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Excimer laser correction of high astigmatism after keratoplasty
M Amm1, G I Duncker, E Schröder
1Kiel University Eye Hospital, Germany.
Purpose:
To assess the effectiveness of excimer laser correction of high astigmatism after keratoplasty.
Setting:
Kiel University Eye Hospital, Kiel, Germany.
Methods:
In a prospective study, we treated high astigmatism in 16 patients using a 193 nm excimer laser with a rotating mask system to make a toric ablation. Thirteen patients had postkeratoplasty astigmatism, 3, idiopathic natural astigmatism. Preoperative refractive cylinder ranged from 3.0 to 9.0 diopters (D). Minimum follow-up was 6 months.
Results:
Mean uncorrected visual acuity increased by 3.3 lines in 13 patients. Best corrected visual acuity decreased by no more than two lines in 6 patients and improved by at least one line in 6 patients. Mean cylindrical reduction was 2.8 D. Haze was classified from 0.5 to 2.0.
Conclusions:
In this study, the excimer laser technique effectively reduced high corneal astigmatism. The main problems incurred were development of a hyperopic shift and, in some patients, an uncertain refractive outcome. Reasons for inadequate correction of postkeratoplasty astigmatism included a slightly decentered mask and irregular astigmatism from the circular scar.