Objectives: To determine upper and lower tear menisci using optical coherence tomography (OCT) in volunteers after laser in situ keratomileusis (LASIK) for myopia.
Methods: Thirty-five eyes of 35 nonsurgical volunteers were evaluated. Twenty-eight eyes of 28 volunteers who underwent LASIK served as the study group. The height, area, and volume of the upper and lower tear menisci were obtained in the study group, using OCT before surgery, 1 week, 1 month, and 20 months after surgery. At each visit, Schirmer test (type I, without anesthesia), tear break-up time, and corneal fluorescein staining score were evaluated. OCT imaging was conducted in the nonsurgical group with the same settings.
Results: The lower tear meniscus volume at baseline were significantly smaller in the study group compared with the nonsurgical group (t test, P < 0.01). The upper tear meniscus volume decreased from 0.44 +/- 0.11 microL to 0.37 +/- 0.08 microL at 1 month after surgery (P < 0.05). The lower tear meniscus volume (0.54 +/- 0.15 microL) reduced to 0.44 +/- 0.10 microL at 1 month after surgery (posthoc, P < 0.05). For the subgroup analysis, tear menisci, Schirmer test, and tear break-up time after LASIK decreased during the first 1 month (P < 0.05) and recovered by 20 months after surgery (t test, P > 0.05).
Conclusions: The upper and lower tear menisci decreased up to 1 month after LASIK and recovered by 20 months. OCT is a useful tool for evaluating the tear system in a noninvasive manner.