ESCRS - FP30.07 - Effects Of Optical Zone On Corneal Epithelial Thickness Mapping After Transepithelial Photorefrative Keratectomy

Effects Of Optical Zone On Corneal Epithelial Thickness Mapping After Transepithelial Photorefrative Keratectomy

Published 2025 - 43rd Congress of the ESCRS

Reference: FP30.07 | Type: Free paper | DOI: 10.82333/wqsw-9j16

Authors: Christopher Reischl* 1 , Leon Pomberger 1 , Sophia Reifeltshammer 1 , Peter Laubichler 1 , Haidar Khalil 1 , Matthias Bolz 1 , Josef Huemer 2 , Clemens Waser 3 , Nino Hirnschall 1

1Kepler University Hospital,Linz,Austria;Kepler University ,Linz,Austria, 2³Moorfields Eye Hospital Foundation Trust,London,United Kingdom, 3Kepler University ,Linz,Austria;Kepler University ,Linz,Austria

Purpose

PURPOSE:

The present study aimed to evaluate the impact of optical zone diameter on corneal
epithelial thickness (CET) in myopic eyes at three months post-transepithelial photorefractive
keratectomy (TPRK). Specifically, CET changes were compared between eyes receiving an
optical zone of ≤7.00 mm and those receiving an optical zone of >7.00 mm.


Setting

This is a cross-sectional and  retrospective study. 

Methods

 

This retrospective, cross-sectional study included 122 eyes of 61 patients who
underwent TPRK for myopia correction. CET was measured preoperatively and at three
months postoperatively using spectral-domain optical coherence tomography (OCT).
Measurements were taken at 25 distinct locations within a 9-mm diameter circular region
centred on the pupil. Patients were categorized into two groups based on optical zone
diameter: ≤7.00 mm (n=51 eyes) and >7.00 mm (n=71 eyes). Statistical analysis was
performed to compare CET changes between the two groups.


                                

                            

                            

                                
Results

                                

                                    
The mean age of the patients was 27.06 ± 5.44 years in the ≤7.00 mm group and 28.93 ± 5.90 years in the >7.00 mm group. The mean optical zone diameters were 6.82 ±0.17 mm and 7.40 ± 0.10 mm, respectively. In the ≤7.00 mm group, statistically significant increases in CET were observed at 5 of the 25 measurement locations (>0.05). In the >7.00 mm group, statistically significant increases in CET were observed at 18 of the 25 measurement locations (>0.05). In both groups, the mean CET was greater at all locations postoperatively compared to preoperatively. There was no statistically significant difference in the safety index between the two groups (p=0.20). However, the efficacy index was significantly higher in the ≤7.00 mm group (p=0.02).

                                

                            

                            

                                
Conclusions

                                

                                    
The findings of this study suggest that a larger optical zone diameter during
TPRK is associated with more extensive corneal epithelial remodelling, as evidenced by a
greater number of locations exhibiting significant CET increases. This information may be
valuable for surgeons when determining the optimal optical zone size for myopic patients
undergoing TPRK.