Abstract
Purpose:
In corneas requiring endothelial keratoplasty for Fuchs endothelial corneal dystrophy (FECD), high-order aberrations from the anterior corneal surface are higher than normal and remain higher after keratoplasty. In this study, we examined the changes in anterior corneal aberrations over a range of severity of FECD.
Methods:
In a cross-sectional study, 70 corneas of 44 patients with FECD (mean age, 67 years; range, 42-83 years) and 67 normal corneas of 35 control participants (mean age, 58 years; range, 40-80 years) were examined by slit-lamp and Scheimpflug imaging. Clinical grade of FECD was based on the presence and extent of guttae and the presence or absence of clinically evident edema (modified Krachmer grades 1-6). FECD was categorized as mild (grades 1-2), moderate (grades 3-4), or advanced (grades 5-6). Corneas of control subjects were devoid of any central guttae (grade 0). Aberrations from the anterior corneal surface were measured from Scheimpflug images (Pentacam, Oculus), and wavefront errors over a 6 mm-diameter optical zone were expressed as Zernike polynomials through the 6th order. High-order aberrations, expressed as the root-mean-square of wavefront errors, were compared between severities of FECD and normal by using generalized estimating equation (GEE) models to account for any correlation between fellow eyes of the same subject, and with an adjustment for age.
Results:
Over a 6 mm-diameter optical zone, total anterior high-order aberrations in FECD (0.63 ± 0.31 µm) were higher than normal (0.45 ± 0.17 µm, p=0.002). Aberrations were higher in moderate FECD (0.64 ± 0.32 µm, n=27) and advanced FECD (0.68 ± 0.33 µm, n=21) compared to normal (p=0.03 for both comparisons), whereas there was no difference between mild FECD (0.58 ± 0.27 µm, n=22) and normal (p=0.10, minimum detectable difference, 0.14 µm [α=0.05, β=0.20]).
Conclusions:
The increase in anterior corneal high-order aberrations, which affect visual acuity after endothelial keratoplasty, begins earlier in the course of FECD than the onset of clinically detectable corneal edema. Anterior corneal changes over the course of FECD suggest the possibility of suboptimal vision even after endothelial keratoplasty for moderate FECD.
Keywords: 626 aberrations •
481 cornea: endothelium •
741 transplantation