Visual Acuity Outcomes in Diseases Associated with Reduced Visual Acuity: An Analysis of the National Health Insurance Service Database in Korea.

Visual acuity declines with age, and disease-related visual acuity changes vary. We evaluated factors affecting visual acuity and age-related visual acuity in diseases associated with reduced visual acuity such as hypertension, diabetes mellitus (DM), glaucoma, and diabetic retinopathy (DR). The Korean National Health Insurance Service 2015-2016 data were analyzed for age-related visual acuity changes and prevalence of diseases associated with reduced visual acuity.

Changes in Postural Control Ability after Wearing Corrective Glasses for Distance in Older Adults and Their Causes.

Deterioration of postural control in older adults is unavoidable due to age-associated degeneration of the visual system. Our study objective was therefore to verify whether there is a positive effect on postural control ability after providing older adults, whose postural control function had deteriorated, with corrective glasses to correct refractive errors. Twenty-seven participants, 66 to 90 years of age, were included in this study.

Comparison of image-based quantification methods in evaluating fixation stability using a remote eye tracker in abnormal phoria.

Objective: This study was performed to establish a quantitative evaluation and comparison of fixation stability, as measured by an eye tracker, using image-based areas determined by the bivariate contour ellipse area (BCEA), kernel density estimation (KDE), and Scanpath methods.

Methods: This prospective cross-sectional study included 45 and 20 participants with abnormal and normal phoria, respectively. Eye movements were recorded using a remote eye tracker and were plotted using RStudio software.

Quantitative Evaluation of the Association Between Fixation Stability and Phoria During Short-Term Binocular Viewing.

Purpose: Fixation stability for binocular anomalies with a phoria cannot be detected by direct observations. This study aimed to quantitatively evaluate fixation stability using an eye tracker rather than direct directions in binocular vision with abnormal and normal phorias.

Methods: Thirty-five and 25 participants with abnormal and normal phoria, respectively, were included in the study.

The effect of uncorrected ametropia on ocular torsion induced by changes in fixation.

Background And Objective: Ocular torsion, the eye movements to rotating around the line of sight, has not been well investigated regarding the influence of refractive errors. The purpose of this study was to investigate the effect of uncorrected ametropia on ocular torsion induced by fixation distances.

Methods: Seventy-two subjects were classified according to the type of their refractive error, and ocular torsion of the uncorrected eye was compared based on changes induced by different fixation distances.

Measurement of ocular counter-roll using iris images during binocular fixation and head tilt.

Objective: To compare the ocular counter-roll (OCR) measured using iris images during binocular fixation and head tilt with OCR measured via fundus photography.

Methods: Fifty-three healthy college students participated in this study. The mean OCR was measured by collection of iris images and fundus images under seven head tilt conditions (0 degrees; 10, 20, and 30 degrees right; and 10, 20, and 30 degrees left).

Effect of optical correction by fully corrected glasses on postural stability.

Although various previous studies have reported that the experimentally induced refractive errors interfered with postural control, few studies have demonstrated the optical correction effect of wearing glasses. The purpose of this study was to investigate whether wearing full corrected glasses to correct myopia and hyperopia can have a positive effect on postural stability. To this end, a total of 34 subjects (19 males and 15 females) of an average age of 22.

Differences in the optical properties of photochromic lenses between cold and warm temperatures.

The aim of our study was to quantitatively evaluate the optical properties of photochromic lenses available on the market under cold and warm temperatures corresponding to the winter and summer seasons. The transmittance of 12 photochromic lenses from five manufacturers was measured using an UV/VIS spectrophotometer at cold (6 ± 2°C) and at warm (21 ± 2°C) temperatures. Transmittances were recorded from 380 to 780 nm and at the wavelength with maximum absorbance, which was calculated from the transmittance.

Fusional Single Vision with Prism-induced Vergence Has More Influence than Diplopia on Postural Stability.

Significance: Prism-induced convergence and vertical vergence for maintaining binocular fusion induced postural instability to a greater extent than diplopic conditions. This finding has important implication in relation to postural control of patients with large exophoria or vertical phoria in optometric clinic.

Purpose: The purpose of this study was to examine whether binocular single vision with prism-induced horizontal and vertical vergence and diplopia might affect the static postural stability.

Receiver operating characteristic curve analysis of clinical signs for screening of convergence insufficiency in young adults.

Convergence insufficiency (CI) is a dysfunction of binocular vision that is associated with various signs and symptoms in near work. However, CI screening is performed less frequently in adults than in children. We aimed to evaluate the ability of screening tests to discriminate CI from other binocular vision anomalies and normal binocular vision in young adults.

Effect of induced hyperopia on fall risk and Fourier transformation of postural sway.

Background And Purpose: Fall accidents are a social challenge in Korea and elsewhere. Most previous studies have focused on the effects of reduced visual acuity due to myopia on falls and body balance. The objective of this study was to investigate whether uncorrected hyperopia was a major risk factor for falls and to establish whether the risk of falls was absolutely correlated with visual acuity.

Diurnal variations of amplitude of accommodation in different age groups.

Clinical assessment of amplitude of accommodation (AA) involves measuring the ability of the eye to change its optical power and focus on near tasks/objects. AA gradually decreases with increasing age. However, details of age-related diurnal changes in AA are not well known.

Uncorrected low hyperopia in young subjects induces postural instability even in those with clear visual acuity.

Reports have indicated the effect of myopic blur on postural stability. The objective of this study was to investigate the minimum refractive error to significantly affect postural stability through a various levels of hyperopia and myopia induced by ophthalmic lenses. Forty subjects with a mean age of 22.

Effects of prolonged continuous computer gaming on physical and ocular symptoms and binocular vision functions in young healthy individuals.

Background And Objective: Addiction to computer gaming has become a social problem in Korea and elsewhere, and it has been enlisted as a mental health disorder by the World Health Organization. Most studies related to computer use and vision have individually assessed physical and ocular symptoms and binocular vision. Accordingly, the present study comprehensively assessed subjective physical and ocular symptoms and functions related to binocular vision after prolonged continuous computer gaming.

Comparison of predicted and measured axial length for ophthalmic lens design.

Ocular parameters have been applied to ophthalmic lens designs in order to satisfy individual wearers. An axial length (AL) of them can be used in individual ophthalmic lens designs. Our aim was to propose a reliable formula that predicts an individual's AL using the corneal radius and refractive error, and to demonstrate the applicability of this formula.

Comparison of presbyopic additions determined by the fused cross-cylinder method using alternative target background colours.

Purpose: To compare and contrast standard and alternative versions of refractor head (phoropter)-based charts used to determine reading addition.

Methods: Forty one presbyopic subjects aged between 42 and 60 years were tested. Tentative additions were determined using a red-green background letter chart, and 4 cross-grid charts (with white, red, green, or red-green backgrounds) which were used with the fused cross cylinder (FCC) method.