Safety and efficacy of small incision lenticule extraction (SMILE) in eyes with flat and steep keratometry: a matched comparative study

Session Details

Session Title: Presented Poster Session: Keratorefractive Surgery Results I

Venue: Poster Village: Pod 2

First Author: : J.Siedlecki GERMANY

Co Author(s): :                           

Abstract Details

Purpose:

To determine the influence of extreme (flat and steep) baseline corneal keratometry on the safety and efficacy of small-incision lenticule extraction (SMILE).

Setting:

Department of Ophthalmology, Ludwig Maximilians-University Munich; SMILE Eyes Clinic Linz, Austria

Methods:

The databases of the involved centres were screened for eyes that had undergone conventional myopic SMILE with markedly flat (39 – 41.9 D) or steep (47 – 49.9 D) preoperative corneal keratometry values. Both groups were matched to a cohort of eyes with regular keratometry (42 – 46.9 D) by preoperative mean refractive spherical equivalent (MRSE), sphere, astigmatism, age and corrected distance visual acuity. Main outcome measures were target accuracy and safety as well as corrected (CDVA) and uncorrected visual acuity (UDVA). Postoperative changes in higher order aberrations (RMS HOA, spherical aberration, coma, and trefoil) were evaluated on Scheimpflug imaging.

Results:

A total of 63 eyes (21 each) were followed up for 9±6 months. Mean baseline keratometry was 41.3±0.7 (flat), 45.5±1.0 (regular) and 47.7±0.6 (steep) D (p=0.0001). Baseline MRSE was -5.28 ± 1.56 D. Compared to the regular group, the flat and the steep cornea groups showed comparable MRSE accuracy (p=0.43, p=0.32), final UDVA (p=0.90, p=0.73) and CDVA (p=0.24, p=0.29). Resulting safety (1.13 vs. 1.13 vs. 1.11) and efficacy indices (1.04 vs. 1.03 vs. 1.01) were comparable. Flat corneas however experienced a stronger induction of spherical aberration (p=0.02), while steep corneas showed higher coma postoperatively (p=0.03).

Conclusions:

Compared to eyes with regular corneal curvature, non-inferior outcomes of SMILE concerning predictability, safety, and efficacy can also be expected in eyes with steep (>47 D) or flat (<42 D) preoperative keratometry. SMILE however induces more spherical aberrations in eyes with flat, and more coma in eyes with steep corneas.

Financial Disclosure:

None