% or 2% dionine solution is instilled into the conjunctival sac.

This text is an introductory fragment. From the author's book

Cataract This disease is characterized by clouding of the lens. In some cases, cataracts are clearly visible to the naked eye as whitish lumps that give the lens a milky-gray or bluish-white mottled appearance behind the pupil. Cataracts are observed in any

From the author's book

Cataract Cataract is clouding of the lens. Some scientists consider it a widespread eye disease in dogs, mostly older than eight years of age. Typically, cataracts are easily visible to the naked eye as a white, cloudy spot in the

From the author's book

Cataracts, glaucoma, retinal detachment All these diseases are quite common in dogs, especially older ones. Cataract is accompanied by clouding of the lens; externally, the disease is expressed in clouding of the eye, which acquires a dull gray-bluish color,

From the author's book

Cataracts, glaucoma, retinal detachment These diseases are quite common in dogs, especially older ones, and can deprive the pet of his vision. Cataract is accompanied by clouding of the lens; externally, the disease is expressed in clouding of the eye, which becomes dull

From the author's book

Cataracts, glaucoma, retinal detachment All these diseases are quite common in dogs, especially older ones, and can deprive the pet of vision. Cataract is accompanied by clouding of the lens; externally, the disease is expressed in clouding of the eye, which acquires

From the author's book

Cataracts Cataracts are considered the second most common eye disease in dogs. Juvenile cataracts can appear in purebred dogs at a very early age. There are two forms of this disease - absorbable and non-absorbable. In the first case

Authors): S.A. Boyarinov is a veterinary ophthalmologist at the IVC MBA, head of the treatment and preventive department of the SBBZh in Pushkino, graduate student of the department of the Federal State Budgetary Educational Institution FSBEI HE MGAVMiB - MBA named after. K.I. Scriabin, member of RVO, ESVO, Russian Geographical Society.
Organization(s): Federal State Budgetary Educational Institution of Higher Education “Moscow State Academy of Veterinary Medicine and Biotechnology - MBA named after K.I. Scriabin" (FSBEI HE MGAVMiB - MBA named after K.I. Scriabin)
Magazine: №1 -2017

Introduction

The retina is a unique organ with a complex structure and functionality that provides visual perception of the surrounding world in dogs and cats. Since eye pathologies are often associated with various somatic diseases in animals, it is necessary to take into account the possibilities of primary diagnosis of pathology and, accordingly, prognosis. One of these visual diseases is retinal detachment (RD).

Normally, the retina of the eye is tightly adjacent to the underlying layers, the pigment epithelium (RPE) and choroid. This condition is due to the gentle pressure exerted on it by the vitreous body (VT), which holds the retina in a physiological position. The retina is tightly attached to the underlying layer only in a few places: along the dentate line and near the optic nerve. In other areas, the connection is caused only by gentle pressing of the joint, which, accordingly, allows us to conclude that the likelihood of detachment developing in these places is the highest.

OS is an eye pathology in which there is a complete or partial separation of its 9 layers (neuroretina) from the RPE and choroid (choroid). Normally, these structures fit tightly together, providing trophic functions.

With OS of the eye in animals, vision decreases to the point of complete blindness, and in advanced cases OS leads to the death of the eye. Therefore, this pathology is an emergency condition and requires immediate contact with a veterinary ophthalmologist.

Etiology

This eye disease occurs in both dogs and cats, but often has different causes. For example, hypertensive retinopathy with both total and local OS of an exudative nature is most typical for cats.

Most often, the following factors and pathologies can lead to OS in dogs and cats.

  • - Congenital malformations such as retinal dysplasia (RD), collie eye anomaly (CEA), and primary hyperplastic persistent TS syndrome (PHTVL/PHPV).
  • - Eye injury leading to retinal rupture and hemorrhage.
  • - Inflammatory processes (chorioretinitis), leading to accumulation of exudate or blood in the subretinal space.
  • - Degeneration and dysplasia CT.
  • - Neoplasms of the posterior segment of the eye, including the choroid.
  • - Buphthalmos in glaucoma, leading to stretching of the membranes of the eyeball.
  • - Pathologies leading to damage to the vascular bed: systemic hypertension, blood hyperviscosity syndrome, diabetes mellitus.

Based on the reasons leading to OS, several types of this pathology are distinguished.

Serous OS occurs as a result of the accumulation of fluid under the retina and, accordingly, its separation from the underlying layer. There are two types of serous detachment: the first is the exudative type, characterized by the accumulation of inflammatory fluid (exudate) as a result of infectious diseases, the second is the hemorrhagic type, characterized by the presence of blood under the neuroretina due to systemic arterial hypertension, coagulopathies, thrombocytopenia.

Tractional detachment occurs as a result of tension on the retina from the side of the CT, to which it fits tightly. This condition is possible due to posterior uveitis, the formation of moorings and cords during degeneration of the CT, as well as when it is displaced forward as a result of luxation of the lens and displacement of the iridolenticular diaphragm.

Rhegmatogenous OS is associated with thinning and formation of retinal breaks as a result of degenerative changes, especially in older animals. Through these breaks, CT can penetrate under the retina, leading to detachment.

Traumatic OS is the result of injury to the eyeball (contusion, penetrating injury). In these cases, trauma can lead to both acute detachment as a result of retinal rupture, displacement of the retina, subretinal hemorrhages, and to detachment in the long term (chronic inflammatory process, destruction of the retina, hypotension).

It is also worth mentioning the possible iatrogenic OS after intraocular manipulations, in particular phacoemulsification of cataracts and vitrectomy. Thus, with phacoemulsification of 290 eyes in dogs and their three-year follow-up, postoperative complications in the form of OS amounted to 1–2%, although in the work of other researchers they range from 4 to 9%. Despite the small percentage of detachments after phacoemulsification of cataracts in dogs, it is necessary to regularly assess the condition of the retina using ultrasound in the immediate and late postoperative periods.

According to the degree of prevalence, it is customary to distinguish the following types of OS: local, total, subtotal.

As a result of detachment of the neuroretina from the RPE and choroid, the following disorders occur:

Decreased metabolism in neuroretina; disruption of retinol transport from the RPE to the neuroretina; disruption of the blood supply to the neuroretina from the choriocapillaris; development of atrophy of the photoreceptor layer of the neuroretina; release of vascular endothelial growth factor (VEGF) by hypoxic neuroretina.

It should be noted that OS is a condition that requires emergency treatment by the animal owner to a veterinary specialist and provision of immediate assistance to the patient. In many cases, when treatment is timely, and depending on the type and cause of OS, the prognosis for vision can be favorable. However, the lack of treatment, the inability to diagnose this pathology, as well as late treatment can lead to complications that can arise after OS - retinal atrophy, glaucoma, hemophthalmos, etc. In such cases, irreversible blindness develops and there is a high risk of losing the eye as an organ .

Risk factors

Risk factors for the development of OS in dogs and cats include the following:

High blood pressure (hypertension); old age; the presence of overripe cataracts; luxation of the lens; phacoemulsification of cataracts; genetics.

Clinical signs

Symptoms of OS in dogs and cats include partial or complete loss of vision (acute blindness), decreased or absent pupillary light response (PLR), the appearance of retinal floats and vessels visible without special equipment on a dilated pupil, ultrasound signs characteristic of OS - “gull wings” or the Latin letter V during ultrasound of the eyeball. OS can often be accompanied by hemophthalmos (accumulation of blood in the CT).

As already mentioned, OS in many cases can be a concomitant symptom of the underlying disease. Therefore, it is important to take this connection into account, even in the absence of obvious signs of OS.

Diagnostics

Confirmation of the diagnosis of OS is made on the basis of anamnesis, examination by a veterinary ophthalmologist and diagnostic studies.

Pet owners in most cases complain of dilated pupils and varying degrees of blindness. In cats, fibrin and blood may be present in the intraocular space.

To make an accurate diagnosis, it is recommended to use a comprehensive diagnostic approach: an ophthalmological examination (biomicroscopy, ophthalmoscopy, ultrasound), as well as an assessment of the animal’s somatic condition (clinical and biochemical blood tests, testing for infections, cardiac examination, etc.).

A comprehensive ophthalmological examination provides a complete diagnostic picture of the disease, prognosis and choice of treatment tactics. If OS is suspected, it is necessary to assess the condition of the anterior chamber of the eye, iris and lens, and check pupillary reflexes.

An important diagnostic measure for suspected OS is ophthalmoscopy.

This procedure is possible in the presence of transparent light-refracting media of the eye (cornea, lens, CT) and allows you to visually assess the state of the OS: detection and localization of areas of detachment (vibrating gray-white areas of the retina), the presence of exudate and hemorrhages, the presence of retinal breaks of various configurations.

Ultrasound of the eye is the “gold standard” for diagnosis in animals with suspected OS. It is especially important that this study is relevant when it is impossible to perform ophthalmoscopy and when the optical media of the eye are opaque (hyphema, hemophthalmos, cataracts, corneal edema). With an ultrasound of the eyeball, it is possible to assess the degree and type of OS, the presence of exudate, blood, concomitant pathologies of CT (moorings, destruction) and choroid. When B-scanning, the OS is visualized as a film-like formation in the CT, usually having contact with the dentate line, and the optic nerve head (ONH) in the form of the letter V.

The detached neuroretina is mobile, and when the eye moves during ultrasound, it moves smoothly, as if floating. OS is often accompanied by posterior vitreous detachment (PVD) and is typical for older animals.

Treatment

Since OS is an acute condition leading to decreased vision and blindness, the speed of treatment and the urgency of the assistance provided play a decisive role in the further prognosis of the disease. A long-term lack of medical care, as a rule, leads to disruption of the retina. This is due to the lack of contact between the detached neuroretina and the choroid (choroid) and impaired trophism and metabolism between them. However, with emergency assistance to a patient with a detachment, it is possible to restore vision using both conservative and surgical treatment.

Drug treatment includes the use of medications aimed at relieving the primary cause that caused neuroretinal detachment. For example, cats with arterial hypertension, even without signs of retinopathy, should receive antihypertensive therapy aimed at normalizing blood pressure through the use of systemic antihypertensive drugs (amlodipine) and ACE inhibitors (enalapril), thereby preventing OS. The use of antibacterial therapy is justified if a systemic infection is confirmed. At the same time, it is especially important to take measures in the event of an emergency admission of an animal to a veterinary clinic in the form of diuretic medications (in the absence of contraindications). The use of natural, and in the absence of contraindications, systemic corticosteroids (prednisolone), gives good results, especially in dogs.

Surgical treatment of OS in dogs and cats is relevant if the prognosis for vision is favorable, as well as the absence of contraindications for anesthesia. The procedure to restore the retina to its physiological position is called retinopexy. There are several types of retinopexy:

Laser surgery (photocoagulation);
cryopexy;
pneumatic retinopexy;
vitrectomy with replacement.

The principle of laser surgery and cryopexy is similar and consists in “welding” or “freezing” the retina to the underlying tissues by forming scars at the site of exposure.

Pneumatic retinopexy is somewhat simple to perform and consists of introducing a gas bubble into the CT, which puts pressure on the retina, pressing it to a physiological place.

Vitrectomy for OS is quite complex and requires expensive equipment and the skill of a microsurgeon. The meaning of this procedure is to remove the CT, straighten the OS and introduce heavy oil into the eye cavity (silicone tamponade of the vitreal cavity). Thus, the neuroretina is pressed against the RPE and choroid, providing an anatomical and physiological fit.

Quite often, surgical procedures for OS are performed in combination, for example, laser retinopexy and vitrectomy with replacement, to achieve a better result.

Each method has its own positive and negative sides, as well as indications depending on the type and severity of OS.

Conclusion

In conclusion, I would like to note the importance of urgently contacting a veterinarian, the urgency of providing first emergency aid, referral for ongoing treatment and monitoring by a veterinary ophthalmologist.

Literature:

  • 1. Boyarinov S.A. The use of ultrasound research in the diagnosis of secondary glaucoma in dogs. Veterinary, Animal Science and Biotechnology. 2015; 10:6–12.
  • 2. Andrew S.E., Abrams K.L., Brooks D.E., et al. Clinical features of steroid responsive retinal detachments in twenty-two dogs. Vet. Comp. Ophthalmol. 1997; 7:82–87.
  • 3. Bayón A., Tovar M.C., Fernández del Palacio M.J., Agut A. Ocular complications of persistent hyperplastic primary vitreous in three dogs. Vet Ophthalmol. Mar 2001; 4(1): 35–40.
  • 4. Bergstrom B.E., Stiles J., Townsend W.M. Canine panuveitis: a retrospective evaluation of 55 cases (2000–2015). Vet Ophthalmol. 2016 Oct 12.
  • 5. Chetboul V., Lefebvre H.P., Pinhas C., Clerc B., Boussouf M., Pouchelon J.L. Spontaneous feline hypertension: clinical and echocardiographic abnormalities, and survival rate. J Vet Intern Med. 2003 Jan-Feb; 17(1): 89–95.
  • 6. Cullen C.L., Caswell J.L., Grahn B.H. Intravascular lymphoma presenting as bilateral panophthalmitis and retinal detachment in a dog. J Am Anim Hosp Assoc. 2000 Jul-Aug; 36(4): 337–42.
  • 7. Davidson M. G., Nasisse M. P., Jamieson V. E., et al. Phacoemulsification and intraocular lens implantation: a study of surgical results in 182 dogs. Progress in Veterinary and Comparative Ophthalmology. 1991; 1:233–238.
  • 8. Elliott J., Barber P.J., Syme H.M., Rawlings J.M., Markwell P.J. Feline hypertension: clinical findings and response to antihypertensive treatment in 30 cases. J Small Anim Pract. Mar 2001; 42(3): 122–9.
  • 9. Gallhoefer N.S., Bentley E., Ruetten M., Grest P., Haessig M., Kircher P.R., Dubielzig R.R., Spiess B.M., Pot S.A. Comparison of ultrasonography and histologic examination for identification of ocular diseases of animals: 113 cases (2000-2010). J Am Vet Med Assoc. 2013 Aug 1; 243(3): 376–88.
  • 10. Ginn J.A., Bentley E., Stepien R.L. Systemic hypertension and hypertensive retinopathy following PPA overdose in a dog. J Am Anim Hosp Assoc. 2013 Jan-Feb; 49(1): 46–53.
  • 11. Gornik K.R., Pirie C.G., Duker J.S., Boudrieau R.J. Canine multifocal retinopathy caused by a BEST1 mutation in a Boerboel. Vet Ophthalmol. 2014 Sep; 17(5): 368–72.
  • 12. Grahn B.H., Barnes L.D., Breaux C.B., Sandmeyer L.S. Chronic retinal detachment and giant retinal tears in 34 dogs: outcome comparison of no treatment, topical medical therapy, and retinal reattachment after vitrectomy. Can Vet J. 2007 Oct; 48(10): 1031–9.
  • 13. Grahn B.H., Sandmeyer L.S. Bilateral rhegmatogenous retinal detachments with giant retinal tears. Can Vet J. 2009 Sep; 50(9): 989–90.
  • 14. Grozdanic S.D., Kecova H., Lazic T. Rapid diagnosis of retina and optic nerve abnormalities in canine patients with and without cataracts using chromatic pupil light reflex testing. Vet Ophthalmol. 2013 Sep; 16(5): 329–40.
  • 15. Gwin R.M., Wyman M., Ketring K., Winston S. Idiopathic uveitis and exudative retinal detachment in the dog. J Am Anim Hosp Assoc. 1980; 16: 163–170.
  • 16. Hendrix D.V., Nasisse M.P., Cowen P., Davidson M.G. Clinical signs, concurrent diseases, and risk factors associated with retinal detachments in dogs. Prog Vet Comp Ophthalmol. 1993; 3:87–91.
  • 17. Hisatomi T., Sakamoto T., Goto Y., et al. Critical role of photoreceptor apoptosis in functional damage after retinal detachment. Curr Eye Res. 2002; 24: 161–172.
  • 18. Hoffman A., Wolfer J., Occelli L., Lehenbauer T.W., Sapienza J., Novak J.M., Combs K.L., Konrade K.A. Refractive state following retinal reattachment and silicone oil tamponade in dogs. Am J Vet Res. 2012 Aug; 73(8): 1299–304.
  • 19. Huhtinen M., Derré G., Renoldi H.J., Rinkinen M., Adler K., Aspegrén J., Zemirline C., Elliott J. Randomized placebo-controlled clinical trial of a chewable formulation of amlodipine for the treatment of hypertension in client-owned cats. J Vet Intern Med. 2015 May-Jun; 29(3): 786–93.
  • 20. Itoh Y., Maehara S., Yamasaki A., Tsuzuki K., Izumisawa Y. Investigation of fellow eye of unilateral retinal detachment in Shih-Tzu. Vet Ophthalmol. 2010 Sep; 13(5): 289–93.
  • 21. Labruyere J.J., Hartley C., Holloway A. Contrast-enhanced ultrasonography in the differentiation of retinal detachment and vitreous membrane in dogs and cats. J Small Anim Pract. Oct 2011; 52(10): 522–30.
  • 22. Leblanc N.L., Stepien R.L., Bentley E. Ocular lesions associated with systemic hypertension in dogs: 65 cases (2005-2007). J Am Vet Med Assoc. 2011 Apr 1; 238(7): 915–21.
  • 23. Maggio F., DeFrancesco T.C., Atkins C.E., Pizzirani S., Gilger B.C., Davidson M.G. Ocular lesions associated with systemic hypertension in cats: 69 cases (1985–1998) J Am Vet Med Assoc. 2000; 217:695–702.
  • 24. Montgomery K.W., Labelle A.L., Gemensky-Metzler A.J. Trans-corneal reduction of anterior lens luxation in dogs with lens instability: a retrospective study of 19 dogs (2010–2013). Vet Ophthalmol. July 2014; 17(4): 275–9.
  • 25. Papaioannou N.G., Dubielzig R.R. Histopathological and immunohistochemical features of vitreoretinopathy in Shih Tzu dogs. J Comp Pathol. Feb 2013; 148(2–3): 230–5.
  • 26. Pearce J., Giuliano E.A., Galle L.E., Klauss G., Ota J., Moore C.P. Management of bilateral uveitis in a Toxoplasma gondii-seropositive cat with histopathologic evidence of fungal panuveitis. Vet Ophthalmol. 2007 Jul-Aug; 10(4): 216–21.
  • 27. Pizzirani S., Davidson M.G., Gilger B.C. Transpupillary diode laser retinopexy in dogs: ophthalmoscopic, fluorescein angiographic and histopathologic study. Vet Ophthalmol. 2003 Sep; 6(3): 227–35.
  • 28. Pumphrey S. Canine Secondary Glaucomas. Vet Clin North Am Small Anim Pract. 2015 Nov; 45(6): 1335–64.
  • 29. Rodarte-Almeida A.C., Petersen-Jones S., Langohr I.M., Occelli L., Dornbusch P.T., Shiokawa N., Montiani-Ferreira F. Retinal dysplasia in American pit bull terriers—phenotypic characterization and breeding study. Vet Ophthalmol. Jan 2016; 19(1): 11–21.
  • 30. Sandberg C.A., Herring I.P., Huckle W.R., LeRoith T., Pickett J.P., Rossmeisl J.H. Aqueous humor vascular endothelial growth factor in dogs: association with intraocular disease and the development of pre-iridal fibrovascular membrane. Vet Ophthalmol. Mar 2012; 15 Suppl 1: 21–30.
  • 31. Sakai T., Calderone J.B., Lewis G.P., Linberg K., Fisher S.K., Jacobs G.H. Cone photoreceptor recovery after experimental detachment and reattachment surgery: An immunocytochemical, morphological and electrophysiological study. Invest Ophthalmol Vis Sci. 2003; 44:416–425.
  • 32. Schmidt G.M., Vainisi S.J. Retrospective study of prophylactic random transscleral retinopexy in the Bichon Frise with cataract. Veterinary Ophthalmology. 2004; 7: 307–310.
  • 33. Sigle K.J., Nasisse M.P. Long-term complications after phacoemulsification for cataract removal in dogs: 172 cases (1995–2002). Journal of the American Veterinary Medical Association. 2006; 228:74–79.
  • 34. Steele K.A., Sisler S., Gerding P.A. Outcome of retinal reattachment surgery in dogs: a retrospective study of 145 cases. Vet Ophthalmol. 2012 Sep; 15 Suppl 2: 35–40.
  • 35. Spatola R.A., Nadelstein B., Leber A.C., Berdoulay A. Preoperative findings and visual outcome associated with retinal reattachment surgery in dogs: 217 cases (275 eyes). Vet Ophthalmol. 2015 Nov; 18(6): 485–96.
  • 36. Steele K.A., Sisler S., Gerding P.A. Outcome of retinal reattachment surgery in dogs: a retrospective study of 145 cases. Vet Ophthalmol. 2012 Sep; 15 Suppl 2: 35–40.
  • 37. Stiles J., Polzin D.J., Bistner S.I. The prevalence of retinopathy in cats with systemic hypertension and chronic renal failure or hyperthyroidism. J Am Anim Hosp Assoc. 1994; 30:564–572.
  • 38. Vainisi S.J., Wolfer J.C. Canine retinal surgery. Vet Ophthalmol. 2004 Sep-Oct;7(5): 291–306.
  • 39. Van Der Woerdt A. Ultrasonographic abnormalities in the eyes of dogs with cataracts: 147 cases (1986–1992). Journal of the American Veterinary Medical Association. 1993; 9(5: 281–291.
  • 40. Wang S., Linsenmeier R.A. Hyperoxia improves oxygen consumption in the detached feline retina. Invest Ophthalmol Vis Sci. 2007; 48:1335–1341.
  • 41. Whiting R.E., Pearce J.W., Castaner L.J., Jensen C.A., Katz R.J., Gilliam D.H., Katz M.L. Multifocal retinopathy in Dachshunds with CLN2 neuronal ceroid lipofuscinosis. Exp Eye Res. May 2015; 134: 123–32.
  • 42. Slatter`s fundamentals of veterinary ophthalmology / D.J. Maggs, P.E. Miller, R. Ofri. Saunders Elsevier: St Louis. Mo. 2013. 506 p.
  • 43. Zarfoss M.K., Breaux C.B., Whiteley H.E., Hamor R.E., Flaws J.A., Labelle P., Dubielzig R.R. Canine pre-iridal fibrovascular membranes: morphologic and immunohistochemical investigations. Vet Ophthalmol. 2010 Jan; 13(1): 4–13.
  • 44. Veterinary Ophthalmology: Two Volume Set (5th edition) / Kirk N. Gelatt (Editor), Brian C. Gilger (Editor), Thomas J. Kern (Editor). Chicester, Wiley-Blackwell (an imprint of John Wiley & Sons Ltd), 2013. 2260 p.

Dogs, like other animals, often suffer from eye diseases. By the condition of the eyes you can always determine whether your dog is healthy or not; the eyes are a “mirror” not only of the soul, but also of the health of the animal. In medicine, the eyes are used to diagnose existing diseases in a person. In medicine, as one of the auxiliary diagnostic methods, there is iridodiagnosis - the diagnosis of diseases in a person using the iris of the eyes. When conducting iridology, special equipment and computer programs are used. When making a diagnosis, doctors take into account changes in the structural state, shape of the color areas of the eye, as well as the mobility of the iris.

Before talking about eye disease and its auxiliary organs, it is necessary to have a general understanding of its structure.

A dog's eyes are located in the orbits - bony sockets formed by the bones of the skull, where they are held by several muscles that ensure their mobility and orientation in different directions.

The dog's eye itself is protected by auxiliary organs - eyelids and glands. The dog has three eyelids. The upper and lower eyelids are folds of skin, the inner surface of the eyelids is lined with mucous membrane. The outside of the eyelids is bordered by eyelashes, which protect the eyes from dust and other foreign particles. A dog's third eyelid is a simple film in the inner corner of the eye that dog owners usually cannot see. This film covers the eye when it is closed or irritated, as well as during nervous disorders.

The eye in the cornea area comes into contact with the external dry environment, so it needs protection of the lacrimal glands, which produce tear fluid - a secret that moisturizes the surface of the cornea. A dog's tears accumulate in the space between the eyelids and the eye and are then drained through a narrow channel that begins at the inner corner of the eye and opens into the nasal cavity. When there is excessive lacrimation or blockage of the tear duct, tears flow from the eyes and, when oxidized, form red stripes on the fur that look like blood.

The eye consists of two parts.

  • The anterior portion includes the cornea, iris, and lens. They absorb beams of light from the dog, like a camera lens. The cornea and lens are clear and act like optical lenses, and the iris acts as a diaphragm, regulating the amount of light entering the eye through the pupil (the hole in the iris).
  • The back of the eye consists of the vitreous body, the choroid (choroid) and the retina, which converts optical light signals into nerve impulses that are transmitted to the visual center of the brain.

Thinking of the eye as an analogy to a camera, the back of the eye is like a photographic film on which the dog's brain captures the image.

Experts, depending on the cause, divide all eye diseases in dogs into 3 types:

  1. Infectious – occurring in dogs due to the presence of viral or bacterial diseases, most often as a complication of the underlying disease.
  2. Non-infectious - due to certain mechanical damage, inflammation as a result of improper eyelash growth, neoplasms, eversion of the eyelids.
  3. Congenital – include eversion, entropion of the eyelids, deformations of the eyes and lens. Congenital ones are most often found in some dog breeds (Shar Peis).

Diseases of the eyelids

With this disease, single or multiple hairs appear in a row on the free edge of the eyelid, which should be hairless.

These hairs appear in a dog only at the 4-6th month of life and can be either very delicate or quite hard. With this disease, several hairs most often grow from one point. This disease is most often recorded in English and American cocker spaniels, boxers, Tibetan terriers, collies, and Pekingese.

Clinical picture. During a clinical examination of a dog, a veterinarian notes profuse lacrimation, constant blinking, blepharospasm, irritating hairs have contact with the cornea of ​​the eye. If a dog has curled eyelashes, keratitis is diagnosed.

Diagnosis The disease is diagnosed based on the above symptoms.

Differential diagnosis. D istihnaz is differentiated from trichiasis, entropion and eversion of the eyelids, allergic conjunctivitis, and keratoconjunctivitis sicca.

Treatment. It is carried out in veterinary clinics by electrolysis under an operating microscope. Excision of the third eyelid.

Trichiasis is a condition when hair from a dog's eyelids or muzzle gets into the eye, coming into contact with the conjunctiva and cornea. Trichiasis can be primary or secondary. Primary occurs in dogs with medial inversion of the eyelids and a large nasolabial fold. Trichiasis occurs in the following dog breeds: Pekingese, Pugs, English Bulldogs, English Cocker Spaniels, Chow Chows, Shar-Peis.

Clinical picture. During a clinical examination of a dog, a veterinarian notes lacrimation, hairs in contact with the cornea cause blinking in dogs, constant discharge from the eyes, symptoms of keratoconjunctivitis, inflammation of the skin in the area of ​​the nasolabial fold.

Diagnosis placed on the basis of detection of hair in contact with the cornea, provided there is no other eye pathology.

Differential diagnosis. Trichiasis is differentiated from keratoconjunctivitis sicca, entropion and eversion of the eyelids, dystrichiasis, and ectopic eyelashes.

Treatment. Treatment of the disease is surgical. Temporary improvement can be achieved by trimming the hair that gets into the eye.

Entropion is a pathology of the eye in which part of the organ turns inward towards the eyeball. A dog's eyelid inversion can be either upper or lower, one-sided or two-sided.

Unilateral inversion of the eyelid margin is most often the result of heredity and appears in a dog in the first year of life. Congenital entropion occurs in puppies after the eyes open in some breeds with excessively folded skin on the head (chow chow, shar pei).

In this disease, the eyelashes, hair and skin of the eyelid rub against the surface of the cornea, causing inflammation and irritation.

Clinical picture. During a clinical examination, the veterinarian notes the leakage of liquid secretion from the eye, the dog has photophobia (to an electric light bulb, the sun), the dog rubs its eyes with its paw, blinking, and there may be an eye tic.

Treatment. Treatment of entropion of the eyelids is surgical.

With eversion of the eyelids, the edge of the eyelid turns outward, while the mucous membrane (conjunctiva) of the eyelid is exposed.

This pathology occurs in dogs with too large palpebral fissure and excess, easily removable skin in the head area.

Cause. Mechanical eversion of the eyelids in a dog occurs as a result of pathological changes in the eyelid itself, as well as tissue scarring after injuries or surgery.

Paralytic ectropion occurs in dogs as a result of facial paralysis.

Clinical picture. During a clinical examination, the veterinarian notes incomplete closure of the eyelids, discharge from the eyes, and inflammation of the conjunctiva.

Treatment. Treatment for this pathology should be aimed at eliminating the cause that caused and maintains the ectropion of the eyelids (removal of a neoplasm, conjunctivitis, facial paralysis, surgical removal).

Blepharitis is inflammation of the eyelids.

Cause. Unilateral blepharitis in a dog occurs due to injury and local infection. Bilateral blepharitis occurs as a result of allergies, including demodicosis (), mycoses and systemic diseases.

Clinical picture. During a clinical examination, the veterinarian notes redness, swelling, itching, scaling, loss of eyelashes and hair, erosion and ulcers in the eyelid area of ​​a sick dog.

Treatment. In the case where the cause of blepharitis is an allergy, dog owners should exclude its contact with the allergen and use antihypertensive drugs (diazolin, suprastin, diphenhydramine, tavegil) in treatment. For staphylococcal infections - antibiotics. For demodicosis, anti-mite drugs.

Eyeball diseases

Exophthalmos (protrusion of the eyeball)

Can exophthalmos occur in dogs? species-specific and is characteristic of dogs of brachycephalic breeds, with a normal eyeball size, a flat orbit and an overly large palpebral fissure.

Acquired exophthalmos- In this case, a normal-sized eyeball moves forward due to space-demanding processes in the orbit or its immediate surroundings, or due to an increase in the size of the eyeball as a result of glaucoma in the dog.

Clinical picture. During a clinical examination, the veterinarian notes that the dog has strabismus, an abnormally wide palpebral fissure with protrusion of the eyeball; in some dogs, prolapse of the third eyelid is possible.

Treatment surgical only .

Endophthalmos (Recession of the eyeball)

Reason This eye pathology is a very small eyeball (microphthalmos) - congenital pathology, atrophy of the eyeball, relatively large orbit, neurogenic retraction of the eyeball.

Clinical picture. During a clinical examination by a veterinary specialist, such a dog has a narrow, reduced palpebral fissure, uncontrolled contraction of the eyelids, and prolapse of the third eyelid.

Treatment. Treatment is limited to treating complications of this disease.

Convergent strabismus is a noticeable visual deviation from the normal position and joint movement of both eyes of a dog.

Moreover, with paralytic strabismus, the dog's squinting eye does not repeat the movement of the fixed eye.

Cause. Traumatic eye injuries, hypertrophic processes in the orbit (tumors), damage to the central nervous system.

One of the reasons may be congenital underdevelopment of the periorbital muscles, congenital hydrocephalus.

Treatment. Treatment of convergent strabismus involves treating the underlying disease that led to the strabismus.

Canine conjunctivitis is the most common disease in dogs. Conjunctivitis is accompanied by dysfunction of the conjunctival mucosa and often occurs with infectious diseases. Additionally, the causes of conjunctivitis in dogs can be allergies, clogged tear ducts, viruses, foreign body injuries, irritation of the conjunctiva as a result of eyelid pathology.

Allergic conjunctivitis

Allergic conjunctivitis in dogs occurs as a result of contact with the mucous membrane of the eye of one or another allergen (contact allergy). The allergen can be pollen from flowering plants, dust, etc.

Allergic conjunctivitis in dogs In recent years, allergies to certain food products (food allergy) have often been reported.

Clinical picture. During a clinical examination, a veterinarian notes in such a dog redness of the mucous membrane of the eyes, mucous discharge from the palpebral fissure. As a result of itching, the dog rubs its paw on the affected eye.

Treatment. If contact dermatitis occurs, it is necessary to rinse the eye affected by inflammation with saline solution or chamomile decoction.

In case of food allergies, it is necessary to exclude the allergic product from the dog’s diet and transfer the dog to a hypoallergenic diet (buckwheat, rice, beef).

The sick dog is prescribed antihistamines (cetirizine, diazolin, suprastin, diphenhydramine, tavegil), and Diamond Eyes eye drops are instilled into the conjunctival sac.

Purulent conjunctivitis

Purulent conjunctivitis in a dog develops due to the entry of various pathogenic microorganisms into the conjunctiva. Purulent conjunctivitis is one of the symptoms of carnivore plague......

Clinical picture. During a clinical examination, a veterinarian notes reddening of the conjunctiva, its swelling, and purulent discharge from the eye of a sick dog.

Treatment. With this form of conjunctivitis, a sick dog is treated with eye drops and ointments that contain antibiotics. Tetracycline eye ointment and Tsiprovet drops are widely used. Before applying eye drops and eye ointment, it is necessary to clean the affected eyes of exudate.

This form of conjunctivitis is most typical of chronic conjunctivitis and often develops in a dog when toxic substances get into the eye.

Clinical picture. During a clinical examination, a veterinarian reveals many bubbles with transparent contents on the mucous membrane of the conjunctiva. Mucous discharge comes from the palpebral fissure. The conjunctiva itself is crimson in color, and the dog's inflamed eye is squinted.

Treatment. When treating this form of conjunctivitis, eye ointments containing an antibiotic are used. In severe cases of the disease, specialists are forced to resort to excision of the conjunctiva and subsequent symptomatic treatment.

Keratoconjunctivitis sicca - This disease is characterized by very little tear film in the eye as a result of insufficient or absent tear production. This disease is observed in West Highland white terriers and is inherited by their offspring. Keratoconjunctivitis sicca in dogs occurs due to disorders of sex hormones, canine distemper, trauma to the frontal part of the skull, neuropathy of the facial nerve, congenital hypoplasia of the lacrimal glands, and from the use of certain medications. .

Clinical picture. Veterinary specialists, when conducting a clinical examination of a sick dog, note frequent blinking, dry crusts at the edges of the eye, itching, the presence of mucopurulent discharge from the eyes, viscous mucus is found in the conjunctival sac, follicular conjunctivitis. Later, as the disease progresses, symptoms of ulceration and unevenness of the corneal surface appear, and swelling of the conjunctiva develops. If there are dry crusts in the area of ​​the nostrils on the affected side, we can talk about the presence of damage to the facial nerve in the sick dog.

Treatment. Treatment for this form of keratoconjunctivitis should be aimed at eliminating the underlying cause of the disease. The area of ​​the conjunctiva and cornea is washed generously every two hours with saline before each application of the drug. The inner corners of the eyes of a sick dog are washed with a solution of chamomile or chlorhexidine, since the lacrimal sac in a sick dog is a reservoir for various microorganisms.

During treatment, eye ointment with an antibiotic is used.

Diseases of the cornea.

Keratitis- disease of the cornea of ​​the eye. The most common types of keratitis in dogs are:

  • Purulent superficial keratitis.
  • Vascular keratitis.
  • Purulent deep keratitis.

Causes The occurrence of keratitis in dogs is very diverse:

  • Mechanical injuries.
  • Burn damage to the ocular surface.
  • Hypovitaminosis state.
  • Infectious diseases (,).
  • Invasive eye diseases ().
  • Diseases of the endocrine system ().
  • Weakening of the immune system.
  • Genetic predisposition.
  • Allergic reactions.

Clinical picture. During a clinical examination of a sick dog, a veterinarian notes in a sick animal:

  • Profuse lacrimation from the affected eye.
  • Cloudiness of the eye cornea.
  • Photophobia.
  • Swelling.
  • The sclera and conjunctiva are hyperemic.
  • Purulent discharge comes from the eye.
  • Gray, yellow and white spots appear in the cornea of ​​the eye.
  • Redness of the white of the eyes and mucous membranes.
  • The ocular membrane is rough.
  • The dog blinks frequently.
  • Dark smudges appear in the inner corner of the diseased eye.
  • The dog becomes nervous, restless or lethargic and depressed, trying to hide from the light, constantly rubbing its eyes with its paws.

If keratitis in a dog is not treated in a timely manner. As the disease begins to progress, inflamed blood vessels grow into the eye cornea, causing it to become lumpy and thickened.

Consequences of keratitis. Keratitis for a dog is fraught with the development of complications such as the development of glaucoma, cataracts, and corneal perforation. Partial or complete loss of vision.

Treatment Keratitis in a dog depends on the cause that caused the keratitis, as well as on the factors that provoked its development.

Based on this, the clinic’s veterinary specialist prescribes appropriate treatment for the dog. At the same time, in all forms of keratitis, the sick dog’s lacrimal sacs are washed daily with solutions of furatsilin, rivanol, boric acid, which have an antiseptic effect.

Treatment of each type of keratitis is strictly individual. For superficial keratitis, the dog is prescribed chloramphenicol drops or sodium sulfacide, injections of novocaine and hydrocortisone.

For purulent forms of keratitis, the sick dog is treated with antibiotics. Oletterin or erythromycin ointment is applied to the affected eye.

For allergic keratitis, treatment begins with eliminating the effect of the allergen on the body and prescribing a special hypoallergic diet. Antihistamines are used.

In other forms of keratitis, the sick dog is given a course of antibiotic therapy, using broad-spectrum antibiotics, corticosteroids, antiviral drugs, vitamins, eye drops and antiseptic solutions to wash the sore eye.

With advanced keratitis, it is necessary to resort to tissue therapy. To resolve scars on the eye cornea, lidase and yellow mercury ointment are used. Sometimes in a clinical setting it is necessary to resort to surgical treatment by performing superficial keratectomy.

Dog owners should know. That the treatment of keratitis in a dog is long and takes 1-2 months.

Lens luxation (luxation) - the corresponding part of the eye is displaced from the hyaloid fossa. Lens luxation in a dog can be partial or complete.

Cause. Lens luxation in a dog can be due to genetic predisposition, glaucoma, cataracts, and as a result of severe injuries and infectious diseases suffered by the dog. Lens luxation occurs in dogs as a result of rupture of the ligaments of the lens and the ciliary muscle. Terriers are more susceptible to this disease.

Symptoms. During a clinical examination of a dog with a similar pathology, a veterinarian notes a deformation of the pupil, its displacement away from the center or it is swollen, and the shape of the eyeball itself may change. There is a disruption in the movement of fluid in the ocular body.

Treatment. Treatment of lens luxation is carried out in a veterinary clinic through surgical correction. After removal of the lens, an intraocular lens implant is placed. In especially valuable dogs, it is possible to implant the entire eyeball.

When the eyeball is dislocated, dog owners note that the eyeball comes out of the orbit behind the eyelid completely or partially.

This pathology is most often found in Pekingese, Japanese hips and similar breeds of dogs.

Cause. Dislocation of the eyeball in a dog most often occurs due to mechanical damage to the bones of the head and temples, high muscle tension in dogs with a shallow depth of the bone orbit.

Clinical picture. During a clinical examination, the veterinary specialist of the clinic notes a strong extension of the eyeball beyond its natural boundaries, the conjunctiva is swollen, often dries out, and externally takes the form of a hanging cushion.

Treatment . The treatment of this pathology is surgical.

Fundus diseases

Clinical picture. At the onset of the disease, experts note an increasing decrease in visual acuity at dusk and night blindness. Subsequently, such a dog’s daytime vision deteriorates and blindness develops. During a clinical examination, veterinary specialists note paleness of the pupil.

The cause of retinal detachment can be trauma, high blood pressure, progressive retinal atrophy, or neoplasms in the eye area.

Clinical picture. Dog owners note rapid or sudden blindness; during a clinical examination, veterinary specialists record a violation of the pupillary reflex, hemorrhage in the eyeball.

Lens diseases

- a disease of the lens accompanied by partial or complete opacity of the lens and its capsule.

Cataracts in dogs can be primary. In which a veterinarian, during a clinical examination, notes isolated damage to the eye area or systemic diseases in the animal.

In Boston Terriers, West Highland White Terriers, and Miniature Schnauzers, cataracts may have a hereditary form.

Primary juvenile cataract is considered the most common form of cataract in all breeds of dogs and mixed breeds. It is usually registered in dogs under 6 years of age.

Secondary or sequential cataracts in dogs are non-inherited cataracts.

Congenital cataracts usually occur in dogs together with other congenital eye changes.

Acquired - occurs in dogs with retinal diseases, eye abnormalities in collies, injuries, diabetes.

Glaucoma refers to eye diseases that are accompanied by increased intraocular pressure.

Clinical picture. Glaucoma in dogs is characterized by the so-called glaucoma triad:

  • Increased intraocular pressure.
  • Wide pupil.
  • Redness of the eye.

During a clinical examination, the veterinarian notes the dog's blindness, photophobia, lethargy, and decreased appetite. Subsequently, as the disease progresses, the eyeball enlarges and the pupil's reaction to light becomes slower.

Treatment. Treatment of glaucoma in a dog should be carried out by an ophthalmologist.

Many of the diseases listed above, including corneal opacity, cataracts, inherited retinal diseases, and glaucoma, are discussed elsewhere in these works. The following is a discussion of the leading causes of acute blindness (not glaucoma).

1. Retinal detachment

Retinal detachment is the separation of the retina and choroid, more specifically between the retina and the retinal pigment epithelium). The result of this separation is ischemia of the visual receptors. If this separation is not quickly corrected and the blood supply restored, the cones and rods begin to die, leading to irreversible blindness.

There are 3 types of detachment, depending on the mechanism of its formation. Serous detachment is caused by the accumulation of fluid in the space under the retina, between the retina and the choroid. This fluid arising from the choroid may be blood or exudate.

Traction The detachment is caused by the force that pushes the retina away from the choroid. This force can be generated by forward movement of the vitreous (for example, after displacement of the anterior lens) or due to stretching by fibrin clots.

Rheumatogenous Detachment is caused by the penetration of liquefied vitreous humor into the space under the retina through holes in the retina.

Causes of fiber detachment

The list of possible causes of fiber detachment depends on the type of detachment.

□Rheumatogenic detachment may be caused by age-related changes, injury, or
inflammation (see below).

□Tractional detachment can be caused by lens luxation or inflammation (see below).
□Serous detachments are caused by bleeding or inflammation.

Causes of exudative (serous) detachment

The inflammation that leads to retinal detachment usually involves the choroid and retina (chorioretinitis or retinochoroiditis). As with anterior uveitis, it is possible that any ocular or systemic inflammation leads to chorioretinitis. However, chorioretinitis is usually inflammation caused by an infectious pathogen. This may be a viral infection (for example, canine distemper), rickettsiosis ( Ehrlichia canis ), protozoal diseases ( Leishmania, Toxoplasma ) or fungal infections.

Causes of hemorrhagic (serous detachment)

Any cause of systemic bleeding can lead to hemorrhagic retinal detachment. Common causes include systemic hypertension, thrombocytopenia, ( Ehrlichia canis ), coagulopathy, increased blood viscosity, anemia and trauma.

Clinical signs of retinal detachment

□ Blind eye (no response to threat)

□ Fixed dilated pupil. When stimulating the contralateral eye, a friendly response is observed PLR.

□ When conducting an ophthalmoscopic examination, the doctor has difficulty trying to focus on the retina (since it is displaced from its natural location). A streak can be seen floating in the posterior chamber of the eye. This strip, which is the retina, may be clear, white (ie, swollen), or hemorrhagic, depending on the cause of the detachment. Blood vessels in the retina can be visible even without the use of an ophthalmoscope.

□ Ultrasound. Sensor with frequency 10 MHz can create an image of a detached retina. This image is called the "gull sign" because the detached retina usually remains attached to the eye - to the optic disc and to the serratus margin ( ora serrata ). Ultrasound examination is especially useful when ophthalmoscopic examination cannot be performed due to severe corneal edema, hyphema, etc.

Treatment of retinal detachment

□The underlying cause of the detachment must be diagnosed and treated. Therefore, systematic preparation must be carried out. Depending on the type of detachment, this preparation should be aimed at diagnosing cardiovascular or infectious diseases.

□Lens removal is indicated when detachment is secondary to lens displacement.

□Fibrin clots and fibers can be dissolved by injecting tissue plasminogen activator (TPA) into the eye, thereby preventing tractional detachments.

□Treatment of exudative serous detachment involves drainage of fluid under the tissue. This can be accomplished using hyperosmotic factors. Systemic carbonic anhydrase should also be considered. If the cause of the exudate is an inflammatory process, systemic steroids are prescribed.

□Specialized centers may perform retinal attachment or retinal reattachment surgeries.“clogging” of holes in the retina.

2. Sudden acquired retinal degeneration ( SARD)

It is an acquired disease of unknown etiology, usually occurring in middle-aged female dogs. There is a sudden onset of blindness. Typical patients are lap dogs. Many dog ​​owners report lethargy, weight gain and PU/PD over the past few months.

Examination reveals a blind eye with a fixed, dilated pupil. During the first few months the bottom looks normal. Degenerative changes may appear on late stage (after several months). ERG flat, indicating insufficient retinal activity.

There are currently no treatments SARD . We hope that once the cause is identified, treatment can be offered.

3. Optic neuritis

A. Cause

Inflammation of the optic nerve caused by: D Meningitis of any etiology D Infections - canine distemper, fungal diseases (for example, Cryptococcus), toxoplasmosis,

bacteremia, etc. Many systemic diseases may cause eye complaints. D Neoplasia, trauma, or abscesses in areas where the optic nerve passes (especially when

chiasme!)

□CNS diseases - GME , reticulosis, etc.

□Idiopathy - perhaps the most common cause

B. Diagnostics

□Blind eye with a fixed, dilated pupil.

□ERG normal, since the retina is not affected (thus, optic neuritis is differentiated from SARD)

□The optic disc appears normal or inflamed, depending on which part of the nerve is involved. If the proximal part of the optic nerve is involved, then when examining the fundus, swelling of the optic nerve nipple and blockage of blood vessels are visible.
As the disease resolves, optic disc atrophy is observed. Inflammation of more distal portions of the nerve may occur when the disc appears normal.

C. Treatment

Treatment is based on identifying and eliminating the underlying cause. If no systemic cause is found, systemic steroids should be prescribed. The forecast is cautious.

Ophthalmic examination

An eye exam doesn't have to be scary! Although it must be recognized that interpretation of data can be difficult at times, the examination itself follows a logical anatomical order. In addition, it does not require expensive equipment. In fact, the most important things needed for an examination are those that are nonophthalmic in nature: a room that can be darkened, a good source of focal light, and a magnifying loupe. A hand lens, an ophthalmoscope, a Shiotz tonometer and some consumables (paints, solutions, etc.) complete the list of basic equipment.

As with any other system, the doctor must pay special attention to the signs. Many eye diseases can be related to breed or age. Because many ocular disorders may be a manifestation of systemic lesions, a complete medical history and a comprehensive physical examination should be performed. Likewise, if neuro-ophthalmological abnormalities are present (blindness, strabismus, anisocoria, etc.), the nervous system should be examined, since the above disorders may be signs of a nervous system disease.

1. Quick Look

The patient should be observed when he enters the room, since this is an unfamiliar environment for him, which may reveal poor vision; this should be analyzed later. After the anamnesis and physical examination begins assessment of the visual system through careful observation behind the patient from a distance, without touching him (as this may cause distortion of the palpebral fissure). As you observe, ask yourself:

□ Are both eyes open normally? Are there any signs of pain or photophobia? Does the animal blink normally?

□ Are the eyes normal size and position? Are there any signs of exophthalmos or buphthalmos? Are the pupils the same size?

□Is the shape of the eyelids normal? Are there any signs of entropion or ectropia (usually the lower eyelid)? Is there any loss of the upper eyelid? Is the third eyelid raised?

□Is there any discharge from the eyes? What character? The orbital area is then palpated to identify any cracks, abnormal swelling, etc. Take the opportunity to apply pressure to the eyeball through the upper eyelid. This both serves as a test of retropulsion (indicating the presence of a retrobulbar mass) and induces proptosis of the third eyelid, allowing the outer surface to be examined. It is NOT an effective way to determine intraocular pressure (IOP).

Take a quick look at your eyelids. Examine the surface of their skin, the mucocutaneous border and turn them slightly outward to see the conjunctiva of the eyelids and the 2 eversions of the lacrimal punctum. Take the opportunity to test the blink reflex in response to touching the skin of the canthus. Continue by examining the conjunctiva of the eyeball and the surface of the cornea.

2. Vision assessment

A. Threat Response: This involves making sudden threatening gestures that are supposed to should reveal the blink reflex. The centripetal path of the reflex includes the retina, axons optic nerve, as well as optic tract and irradiation. The efferent component of the response includes the cerebral cortex, cerebellum and nucleus and nerve YII cranial nerve (facial nerve).

It is important to note that the threat response involves cortical integration and interpretation and is therefore not a reflex. Rather, this reaction of the cerebral cortex, which requires everything peripheral and central visual pathways, as well as the integrity of the visual cortex and facial nerve center. Also, remember that the threat response is a very rough test of vision and actually requires only 6 out of 600 visual activity!.

Threat response should be assessed in one eye at a time while the other eye is covered.... Be careful not to touch the patient's eyelashes/fur or cause a breeze as this may result in a "false positive" reaction; make threatening gestures behind a glass partition. “False negative” results are also possible (lack of reaction to a threat in sighted animals). One possible cause is facial nerve palsy, which eliminated through the use of the blink reflex. There is no reaction to threat in very young (<10-12 недель) животных, и на нее так же может воздействовать психическое состояние пациента.

b ) Additional Vision Testing: Vision can also be assessed through the use of an obstacle course. You must be consistent in choosing the obstacle course, and make sure it can be completed by normal animals! Assess patients in bright and dim lighting while covering one eye.

Another test is the visual placement response, which is useful when the strip resultsobstacles and responses to threats are questionable. This is done by lifting the animal towards the table; at the same time he is allowed to see the approaching surface. A normal animal extends its paw toward the surface before the paw touches the table.

3. Examination in the dark.

After the light goes out, pupil dilation should increase. Use dim light (to prevent constriction), and stand at a distance so you can see both pupils at the same time using tapetal reflection. Tapetal reflection also serves to reveal (through retro-illumination) any visual opacity, especially of the lens or vitreous.

Next, use bright lighting to assess the pupillary light reflex ( PLR ). Unlike the reaction to a threat, PLR - This is a subcortical reflex. Therefore, he does NOT test vision, and normal PLR a subcortically blind animal can be detected. Besides, PLR usually present (although it may be reduced or delayed) in animals suffering from retinal degeneration ( PRA ), cataracts and other causes of subcortical blindness. Nevertheless, PLR is a very important test that helps localize the damage causing vision loss.

If one of the pupils does not respond to light or cannot be seen (for example, in cases of severe corneal edema or hyphema), the agreed PLR . Alternatively, you can test the blinding reflex. It is also a subcortical reflex that manifests itself as a bilateral partial blink in response to bright light.

For the next stages of the examination, magnification is required. The eyelid margins, conjunctiva, and corneal surface are again examined. Use magnification to check for distorted eyelashes (trichiasis, distichiasis); this can be seen on the white background of the conjunctiva by lightly pressing the eyelid. Following the anatomical order, the anterior chamber of the eye (detecting the opacity of the aqueous humor), the surface of the iris and the anterior segment of the lens are then examined.

4. Ophthalmoscopy

This is the part of the examination that doctors usually dread the most. In part, this undoubtedly stems from the wide range of normal variations in fundus appearance in dogs (and to a lesser extent in cats). It is common knowledge that if you are not accustomed to examining the fundus, it will be difficult for you to diagnose deviations from the norm. Therefore, you should make it a habit to examine the fundus, however, briefly, of every patient you see. Your customers will appreciate the extra touch, and so will you. achieve the necessary professionalism.

Due to the high cost of reverse ophthalmoscopy, direct ophthalmoscopy is used in most general clinical practice. This tool provides a high degree of magnification (x16 for medium-sized dogs). An unfortunate consequence of high magnification is a small field of view (4o), which increases the time required to fully fundus examinations. A quick fundus examination can be achieved by using bright light source and hand lenses (20-30 D ), which provides reverse monocular ophthalmoscopy capabilities. Direct ophthalmoscopy is characterized by several features:

□Ocular grid - used to compare the size of the lesion in the optic disc
nerve.

□Red free filter (emits green light) - Helps evaluate hemorrhages and blood vessels that appear black.

□Holes of different diameters - the largest one that matches the patient's pupil is used.

□Changing lenses allows the doctor to determine the depth/height of the lesion or to examine more anterior structures, such as the lens. The identified lesion is brought into focus by adding convex magnifying lenses (+). The vitreous depression/coloboma comes into focus with the addition of concave diverging lenses (-). In dogs, each diopter you add is equivalent to 0.28 mm.

□Use a narrow beam that allows you to identify the depressions and elevations of the fundus lesion. Ophthalmoscopy should be performed in a dark room after dilation of the pupil. Initially, determine the tapetal reflex at a distance to identify any biconvex or vitreal opacities. As you approach the patient, focus on the more successful posterior structures - the cornea, iris, lens and vitreous - until you focus on the fundus. Carefully examine the fundus as a whole, looking for changes in the lining layer, blood vessels and optic nerve head. It is best to maintain the same position and allow the patient's eye movements to bring the structures closer to you, rather than chasing them.

5. Additional tests

□Srimer's tear test is used to evaluate tear production and diagnose

keratoconjunctivitis. It should be carried out at an early stage of the examination, since anyvisual manipulations can cause the tear reflex to be indicated.

□Fluorescein staining is used to diagnose corneal ulcers. Superficial ulcers
can be painted with pink bengal paint.

□Specimens for bacteriology, mycology and cytology may be collected as indicated. The first two should be taken before any drops are put into the eye, since ophthalmic solutions often contain preservatives.

□Nasolacrimal patency is determined by the passage of fluorescein from the eye to the nose, through catheterization of the nasolacrimal system and through dacryocystorhinography.

□Ultrasound is often used in ophthalmology. The main indications are
images of the retroburbal area and images of the posterior segment when this is not possible
see (for example, due to hyphema or cataract). ST and MRI can be
used in certain cases.

□Tonometric measurement of intraocular pressure for the diagnosis of glaucoma.

□Additional tests, including gonioscopy (measuring the iridocorneal angle as part of the diagnosis of glaucoma) and electroretinography (recording the retina's electrical response to flashes of light to determine retinal function), may be available in specialized centers and are discussed elsewhere in these works.

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