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1.
PLoS One ; 11(3): e0150676, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27002333

RESUMEN

Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc.) and three ETDRS (Early Treatment Diabetic Retinopathy Study) visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off) exceeded the most stringent requirement for mean luminance (≥ 120 cd/m2) providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90%) regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (Lmin/Lmax ≥ 80%). Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off) had adequate mean luminance (≥ 120 cd/m2) and Weber contrast (≥ 90%), but all three charts failed to meet the luminance uniformity standard (Lmin/Lmax ≥ 80%). Two charts were operating beyond manufacturer's recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out-performed ETDRS charts in terms of photometric compliance with high contrast acuity standards.


Asunto(s)
Telecomunicaciones/instrumentación , Agudeza Visual/fisiología , Computadoras de Mano , Humanos , Luz , Iluminación/instrumentación , Iluminación/métodos , Fotometría/instrumentación , Fotometría/métodos , Pruebas de Visión/métodos
2.
Artículo en Inglés | MEDLINE | ID: mdl-25570420

RESUMEN

Mobile devices have shown promise in visual assessment. Traditional acuity measurement involves retro-illuminated charts or card-based modalities. Mobile platforms bring potential to improve on both portability and objectivity. The present research activity relates to design and validation of a novel tablet-based infant acuity test. Early results in an adult cohort, with various levels of artificially degraded vision, suggest improved test-retest reliability compared with current standards for infant acuity. Future pragmatic trials will assess the value of this emerging technology in pediatric visual screening.


Asunto(s)
Trastornos de la Visión/diagnóstico , Pruebas de Visión/instrumentación , Visión Ocular/fisiología , Agudeza Visual/fisiología , Adulto , Niño , Estudios de Cohortes , Humanos , Lactante , Luz , Iluminación , Reproducibilidad de los Resultados , Programas Informáticos , Interfaz Usuario-Computador , Juegos de Video , Pruebas de Visión/métodos
3.
Artículo en Inglés | MEDLINE | ID: mdl-25570419

RESUMEN

A novel, tablet-based application (app) has been developed to act as a screening tool for visual impairment in stroke survivors; The Stroke Vision app. The app includes assessments for visual acuity, visual fields and visuospatial neglect, as well as novel tools for the education of patients, carers and staff. The app has been devised by experts in the field to address two important deficiencies; firstly a set of visual assessment tools to support and improve evaluation and rehabilitation of visual impairments in stroke survivors, and secondly to provide education for staff and information to carers about their relatives visual disabilities.


Asunto(s)
Rehabilitación de Accidente Cerebrovascular , Trastornos de la Visión/diagnóstico , Cuidadores , Computadores , Humanos , Destreza Motora , Rehabilitación , Accidente Cerebrovascular/fisiopatología , Sobrevivientes , Pruebas de Visión , Visión Ocular , Agudeza Visual , Campos Visuales
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