[Comparative study of multifocal LASIK for the correction of pre-presbyopic myopia].

OBJECTIVE

To evaluate the feasibility of multifocal LASIK for the correction of pre-presbyopic myopia

METHODS

In this prospective,comparative case series, thirty-two patients were recruited into the study,mean age was (38.5 +/- 2.7) years, standard LASIK using Planoscan was performed on the patient's dominant eye, while multifocal LASIK was performed on the nondominant eye. Routine examinations included distance and near vision, refraction, corneal topography, intraocular pressure, ultrasonic corneal pachymetry, contrast sensitivity function, amplitude of accommodation ,depth of defocus, wavefront aberration.

RESULTS

The mean follow-up duration was 6.67 +/- 2.75 (range, 6 to 11 months). In the nondominant eyes,the near visual acuity was statistically significant difference, better in the postoperative visual acuity, however, there was no statistically significant difference between preoperation and postoperation in dominant eyes. The Q value of 6 mm diameter in the nondominant eyes was 0.081 +/- 0.274 (range, -0.53 to +0.53) and 0.464 +/- 0.266 (range, - 0.02 to +0.99) in the dominant eyes, significant difference were noted between two groups. Topography revealed high degree refractive power zone of (5.64 +/- 3.05) mm2 at central cornea in nondominant eyes. The wavefront analysis showed that after the multifocal procedure, a positive spherical aberration was induced ,which is opposite to that normally seen following a standard LASIK treatment for myopia. At 6 months, the nondominant eyes attained pseudoaccommodation of (0.84 +/- 0.61) diopters (range, 0 to 2.25 D), the amplitude of pseudoaccommodation are related to corneal multifocal index, spherical aberration. However, amplitude of accommodation was decreased (0. 10 +/- 0.67) diopters in dominant eyes at 6 months visit.

CONCLUSIONS

The results of this study show that multifocal LASIK is safe and effective in preserving near vision for pre-presbyopic myopia patients . Multifocal LASIK are reasonably to induce pseudoaccommodation by decreasing negative spheric aberration.