Initial results of automated lamellar keratoplasty for correction of myopia: one year follow-up.

PURPOSE

To report our initial results with automated lamellar keratoplasty (ALK) to correct myopia and to evaluate the short-term efficacy, safety, and predictability of this procedure.

METHODS

A prospective series of 128 eyes of 81 consecutive patients who had ALK were reviewed for a mean follow-up of 13.6 months (range 12 to 19 months). Preoperative data, intraoperative parameters, and postoperative visual acuity, refraction, keratometric readings, and complications at 1 day, 1 week, 1, 3, and 6 months, 1 year, and last follow-up visit were used for analysis. The procedure was performed for myopia in 120 eyes (-4.50 to -13.25 diopters [D]) and for residual myopia following radial keratotomy (RK) in eight eyes (-1.75 D to -3.75 D). A hinged-flap technique was used in 17 cases (13%) once this method was introduced.

RESULTS

Preoperative mean uncorrected visual acuity was 0.04 +/- 0.05 (20/500). Postoperatively (12 to 19 months), overall uncorrected visual acuity was 20/40 or better in 86.4% of eyes with a mean uncorrected acuity of 0.68 +/- 0.22 (20/30) 76.2% of eyes were within 1.00 D of emmetropia and 93.6%, within 2.00 D. After the initial ALK procedure, 77% of eyes had RK or astigmatic keratotomy (AK). Among the 29 eyes with ALK alone, 86% had 20/40 or better uncorrected visual acuity, with mean uncorrected acuity and mean corrected acuity of 0.69 +/- 0.21 (20/30) and 0.95 +/- 0.10 (20/21), respectively; 72% of eyes were within 1.00 D of emmetropia and 90%, within 2.00 D. In 4%, astigmatism increased more than 1.00 D from the preoperative value and 4% of eyes (5/128) had persistent irregular astigmatism. Four percent of eyes (5/128) had overcorrection, with a final spherical equivalent greater than +1.00 D. Epithelial growth in the interface requiring surgical removal occurred in 2% of cases. One eye with residual myopia from a previous RK lost the cap after ALK. A homologous donor graft was performed, which resulted in 20/30 uncorrected visual acuity. Best corrected visual acuity of two lines or more was lost in 6.3% of eyes (8/128). This was caused by irregular astigmatism in 63% of cases.

CONCLUSIONS

The results of our initial experience indicate that ALK is a reasonably safe, effective, and predictable procedure for correction of high myopia and myopia following previous RK. With additional enhancement with RK/AK, good visual and refractive outcome can be expected.