Posters

Ultrathin corneal grafts for Descemet's stripping automated keratoplasty (DSAEK) prepared by a low-pulse energy, high-frequency femtosecond laser with endothelial approach

Poster Details

First Author: Y.Liu SINGAPORE

Co Author(s):    E. Teo   K. Adnan   G. Yam   D. Tan   J. Mehta  

Abstract Details

Purpose:

The posterior lamellar corneal grafts for Descemet stripping automated keratoplasty (DSAEK) are traditionally cut by a microkeratome from the epithelial side. This approach often results in variable graft thickness and meniscus-shape grafts, leading to a postoperative hyperopia shift. The newer generation of femtosecond laser, Femto LDV, may provide advantages to overcome these problems when adopting endothelial approach. The aims of this study were to optimize the procedures and parameters during the femtosecond laser ultrathin cutting, and to investigate the quality of these grafts with regard to the accuracy of the cutting depth, endothelial cell damage, and graft interface smoothness.

Setting:

Singapore Eye Research Institute, Singapore

Methods:

Twenty-five human corneoscleral buttons were cut from the endothelial side by the LDV Femto femtosecond laser (Ziemer Ophthalmic Systems AG) with viscoelastic materials coating on it. Specular microscopy was used to determine the postcut endothelial count, and the graft thickness was evaluated by anterior segment optical coherence tomography. The endothelial viability was determined using Trypan blue/Alizarin red vital staining, calcein-AM/EthD-1 live/dead cell assay, and scanning electron microscope (SEM). The graft interface smoothness was evaluated by SEM. Another nine human corneascleral buttons were used as controls for the endothelial viability comparisons.

Results:

The targeted cutting depth and the achieved cutting depth were significantly highly correlated (r = 0.84; Pearson's correlation). The average deviation in the cutting depth was 1.9±1.2%, and the average postcut endothelial count loss was 2.9±2.5%. The percentages of the damaged endothelium cells were 16.2±3.9% and 15.4±2.6% for the laser group, and 14.7±4.1% and 13.1±4.4% for the control group assessed by the vital staining and SEM, respectively (P = 0.76 and P = 0.71 in the comparison of 2 groups). The graft interface was smooth (grade 2.3±0.6). No endothelial toxicity was observed for the laser applanation head assessed by the live/dead cell assay.

Conclusions:

The ultrathin corneal grafts prepared by the LDV Femto femtosecond laser with endothelial approach produces corneal grafts in uniform shape and good quality, which may provide better postoperative visual outcomes for DSAEK patients. FINANCIAL INTEREST: NONE