Hypermetropic LASIK induced corneal wave front changes

ABSTRACT

As an object approaches the eye, the eye has to increase its power to keep the image focused on the retina. If the eye is short or the lens not round enough as in hypermetropia, the image is defocused. The aim of the study was to report the visual outcome and keratometric values of the higher order aberrations after hypermetropic correction with LASIK. A retrospective patient chart review study of 60 eyes of 30 patients. Prospective and postoperative analysis of the wavefront scans of the patients, utilizing zernike's polynomials was done and calculations of the RMS of the anterior higher order aberrations recorded. There were 60 eyes of 30 patients. 28 females [46.7%] and 32 males [53.3%]. 32 [53.3%] right eyes and 28 [46.7%] left eyes. Mean patient age was 36.46+13.99 years [range 16 to 54 years]. Mean sphere was+3.30+1.55D range+1.0 to+5.50D]. Mean cylinder was-1 .31+1.45 D [range-4.75 to+0.5D]. Spherical aberration preoperatively was 0.29 [+0.05] and postoperatively-0.02 [+0.24] and a mean difference of 0.23 and p value of 0.01. Coma aberration preoperatively was 0.29 [+0.10] and postoperatively 0.44 [+0.32] and a mean difference of-0.15 and p value of 0.86. RMS of higher order aberrations preoperatively was 0.43 [+0.10] and postoperatively 0.66 [+0.29] and a mean difference of-0.22 and p value of 0.05. LASIK for correction of hypermetropia and hypermetropic astigmatism causes increasing in all corneal higher order aberrations which is directly proportional to the refractive error