Purpose: The aim of this study was to assess signs and symptoms of ocular surface disease (OSD) and the cytomorphological changes of ocular surface in glaucoma patients using preserved antiglaucoma drops.
Methods: In this cross-sectional study, 109 participants (79 patients with topical medication and 30 untreated controls) completed the Ocular Surface Diseases Index (OSDI) questionnaire and underwent an ophthalmic examination, including Schirmer test, tear film breakup time (TBUT), and fluorescein staining. Conjunctival specimens were collected by impression cytology and analyzed by light microscopy using Nelson's grading scheme (grades 0-3). This classification is based on the nucleus-to-cytoplasm ratios of epithelial cells and the numbers of goblet cells, with grade 2 considered abnormal.
Results: The medication group had significantly shorter TBUT (median [interquartile range]: 6.0 seconds [5.0-8.0 seconds] vs 9.5 seconds [6.0-12.3 seconds]; P<0.03), greater fluorescein staining (1.0 [0.75-1.25] vs 0 [0-0.25]; P<0.001), and higher impression cytology grade than the control group (median [range]: 1.0 [1:2 to 1:6] vs 0.6 [1:2 to 1:4]; P<0.001). The increasing number of drops instilled per day was associated with an increase in fluorescein staining (Spearman's rho r=0.475; P<0.001) and shorter TBUT (r=-0.278; P=0.014). The OSDI did not discriminate between the two groups.
Conclusion: Clinical tests and impression cytology showed ocular surface damage in patients using preserved antiglaucoma medications. However, there was no statistically and clinically significant difference in symptoms measured by OSDI score between the medication and control groups.
Keywords: dry eye diagnostic tests; impression cytology; ocular surface disease; ocular surface disease index questionnaire; topical glaucoma medication.