Reducing cytotoxic action of the preservative employed in ophthalmic hypotensive medications with tear replacement therapy

Abstract

to assess the possibilities of reducing the cytotoxic effect of benzalkonium chloride (a preservative used in ophthalmic hypotensive drugs) with the help of tear replacement therapy. The study included 28 patients (56 eyes) who had been using antiglaucomatous drugs containing benzalkonium chloride as a preservative for various periods (from 2 months to 17 years). The examination was performed in the setting of compensated IOP. In addition to hypotensive topical medication regimen, all patients were prescribed Stilavit eye drops. Subjects were examined prior to the prescription of artificial tears and after 1, 3 and 6 months of its usage. Effectiveness of the treatment was evaluated with biomicroscopy, Norn's test, Jones test, tearscopy, OCT-meniscometry, confocal microscopy, and impression cytology. The use of 'Stilavit' artificial tears in combination with antiglaucoma drugs led to an improvement of the corneal epithelium condition in 85% of cases, a statistically significant increase in the mean values of precorneal tear film rupture time after 1, 3 and 6 months by 26%, 61.2% and 85.8% respectively. Maximum increase of main tear production level was achieved after 3 months of treatment (increased by 43.5%), and was accompanied by 18.6% rise of the lower tear meniscus height after 3 months; in 6 months it raised by 29.4%. A tendency for restoration of the lipid layer of the tear film was observed. According to confocal microscopy and impression cytology, positive dynamics in the condition of corneal epithelium and conjunctival epithelial layer were present. The study results justify the use of tear replacement therapy, in particular the tear substitute Stilavit, as an additional protective agent for glaucoma treatment regimen.