I read with interest the valuable cross-sectional study performed by Skalicky and associates in the January 2012 issue of the Journal . The authors investigated the relationship between ocular surface disease and glaucoma-related quality of life, glaucoma severity, and treatment in patients with open-angle glaucoma. They found that ocular surface disease index (OSDI) scores and the number of patients with ocular surface disease (OSD) increased with increasing glaucoma severity. In addition, OSDI was significantly correlated with Glaucoma Quality of Life-15 summary score, glaucoma severity, multiple topical glaucoma medications, worse eye mean deviation and pattern standard deviation, use of topical beta blockers, topical carbonic anhydrase inhibitors, daily dose of benzalkonium chloride, and glaucoma filtration surgery. In addition to preservatives in glaucoma medications, they mentioned in the article that elevated and exposed blebs can aggravate OSD symptoms. I think this merits more discussion and explanation: McDonald and Brubaker previously suggested tear meniscus and meniscus-induced thinning, and ocular surface irregularities had ectopic meniscus and a thinned meniscus area and resultant staining. They reported that tear film fractured in these thin areas. Also, they predicted that perilimbal elevations such as filtering blebs have secondary tear menisci and adjacent thinning area. I think the ectopic meniscus and thinning area can be demonstrated by video-meniscometer.

Irregularities or redundant tissue on ocular surface can have punctate keratopathy, fluorescein staining, and even corneal erosions without findings of aqueous deficiency. Therefore, OSD is caused not only by topical eye drops and their preservatives but also by irregularities or protrusion on ocular surface in glaucoma patients. Frequent instillation of artificial tears or elimination of elevated tissue on the ocular surface can increase patients’ comfort.