Is A Postoperative Cornea Flatter Than 34D Associated With Worse Outcomes?
Published 2025 - 43rd Congress of the ESCRS
Reference: FP30.01 | Type: Free paper | DOI: 10.82333/2d09-8r03
Authors: Michael Mimouni* 1 , Eitan Livny 2 , Dorin Sade Yazdi 3 , Yishay Hayardeni 3 , Amos Eitan 3 , Lior Rosenberg Belmaker 3 , David Zadok 4
1Rambam Health Care Campus,Haifa,Israel, 2Rabin Medical Center,Petah Tikva,Israel, 3Precise Bio,Modi'in-Maccabim-Re'ut,Israel, 4Shaare Zedek,Jerusalem,Israel
Purpose
To compare the postoperative outcomes of patients who underwent myopic photorefractive keratectomy (PRK) with a postoperative corneal curvature below 34 diopters (D) versus those with a curvature above 34 D.
Setting
Care Vision Laser Center.
Methods
This retrospective study included 17,019 eyes that underwent myopic PRK at Care Vision Laser Centers with 183 eyes (1.08%) classified as having a flat postoperative cornea (average keratometry <34 D). Baseline and intraoperative characteristics were compared between the flat cornea group and a control group (average keratometry ≥34 D). Postoperative outcomes, including uncorrected visual acuity (UCVA), spherical equivalent (SEQ), and other refractive and visual parameters, were analyzed both before and after adjusting for differences in baseline and intraoperative variables.
Results
Patients in the flat cornea group were more likely to be male (83.1% vs. 54.8%, p<0.001), had greater preoperative myopia (SEQ: -10.2±2.3 D vs. -4.9±2.6 D, p<0.001), and exhibited thicker minimal corneal thickness (540.7±33.5 µm vs. 530.2±33.6 µm, p<0.001). Intraoperatively, they received a higher spherical correction (8.9±1.5 D vs. 4.8±2.2 D, p<0.001) and deeper maximum ablation depth (131.7±17.2 µm vs. 82.8±36.2 µm, p<0.001). Unadjusted postoperative outcomes indicated significantly worse UCVA (logMAR: 0.06±0.11 vs. 0.03±0.07, p<0.001) in the flat cornea group. After adjusting for baseline differences, no significant differences were observed in UCVA (logMAR: 0.03 vs. 0.03, p=1.00) or other key refractive outcomes between the groups.
Conclusions
Patients with postoperative flat corneas (<34 D) following myopic PRK demonstrated distinct baseline characteristics and received more aggressive treatments. Although these patients had worse uncorrected visual acuity and higher astigmatism postoperatively, these differences were not significant after adjusting for baseline and intraoperative variables. The differences observed in the unadjusted analysis were likely due to confounding variables, suggesting that the initial concerns about worse visual outcomes in flatter corneas may be unfounded.