Surface ablation after laser in situ keratomileusis: Retreatment on the flap
Accepted 19 April 2007.
Purpose
To evaluate the safety and efficacy of superficial laser ablation on the flap as a treatment for residual ametropia after laser in situ keratomileusis (LASIK).
Setting
Private practice refractive surgery center, Utrecht, The Netherlands.
Methods
This retrospective study comprised 18 eyes of 15 patients who had alcohol-assisted photorefractive keratectomy (PRK) or laser-assisted subepithelial keratectomy (LASEK) retreatment for residual ametropia after LASIK. All patients who had retreatment on the flap between June 2004 and June 2005 were included in the study. Retreatments were performed by wavefront-guided excimer laser surface ablation using the Visx Star S4 laser. Outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), subjective refraction, and biomicroscopy at the 3-, 6-, and 12-month postoperative visits.
Results
The preoperative spherical equivalent (SE) refraction was −0.63 diopter (D) ± 0.87 (SD) (range −2.00 to +1.38 D). The mean amount of ablated cornea was 21.3 ± 7.4 μm. At 3 months, the mean UCVA was 0.83 ± 1.5 lines (range 0.40 to 1.25), yielding an efficacy index of 0.87. At 6 months, the mean UCVA increased to 0.98 ± 0.8 line (range 0.63 to 1.25) and the efficacy index, to 1.03. At 12 months, 6 eyes were lost to follow-up. The mean UCVA was 0.83 ± 2.2 lines (range 0.20 to 1.25), with an efficacy index of 0.87. The mean BSCVA was 0.98 ± 0.9 line (range 0.80 to 1.25) at 3 months and 1.05 ± 0.6 line (range 0.80 to 1.25) at 6 months, yielding a safety index of 1.03 and 1.11, respectively. At 12 months, the mean BSCVA was 0.95 ± 1.0 line (range 0.63 to 1.25), with a safety index of 1.0. At 6 months, no eye had lost lines of BSCVA, 11 eyes had no change, and 7 eyes gained 1 line. At 12 months, 2 eyes lost 1 line of BSCVA, 8 eyes had no change, and 2 eyes gained 1 line. The mean SE refraction was +0.10 ± 0.27 D (range −0.25 to +0.63 D) at 3 months, +0.06 ± 0.37 D (range −0.50 to +1.13 D) at 6 months, and +0.15 ± 0.39 D (range −0.50 to +0.88 D) at 12 months. On biomicroscopic examination, 1 eye had prolonged grade 1 haze that disappeared before 6 months. Two eyes of 1 patient who had hyperopic retreatment developed late-onset haze 8 months postoperatively. Eyes with microstriae in the flap before retreatment showed significant improvement after retreatment. There were no sight-threatening complications.
Conclusion
Wavefront-guided LASEK or alcohol-assisted PRK retreatment on the surface of a LASIK flap was safe and effective in correcting small amounts of residual myopia.
From Eyescan Laser Clinic, Utrecht, The Netherlands
Corresponding author: Jeroen J.G. Beerthuizen, MD, FEBOphth, Department of Ophthalmology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
Neither author has a financial or proprietary interest in any material or method mentioned.
Presented in part at the Annual Congress of the Dutch Ophthalmological Society, Groningen, The Netherlands, March 2006.
ABSTRACT