Abstract
Purpose :
Creation of shaped trephinations profiles by femtosecond laser (FSL) has improved penetrating keratoplasty (PK). Many profiles can be designed (“decagonal”,”zig-zag” and “butt-joint”) and all of these increase healing corneal area, improved graft adaptation, require less suture tension with less post-op astigmatism and superior biomechanical strength as compared with PK. The aim of the study is to identify the wound configurations that provides better topographic parameters and mechanical stability.
Methods :
Experimental ex vivo study in 18 donor human corneas (DHS) not eligible for transplantation was carried out. All corneoscleral rims were mounted on artificial anterior chamber (AAC) and underwent full-thickness keratoplasty by FSL. 6 DHS were assigned to the “decagonal” group, 6 to “zig-zag” group and 6 to “button-joint” group. In each group donor-recipient couples were matched and interrupted 10-0 nylon sutures were performed. Intracameral pressure was maintained 20 mmHg. Post-op astigmatism, deformation amplitude (DA)using scheimpflug noncontact tonometry and wound bursting pressure were evaluated and compared between groups. The AAC were fixed to each instrument through a custom-made standard support previosly each evaluation. The maximal pressure that the wound could withstand prior to visualisation of any fluid emerging at the interface was measured using a 27-gauge infusion cannula and a 3-way connector to a digital manometer.
Results :
All FSL assisted wound configuration was performed successfully. Mean astigmatism was 5.86 D for the “zig-zag” group, 7.59 D for the “decagon” group and 10.75 D for the “butt-joint” group. Mean corneal eccentricity was 8.1 for the “zig-zag” group and 8.7 for the “decagon” group. SAI was 3.69 D for the “zig-zag” group and 8.1 D for the “decagon” group. Leakage occurred at a mean of 75,4 mmHg for the “zig-zag” group, 45 mmHg for the “decagon” group, 44 mmHg for “butt-joint” group. DA was 0.81 mm for the “zig-zag” group, 0.93 mm for the decagon group and 0.96 mm for the “butt-joint” group.
Conclusions :
The FSL-assisted “zig-zag” wound configuration for PK was found to be the most mechanically stable compared with the standard “butt-joint” method and decagonal configurations. It also showed less astigmatism, lower eccentricy, lower SAI values and lower DA. The “zig-zag” wound configuration permormed by FS could be the best choice for PK.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.