Ron Ofri DVM, PhD, DECVO

Ron Ofri DVM, PhD, DECVO

Ron Ofri was a member of the charter class of the Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Israel. Upon his graduation he traveled to the University of Florida, where he spent the next 4 years undergoing clinical training in veterinary ophthalmology and obtaining his Ph.D

I expect many colleagues have been following Ron’s excellent lectures. There are five vet CPD webinars in The Webinar Vet archives (including this one) and he reminds us that there will be one more, which I will be eagerly waiting for, on Inherited Retinal Diseases in Dogs. This will be on the 23rd. of September 2021  

The outline of the “Why Cats Go Blind” webinar is as follows: 

  • Feline Uveitis 
  • Cataracts and Glaucoma 
  • Hypertensive retinopathy 
  • Other feline retinopathies 

We are reminded of the large number of potential causes of uveitis in dogs, with fewer causes in cats. Even this list can be narrowed down to the situation in the real world. Leading causes of posterior feline uveitis are shown: – 

  • FIV, FeLv, FIP, toxoplasmosis 
  • Fungal diseases (in endemic regions) 
  • Tumours-consider these in unilateral cases in elderly patients 

An article from North Carolina veterinary school documents 120 cats with uveitis: – 

  • Toxoplasma 23.7% 
  • FIP 15.8% 
  • FIV, FeLv 10% 
  • Neoplasia 5% 
  • Idiopathic 40.8%       

(Some cats had more than one disease.) 

Even though the cause in many cases is idiopathic it is essential to look for known underlying causes before applying symptomatic treatment.   This involves history, physical and neurological examination, haematology and biochemistry, PCR, IFA and ELISA, urinalysis, imaging and potentially at referral institutions aqueous paracentesis for serology and cytology. After a review of the relevant literature there is a summary of treatment emphasising that because systemic disease is only diagnosed in 40-70% of cases only 33-56% of cats will respond to treatment. Symptomatic treatment relies on topical steroids, with some caveats, and importantly atropine. This causes mydriasis, reducing the risk of synechiae and is effective as an analgesic. Ron mentions that people who have had uveitis have told him how beneficial atropine is in reducing the painful spasm of ciliary muscle. Having had a solitary attack of uveitis years ago I can agree with that. It is an intensely painful condition. The specialist correctly said I would feel a lot better after the atropine drops went in.  

Speaking of specialist treatment we are advised (probably at referral level) to consider the intraocular injection of Tissue Plasminogen Activator (TPA) to prevent/breakdown adhesions. Amazing before and after pictures demonstrate the effectiveness of this treatment. Uveitis is not without a proportion of complications including cataract, secondary glaucoma and if retinal detachment occurs blindness. These are all considered with the usual high standard of illustrations, a hallmark of Ron’s webinars. 

Measurement of glaucoma is demonstrated with two tonometers, the tonopen and the tonovet. Both give reproducible readings but the tonovet is much closer to the true intraocular pressure. Medical treatments for glaucoma are reviewed  

Feline cataracts are often secondary to uveitis (22-36% of cases) and therefore require a full investigation for this disease when they occur. In dogs the reverse is true cataracts cause uveitis. 

Hypertensive retinopathy most often presents in elderly cats with acute blindness. A series of illustrations demonstrate detached retinas and also a surprisingly almost identical correlation between a histological slide and ultrasound findings. Yet another use for an ultrasound! Figures are given for normal and abnormally high blood pressure. Many of these cats had an underlying chronic kidney disease and/or hyperthyroidism, and with good control of the hypertension, vision may recover in some cats. 

The final part of the webinar looks at inherited retinal degeneration, less common in cats than in dogs. There is information on the condition in Bengal cats. Some feline retinopathies can be avoided. Those mentioned are taurine deficiency, enrofloxacin toxicity and iatrogenic ones-blindness caused by mouth gags during anaesthesia, (20 cases in a report in the Veterinary Journal) and a further six cases recently reported following eye enucleation with optic neuropathy developing in the contralateral eye.  

Ron Ofri’s webinars are superb and I would recommend searching in the WebinarVet archives to watch his other contributions in this series-and as I suggested in the beginning of this summary, reserve the date (23rd September) for the last one on inherited retinopathies in dogs