Optical phase nullification partially restores visual and stereo acuity lost to simulated blur from higher-order wavefront aberrations of keratoconic eyes.

Contrast demodulation and phase distortions are exaggerated in retinal images blurred by the higher-order wavefront aberrations of keratoconic eyes. While the performance loss from the former parameter is well understood, little is known about the impact of the latter on visual functions in this disease condition. The present study investigated the impact of phase distortions on the monocular logMAR visual acuity, letter discriminability and random-dot stereoacuity of seventeen visually healthy adults (ten for visual acuity and letter discriminability; ten for stereoacuity and three common to both experiments) using images that were computationally blurred by four different higher-order wavefront aberration profiles of keratoconic eyes that showed significant distortions in the phase spectrum.

Efficacy of coloured lenses for patients diagnosed with visual stress.

Clinical Relevance: Colour overlays and lenses are used to relieve symptoms in some patients diagnosed with visual stress, but evidence to support this practice is lacking. In this small randomised crossover trial, a range of colours are beneficial and precise colour specification does not enhance this effect.

Background: This randomised, double-masked crossover trial aimed to test effectiveness of precisely selected lens tints for visual stress.

Prevalence of presenting bilateral visual impairment associated with refractive error - findings from the See4School, pre-school vision screening programme in NHS Scotland.

Background/objectives: The See4School programme in Scotland is a pre-school vision screening initiative delivered by orthoptists on a national scale. The primary objective of any vision screening programme is to identify amblyopia, given the common understanding that this condition is unlikely to be detected either at home or through conventional healthcare channels. The target condition is not bilateral visual impairment, as it is believed that most children will be identified within the first year of life either through observations at home or as part of the diagnosis of another related disorder.

Deficits in Reach Planning and On-Line Grasp Control in Adults With Amblyopia.

Purpose: Adults with amblyopia exhibit impairments when reaching to grasp three-dimensional objects. We examined whether their deficits derive from problems with feedforward planning of these prehension movements or in using visual feedback to control them on-line.

Methods: Twenty-one adults with mild to severe anisometropic and/or strabismic amblyopia and reduced binocularity participated, along with 21 normally sighted age- and gender-matched controls.

An investigation of barriers and enablers to community eye care for children in England: A qualitative descriptive study.

Purpose: Research suggests that there are challenges in the accessibility of eye care for children in England. This study explores the barriers and enablers to eye examinations for children under 5 years of age from the perspective of community optometrists in England.

Methods: Optometrists working in community settings were invited to participate in virtual focus group discussions using an online platform based on a topic guide.

Interocular Contrast Balancing Partially Improves Stereoacuity in Keratoconus.

Significance: Partial improvement in stereoacuity may be achieved by balancing the contrast input to the two eyes of patients with bilaterally asymmetric keratoconus.

Purpose: Interocular differences in image quality, characterized by dissimilar contrast loss and phase shifts, are implicated in stereoacuity loss in keratoconus. This study determined whether contrast balancing improves stereoacuity in this disease condition and, if so, whether it is dependent on the baseline interocular contrast imbalance.

Refractive prescribing for preschool children by optometrists in England.

Purpose: Correction of refractive error in children is important for visual and educational development. The aim of this questionnaire-based study was to explore paediatric refractive correction by optometrists in England.

Methods: An online questionnaire was piloted and distributed to optometrists in England.

Systematic review and meta-analysis on the agreement of non-cycloplegic and cycloplegic refraction in children.

Objective: To determine the diagnostic agreement of non-cycloplegic and cycloplegic refraction in children.

Method: The study methodology followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases were searched for comparative studies exploring refraction performed on children under non-cycloplegic and cycloplegic conditions.

Contrast Rivalry Paradigm Reveals Suppression of Monocular Input in Keratoconus.

Purpose: Keratoconus results in image quality loss in one or both eyes due to increased corneal distortion. This study quantified the depth of monocular suppression in keratoconus due to this image quality loss using a binocular contrast rivalry paradigm.

Methods: Contrast rivalry was induced in 50 keratoconic cases (11-31 years) and 12 age-matched controls by dichoptically viewing orthogonal Gabor patches of 5 cycles per degree (cpd) and 1.

Some binocular advantages for planning reach, but not grasp, components of prehension.

Proficient (fast, accurate, precise) hand actions for reaching-to-grasp 3D objects are known to benefit significantly from the use of binocular vision compared to one eye alone. We examined whether these binocular advantages derive from increased reliability in encoding the goal object's properties for feedforward planning of prehension movements or from enhanced feedback mediating their online control. Adult participants reached for, precision grasped and lifted cylindrical table-top objects (two sizes, 2 distances) using binocular vision or only their dominant/sighting eye or their non-dominant eye to program and fully execute their movements or using each of the three viewing conditions only to plan their reach-to-grasp during a 1 s preview, with vision occluded just before movement onset.

Eye care in young children: a parent survey exploring access and barriers.

Background: A questionnaire was designed to investigate the attitudes of parents toward eye care for their young children (4-6-year-olds) and possible barriers to accessing eye care for this age group. An exploration was undertaken to determine whether these beliefs and barriers are influenced by certain demographic factors such as ethnicity, level of parental income, level of parental education, confidence with speaking English and a reported family history of eye problems.

Methods: A total of 1,317 questionnaires (hard copies) were distributed to parents of children in primary school reception and year one classes (ages four to six) from 14 schools across five London boroughs.

Efficacy of coloured overlays and lenses for treating reading difficulty: an overview of systematic reviews.

Coloured overlays or lenses are widely available for use by children and adults with difficulties or discomfort while reading. In recent years, systematic reviews have been conducted in an attempt to establish the strength of the evidence base for this intervention. The aim of this overview is to systematically review these reviews.

Coloured overlays and precision-tinted lenses: poor repeatability in a sample of adults and children diagnosed with visual stress.

Purpose: Visual stress consists of perceived distortions or discomfort while reading. It is claimed that these symptoms are alleviated by viewing through coloured lenses or overlays, with a specific colour required for each individual. This has been explained on the basis of altered visual cortex excitation as affected by the spectral content of the viewing light.

Does Gender Influence Colour Choice in the Treatment of Visual Stress?

Purpose: Visual Stress (VS) is a condition in which words appear blurred, in motion, or otherwise distorted when reading. Some people diagnosed with VS find that viewing black text on white paper through coloured overlays or precision tinted lenses (PTLs) reduces symptoms attributed to VS. The aim of the present study is to determine whether the choice of colour of overlays or PTLs is influenced by a patient's gender.

Does the Swedish Interactive Threshold Algorithm (SITA) accurately map visual field loss attributed to vigabatrin?

Background: Vigabatrin (VGB) is an anti-epileptic medication which has been linked to peripheral constriction of the visual field. Documenting the natural history associated with continued VGB exposure is important when making decisions about the risk and benefits associated with the treatment. Due to its speed the Swedish Interactive Threshold Algorithm (SITA) has become the algorithm of choice when carrying out Full Threshold automated static perimetry.

Reach-to-precision grasp deficits in amblyopia: Effects of object contrast and low visibility.

Adults with a history of unilateral amblyopia and abnormal binocularity have a range of visual deficits, with some of the 'higher' levels ones generalizing to their dominant (non-amblyopic) eye and linked to widespread binocular cortical network dysfunctions. Our interests are in how these problems also impact on their hand action control in real-world situations. We investigated whether eye-hand coordination deficits, known to exist in amblyopia when goal objects are presented under full-lighting and at high contrast, are exacerbated under low object-background contrast or in dim lighting/low visibility conditions.

Age- and stereovision-dependent eye-hand coordination deficits in children with amblyopia and abnormal binocularity.

Purpose: To examine factors contributing to eye-hand coordination deficits in children with amblyopia and impaired stereovision.

Methods: Participants were 55 anisometropic or strabismic children aged 5.0 to 9.

Micro-costing the provision of emotional support and information in UK eye clinics.

Background: Sight loss has wide ranging implications for an individual in terms of education, employment, mobility and mental health. Therefore there is a need for information and support to be provided in eye clinics at the point of diagnosis of sight threatening conditions, but these aspects of care are often missing from clinics. To meet these needs, some clinics employ an Eye Clinic Liaison Officer (ECLO) but the position has yet to be widely implemented.

Is the aligning prism measured with the Mallett unit correlated with fusional vergence reserves?

Background: The Mallett Unit is a clinical test designed to detect the fixation disparity that is most likely to occur in the presence of a decompensated heterophoria. It measures the associated phoria, which is the "aligning prism" needed to nullify the subjective disparity. The technique has gained widespread acceptance within professions such as optometry, for investigating suspected cases of decompensating heterophoria; it is, however, rarely used by orthoptists and ophthalmologists.

Ocular blood-flow hemodynamics before and after application of a laser in situ keratomileusis ring.

Purpose: To evaluate blood-flow responses before and after microkeratome application.

Setting: School of Life and Health Sciences, Aston University, Birmingham, United Kingdom.

Methods: Hemodynamic responses were measured in eyes of healthy volunteers before and after transient elevation in intraocular pressure (IOP) resulting from microkeratome application.