Clinical Management of Corneal Opacity - A Study of 11 Dogs.
Eleven dogs were diagnosed with corneal opacity based on clinical and opthalmic examination. Antibiotic and corticosteriod therapy initially for seven days followed by cyclosporine after confirmation of epithelization. Negative fluorescin dye test was confirmation for effective therapy.
Keywords: Canine; corneal opacity; corticosteroid; cyclosporine; fluorescin dye test
The cornea is a clear transparent structure composed of five layers, anterior epithelium, sub epithelial basement membrane, stroma, descemet's membrane and posterior epithelium or endothelium. These layers contribute to the cornea's unique transparency by providing a non keratinized surface, maintaining control of its water content and of its highly organized arrangement of collagen fibrils and ensuring absence of blood vessels and pigment (Janseens, 2007). The incidence of corneal opacities are recorded highest amongst corneal affections.
Material and Methods
In order to assess the incidence of corneal opacities in canines, total of 80 cases of ocular affections referred by Veterinarians from Nagpur and adjacent districts were included in the study and incidences, breed-wise/sex wise, involvement of eye and also season wise distribution of ocular affections were recorded.
A general ophthalmic examination was conducted for all the animals in the study, which included gross examination, reflex evaluation using menace reflex, cotton ball test, obstacle test and pupillary light reflex to confirm vision. Clinical symptoms such as epiphora, blepharospasms, ocular discharge, location of lesion, depth of lesion, growth, vascularization, pain, photophobia, blepharitis etc. were recorded.
All cases in the study were subjected to general ophthalmic examination for thorough examination of adnexa, anterior segment, anterior chamber, iris and lens. Direct Ophthamoscopic examination was performed on a setting of +20 diopters for lids and cornea.
In present study, a thorough general examination along with ophthalmic examination was conducted which resulted in early and correct diagnosis, presence of any concurrent disease and for deciding further line of treatment.
Management of Corneal Affections Pre-Operative/ Conservative Treatment
A total of 11 clinical cases of corneal affection were treated with conservative method post diagnosis. The affected eye was cleaned with normal saline in the cases of descemetocele and corneal opacity (Ramani et al., 2010).
A regime of conservative treatment was initiated with topical application of antibiotic (Ofloxacin) eye drops four times a daily in all corneal affections for first 7 days. Corticosteroid (1% Prednisolone acetate) eye drops were instilled topically from 7th day onwards (or after corneal epithelialization) in affected eye every 6 hours to control conjunctivitis and enhance tear drainage. This treatment regime for two weeks showed marked regression of granulation tissue and corneal clearing.
Cyclosporine (Visiocare (a)) a polypeptide agent was instilled. Ramani etal. (2008) stated that cyclosporine suppresses the immune system and hence is used to prevent organ rejection following transplantation. They also suggested treatment with Ofloxacin and Dexamethasone combination eye drops four times a day for two weeks, followed by tapering doses of Ofloxacin eye drops to two times a day for next two weeks, followed by Cyclosporine ophthalmic emulsion (0.05%) two times a day for period of one month, proved to be an effective treatment for superficial keratitis.
The cases were also subjected to haematological examination on 0th, 3rd, 7th and 15th day to study the effect of corneal affections as well as to rule out concurrent diseases.
Result and Discussion
In the present study, total 11 cases of corneal opacity (34.38%) were recorded, out of which three dogs showed bilateral complete corneal opacity due to systemic disease, three dogs showed unilateral stromal opacity with radiating streaks formed due to injury due to barbed wire or dew claw while rubbing, and five dogs showed unilateral opacity except in one (bilateral opacity) with non specific history on day of presentation. Corneal opacity were graded as Nebula, maculas or leukomas in increasing order of size and density. All the dogs from this group were treated with Ofloxacin eye drops for initial four days.
Following the negative fluorescein dye test which is indicative of re-epithelialization and intact cornea, 1% Prednisolone acetate eye drops, four times a day were advised in all the dogs along with Ofloxacin eye drops as recommended by Maggs (2008). All dogs were injected with Vitamin A @ 3 lakhs IU intramuscularly once a week for three weeks. Singh et al. (1965) stated that Vitamin A helps maintaining normal structure and functions of eyes and conjunctiva.
Whereas two cases, showed dense white (leucoma) opacity as a result of scar formation sequele to corneal ulceration on 7 (th) day and further the opacities did not show any regression in size or density upto 15 (th) day, which was attributed to the deeper initial injuries which produced more dense and permanent scars with no tendency for clearing.
The findings of the study were in accordance with Slatter and Dietrich (2003) who stated that 1% Prednisolone acetate eye drops decreases vascularization, reduces scarring and pigmentation and improves final transparency.
Therefore, it can be concluded that corticosteroid therapy should be initiated 7 days after wounding, only after confirmation of corneal epithelialization with negative fluorescein dye test, to confirm effective healing of corneal defects.
The corneal affection wise haematological observations viz. haemoglobin (Hb), Total Erythrocyte Count (TEC), Total Leucocyte Count (TLC) and Differential Leucocyte Count (DLC) were recorded on 0th, 3rd, 7th and 15th day for each case were undertaken in the study.
The values were within normal physiological limits for whole period of observation. The corneal affections reported were localized and therefore they did not reflect any systemic reaction. The findings of the study were in conjunction with Bath and Dua, (2006) who recorded normal haematological values in corneal disease. Therefore, it could be concluded that haemoglobin values, total leukocyte, neutrophil were not affected by corneal affections.
The findings were in agreement with Nair and Vasanth (2007) who reported haematological values in normal in dogs with ocular disease. Therefore, it can be concluded that corneal affections did not affect the haematology and blood glucose in canines.
There are several systemic infectious diseases including viral, bacterial, fungal and parasitic diseases that cause adverse changes in cornea. However such changes were not seen in the present investigation. This could be because of selection of clinically healthy dogs for the investigation and also due to the fact that the investigation was undertaken over a short span of 6-7 months.
Corneal ulcers and corneal opacity contribute highest incidence in corneal affection in dogs. Young to middle age dogs suffered most. Pug breed was mostly affected. Prompt and appropriate use of antibiotics and corticosteroids along with nictitating membranoplasty and tarsorrhaphy, help in repair of corneal defect and restoration of vision.
Bath, G.S. and K. Dua (2006). Diagnosis treatment of keratitis in dogs. Indian J.Vet. 26: 160-61.
Janssens, G. (2007). Indolent ulcers in dogs' eyes. EJCAP 17: 280-84.
Maggs, D.J. (2008). Cornea and Sclera. Slatter's Fundamentals of Veterinary Ophthalmology. 4th Edn., Saunders Elsveier publishers. pp 175 -78.
Nair, S.S. and Vasanth, M.S. (2007). Incidence of cataract and haematological, biochemical changes during lens extraction in dogs. Indian Vet. J. 84: 476-78.
Ramani, C., L. Nagarjan., R. Rajasekar., T.N. Ganesh and R. Suresh Kumar (2008). Chronic Superficial keratitis in dog. Indian Vet. J. 85 : 1219-20.
Ramani, C., Sooryadas. S., Rajib Das and R. Sureshkumar (2010). Surgical Correction of everted membrane nictitans inthrough anterior conjunctival approach in dog. Tamilnadu J Vet Ani Sci. 6: 104-06.
Singh, M. M., Sinha, G.K. and Gupta, B.N. (1965). Corneal opacity in dog. Indian Vet. J. 42: 879.
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V.A. Uike (1), P.T. Jadhao (2), S.V. Upadhye, S.P. Salvekar and S.S. Pitlawar
Department of Surgery and Radiology
Nagpur Veterinary College
Maharashtra Animal and Fishery Science University (MAFSU)
Nagpur - 440006 (Maharashtra).
(1.) Part of the Post Graduate Thesis of the first author
(2.) Professor and Head/Corresponding author.
(a) - Brand of Savavet, Pune
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|Title Annotation:||Clinical Article|
|Author:||Uike, V.A.; Jadhao, P.T.; Upadhye, S.V.; Salvekar, S.P.; Pitlawar, S.S.|
|Date:||Jul 1, 2016|
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