The Effect of Dry Eye Treatment on Biomechanics in Refractive Surgery Candidates

To evaluate changes in corneal biomechanical parameters after dry eye treatment for refractive surgery candidates.

In this retrospective, cohort, single-center study, adults older than 21 years who presented for refractive surgery assessment from August 2020 to July 2022 were included. Patients underwent history taking, ocular examination, corneal tomography, and biomechanical evaluation. Patients with abnormal Tomographic Biomechanical Index (TBI) values or clinical signs of dry eye disease underwent dry eye treatment and repeat biomechanical evaluation. Paired t-tests were used to compare parameters before and after treatment and unpaired t-test to compare treated eyes to age-matched controls. The significance threshold was a P value less than .05.

Among 482 eyes from 241 patients, 99 (41.1%) had abnormal TBI values in ⩾1 eye. Of the cohort who completed dry eye treatment, 50 eyes from 34 patients showed improved TBI values, with a mean change of -0.2 ± 0.14 and a mean increase in pachymetry value of 7.6 ± 10.1 µm. Eyes with an increase in biomechanically corrected intraocular pressure had an increase in stiffness parameter at first applanation (SP-A1) and highest concavity (SP-HC). Comparisons between eyes after dry eye treatment with age-matched control eyes showed no differences in SP-A1 and SP-HC, but integrated inverse radius and deformation amplitude ratio were significantly stiffer in controls. Eyes after dry eye treatment had higher mean TBI values (0.2 ± 0.1) compared to age-matched controls (0.1 ± 0.1), although both were within the normal TBI cut-off value of 0.29.

Dry eye treatment can modify the biomechanical profile in mild subclinical dry eye, rendering improvements in TBI values that may reduce the risk for subsequent refractive surgery.