Tomographic Predictors of Ectasia Development After Keratorefractive Surgery

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Post-keratorefractive surgery ectasia is a serious complication.
• Identifying risk factors in patients with seemingly normal preoperative tomography is crucial for prevention.

Purpose of the Study:

• To identify risk factors for post-keratorefractive surgery ectasia in patients with unremarkable preoperative tomography.
• To introduce and evaluate a new index: diameter of peak locations (DPL).

Main Methods:

• Retrospective case-control study of patients who underwent keratorefractive surgery.
• Inclusion of 19 ectasia cases and 58 matched controls.
• Multivariate analysis to assess predictors of ectasia.

Main Results:

• No significant differences in ablation depth, spherical equivalent, percent tissue altered, residual stromal bed, or Ectasia Risk Score System between groups.
• Significantly higher anterior and posterior symmetry index and a tighter DPL in the ectasia group.
• Posterior corneal symmetry index and DPL were superior predictors compared to other factors.

Conclusions:

• Elevated posterior corneal symmetry index and a narrow DPL are significant predictors of ectasia.
• A tight DPL may indicate a vulnerable corneal area, increasing ectasia risk.