To examine the long-term safety and efficacy of hyperopic automated lamellar keratoplasty (H-ALK) for correction of primary hyperopia and for consecutive hyperopia following overcorrected myopic refractive surgery.Methods
A prospective study was done on 67 eyes of 50 consecutive patients who underwent H-ALK between March 17, 1993, and August 18, 1995. Hyperopic automated lamellar keratoplasty was performed for primary hyperopia in 25 eyes (group 1) and for consecutive hyperopia after myopic refractive surgery in 42 eyes (group 2, radial keratotomy, 41 eyes, and myopic automated lamellar keratoplasty, 1 eye). The eyes were followed up for a mean +/- SD of 19.2 +/- 12.8 months (range, 3-49 months), 58 (87%) of them with 6 months' follow-up, and 45 (67%) of them with at least 1 year's follow-up. Twenty-one eyes were followed up for 2 to 4 years.Results
The overall mean +/- SD preoperative spherical equivalent was +2.87 +/- 1.28 diopters (D). The mean +/- SD postoperative spherical equivalent was -0.03 +/- 1.42 D at 3 months, -0.42 +/- 2.25 D at 6 months, -0.55 +/- 3.00 D at 1 year, -1.58 +/- 1.53 D at 2 years, and -0.35 +/- 1.79 D at the last follow-up. A mean myopic shift of 0.50 D was noted between 3 months and 1 year, and of 1.00 D between 1 and 2 years. Hyperopia was meaningfully reduced and visual acuity was improved by H-ALK, especially for patients with primary hyperopia. Long-term refractive instability, however, is a serious problem with this procedure. In this series, 11 (26%) of 42 eyes in which H-ALK was performed for consecutive hyperopia developed iatrogenic keratoconus.Conclusion
Based on this study, the long-term instability of H-ALK and the high incidence of iatrogenic keratoconus following the procedure should discourage its use, especially for consecutive hyperopia following radial keratotomy.