Non-invasive assessment of the tear film after LASIK

Abstract

Objective: The aim of the study was to compare the assessment of the ocular surface using classic methods with the newly developed keratoscopy-based MYAH (Topcon EU, Visia Imaging, Japan) device after femtosecond laser-assisted in situ keratomileusis (LASIK).

Patients and methods: This cross-sectional and observational study analyzed 80 eyes of 40 patients. Tear film and ocular surface evaluation were performed at baseline, postoperative week 1, and month 1. Measurements obtained using the Schirmer I test and invasive tear-film breakup time (I-TBT) were compared with non-invasive evaluation of the tear break-up time (NI-TBT), tear meniscus height (TMH) and blink analysis obtained using the MYAH device. Findings were correlated with the Ocular Surface Disease Index (OSDI) questionnaire in all subjects.

Results: The study included 80 eyes of 40 consecutive patients (21 males and 19 females) with a mean age of 26.6 ± 5.9 years (18-40 years) and a mean spherical equivalent value of -3.64 D (-9.63 to -0.25 D). There was a significant decrease in Schirmer I test (19.21 ± 8.4 vs. 16.61 ± 9.1 vs. 14.69 ± 9.86, p= 0.02, respectively) and I-TBT values (8.59 ± 3.4 vs. 7.4 ± 3.25 vs. 6.17 ± 3.01, p=0.03 respectively). OSDI values showed a significant increase after LASIK (11.56 ± 6.3 vs. 17.24 ± 7.5 vs. 14.71 ± 9.6, p=0.03, respectively). 5% level NI-TBT was significantly lower at 1 week 6.75 and 1 month 7.45 than baseline 13.2 at follow-up (p=0.037). Ocular protection index (6.6 vs. 2.3 vs. 2.6, p=0.009, respectively) and blink/minutes (18 vs. 17 vs. 15, p=0.002, respectively) values showed a statistically significant decrease. Our data detected a weak correlation between I-TBT and noninvasive first TBT, 5% level TBT parameters at month 1 follow-up. This study also found no correlation between contact lens use, older age, female gender, and pre-operative refractive error with the noninvasive MYAH dry eye parameters.

Conclusions: This study demonstrated the ability of the new keratoscopy-based MYAH device to detect changes in the short term after LASIK surgery.