gms | German Medical Science

The topical application of drugs is the most effective method of non-invasive treatment of glaucoma. However, if treatment lasts long, it can cause chronic toxic reactions at the ocular surface. Clinical symptoms include a chronic state of red eye, keratinization and scaring visible biomicroscopically. First microchanges of the superficial epithelium can be recognized in impression cytology (IC) much earlier than squamous conjunctival metaplasia.

In a prospective intraindividual comparative cytomorphological process control over a 3-month period we studied the effects of the topical application of timolol (group I n=15) and latanoprost (group II n=30) on the conjunctival epithelial barrier in 45 newly adjusted glaucoma patients. To track the cytopathological microchanges of the epithelium, we carried out standardized topographic IC (8 draw positions, 16 IC per probands). Biomicroscopic quantitative examination of the tear secretion and the non-invasive determination of break-up-time (tearscope) complemented the examinations.

The topical drug therapy induced changes of the parameters evaluated in both groups. The intraindividual comparison of BUT was lower by 73% of group I subjects and by 52% of group II patients. However, no secure pathological data was obtained in either group. A reduction of the quantitative tear secretion (< 5 mm/ 5 minutes) occurred in 26 % in group I and 12 % in group II. Topographic cytological diagnosis revealed an increase in the cytopathological changes of the epithelium after application of topical antiglaucomatosa over the investigation period of 40 % in group I and 33 % in group II.

The results show that changes of the conjunctival surface epithelium can become manifest in connection with the long-term treatment of glaucoma. In contrast with a known experimental study in animals, no significant differences among the tested antiglaucomatosa were found in regard to cytomorphological microchanges of the epithelium in the human conjunctiva.