THE EFFECTS OF LONG-TERM TOPICAL GLAUCOMA MEDICATION ON CONJUNCTIVAL IMPRESSION CYTOLOGY

Long-term use of topical drugs can induce changes in the conjunctiva a nd ocular surface. To determine the conjunctival changes resulting fro m topical glaucoma medication, patients with glaucoma were selected an d classified into seven groups, according to the medication received: 24 eyes were treated with betaxolol, 20 eyes with levobunolol, 32 eyes with timolol maleate, 22 eyes with pilocarpine, 52 eyes with beta-blo cker and pilocarpine, 34 eyes with beta-blocker and dipivefrin, and 32 eyes with maximum therapy. Patients who were under 18 were excluded, as were those with any history of ocular surgery and other interventio ns, long-term use of any topically administered medication except glau coma drugs, and any history or slit-lamp examination evidence of ocula r surface disorders. The changes in the conjunctiva of 216 eyes were e valuated by means of ocular surface impression cytology. The medicatio n group showed statistically significant degrees of conjunctival metap lasia when compared to the control group (p < 0.01). The cytological g rading was nor correlated with age, sex, type of medication, duration of topical treatment or the number of drugs (p > 0.05). Duration of tr eatment exceeding three months was not correlated with cytological gra ding. Thus, as far as surgical treatment was concerned, it was conclud ed that intervention within the first three months after the diagnosis would be most beneficial in the management of glaucoma. The fact that the presence of the preservative benzalkonium chloride was the same i n all preparations suggests that it may be the major factor in conjunc tival metaplasia.