Abstract
Purpose: :
Lamellar techniques for selective replacement of diseased corneal structures are currently replacing penetrating keratoplasty (PK). Descemet membrane endothelial keratoplasty (DMEK) allows the sole replacement of the endothelium-Descemet membrane layer (EDM) while Descemet’s stripping (automated) endothelial keratoplasty (DSEK/DSAEK) requires transplantation of additional posterior stroma. In this retrospective analysis we compared higher-order aberrations (HOAs) of the cornea after the three different keratoplasty techniques.
Methods: :
30 patients who underwent DMEK with a standardized approach were analyzed by the Pentacam high resolution rotating Scheimpflug imaging system. Data were compared with 20 patients after penetrating keratoplasty (PK), 20 patients after DSAEK and 20 controls.
Results: :
Patients were examined 6.5 ± 1.2 months after DMEK, 22.6 ± 11.8 months after DSAEK and 103.1 ± 74.2 months after PK. In the central 4-mm zone of the posterior surface of DMEK corneas all aberrations except total HOA and Z62 showed no significant difference compared to the control group. In the 6-mm zone Z33 and Z44 also were significantly higher. However, compared to the DSAEK eyes, DMEK corneas showed significantly lower values for total HOA, Z31, Z42, Z51, Z53 and Z66 in the 4-mm zone and for total HOA, Z42, Z51, Z53, Z55 and Z66 in the 6-mm zone. DMEK compared with PK showed lower values for HOAs and all Zernike terms except for Z33, Z53 and Z55 in the posterior 4-mm zone and for Z33, Z42, Z53, Z55 and Z60 in the posterior 6-mm zone. The aberrations were not significantly related to the rate of rebubbling. BCVA after DMEK was significantly better than after DSAEK (p=0.001) and PK (p=0.005). There was no significant difference compared to controls (p=0.998).
Conclusions: :
Both DSAEK and PK exhibit an increase in HOAs even years after surgery. This observation likely reflects the quality of vision limits of these procedures. DMEK patients display only slight changes in HOAs, which probably explains the better functional results in the early postoperative course.
Keywords: cornea: clinical science • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • transplantation