Evaluation of ocular surface disease in patients with glaucoma

Purpose: To evaluate the subjective and objective measures of ocular surface disease in patients with glaucoma. Design: Cross-sectional study. Participants: Sixty-four glaucoma subjects with bilateral visual field (VF) loss and 59 glaucoma suspects with normal VFs. Methods: Consecutive patients were recruited prospectively from the Wilmer Eye Institute Glaucoma Clinic. Main Outcome Measures: Tear film breakup time (TBUT), corneal staining score (0-15), and Schirmer's test results were included as objective metrics, whereas the Ocular Surface Disease Index (OSDI) questionnaire was administered to assess symptoms. Total OSDI score, vision-related subscore (derived from questions about vision and task performance), and discomfort-related subscore (derived from questions about ocular surface discomfort) were calculated for each subject. Results: Seventy-five percent (48/64) of glaucoma subjects and 41% (24/59) of glaucoma suspects were receiving topical medications. The corneal staining grade was greater in glaucoma subjects than in glaucoma suspects (6.4 vs. 4.1; P<0.001), but groups did not differ with regard to TBUT or Schirmer's results (P>0.20 for both). Multivariate regression models showed that topical glaucoma therapy burden was associated with a significantly higher total corneal staining grade (β, +0.9 for each additional glaucoma drop; 95% confidence interval [CI], 0.5-1.3; P<0.001), but not with TBUT or Schirmer's results (P>0.20 for both). Glaucoma subjects had significantly higher total OSDI scores than glaucoma suspects (16.7 vs. 7.9; P<0.001). This largely was the result of higher vision-related subscores in the glaucoma group (11.1 vs. 3.3; P<0.001). Ocular discomfort-related subscores, however, were similar in both groups (5.7 vs. 4.6; P = 0.30). In multivariate analyses, each 5-decibel decrement in better-eye VF mean deviation was associated with a 4.7-point increase in total OSDI score (95% CI, 1.9-7.5; P = 0.001) and a 3.7-point increase in the vision-related subscore (95% CI, 1.7-5.6; P<0.001) but did not predict a higher discomfort-related subscore (β, 1.1 point; P = 0.07). Topical glaucoma therapy burden was not associated with higher total OSDI score or vision- or discomfort-related subscore (P>0.20 for all). Conclusions: Glaucoma is associated with significant ocular surface disease, and topical glaucoma therapy burden seems predictive of corneal staining severity. However, OSDI is a poor metric for capturing ocular surface disease in glaucoma because symptoms seem to be related largely to VF loss. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references.