Detection and resolution acuity was measured at 30 degrees in the periphery for sinusoidal gratings under differing amounts of optical defocus. Within the range -2.0 to +2.5 diopters defocus, detection acuity was higher than resolution acuity. As defocus increased, detection acuity decreased continuously but resolution acuity was little affected until around 2.0 diopters defocus. The results in...

Many people coming to eye clinics have refractive errors and can have their vision improved by spectacles (glasses). Most of these can be tested by general eye health workers without special training and using only a trial set of lenses. It is also useful to find out quickly which people do not have refractive errors and do not need glasses. Most errors can be corrected satisfactorily with sphe...

The distribution of refractive errors was followed in chicks from hatching to 8 weeks of age. A dramatic progressive decrease in the variability of refractions was observed over this period. In addition, there appeared to be a parallel decline in hyperopia, even when the artifactual hyperopia of retinoscopy was taken into account. These results are evidence for a postnatal development regulator...

Distance and size estimates and stereoacuity judgments were made in water by divers, both with and without facemasks. Without the mask, only stereoacuity was markedly degraded. Distance estimates were slightly more accurate, despite a great decrease in the range of visibility. Size estimates were slightly too small. Divers with refractive errors did not appear to be more handicapped than those ...

We investigated differences in higher order monochromatic aberrations between hyperopic and emmetropic eyes from two large cohorts (mostly 6 and 12 year old) of Caucasian children. Additionally, we investigated the differences of higher order monochromatic aberrations between age groups. In both cohorts, hyperopic eyes had significantly higher levels of positive spherical aberration (SA) and hi...

PURPOSE To report normal interpupillary distance (IPD) values in different age groups of an Iranian population. METHODS This study was performed on 1,500 randomly selected subjects from 3,260 consecutive out-patients with refractive errors referred to Farabi Eye Hospital, Isfahan, Iran over a period of two years (2008 to 2010). Measurement of refractive errors and IPD for far distance were pe...

PURPOSE Axial length has been shown to explain up to 50% of the total variance in refraction, with axial length and refraction having a major genetic component. However, no study has attempted to determine whether the correlation between axial length and refraction is explained by shared genetic or environmental factors. METHODS All twins from Victoria aged 18 years or older were invited to p...

INTRODUCTION The uncorrected refractive error is an important cause of childhood blindness and visual impairment. OBJECTIVE To study the patterns of refractive errors among the urban and rural school going children of Nepal. SUBJECTS AND METHODS A total of 440 school children of urban and rural schools within the age range of 7-15 years were selected for this study using multi-stage randomi...

introduction: today, lasik surgery is one of the most common and effective procedures for correction of refractive errors. less than 1% of patients undergoing lasik operation suffer from serious and 3-5% suffers from mild complications. also, results of lasik in most centers are promising. with the recent inauguration of the lasik center of yazd, it was decided to evaluate the results and compl...

Visual optics is taking on new clinical significance. Given that current refractive procedures can and do induce large amounts of higher order ocular aberration that often affects the patient's daily visual function and quality of life, we can no longer relegate the considerations of ocular aberrations to academic discussions. Instead, we need to move toward minimizing (not increasing) the eye'...