Upper and lower tear menisci on contact lenses

The purpose of this study was to measure upper and lower tear menisci on contact lenses using real time optical coherence tomography (OCT).

Both eyes of 20 adapted contact lens wearers were imaged when they wore two types of silicone hydrogel lenses, balafilcon A on one eye and galyfilcon A on the other eye. The height, radius, and area of upper and lower tear menisci were obtained before, immediately after, and 20 minutes after lens wear on two consecutive days. On a third visit, the lenses were switched between eyes and an investigative lubricant was instilled after 4 hours of lens wear. OCT images were obtained as before and additionally at 1 and 4 hours after lens insertion. Imaging was also conducted immediately after lubricant instillation and 20 minutes post-instillation.

There were no significant differences in the measured variables between lenses (P > 0.05) and between consecutive visits (P > 0.05). The menisci around both eyelids immediately after lens insertion were significantly greater than that before (P < 0.005). By 20 minutes after lens insertion, all variables had returned to baseline values and remained that way for at least 4 hours. Immediately after the instillation of the lubricant at 4 hours, meniscus variables increased (P < 0.001), but recovery to baseline occurred within 20 minutes.

It is feasible to use OCT in the measurement of both upper and lower tear menisci on contact lenses in situ. Tear menisci increased on insertion of contact lenses and on instillation of lubricants. However baseline values were re-established with 20 minutes.