Abstract
Purpose :
Bowman Layer Transplantation (BLT) represents a promissing treatment for moderate keraoconus. The technique has proven to decrease corneal steepening, increase visual acuity and improve contact lens tolerance. Despite its encouraging results, the physilogical mechanisms behind the technique remain partially unknown. This study aims to morphologically validate the graft preparation technique for BLT.
Methods :
A total of 10 human cornea of 8 donors were used. The graft preparation was performed until half of the Bowman Layer (BL) was detached. Samples were cut longitudinally into two sections previous to fixation. The first section of each sample were cut and stained using hematoxilin-eosin and PAS to identify the BL. Central and periferal areas were prepared and mounted for microscopical examination. The second part of each sample underwent preparation for scanning electron microscopy (Quanta 3D scanning electron microscope, FEI, Eindhoven, The Netherlands). The detached BL was folded backward, exposing the graft-stroma interface. Standardized imaging was performed in four distinctive regions: central interface, mid-peripheral interface, peripheral interface and periphery of the graft.
Results :
All grafts presented a mixed BL-stroma composition under SEM. These results were consistent thorughout different regions and were confirmed by histological H&E and PAS stainings. Mean graft thickness was 18.5 μm (range: 9-29) in the center and 12.3 μm (range: 8.6- 19) in the periphery. Mean BL thickness was 10.1 μm (range 8.2-9.4) without statistically significant differences between regions.
Conclusions :
The presence of remnant stromal tissue in BL grafts may not be completely avoidable by manual preparation. The variability in the thickness of the BL graft relates to its stromal component, and may potentially affect its optical characteristics and postoperative outcomes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.