The topical treatment of cataracts in dogs is a composition having an aldose reductase inhibitor (ARI) in a topical carrier. The ARI is preferably 2R,4S-6-fluoro-2-methyl-spiro[chroman-4,4′-imidazolidine]-2′,5′-dione, referred to as 2R-methyl sorbinil, having the structure:The topical carrier is formed from EDTA and deionized water containing about 2.5% carbomer, 1.5% glycerin, 0.02% EDTA and 0.1% benzalkonium chloride mixed to form a uniform emulsion. The concentration of the ARI in the topical carrier is preferably about 5-6%. The treatment includes administering to a dog an effective amount of the composition for preventing the formation of cataracts, reversing the formation of cataracts, and for treating diabetic retinopathy and pathological conditions resulting from diabetes affecting the cornea, iris, ciliary bodies, etc. The composition is preferably administered in the form of about two to four eye drops daily.