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Persisting astigmatism following suture removal after penetrating keratoplasty in eyes with keratokonus and eyes with Fuchs dystrophyC. Althaus, J. Best, D. Pop
Introduction: Persisting corneal astigmatism after complete suture removal following penetrating keratoplasty (PK) in eyes with keratokonus (KK) and eyes with Fuchs dystrophy (FD) can prevent good visual function in eyes with a clear graft and an otherwise healthy visual system. We compared the outcome in these two different groups in regard to refractive and keratometric astigmatism, spherical equivalent and visual acuity.
Methods: 89 eyes with KK and 70 eyes with FD underwent PK at an average age of 38 and 67 years respectively. All surgeries were performed by 3 surgeons (CA, TR, RS). Graft size routinely was 7,7 mm and recipient bed size 7,5 mm. Trephination of the recipient eye was performed with a Franceschetti manual trephine. The graft was punched from the endothelial side on a silicone block. A double running crosstich suture technique with 10.0 nylon was used in all eyes with additional single sutures when needed.
Results: After complete suture removal the mean refractive astigmatism did not differ significantly (Wilcoxon signed-rank test) between the KK and FD group (4,1±2,4 D vs. 4,2±2,5 D; p=0.885). The difference in mean keratometric astigmatism nearly reached statistical significance (KK 5,0±2,9 D vs. FD 5,6±3,4 D; p=0,057). Mean spherical equivalent was significantly less myopic in the FD group (FD 0,3±3,2 D vs. KK -2,2±3,4 D; p=0,0001). Mean visual acuity was significantly higher in the KK group (KK 0,8±0,3 vs. FD 0,6±0,25; p=0,001). There were no differences in regard to the outcome parameters between the 3 surgeons.
Conclusions: Although it would have been expected that eyes with KK show a higher persisting astigmatism after complete suture removal due to a higher instability of the recipient cornea, our results unexpectedly show a tendency towards higher astigmatism in eyes with FD after PK.
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