Tear Menisci and Corneal Subbasal Nerve Density in Patients After Laser In Situ Keratomileusis

Objective: To investigate the relationship between tear menisci and corneal nerve density in patients after laser in situ keratomileusis (LASIK). Methods: Twenty-eight eyes of 14 myopic patients were enrolled. Height and area of the upper and lower tear menisci-upper tear meniscus height, upper tear meniscus area, lower tear meniscus height (LTMH), and lower tear meniscus area (LTMA)-were measured by spectral domain optical coherence tomography before surgery, 1 week, 1 month, and 3 months after surgery. Central, temporal, and nasal corneal nerve densities were measured by confocal microscopy before surgery, 1 month, and 3 months after surgery. Results: After surgery, LTMH and LTMA increased significantly from 1 week to 1 month (P=0.009 and =0.011, respectively) and 1 month to 3 months (P=0.003 and =0.039, respectively); temporal and nasal nerve densities increased significantly from 1 month to 3 months (P<0.001, P=0.016, respectively). Lower tear meniscus area was significantly correlated with central and nasal nerve densities at 1 month (R=0.478 and 0.46, P=0.01 and 0.014, respectively), whereas LTMH and LTMA at 3 months were significantly correlated with central nerve density at 1 month (R=0.449 and 0.608, P=0.017 and 0.001, respectively). Conclusions: Lower tear menisci and peripheral corneal nerves recovered continually after LASIK during the early stage. However, tear volume might depend on residual central corneal nerves at 1 month, rather than on corneal nerve recovery.