Corneal higher order aberrations changes after lasik for correction of hypermetropia and mixed astigmatism

ABSTRACT

Hypermetropia is a defect of vision caused by an imperfection in the eye [often when the eyeball is too short or when the lens cannot become round enough], causing difficulty focusing on near objects. As an object moves toward the eye, the eye must increase its power to keep the image in focus on the retina. If the power of the cornea and lens is insufficient, as in hyperopia, the image will appear blurred. to report the visual outcome and keratometric values, in addition to the corneal higher order aberration after laser instu keratomillusis for the correction of hypermetropia and mixed astigmatism. This prospective observational comparative study comprised 60 eyes of 30 individuals. Wavefront analysis for each cornea was performed; Root Mean Square [RMS] of anterior corneal higher order aberrations and separate types of corneal higher order aberrations using Zernike Polynomials were analyzed for all patients pre and postoperatively. 60 eyes of 30 individuals [28 [46.7%] women and 32 [33.3%] men]. 32 [53.3%] right eyes and 28 [46.7%] were left eyes. Mean patient age was 36.46+ 13.99 years [range 16 to 54 years]. Mean sphere was+3.30+ 1.55 D [range+1.0 to+5.5 D] Mean cylinder was-1.31+ 1.45 D [range-4.75 to+0.5 D]. Spherical aberration [SA] preoperatively was 0.21 [+ .05] and postoperatively-0.02 [+ .24] and a mean difference of 0.23 and p value of 0.01. Coma aberration preoperatively was 0.29 [+ .10] and postoperatively 0.44 [+ .32] and a mean difference of-0.15 and p value of 0.86. While Root Mean Square [RMS] of higher order aberrations [HOA] preoperatively was 0.43 [+.10] and postoperatively-0.66 [+ .29] with a mean difference of 0.22 and p value of 0.05. Conventional LASIK increases all corneal higher order aberrations with induced aberrations increasing with the magnitude of refractive correction