A comparison of safety and clinical outcomes of 100 µ versus 160 µ cap in patients undergoing ReLEx-Small Incision Lenticule Extraction (SMILE)

• Published in: International ophthalmology 2021-08, Vol.41 (8), p.2657-2665
• Main Authors: Ganesh, Sri, Brar, Sheetal, Pereira, Savio
• Format: Article
• Language: English
• Subjects: Clinical outcomes; Complications; Contact lenses; Equivalence; Medicine; Medicine & Public Health; Myopia; Ophthalmology; Original Paper; Patients; Questionnaires; Safety; Statistical analysis; Thickness
• ISSN: 0165-5701; 1573-2630
• DOI: 10.1007/s10792-021-01821-1

Purpose To determine the safety, efficacy and clinical outcomes of 100 µ versus 160 µ cap in patients undergoing ReLEx-Small Incision Lenticule Extraction (SMILE). Methods This prospective, comparative, non-randomized clinical trial included hundred eyes from 50 patients, undergoing bilateral ReLEx SMILE for myopia ranging from − 1 to − 6 D spherical equivalent. Twenty-five patients received treatment with standard 100 µ cap thickness, while the remaining 25 patients underwent the same procedure but with a 160 µ cap thickness in both eyes. Manifest refraction, UDVA, CDVA, contrast sensitivity, aberrations and dry eye were evaluated along with a subjective questionnaire at 2 weeks and 3 months post-operatively. Mean follow-up was 90 ± 15 days. Results At two weeks and 3 months post-operative, compared to the preoperative values, the mean log-MAR UDVA, CDVA, spherical equivalent, contrast sensitivity higher order aberrations did not show statistically significant differences ( p  > .05) between the two study groups. However, significant reduction in Schirmer’s II and TBUT scores was observed compared to preoperative scores at 3 months in 100 µ group ( p  > .05) but not in160 µ group. Patients did not report significant subjective complaints in either groups treated, when leading questions were asked through a subjective questionnaire. Conclusion ReLEx SMILE with 160 µ cap thickness was equally safe and efficacious as 100 µ cap, with no unique complications observed by keeping a thicker cap. Post-operative dry eye was significantly less in 160 µ group, suggesting an advantage in patients with pre existing dryness or contact lens users. Trial registration number CTRI/2014/09/005,005.