A common concern among people considering laser eye surgery is whether the procedure is safe and effective — both immediately and years after surgery.
Researchers in Spain recently conducted a 10-year follow-up study of patients who underwent either PRK or LASIK for the correction of -6.00 to -10.00 diopters (D) of nearsightedness.
All procedures were performed with a VISX 20/20 excimer laser at a single surgical center between April 1992 and December 1995.
The study evaluated 34 eyes of 33 patents treated with PRK and 34 eyes of 32 patients treated with LASIK. The two groups were matched for patient age and degree of nearsightedness and astigmatism.
All patients in the study returned to the center for follow-up visits at 3 months, 1 year, 2 years, 5 years and 10 years after surgery for an evaluation their vision and any PRK or LASIK complications.
At 10 years after surgery, the study data revealed:
- 71 percent of the PRK-treated eyes and 88 percent of the LASIK-treated eyes were within 1.00 D of the intended correction.
- Re-treatments were performed on 35 percent of the PRK-treated eyes and 18 percent of the LASIK-treated eyes to achieve satisfactory visual acuity.
- 62 percent of the PRK-treated eyes and 50 percent of the LASIK-treated eyes demonstrated an increase in best spectacle-corrected visual acuity (BSCVA), compared with BSCVA prior to surgery.
- No eye in either group lost more than two lines of BSCVA after surgery.
The most common complication among PRK-treated eyes was mild corneal haze, which was present in one (2.9 percent) of the 34 treated eyes at the end of the study.
The most common complications among LASIK-treated eyes were fine wrinkles (striae) in the corneal flap (2.9 percent) and necrosis or “melting” of the corneal flap edge (2.9 percent). Neither of these problems affected visual acuity at the end of the study.
No eye in either group showed clinical signs of corneal ectasia over the 10-year period of the study.
The researchers concluded that both PRK and LASIK were safe for the correction of -6.00 to -10.00 D of myopia in this group of patients. LASIK demonstrated slightly better predictability and a lower rate of re-treatment than PRK.
They also said that technical improvements in both PRK and LASIK should be taken into account when comparing the results of this study with results of other studies evaluating laser vision correction performed more recently.
Source: Ten years after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for moderate to high myopia (control-matched study). British Journal of Ophthalmology. October 2009.
Tags: myopia