Abstract
Abstract: :
Purpose: This study examines the effect of eyewear on periocular humidity levels. Humidity is known to be an important factor in tear film stability and the relief of dry eye symptomology. Methods: An Omega® RH 31 Handheld Temperature/Humidity Indicator with probe was used. Six eyewear designs were compared: swim goggles, lab goggles, Oakley® wrap–around sunglasses, IronMan® wrap–around sunglasses, reading glasses, and filtered goggles (a modified spectacle with peripheral HEPA–like filters and silicon gasket eyepieces). The probe was inserted at the level of the lateral canthus. A 1 cm incision was made in the swim goggles, filtered goggles, and lab goggles to accommodate the probe. The insertion site was sealed with surgical tape. Testing order was randomized by drawing numbers. Relative humidity at room temperature was recorded prior to periocular measurements which were recorded in 3 minute intervals for 15 minutes. One way analysis of variance with repeated measurements was used to compare the effect of eyewear on humidity. Six trials were performed on 3 subjects asymptomatic for dry eyes (2 males and 1 female, mean age 25 ± 1yrs). Relative humidity data was converted to absolute humidity to correct for temperature variation between trials. The difference in absolute humidity between the room and periocular environment was calculated. Results:After 3 minutes, humidity levels stabilized over time in all frames except swim goggles (p=0.025) and lab goggles (p=0.020) which increased at the rate of 0.15 g m–3/min and 0.14 g m–3/min, respectively. Humidity levels differed between any two pairs (p<0.001). Fogging was observed in swim goggles (n=6), filtered goggles (n=6), and lab goggles (n=2). The least squared mean difference was used to compare the mean difference in absolute humidity between room and periocular levels after adjusting for the time effect. After 15 minutes, results were as follows: swim goggles 14.40 ± 1.46 g m–3, filtered goggles 13.48 ± 0.47 g m–3, lab goggles 9.86 ±1.13 g m–3, Oakley® wrap–around 4.73 ±1.37 g m–3, IronMan® wrap–around 3.74 ± 0.73 g m–3, and reading glasses 0.89 ± 0.39 g m–3. Conclusion:Humidity levels differ between types of eyewear. Wrap–around frames were more effective than reading glasses in creating higher periocular humidity. Eyewear with a periocular seal provided the largest effect: swim goggles and filtered goggles, respectively, followed by lab goggles. Eyewear design that incorporates a periocular seal may be of greatest benefit for dry eye sufferers.
Keywords: cornea: tears/tear film/dry eye