Palpebral aperture sizes of rigid and soft contact lens wearers compared with nonwearers.

Previous studies have shown that contact lens wear may affect palpebral aperture size (PAS). In this study, 74 wearers of rigid lenses were matched for sex and age with soft lens wearers and nonwearers. Partial face photographs were taken of all subjects, in the case of contact lens wearers, after lens removal. PAS was determined by measuring the resulting 35-mm transparencies on a Mitutoya profile projector. The mean PAS of the rigid lens wearers (9.76 +/- 0.99 mm) was found to be significantly smaller than that of the soft lens wearers (10.24 +/- 0.94 mm) and the nonwearers (10.10 +/- 1.11 mm) (p = 0.0154, analysis of variance). There was no significant difference between the PAS of soft lens wearers and nonwearers. This study supports the hypothesis that rigid lens wear causes a decrease in PAS.