Is excimer laser corneal surgery appropriate after resolution of corneal edema in fuchs dystrophy by descemet membrane endothelial keratoplasty?

PURPOSE

To report a case of apparent central corneal thinning diagnosed after treatment of Fuchs dystrophy by Descemet membrane endothelial keratoplasty (DMEK) and to discuss treatment options with laser refractive surgery.

METHODS

A pseudophakic patient with Fuchs dystrophy underwent DMEK, with removal of dysfunctional recipient endothelium and replacement with bare endothelium and Descemet membrane from a donor cornea. Subsequently, a standard preoperative evaluation for LASIK, including refraction, topography, Pentacam (Oculus Optikgeräte GmbH), and slit-lamp examination was performed.

RESULTS

After DMEK, refraction was +0.75 +2.50 × 115. Corneal topography did not show evidence of corneal ectasia or suspicion of keratoconus. Simulated keratometry was 43.03×40.49. Central corneal thickness was 481 μm by ultrasonic pachymetry. Pentacam evaluation of the anterior and posterior surfaces showed normal contours relative to a best-fit sphere on the anterior surface, but central elevation of 25 μm on the posterior surface. The typical increased central corneal thickness of Fuchs dystrophy could have masked a latent forme fruste keratoconus that became evident after the edema resolved with DMEK, or the central edema could have led to loss of stromal thickness causing the forward displacement of the posterior corneal surface.

CONCLUSIONS

It is uncertain whether this eye is safe for LASIK or PRK correction of the residual refractive error. This finding of posterior surface forward displacement would be difficult to impossible to detect in an eye after Descemet stripping endothelial keratoplasty due to the addition of stromal tissue on the graft.