Abstract
Purpose: :
There is controversy in the field of endothelial keratoplasty concerning the relationship of graft thickness to visual outcome, with some surgeons believing that requesting thinner grafts from their eye bank will yield better visual results. The few published series to date have analyzed 50 eyes or less and have drawn conflicting conclusions. This is the first large prospective series to evaluate that relationship.
Methods: :
DSAEK was performed with pre-cut donor tissue in 331 Fuchs’ dystrophy eyes with no retinal disease or other vision limiting co-morbidity. Best corrected visual acuity (BCVA) was measured at 6 months post-operatively and this outcome data analyzed in relation to the graft thickness reported pre-operatively to the surgeon by the eye bank for each case. Pearson Correlation Coefficient analysis was performed for the series. Chi Square tests, independent samples t-tests, and Mann-Whitney U tests were performed for specific graft thickness subgroups.
Results: :
Mean graft thickness was 167.9 microns (range: 101 to 367). For the 293 grafts that were from 101 to 200 microns in thickness, the mean LogMAR visual acuity was 0.156 (20/28). There was no significant correlation between graft thickness and visual acuity in this thickness group. (Pearson = 0.094; R2 = 0.009; p = 0.107). The 38 grafts that were thicker than 200 microns had a mean LogMAR vision of 0.245 (20/35), which was significantly worse than the grafts 200 microns or less (Mann-Whitney: p=0.003).
Conclusions: :
Excellent vision can be obtained with grafts 200 microns and thinner and no correlation can be found between pre-operative graft thickness and visual results, calling into question the validity of special requests by surgeons for ‘thin" tissue from eye banks. Excessively thick tissue (ie: > 200 microns) may be associated with a reduction in visual results following DSAEK surgery.
Keywords: cornea: clinical science • cornea: endothelium • transplantation