Are All Thin Corneas (<480 Microns) Indicative Of Keratoconus?
Published 2025 - 43rd Congress of the ESCRS
Reference: FP06.15 | Type: Free paper | DOI: 10.82333/s9yb-v048
Authors: Shafiq Rehman 1 , Nabila Jones 1 , Amir Hamid 1 , Clare O'Donnell* 2
1Eye Sciences,Optegra Eye Health Care,Manchester,United Kingdom, 2Eye Sciences,Optegra Eye Health Care,Manchester,United Kingdom;Faculty of Biology, Medicine and Health,University of Manchester ,Manchester,United Kingdom;College Health Life Sciences,Aston University,Birmingham,United Kingdom
Purpose
To assess the refractive stability and potential risk of ectasia in thin corneas (<480 µm) following photorefractive keratectomy (PRK) by analyzing preoperative data using an advanced AI model for corneal collagen distribution.
Setting
Prospective study conducted at a tertiary ophthalmology center.
Methods
Sixty eyes from 30 myopic patients unsuitable for LASIK or SMILE due to corneal biomechanical and tomographic profiles underwent PRK. Preoperative evaluations included ultrahigh-resolution polarization-sensitive optical coherence tomography (PS-OCT) for epithelial thickness, Bowman's layer, stroma, and collagen distribution; CORVIS-ST and Pentacam assessed biomechanical parameters. An AI model analyzed collagen fibril distribution, scoring from 0 (healthy) to 1 (clinical keratoconus). Patients were re-examined one year postoperatively for refractive error correction, visual acuity, and corneal stability.
Results
Preoperatively, Group 1 (TBI: 0.43±0.01) and Group 2 (TBI: 0.82±0.14) showed significant differences in corneal biomechanics (CBI, BAD-D, stiffness parameters), with Group 2 indicating higher ectasia risk. AI scores based on PS-OCT were G1: 0.3±0.2 and G2: 0.39±0.23, both below the early keratoconus cut-off (AI <0.5). At one year follow-up, all patients had stable refractive outcomes and visual acuity, with no signs of corneal ectasia or instability; postoperative tomography and biomechanical parameters showed no significant deterioration.
Conclusions
Despite traditional diagnostic tools suggesting higher ectasia risk in thin corneas, AI-based PS-OCT assessments provided information on collagen distribution. PRK can be safely performed in selected thin corneas (<480 µm) without signs of ectasia at one year postoperatively. Integrating AI and advanced imaging modalities like PS-OCT may enhance refractive surgery decision-making, allowing better patient selection even when traditional risk assessments indicate otherwise.
Financial Disclosure: None of the authors have financial interests to disclose.