Abstract
Purpose: :
To assess whether changes in ocular wavefront aberrations and corneal thickness after Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) correlated with changes in visual acuity.
Methods: :
A prospective study of 20 eyes that underwent DSAEK for endothelial dysfunction was conducted. Data were obtained at 1, 3, 6, and 12 months post- DSAEK. Best spectacle corrected visual acuity (BSCVA) was measured monocularly. Wavefront measurements were obtained using a large-dynamic range Shack-Hartmann wavefront sensor. Ocular aberrations were computed over the largest pupil diameter possible using the Zernike polynomial expansion up to the 10th order, and renormalized over a 4.0 mm pupil diameter. Ocular Coherence Tomography (OCT) was performed to measure host stromal, donor stromal, and total corneal thicknesses. When comparing a single measure across time, Kruskal-Wallis tests with Dunn’s multiple comparisons post-tests and Bonferroni adjustments were performed. Spearman Rank tests were conducted to determine correlations.
Results: :
Mean BSCVA varied significantly across postop timepoints (p<0.0001). Dunn’s post hoc tests indicated significantly improved BSCVA from preop (0.65 +/- 0.38, Snellen 20/90) and 1 month (0.47 +/- 0.21, Snellen 20/60) compared to 12 months (0.22+/- 0.14, Snellen 20/33) (D= 51.4, p<0.001 for preop comparison; D=36.5, p<0.001 for 1 month comparison). Host stromal thickness also varied significantly (p<0.0001) and post hoc tests found it decreased significantly from preop levels (650 +/- 63 microns) to 1 month post-op (508 +/- 53 microns) (D=44.5, p<0.001) and then remained stable. Donor thickness did not change significantly. Ocular lower order aberrations (LOAs) and higher order aberrations (HOAs) remained stable across postop timepoints. Postop BSCVA was negatively correlated with ocular HOAs (Spearman r = -0.3161, 95%CI -0.51 to -0.09, p = 0.0064), but not with LOAs. No correlations were identified between postoperative BSCVA, HOAs, or LOAs and total, host stromal, or donor stromal thicknesses.
Conclusions: :
Overall, BSCVA was negatively correlated with ocular HOAs. However, while BSCVA improved between 1 and 12 months post-DSAEK, HOAs, LOAs, and corneal thicknesses were stable during this period. Thus factors other than aberrations (e.g. changes in light scatter) likely account for the improved BSCVA between 1 and 12 months post-DSAEK.
Keywords: cornea: clinical science • aberrations • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)