Abstract
Purpose: :
Evaluate the results of different methodologies to correct high amounts of astigmatism after penetrating keratoplasty.
Methods: :
Patients with high astigmatism after penetrating keratoplasty were treated with astigmatic keratotomy, femtosecond flap(IntraLase) conventional or wavefront guided LASIK (VISX), or a toric intraocular lens (ReSTOR)The primary outcome measure was the change in pre-operative verses post-operative astigmatism. Simulated keratometry measurements were obtained from either the Pentacam (Oculus) or the Orbscan (Bausch & Lomb). Outcomes were stratified by modality of correction. Statistical comparisons were made using the paired t-test.
Results: :
A total of 14 eyes from 11 patients have been studied to date. Distribution of procedures was as follows: LASIK (n=2), AK alone (n=4), toric IOL alone (n=6), combined toric IOL and AK (n=2). Data are presented as mean ± standard deviation in units of diopters (D). The following analyses group the refractive procedures together. Prior to refractive correction the manifest cylinder was 4.6 ± 2.9 D. After refractive procedures the manifest cylinder was significantly less than baseline at month 1 (2.8 ± 3.1 D, p=0.013) and month 2 (2.9 ± 2.7 D, p=0.008). Simulated cylinder also showed a statistically significant decrease from baseline (5.7 ± 2.7 D) compared with post operative month 1 (1.8 ± 3.1, p=0.0003) and month 2 (1.4 ± 3.4, p=0.049). There are currently too few subjects to statistically compare between modalities.
Conclusions: :
Refractive procedures resulted in a significant decrease in cylinder (both manifest and simulated) at post-operative months 1 and 2. More data are required to make further conclusions or to compare individual procedures. These data are currently being collected. The results of this study have the potential to guide surgeon use of refractive procedures in the treatment of post-keratoplasty astigmatism.
Keywords: refractive surgery: comparative studies