The effects of antiglaucoma medications on the ocular surface in unilaterally treated glaucoma patients.

PURPOSE: To investigate the cytological and inflammatory effects of topical antiglaucoma medications on the ocular surface by comparing treated and untreated eyes in unilateral glaucoma patients.

METHODS

This observational, case-control study involved 69 patients with unilateral glaucoma, receiving monotherapy with prostaglandin analogues. The untreated fellow eyes served as controls. Tear break-up time (TBUT), Schirmer test, conjunctival impression cytology, and tear cytokine levels [interleukin (IL)-1β and IL-6] were assessed in both eyes. Comparisons between treated and untreated eyes, correlations among ocular surface parameters, and linear mixed-effects analyses according to treatment duration were performed.

RESULTS

TBUT was significantly lower in treated eyes than in untreated eyes (p < 0.001), whereas Schirmer test results did not differ significantly (p = 0.318). Conjunctival impression cytology analysis showed that goblet cell count was significantly lower (p < 0.001) and Nelson grading was higher (p < 0.001) in the treated eyes. Inflammatory cytokine analysis revealed significantly elevated levels of IL-1β and IL-6 in the treated group (p < 0.001). Goblet cell count correlated positively with TBUT, whereas both cytokines correlated negatively with goblet cell count. Linear mixed-effects analyses showed that longer treatment duration was associated with greater treated-fellow eye divergence in TBUT and IL-6, but not in the other parameters.

CONCLUSION

Long-term use of preservative-containing antiglaucoma medications is associated with goblet cell loss, conjunctival squamous metaplasia, increased ocular surface inflammation, and tear film instability, findings that are most consistent with an evaporative-type dry eye pattern. This interpretation is further supported by the concordant findings of conjunctival impression cytology and tear inflammatory cytokine analysis.