PURPOSE Previous studies have shown that myopes produce an asymmetrical loss in contrast sensitivity with positive and negative defocusing lenses at low-medium spatial frequencies (1-7c/deg) compared to non-myopes. The measurement of contrast detection in noise allows any given loss in visual sensitivity to be attributed to two components namely sampling efficiency and/or equivalent noise. Prev...

PURPOSE Corneal collagen cross-linking (CXL) is a treatment strategy used in keratoconic eyes. Evaluation of long-term changes of higher-order aberrations (HOAs) after CXL is useful in understanding the efficacy of this procedure in improving optical, refractive, and visual acuity. This study aims to investigate the long-term effect of CXL on ocular HOA in patients with progressive keratoconus ...

PURPOSE To compare higher order aberrations (HOA) in AcrySof SN60AT and Acrysof IQ SN60WF intraocular lenses (IOLs) and natural crystalline lenses in an age-matched population. METHODS Sixty-nine eyes of 55 patients were examined. Group I included AcrySof spheric lenses, group II AcrySof aspheric lenses, and group III included patients with the natural crystalline lens. The HOA data were obta...

BACKGROUND The aim was to assess the agreement in the measurement of ocular aberrations between a new Adaptive Optics Vision Analyzer (AOVA, Voptica, Murcia, Spain) and a commercial aberrometer (KR-1 W, Topcon, Tokyo, Japan), both based on the Hartmann-Shack technique. METHODS One experienced examiner measured 29 healthy right eyes nine consecutive times with the two instruments. The individu...

PURPOSE To measure in vivo and objectively the monochromatic aberrations at different wavelengths, and the chromatic difference of focus between green and infrared wavelengths in eyes implanted with two models of intraocular lenses (IOL). METHODS EIGHTEEN EYES PARTICIPATED IN THIS STUDY: nine implanted with Tecnis ZB99 1-Piece acrylic IOL and nine implanted with AcrySof SN60WF IOL. A custom-d...

Purpose: To assess the accommodation response after short reading periods using a tablet and a smartphone as well as determine potential differences in the accommodation response at various stimulus vergences using a Hartmann- Shack aberrometer. Methods: Eighteen healthy subjects with astigmatism of less than 1 D, corrected visual acuity of 20/20 or better, and normal findings in an ophthalmi...

This study investigated the effect of lens induced defocus on the contrast sensitivity function in myopes and non-myopes. Contrast sensitivity for up to 20 spatial frequencies ranging from 1 to 20 c/deg was measured with vertical sine wave gratings under cycloplegia at different levels of positive and negative defocus in myopes and non-myopes. In non-myopes the reduction in contrast sensitivity...

We performed measurements of refraction (with retinoscopy), axial length (with ultrasound biometry) and ocular aberrations (with a custom-built Hartmann-Shack aberrometer) on seven awake White-Leghorn chicks occluded monolaterally with diffusers for two weeks. Treatment started on the first day after hatching (day 0) and measurements were conducted on several days between day 0 and 13. Non-occl...

OBJECTIVE To compare the mean root mean square (RMS) of total higher order aberrations (HOAs), coma and spherical aberrations in individuals with myopia, hypermetropia and myopic astigmatism. METHODS This prospective analytical study was conducted at Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan from Jan 2014 to Dec 2014. Two hundred eyes of 121 patients with age ranging from ...

PURPOSE This study aimed to assess the value of intraoperative aberrometry (IA) in determining the intraocular lens (IOL) sphere power in eyes with no previous ocular surgery. PATIENTS AND METHODS We conducted a retrospective review of patients who underwent uncomplicated cataract surgery where standard preoperative (Preop) measurements and IA were performed. Calculated IOL sphere powers and ...