Abstract
Purpose :
The tear meniscus is separated by the peripheral area of a soft contact lens (SCL), and this factor may be related to thinning and instability of the pre-SCL tear film and to eye dryness. To test this hypothesis, the effects of the peripheral thickness of a SCL on tears and eye dryness were investigated.™
Methods :
This study involved 10 daily SCL wearers without dry eye (5 males and 5 females; mean age: 34.9 years). In bilateral eyes, the subjects wore a different commercially available hydrogel SCL design (SCL-1 and SCL-2) made of the same material and with a similar central thickness (SCL-1: 0.12mm, SCL-2: 0.11mm) but a different peripheral thickness (SCL-1: 0.11mm, SCL-2: 0.23mm). One of the eyes was then evaluated before SCL wear, at 15 minutes and 1-, 2-, 3-, and 6-hours during SCL wear, and at 15-minutes post SCL removal. Examination involved the measurement of the tear meniscus radius (TMR) by video-meniscometry at the central (C-TMR, mm) and temporal [T-TMR, mm (outside the SCL)] portion of the lower lid margin, measurement of non-invasive breakup time (NIBUT, seconds) of the precorneal and pre-SCL tear film by video-interferometry, and the evaluation of eye dryness using a visual analogue scale (VAS, mm).
Results :
In either SCL, C-TMRs during SCL wear were significantly less than those before the SCL wear and C-TMRs at 15-minutes and 6-hours during SCL-2 wear were significantly less than those for SCL-1 wear (p<0.01). There were no significant differences in the T-TMRs among before, during, and after the removal of either SCL, or between SCL-1 and SCL-2. In either SCL, NIBUTs during SCL wear were significantly shorter than those before SCL wear except for 15-minutes during SCL-1 wear. At 1-, 2-, 3-, and 6-hours during SCL wear, NIBUTs for SCL-2 were significantly shorter than those for SCL-1 (p<0.01). VAS scores were significantly greater at 6-hours during SCL-1 wear, and 3- and 6-hours during SCL-2 wear than those before each SCL was worn. VAS scores were greater in SCL-2 than those in SCL-1 at 6-hours during SCL wear (p<0.05).
Conclusions :
The findings of this study may prove the hypothesis that SLCs with greater peripheral thickness may result in a greater decrease of meniscus tear volume where the SCL is inserted, as well as less stability of the pre-SCL tear film which leads to greater eye dryness during SCL wear.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.