The effect of prophylactic topical carbonic anhydrase inhibitors in canine primary closed-angle glaucoma

Abstract

OBJECTIVES: To determine the effect of 1% brinzolamide, 2% dorzolamide hydrochloride or combination 2% dorzolamide hydrochloride/0 · 5% timolol to delay the elevation of the intraocular pressure in second eyes of dogs with primary closed-angle glaucoma. METHODS: Analysis of retrospectively collated data from 40 dogs with primary closed-angle glaucoma, where the non-affected eye was treated prophylactically with brinzolamide (n = 10), dorzolamide (n = 18) or combination dorzolamide/timolol therapy (n = 12). RESULTS: The 40 treated dogs (median age of 76 · 2 months) comprised 25 females/15 males, 19 entire/21 neutered. Twenty dogs developed glaucoma in the contralateral eye (median time of 9 · 2 months). No statistically significant difference was identified during treatment failure between the treatment groups (P = 0 · 66). The second eye remained normotensive in 20 dogs; four dogs until the conclusion of the study (median: 27 · 0 months), three dogs until death (median: 15 · 4 months), seven dogs until lost to follow-up (median: 11 · 6 months). Out of these 20 dogs, treatment was discontinued because of lack of owner compliance in two dogs and following a local drug reaction in four dogs (median: 8 · 9 months). CLINICAL SIGNIFICANCE: There was no evidence that the tested drugs delayed elevation of intraocular pressure in contralateral eyes of dogs with primary closed-angle glaucoma.