Excimer Laser Photorefractive Keratectomy: Two-year follow-up

ABSTRACT

Excimer laser photorefractive keratectomy(PRK) for myopia has been performed recently by refractive surgeons, in spite of myopic regression and corneal opacity following excimer PRK. We analyzed refractive change, corneal opacity, and uncorrected visual acuity of 313 eyes (233 patients) for one year and 115 eyes(83 patients) for two years after excimer PRK. The patients were divided tnto 3 groups accordign to theit refractive errors [group 1 (n=123 eyes) from -2.25D to -6D, group 2 (n=145 eyes) from -6.25D to -10D, and group 3 (n=45 eyes) less than -19.25D]. Mean refractive errors one year after excimer PRK were -0.31+/-0.57D, -0.54+/-0.90D, and -1.71+/-2.01D in group 1, 2, and 3, respectively. These errors were increased to -0.45+/-0.68D, -0.90+/-1.20D, and -3.37+/-3.20D two years after excimer PRK in group 1, group 2, and group 3, respectively. These changes were staistically significant in group 2 (p=0.000) and group 3 (p=0.015), not in group 1 (p=0.426). Corneal opacity was more severe in group 3 than in group 1 and 2 and decreased depending on time passing by. Diopteric error within +/-1.0D from the attempted correction one year after excimer PRK was found in 89% of group 1, 74% of group 2, and 40% of group 3. These percentages were after excimer PRK. Uncorrected visual acuity equal to or better than 0.5 were 95% in group 1, 87% in group 2, and only 44% in group 3 two years after excimer PRK. With these results we thought that excimer PRK was effective and safe for myopia more than -6D, while unpredictable for myopia less than6D.