Abstract
Purpose :
Prolonged use of topical antiglaucoma drugs is implicated in ocular surface dysfunction leading to signs and symptoms of dry eye disease. In this study, we have examined the impact of the drugs on the rate of fluorescein clearance from the tears (ke; as a measure of the tear dynamics), tear volume (Vd), and corneal epithelial permeability to fluorescein (Pdc; as a measure of the barrier function) using an ocular fluorometer.
Methods :
Measurements were performed in glaucoma patients on anti-glaucoma medications (2-5 years) and healthy controls. Pdc was determined using the multi-drop method that we recently developed for use with our custom-built spot fluorometer. As per the protocol, we first determine ke by measurement of tear fluorescence every 10-15 seconds following a 2 µL drop of fluorescein (F; 0.35%). Subsequently, Pdc is determined by stromal fluorescence following additional two drops of F (2%; 6 µL; administered 15 min apart). Other measurements including keratography were performed to further correlate ke, Vd, and Pdc with ocular surface damage.
Results :
Pdc and ke in glaucoma patients (21 eyes) on many different drugs (many with BAK as the preservative) were 1.86+1.12 nm /sec and 0.006 + 0.0064/sec in contrast with 1.18 +0.98 nm/sec and 0.0125 + 0.015/sec in normal eyes (22 eyes). The ratio of Vd between normal to glaucoma eyes was 3.30. The mean values of all the parameters were statistically significant (p < 0.05). These observations were in consonance with keratography measurements which showed significant loss of Meibomian glands (33-66%) in glaucoma patients.
Conclusions :
The corneal epithelial barrier function is significantly disrupted along with tear secretion dynamics in patients on topical anti-glaucoma drugs for a prolonged time. This is indicative of ocular surface dysfunction, which not only reduces the success rate of filtrating surgeries but is also associated with the loss of quality of life.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.