Tear secretion and lacrimal gland function of rabbits treated with isotretinoin.

Adverse ocular reactions including dry eye symptoms and blepharoconjunctivitis are common side effects of treatment with isotretinoin (13-cis-retinoic acid). However, there is little agreement in the literature on the effect of this drug on the tears. Because we have previously shown that the lacrimal gland secretes isotretinoin, we conducted a study of the effect of isotretinoin on lacrimal gland function. Rabbits were treated with isotretinoin for 5 months. Throughout the study tear secretion was monitored by the Schirmer test. At the end of the study lacrimal gland function was assessed by measurement of fluid and protein secretion rates and secretion of retinol in response to a pilocarpine stimulus. Lacrimal gland function was not affected by isotretinoin as compared with a group of age-matched control rabbits; however, Schirmer test scores were significantly increased in the treated animals as compared with control values. We conclude that isotretinoin is not toxic to the lacrimal gland of rabbits. This suggests that ocular irritation in patients treated with isotretinoin is not caused by decreased tear secretion during therapy.