Peripheral Refraction After LASIK for the Treatment of Myopia
Purpose
To evaluate the relation between peripheral refraction and the change of axial length after laser-assisted in situ keratomileusis (LASIK) for the treatment of myopia.
Methods
We retrospectively examined 20 eyes of 10 patients(mean age: 32.0±4.1 years) with mean myopic refractive errors of -5.52±2.08 diopters(D) who underwent LASIK at the Baptist Eye Clinic, Kyoto, Japan. In all patients, central and peripheral refractions were measured by use of an open field auto-refractor along the horizontal meridian up to 30°of the eccentricity in the nasal and temporal retinal areas in 10°visual fieldsteps at 5-years post LASIK. Forperipheral refractions,we used the relativeperipheral refraction which was defined as the difference between the axial refraction(at a 0°angle) and each peripheral refraction.Theaxial lengthswere measured by IOL Master preoperatively and at 1, 2, 3, 4, and 5 years postoperatively. Spearman correlation analysis was used to assess betweenthe relative peripheral refractionat 5-years postoperative andthe change of axial length from 1 to 5-years postoperative.
Results
The mean relative peripheral refraction(OD: -30°, OS: 30°, both in the nasal area of the retina) at 5-years postoperative was -2.23±1.59D. The mean axial length before surgery was 25.69±0.97mm and the change of axial length from 1 to 5-years postoperative was 0.04±0.06mm. The change of axial length was correlated with the relative peripheral refraction (r=0.53, p<0.01). The mean myopic regression from 1 to 5- years postoperative was -0.04±0.25D.
Conclusion
Our findings indicate that LASIK might play a role in preventing the elongation of axial length due to the creation of myopic defocus in the peripheral retina.