Corneal Epithelial Remodelling And Its Effect On Optical Quality And A-Sphericity

Published 2022 - 40th Congress of the ESCRS

Reference: PO489 | Type: Free paper | DOI: 10.82333/4dj3-xb79

Authors: Sara Sella* ¹ , Yocheved Aronovitz ² , Rony Wiener ³ , David Zadok ⁴

¹Ophthalmology,Shaare Zedek Medical Center,Jerusalem,Israel;Hebrew University,Haddasa Medical school ,Jerusalem ,Israel, ²Ophthalmology,Shaare Zedek Medical Center,Jerusalem,Israel, ³Ophthalmology,Shaare Zedek Medical Center,Jeruslaem,Israel, ⁴Ophthalmology,Shaare Zedek Medical Center,Jerusalem,Israel;Hebrew University ,Haddasa Medical school ,Jeruslaem ,Israel

Purpose

To evaluate the changes in epithelial thickness profile using RTVue® (Optovue Inc, Fremont, CA) before and after photorefractive keratectomy (PRK) and Laser-assisted in situ keratomileusis (LASIK) for myopia, hyperopia, and astigmatism and to investigate the assosiation of the epithelial remodeling and the objective optical quality such as: corneal a-sphericity and Modulation Transfer Function, MTF, (expressed in cycle per degree) using Optical Path Difference Scanning System (OPD-Scan II-III; Nidek Inc, Tokyo, Japan) to assess the healing effect.

Setting

Refractive service at the ophthalmology department, Shaare Zedek medical center, Jerusalem, Israel. A multi-disciplinary, tertiary hospital, Affiliated with the Hebrew University of Jerusalem. A Collaboration with Laser refractive surgery service of Assuta Optic Medical Center, Jerusalem.

Methods

Pre/post operative evaluation including: Epithelial thickness was measured using with RTVue® (Optovue Inc, Fremont, CA) at different corneal zones (S paracentral, 2–5 mm; min, max, different) preoperatively and at 3 to 5 months postoperatively. Path Difference Scanning System (OPD-Scan II-III; Nidek Inc, Tokyo, Japan). Full subjective refraction with certified optometrist. Slit lamp examination with ophthalmologist. The asphericity will be measured from the Q value taken from the OPD-Scan II-III. The Modulation Transfer Function, MTF, (expressed in cycle per degree cpd) will be taken from OPD. The correlation between the changes in corneal epithelial thickness (ΔCET) and MTF, Q-value changes (ΔQ) were analyzed.

Results

Thirty five patients underwent laser refractive surgery. 33 had myopic correction and 2 LASIK hyperopic correction. At the time of the surgery patients age was 25±9 years (range 18.10 to 41 years). Preoperative spherical aquivalent was -4.31±3.7D (range +2.2D to -8.5D). Epithelial remodeling changes from min 50.96±2.7microns to 49.3±3.3 (p= 0.07) and at max from 56.23±2.95 microns to 60.7±3.8 (p<0.05). A significant positive relationship was observed between epithelial thickening and ΔQ 3-5 months postoperatively (𝑟= 0.650, and 0.504, resp., 𝑃 < 0.01).Patients experienced statistically significant improvements in contrast sensitivity at all spatial frequencies (P<.05, Student t test).

Conclusions

Previous studies showed an assosiation between epithelial remodeling and conreal asphericty, we would like to present our investigation on the assosiation between corneal asphericty and contrast sensetivty with OPD SCAN measurments. The remodeling effects on the MTF can be assosiated with high profile ablation. Further studies should investigate the epithelial effect specificaly with photopic condition.