Abstract
Purpose:
To identify factors predicting the ocular surface response to experimental desiccating stress.
Methods:
The ocular surfaces of both eyes of 15 normal and 10 dry eye subjects were exposed to a controlled desiccating environment (15-25% RH and 3 L/min airflow) in goggles for 90 minutes. Eye irritation symptoms, blink rate, tear meniscus dimensions, non-invasive (RBUT) and invasive tear break-up time, and corneal fluorescein and conjunctival lissamine green dye staining were recorded before and after desiccating stress. Pre- and post-exposure measurements were compared and Spearman correlations between clinical parameters before and after desiccating stress were calculated.
Results:
Conjunctival and corneal dye staining significantly increased in all subjects following 90-minute exposure to desiccating environment and the magnitude of change was similar in normal and dry eye subjects, except superior cornea staining was greater in dry eye. Irritation severity in the desiccating environment was associated with baseline dye staining, baseline tear meniscus height and blink rate after 45 minutes. Desiccation-induced change in corneal fluorescein staining was inversely correlated to baseline tear meniscus width, whereas change in total ocular surface dye staining was inversely correlated to baseline dye staining, RBUT and tear meniscus height and width. Blink rate from 30-90 minutes of desiccating environment was higher in the dry eye than normal group. Blink rate significantly correlated to baseline corneal fluorescein staining and environmental induced change in corneal FL staining.
Conclusions:
Ocular surface dye staining increases in response to desiccating stress. Baseline ocular surface dye staining, tear meniscus height and blink rate predict severity of ocular surface dye staining following exposure to a desiccating environment.
Keywords: 486 cornea: tears/tear film/dry eye