Evaluation of the ocular surface in asymptomatic glaucoma patients on topical medications and following trabeculectomy - A cross-sectional study

PURPOSE: This present prospective, cross-sectional study aims to comprehensively evaluate the ocular surface in asymptomatic patients with diffuse blebs after trabeculectomy versus chronic anti-glaucoma medication use and compare it with the age-matched normal population. METHODS: Objective clinical evaluation was done by tear film break-up time (TBUT) and Schirmer’s test (ST) in the three groups–trabeculectomy >6 months with a diffuse bleb (Wurzburg bleb classification score ≧10), chronic anti-glaucoma medication (AGM >6 months) group, and normal population. In all groups, tear film osmolarity was checked with the TearLab(®) device (TearLab Corp., CA, USA), and subjective evaluation was performed by administering Ocular Surface Disease Index (OSDI) questionnaire. Patients already on chronic lubricants or any other drug for the treatment of dry eyes (viz. steroids, cyclosporin) or having symptoms suggestive of an abnormal ocular surface, who had undergone refractive or intraocular surgery, and contact lens users were excluded. RESULTS: In total, 104 subjects/eyes were recruited over 6 weeks. Thirty-six eyes recruited in the trab group were compared with 33 eyes studied in the AGM group, and both these groups were compared to 35 normal eyes. When compared to normals, TBUT and ST were significantly lower (P = 0.003 and 0.014) and osmolarity and OSDI were statistically significantly higher (P = 0.007 and 0.003) in the AGM group, whereas only TBUT was statistically significantly different (P = 0.009) when the trab group was compared to normals. Also, when the trab group was compared to the AGM group, ST was found to be higher (P = 0.003) and osmolarity was lower (P = 0.034). CONCLUSION: To conclude, ocular surface is affected even in asymptomatic patients on AGM but near normalcy is possible following trabeculectomy when blebs are diffuse.