Corneal Higher-Order Aberrations in Three Corneal Transplantation Techniques

1. Shizuka Koh
2. Naoyuki Maeda
3. Tomoya Nakagawa
4. Ritsuko Higashiura
5. Kohji Nishida

Osaka University Graduate School of Medicine, Osaka, Japan

Purpose:
To investigate the characteristics of corneal higher-order aberrations (HOAs) from the anterior and posterior corneal surfaces in eyes that underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet's stripping automated endothelial keratoplasty (DSAEK).

Methods:
Twenty-four eyes underwent PK, 28 eyes DALK, and 19 eyes DSAEK were enrolled in the study. 30 normal eyes served as controls. The anterior and posterior corneal heights and pachymetric data were obtained with a Scheimpflug-based corneal topographer (Pentacam, Oculus, Inc., Wetzlar, Germany). Corneal HOAs (root mean square) for 4-mm pupils were calculated from the height data and expanded with normalized Zernike polynomials. The HOAs due to anterior and posterior corneal surface irregularity were compared among PK, DALK and DSAEK.

Results:
The mean total corneal HOAs of the anterior surface in eyes with PK, DALK, DSAEK, and normal control groups were 1.38 ±0.67 μm, 1.19 ±0.57 μm, 0.61±0.33 μm, and 0.21±0.07 μm, respectively. The anterior corneal HOAs in the DSAEK group were significantly less than those in the PK (P<0.05) and DALK groups (P<0.05). The mean total corneal HOAs of the posterior surface in those groups were 0.20±0.09 μm, 0.24±0.11 μm, 0.27±0.15 v, and 0.07±0.02 μm, respectively. There were no significant differences in the posterior corneal HOAs among the groups.

Conclusions:
Eyes that undergo DSAEK, in which the anterior corneal surfaces are not replaced, have lower anterior corneal HOAs compared with PK or DALK eyes in which the anterior corneal surfaces are replaced.