The Analysis of Tear Meniscus in Soft Contact Lens Wearers by Spectral Optical Coherence Tomography

Purpose: To evaluate the changes of tear meniscus in eyes fitted with soft contact lens (SCL) by spectral optical coherence tomography (SOCT). Methods: Thirty-three contact lens wearers who wore daily-wear frequent-replacement SCL with 55% water content for more than 6 years on average, and 33 normal subjects were enrolled in this study. The meniscus at the central lower lid of the left eye was examined by SOCT. For the lens wearers, the examination was performed twice: once with contact lens and once without. For the non-lens wearers, the examination was performed only once. The image of lower tear meniscus was divided into two parts: the hyperreflective curved layer (PI) and the hyporeflective triangular area (P2). The height of PI and P2 (H-PI and H-P2) was measured, along with the thickness and area of both parts (T-[P1+P2] and A-[P1+P2]). Results: The cornea, lower eyelid, contact lens, and the lower tear meniscus could be clearly visualized in the SOCT images. For the lens wearers, the mean values of H-P1, H-P2, T-[P1+P2], and A-[P1+P2] measured before removing the lenses were 164.18 +/- 41.77 mu m, 148.6 +/- 42.84 mu m, 134.72 +/- 38.39 mu m, and 9914 +/- 469 mu m(2). The values of these parameters measured after lens removal showed no significant differences from those measured with the lens. Variables tested in lens-wearers with and without contact lenses were both significantly lower than those of normal subjects. Conclusions: SOCT can be helpful in evaluation of the lower tear meniscus in the eye fitted with a SCL. Long-term SCL wear could induce decreased tear volume, especially by reduction of the aqueous component.