Comparison of anterior and posterior corneal surface irregularity in descemet stripping automated endothelial keratoplasty and penetrating keratoplasty

Purpose: To evaluate the irregularity of the anterior and posterior cornea after Descemet stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PK). Methods: This clinical study comprised 39 eyes: 13 consecutive eyes after DSAEK, 13 consecutive eyes after PK, and 13 age-matched normal eyes. Corneal elevation data were acquired using a rotating Scheimpflug camera 1 and 3 months after DSAEK and PK. Anterior and posterior corneal elevation data were decomposed into a set of Zernike polynomials up to eighth order. Total higher-order root mean square (RMS) and RMS from third to eighth order were calculated. The astigmatism and irregularity of the anterior and posterior surfaces were compared between DSAEK and PK. Results: The regular astigmatism and tilt components of the anterior surface were significantly lower after DSAEK than after PK at 1 and 3 months (P < 0.001), whereas there was no difference in astigmatism of the posterior surface between the groups (P = 0.07, 0.22). The higher-order RMS and RMSs of third- to eighth-order components of the anterior surface were significantly larger after PK than those after DSAEK at 1 and 3 months (P < 0.01), whereas there were no significant differences between DSAEK and PK in higher-order aberration RMS and RMSs of third- to eighth-order components of the posterior surface. Conclusions: Postoperative corneal irregularity of the anterior surface was greater after PK than after DSAEK, whereas there was no significant difference in posterior surface irregularity. DSAEK is superior to PK in terms of the higher-order irregularity of the anterior surface.