Prevalence of linear keratopathy in a herd of Lipizzaners over an 18-month period.

The prevalence of linear keratopathy with progressing age in a closed population of a single horse breed is reported. All Lipizzaners in three federal states in Austria underwent complete ophthalmic examination four times over a period of 18 months, with six-month intervals. Findings consistent with linear keratopathy were recorded, and associated with factors such as sex, location, boarding system and level of performance throughout the study period. Logistic regression was applied to determine the influence of age on ophthalmic findings. On the first, second, third and fourth examinations, 0.8 per cent, 3.1 per cent, 4.4 per cent and 4.8 per cent (of 266, 261, 249 and 230 horses, respectively) of the study population, were diagnosed with linear keratopathy. This finding was consistently identified in the same horses, and once identified, no further progression was noted. Horses with this finding had no history of previous ocular problems or concurrent ocular abnormalities. Statistical analysis did not reveal any influence of sex, location, boarding, or level of performance; however the prevalence of linear keratopathy was found to increase with progressive age (P<0.5). The results of this study indicate that linear keratopathy was not congenital and was non-progressive in the Lipizzaner over a period of 18 months.