Cornea Cases

Title:

OCT-assisted topography-guided transepithelial ablation in treatment of corneal surface irregularity and stromal scarring after previous treatments for recurrent post-LASIK epithelial ingrowth

Case Report Details

First Author: Y.Feng NORWAY

Co Author(s):    A. Stojanovic                    

Abstract Details

Purpose:

To report a case treated for significantly reduced visual acuity and visual disturbances after recurrent epithelial ingrowth under the LASIK flap

Setting:

Eye dpt., University Hospital North Norway, Tromsø, Norway

Report of case or case series:

A 35-years-old man was referred with decreased visual acuity and severe visual disturbances. He had a myopic LASIK three years before the presentation, followed by persistent epithelial ingrowth in the left eye, which persisted after several attempts of removal. The right eye was unremarkable. On initial examination, we found opaque scar tissue in the anterior stroma of the left eye, within the central 5 mm, reaching 265 µm in depth. Reduced corrected visual acuity to 0.2 and increased corneal RMS HOAs at diameter of 5 mm to 3.85 µm, as well as severely reduced corneal transparency were found. Epithelial thickness map showed the sign of significant epithelial remodelling, ranging in thickness from 22 to 74 µm. Corneal OCT showed a morphological substrate for the optical irregularities and minimum pachymetry of 527 µm, while Scheimpflug imaging showed no sign of pathological posterior surface protrusion. We planned to regularize the corneal surface and to remove the scar tissue of the degenerated epithelial ingrowth within a single OCT-assisted, transepithelial topography-guided ablation, comprising the epithelium, the flap and the interface scar. Ablation planning included a dynamic point-by-point correlation between the ablation map and the OCT-measured pachymetry. Reiterative adjustment of the ablation parameters, such as the diameter and the lamellar ablation depth, were made to achieve the desired amount of tissue removal at the crucial points at OCT pachymetry map. After uneventful surgery, 1.5 years’ follow-up showed a clear central cornea on OCT. Refractive error decreased, visual acuity increased to 0.6 and RMS HOAs decreased to 0.98 µm. Corneal topography showed optical centralization and regularization. The patient reported a vast improvement of visual disturbances.

Conclusions/Take Home Message:

1. Ablation diameter and additional lamellar ablation depth may be iteratively adjusted to achieve a safe, but deep enough ablation. 2. Transepithelial topography-guided ablation may effectively treat secondary corneal optical irregularities as well as the stromal opacities. Assuming the sufficient amount of residual corneal tissue, the treatment may comprise epithelium, flap and interface opacities after LASIK.