Topography guided custom ablation treatment for residual refractive error after keratoplasty

Purpose

To evaluate the efficacy and safety of topography-guided custom ablation photorefractive keratectomy (TCAT) in treating residual refractive error and astigmatism after keratoplasty.

Methods

Medical records of all patients who underwent TCAT from 2013 to 2017 for residual refractive error and irregular astigmatism after keratoplasty were reviewed. Data were collected on patient demographics, surgical details and preoperative and 6 months postoperative refraction, corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA) and keratometry indices. The procedure was comprised of two stages where stage-1 was aimed at decreasing the irregular astigmatism and stage-2 at correcting the refractive error. Stage 2 was only performed if the corneal parameters including residual stromal bed were within acceptable limits.

Results

Forty-six eyes of 46 patients were included. Nineteen eyes underwent stage-1 TCAT treatment only (Group-1). Nine eyes underwent stage-2 TCAT six months after the stage 1 (Group-2) and 18 eyes underwent a simultaneous stage 1 and 2 procedure (Group-3).

Six months following TCAT, CDVA improved in 69.6% This success rate was 63.2% in Group-1, 44.4% in Group-2 and 88.9% in Group-3.

Median spherical equivalent (SE) decreased from −4.5D preoperatively to −2.5D postoperatively and the median cylinder decreased from 3.25D preoperatively to 2.43D postoperatively. Comparing to Group-2, eyes in Group-3 experienced larger reduction in SE and astigmatism.

Conclusions

Treatment of patients with post-keratoplasty residual refractive error and astigmatism with TCAT resulted in successful outcomes with improvements CDVA and UDVA. Performing a simultaneous two-stage TCAT procedure appeared to be more effective in reducing the refractive error.