Dr David L Williams

MA VetMB PhD CertVOphthal FRCVS

Research Interests

David's two main areas of interest as far as research is concerned are age-related cataract and tear film deficiencies. While these may not seem related, the key similarity is that David and the group of researchers in the Centre for Comparative Ophthalmology in Cambridge are looking at the prevalence of these conditions in populations of normal dogs.

Severe keratoconjunctivitis sicca in a cross-bred terrier The problem with the majority of veterinary ophthalmology research is that the animals seen by ophthalmologists are by their very nature an abnormal groups of animals. Look at the gender and age data for 100 dogs referred to a specialist centre with dry eye, for instance, and you run the risk of looking at a biased case population. But look at a group of 1000 dogs randomly sampled from first opinion practices and you see a very different picture.

Cataract prevelance in 2000 dogs examinedThe trouble is that while we can try and obtain a figure for the prevalence of dry eye across the canine population and in different breeds from animals referred for ophthalmic examination, we can only obtain a true prevalence of the condition by examining dogs from the general dog population, either seen in general practice for non-eye-related diseases or in rescue and re-homing facilities. We are currently doing just that for dry eye, and have completed studies on age-related cataract in 2000 dogs (published in January 2004) and cats (currently undergoing data analysis).

Not to be confined to medium-size small animals, we have also looked at horses in countries at different lattitudes, to assess the effect of sunlight on cataract formation and at donkeys too, to compare cataract prevalence in horses and donkeys. Don't think we aren't interested in the 'smallies' though. Last year we looked at eyes disease in a thousand normal guinea pigs and this year we are aiming to perform the same feat with a thousand rabbits! The only trouble is that with this much data aquisition its difficult to find time to write the work up for publication!

It might be thought that all this observation isn't exactly helping the animals much. To counter that, we are investigating the use of N-acetyl carnosine, a topical eyedrop first produced by Dr Mark Babichayev from Moscow, for the treatment of canine cataract. Our preliminary results have been presented at the British Small Animal Veterinary Association and are in the process of being prepared for publication. The raw data is shown in the excel file below, but won't make that much sense until read in the context of the paper, to be submitted for publication in the journal Veterinary Ophthalmology.

Here are some of the cataracts included in the trial. It might seem unlikely that a topical antioxidant drop could ameliorate such lens opacities, but some of the eyes improvements in lens clarity have been noted. We are now conducting a plecbo-controlled trial of the drug, so if you live within reach of Cambridge and would like your dog to be included in this trial, do e-mail me and the wheels can be set in motion!

You can download the raw data from David's forthcoming paper The effect of topical N-acetyl carnosine on canine cataract: a preliminary study here, although without the text as yet it won't mean much to you I guess!
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