High Prevalence of Ocular Surface Disease Among Glaucoma Patients in Thailand.

Purpose: To determine the prevalence of symptoms and signs of ocular surface disease (OSD) among Thai patients with glaucoma receiving topical intraocular pressure (IOP)-lowering therapy.

Methods: Consecutive patients with glaucoma were recruited prospectively for this cross-sectional study from Siriraj Hospital. Subjective symptoms were evaluated using the Ocular Surface Disease Index (OSDI), and objective clinical signs were evaluated using the tear breakup time (TBUT), corneal fluorescein, rose bengal staining, and the Schirmer test.

Results: One hundred nine patients (56% women; mean age, 64.0 ± 13.7 years) were included. The mean number of IOP-lowering eye drops instilled daily was 3.2 ± 2.4; the mean duration of treatment was 5.4 ± 3.9 years. Forty-two (38.5%) patients reported symptoms using the OSDI. The TBUT was normal in 1 patient, and the others (99.1%) had abnormal tear quality. Fluorescein and rose bengal staining showed positive results in 35 (32.1%) and 42 (38.6%) patients, respectively. The Schirmer test showed decreased tear production in 80 (73.4%) patients. A greater number of IOP-lowering eye drops daily was associated significantly with 3.8 and 4.4 times higher odds of abnormal corneal fluorescein and rose bengal staining, respectively (95% confidence interval [CI], 1.62-9.34, P = 0.002 and 95% CI, 1.91-10.32, P = 0.001, respectively). A significant (P = 0.03, 0.04) correlation was seen between OSDI and corneal dye staining tests.

Conclusions: A high prevalence of OSD was found among glaucoma patients in Thailand. OSD is more prevalent in Asians than in westerners. Awareness regarding prescribing multiple IOP-lowering eye drops in Asians should be heightened to avoid ocular surface toxicity.