Evaluation of a microkeratome-based limbal harvester device for limbal stem cell transplantation

To assess the cut quality and reproducibility using a novel microkeratome-based limbal harvester.

An enlarged microkeratome head and stainless steel blades were coupled with a nitrogen gas-driven turbine (15,000 blade oscillations/min) of a microkeratome. A large, 16-mm-diameter suction ring was attached to the globe. A lamellar sclerokeratectomy using head depths of 170 and 200 microm was performed in human donor research eyes. Obtained lenticule thickness was measured by ultrasound pachymetry and the bed size by planimetry. Histologic and scanning electron microscopy (SEM) analyses of the samples were performed.

Central lenticule thickness was 294 microm (standard deviation [SD] 37) for the 170 head and 277 microm (SD 91) for the 200 head (p = 0.720). Lenticule diameter was larger in the horizontal meridian using the 170 head (12.8 mm [SD 0.8] vs. 11.9 mm [SD 0.7], p = 0.028), but similar in vertical meridian (12.0 [SD 0.6] versus 11.4 mm [SD 0.6], p = 0.093). Histology showed a multilayer epithelial cell pattern at the lenticule periphery. The SEM showed a smooth cut surface in both the stromal bed and the lenticule.

Cut reproducibility and quality are similar to those found using standard microkeratomes for corneal lamellar cuts. This system ensures, in a straightforward way, the presence of epithelial cells in the edges of a mechanical sclerokeratectomy for limbal stem cell transplantation.