Posterior Corneal Elevation After Photorefractive Keratectomy And Small Incision Lenticule Extraction For Moderate Myopia
Published 2022 - 40th Congress of the ESCRS
Reference: PO474 | Type: Free paper | DOI: 10.82333/1qt1-6b32
Authors: Shaimaa Azzam 1 , Abdel Rahman ElSebaey 2 , Khaled Elghonemy* 2 , Ahmed Basiony 2
1Ophthalmology department,Faculty of medicine , Helwan university,cairo,Egypt, 2Ophthalmology department,Faculty of medicine , Menoufia university,Shbein Elcom,Egypt
Purpose
To assess the changes in the posterior corneal elevation after photorefractive keratectomy (PRK) and small incision lenticule extraction (SMILE) for moderate myopia.
Setting
PRK and SMILE are two flapless procedures for correction of myopia and astigmatism. The change of corneal posterior surface is of great importance in predicting early corneal ectasia after corneal refractive surgery as the posterior corneal elevation is independent of the axis and orientation and not affected by the tear film.
Methods
Retrospective study conducted on 80 patients classified into two groups (PRK, SMILE) ,40 patients (80 eyes) were included in each group. Assessment was between 6-18 months postoperatively included posterior central elevation (PCE) and the average posterior central elevation change (ΔPCE) using pentacam in addition to the uncorrected distance visual acuity (UCDVA), best corrected distance visual acuity (BCDVA), manifest refraction spherical equivalent (MRSE) and comparing this data with the preoperative data
Results
The mean preoperative PCE in PRK group was 1.50 ± 2.76 and in the SMILE group was 1.82 ± 3.17 (p 0.600). The mean postoperative PCE in the PRK group was 1.45 ± 2.93 and in the SMILE group was 2.05 ± 2.15 (p 0.079). Regarding the ΔPCE: the mean ΔPCE in the PRK group was -0.05 ± 2.08 and in the SMILE group was 0.22± 2.15 (p 0.199), in PRK group: 31.25 % showed +ve results (means foreword posterior corneal surface protrusion),41.25 % showed –ve results (posterior surface moved posteriorly),27.5 % showed no change and in SMILE group : 38.75 % showed +ve results (means foreword posterior corneal surface protrusion),28.75 % showed –ve results (posterior surface moved posteriorly),32.5 % showed no change.
Conclusions
There was change detected in the posterior corneal surface after PRK and SMILE procedures. Although it was within normal range, it need long term follow up to assess its behavior for early detection of any ectatic changes ..