Faculty of Veterinary Science, Department of Surgery, Ophthalmology Clinic, Chulalongkorn University
A successful medical in stead of surgical treatment of descemetocele caused by green pit viper snake bite was reported in a German Shepherd dog.
The bitten left eye was swollen shut, photophobia, chemosis, subconjunctival haemorrhage and constricted pupil without menace reflex were revealed. A large descemetocele, 8 mm. in diameter protruded the dorsal limbus of the eye. Intramuscular injections of cefazolin sodium and dexamethasone, subcutaneous injections of atropine sulphate and vitamin A were given. Topical application of tobramycin eye drop every hour, artificial tear every 2 hours, atropine sulphate once daily and timolol maleate 4 times a day were prescribed together with systemic prescription of cephalexin, serratidopeptidase and carprofen for 3 consecutive days at home. On the 4th day, the pupillary and menace reflexes were normal. The descemet membrane returned to the corneal floor. Conjunctivitis and neovascularization were evident close to the lesion. On the 12th day, only a dark red granulation tissue was present. Timolol, tobramycin and atropine sulphate eye drop were withdrawn while the artificial tear in conjunction with neomycin-polymyxin and dexamethasone ointment were topically applied twice daily. At day 19, an area of corneal opacity was present which disappeared on day 26 after topical corticosteroid application.
Deep corneal ulcer may associated with descemetocele and/or staphyloma which can be treated by various surgical techniques to save vision and resulted in corneal opacity that can impair vision.
The criterion of successful medical treatment of descemetocele caused by snake bite was to decrease the intraocular pressure so that the bulging cornea could return to normal position.