PURPOSE To examine the impact of parental astigmatism on astigmatic error and ocular biometric parameters in children. DESIGN Population-based cross-sectional study. METHODS Six-year-old children (n = 1,741; 78.9% response) and 12-year-old children (n = 2,367; 75.3% response) underwent a comprehensive eye examination, including cycloplegic autorefraction and ocular biometry. Astigmatism was...

BACKGROUND A systematic method of performing radial keratotomy enhancements in undercorrected eyes may increase accuracy and predictability and decrease the number of procedures required. A consecutive series of 372 radial keratotomy procedures, including 110 eyes that received enhancements under a systematic protocol, was evaluated. METHODS Radial keratotomy was performed using the Reliable ...

PURPOSE The propagation of astigmatic wavefronts through astigmatic optical systems is reconsidered in the wavefront perspective. METHODS The stepalong method for vergences, described by 2x2 matrices, is applied and augmented to produce off-axis information like the magnification. This so-called augmented stepalong method (ASAM) is derived by applying the paraxial propagation of astigmatic wa...

We report 2 patients who had radial keratotomy (RK) to correct myopia. The first patient developed a postoperative hyperopic shift and cataract. Nine years post RK, she had intracapsular cataract extraction and implantation of an Artisan aphakic intraocular lens (IOL). Twenty years post RK, hyperopia and astigmatism progressed to +7.0 -5.75 x 100 with a best corrected visual acuity (BCVA) of 20...

There is a long history of corneal refractive surgery. Leonardo Da Vinci in 1508 said the theory of refractive errors. The first systematic analysis of the nature and results of refractive errors came from Francis Cornelius Donders. His classic treatise, “On the anomalies of accommodation and refraction of the eye”, outlined the fundamental principles of physiological optics. Ironically, in thi...

PURPOSE To compare postoperative astigmatic correction between femtosecond lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE) in eyes with myopic astigmatism. METHODS We examined 26 eyes of 26 patients undergoing FLEx and 26 eyes of 26 patients undergoing SMILE to correct myopic astigmatism (manifest astigmatism of 1 diopter (D) or more). Visual acuity, cylindrical re...

BACKGROUND The purpose of this study was to evaluate the American Society of Cataract and Refractive Surgery (ASCRS) intraocular lens (IOL) calculator for eyes with prior radial keratotomy and assess the accuracy of its methods in predicting IOL power in patients with previous radial keratotomy. METHODS This retrospective study included data from 15 eyes with previous radial keratotomy and su...

PURPOSE To assess quantitatively corneal irregular astigmatism in association with best spectacle-corrected visual acuity. METHODS Refractive powers on a mire ring measured with computerized videokeratography were decomposed, using the Fourier series harmonic analysis. Extracting spherical and regular astigmatic components, the remaining irregular astigmatic component was quantified on rings ...

OBJECTIVE To evaluate the aberration and visual quality differences between myopic and astigmatic eyes before and after contact lens application by using corneal aberrometer and low- contrast sensitivity chart. METHODS Eighty eyes of 40 patients were included in this study. Patients were divided into two groups as myopic (40 eyes, n=20) and astigmatic groups (40 eyes, n=20). We used aspheric ...