Abstract
Purpose:
To evaluate the relation between dry eye status and change in dry eye symptoms after exposure to a low humidity environment (LHE).
Methods:
Full time soft contact lens wearers were enrolled in a one-visit study. The Contact Lens Dry Eye Questionnaire Short Form classified subjects as normal or with contact lens discomfort (CLD). Subjects completed pre-LHE measurements including average non-invasive Keratograph break-up time (NIKBUT) on the right eye while wearing habitual contact lenses. These same measurements were performed post-exposure to the LHE. All subjects were exposed to a LHE (4% humidity, 70-75°F, 0.5-1.5 m/s air speed) for approximately 90 minutes. Subjects completed a Post-Humidity Controlled Environment Survey and responded to changes in symptoms of dryness, discomfort, and tearing. For dryness and discomfort, possible responses were significantly better, better, no difference, worse, or significantly worse after exposure to the LHE. For statistical analysis, responses were grouped into two categories: same or better (or worsening—e.g., more tearing) of symptoms. The Chi-Square test was used for data analysis.<br />
Results:
Twenty-five normal (11 males, average age 27.9 ± 5.7 years) and 25 CLD (8 males, average age 28.0 ± 9.8 years) subjects were enrolled. Fourteen of 25 normal subjects reported no difference or an improvement of dryness after exposure to a LHE compared to 7 CLD subjects. Eleven normal subjects reported worsening of dryness compared to 18 CLD subjects (Chi-square statistic 4.0, p-value 0.04). After exposure to a LHE, 15 CLD subjects reported increased discomfort compared to seven normal subjects (Chi-square statistic 5.2, p-value 0.02). Twelve subjects in both the CLD and normal groups reported more tearing (Chi-square statistic 0.0, p-value 1.00).
Conclusions:
Contact lens discomfort subjects were more likely than normal subjects to report worsening of dryness and discomfort after exposure to a LHE. However, there is no difference in reported symptoms of tearing between the two groups after exposure to a LHE.