Study highlights lack of reliable evidence on eye condition

A study has highlighted a shortage in evidence base for recommending one treatment for a specific eye condition in dogs and cats over another.

The study, published in the Journal of Small Animal Practice (JSAP), shows the evidence base for recommending one treatment for keratomalacia in dogs or cats over another is very weak.

Within the paper, “Outcomes of treatments for keratomalacia in dogs and cats: a systematic review of the published literature including non-randomised controlled and non-controlled studies”, current literature was studied to determine the evidence base for keratomalacia treatments.

Evidence base

The aim of the review was to assess the evidence base and identify recommended treatments based on globe survival, visual outcome and time to resolution while maintaining a globe.

A total of 18 studies were identified, and these were reviewed and assigned a level of evidence base before being assessed for the type of study, number of animals induced, outcome criteria, and duration of follow-up and time to resolution.

Systematic reviews of randomised trials, randomised trials or observational studies with dramatic effects would have provided the most reliable evidence on which to base recommendations for treatment(s) but none were available for inclusion. Only one was classed as level three evidence – meaning a non-randomised, controlled trial – and considered use of corneal cross-linking in the treatment of keratomalacia.

Studies

Most studies were level four evidence reporting the outcome of a single treatment, with three prospective studies and seven retrospective studies. The remaining seven studies were level five evidence (mechanism-based reasoning) and were considered not to provide good evidence for answering the particular study question.

Those behind the study say it suggests evidence for improved outcome of one proposed treatment over another for keratomalacia in dogs and/or cats is very weak. A combination of treatments – both medical and surgical – may be the most appropriate depending on the individual case, they say.

Controlled trials

Nicola Di Girolamo, editor of JSAP, concluded: “The findings of this study highlight once more the infrequency of randomised controlled trials in the veterinary literature, and the need for such studies to expand the evidence base in this field.

“Focusing on collecting available evidence in well conducted systematic reviews is a critical step to improve accessibility of the literature for general practitioners and specialists alike.”