Corneal Biomechanical Characteristics After Penetrating Keratoplasty by Femtosecond Laser
Narrative Responses:
Purpose
To compare the biomechanical characteristics in corneas following penetrating keratoplasty (PKP) by femtosecond laser or a trephine blade, or Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK), with those of normal eyes.
Methods
This retrospective study involved 15 eyes that underwent zig-zag PKP by femtosecond laser (z-PKP group), 23 eyes that underwent PKP by trephine blade (t-PKP group), 19 eyes that underwent DSAEK (DSAEK group), and 27 normal eyes (Control group). Corneal hysteresis (CH), corneal resistance factor (CRF), and Keratoconus Match Index (KMI) were measured by use of an ocular response analyzer.
Results
Mean CH/CRF(mmHg), KMI in the z-PKP, t-PKP, DSAEK, and Control groups were 9.71±1.57/9.73±2.07, 0.74±0.25, 8.29±1.53/7.73±2.29, 0.43±0.38, 9.62±1.61/9.17±1.78, 0.77±0.28, and 10.70±1.43/9.90±1.58, 1.12±0.27, respectively. CH/CRF, KMI in the z-PKP group were significantly higher than in the t-PKP group (p<0.05), and those in the t-PKP group were significantly lower than in the Control group (p<0.001). No statistically significant differences of CH/CRF were found between the z-PKP, DSAEK, and Control groups. KMI in the Control group was significantly higher than that in the z-PKP and DSAEK groups (p<0.01), yet no statistically significant differences were found between the z-PKP and DSAEK groups.
Conclusion
The biomechanical characteristics in corneas following PKP by femtosecond laser may be more similar to those in normal eyes than in eyes undergoing PKP by trephine blade.