Referrals from community optometrists in England and their replies: A mixed methods study.

PURPOSE: Community optometrists, through routine eye examinations, identify patients with disease or ocular abnormalities requiring referral to the Hospital Eye Service. In many cases no reply to the referral letter is received, resulting in some patients being re-referred unnecessarily, potentially increasing the number of other patients who lose sight whilst on hospital waiting lists. This study investigated, qualitatively and quantitatively, factors influencing optometric referrals and replies. METHODS: The three-phase, sequential mixed methods study started with a literature review and qualitative phase, interviewing stakeholders to identify issues for exploration in subsequent phases. The second, quantitative phase, undertook documentary analysis of 349 patient referral records from three optometric practice modalities (domiciliary, independently owned, and corporate chain) in England. A final qualitative phase obtained views from stakeholders to explore unexplained findings from the first two phases. RESULTS: Phase 1 identified communication, financial, professional and technological issues for further exploration. In Phase 2, the referral rate was 22.2% for domiciliary provider, 2.1% for independent practice and 2.5% for the corporate chain, with the variation most likely explained by patient age and associated ophthalmic disease, illness and disability. The referral reply rate was 5.7% for domiciliary provider, 25.0% for independent practice and 4.9% for the corporate chain. The community optometrist remained unaware of the outcome of their referral in 72.8% of cases. Qualitative analyses indicate the main factors influencing referral reply rates are technology, the General Medical Practitioner, community optometrists' utility to and utility of the National Health Service and patient mobilisation. CONCLUSIONS: The low referral reply rate creates a break in the feedback loop required to raise the standard of referrals and avoid unnecessary re-referral. Of the factors identified that influence referral reply rates, technology is key in view of the increasing use of online referral platforms. Feedback to the referring optometrist should be embedded in such systems.

An investigation of low power convex lenses (adds) for eyestrain in the digital age (CLEDA) / Investigación sobre las lentes convexas de baja potencia (adiciones) para la fatiga en la era digital (CLEDA)

INTRODUCTION: Digital eye strain (DES; computer vision syndrome) is a common cause of symptoms when viewing digital devices. Low-powered convex lenses (adds) have been recommended for the condition and "accommodative support" designs developed on this premise. The present research reports the extent to which dry eye is present in this population and the effect of convex lenses on symptoms and visual performance. METHODS: The CVS-Q instrument was used to select pre-presbyopic adults with the symptoms of DES. Participants received a full eye examination including an assessment of dry eye with a modified SANDE questionnaire and using DEWS I criteria. The immediate effect of low-powered convex lenses (low adds: +0.50D, +0.75D, +1.25D) was investigated using subjective preference and a double-masked comparison with plano lenses with the Wilkins Rate of Reading Test (WRRT). Throughout this testing, participants wore their full distance refractive correction, based on non-cycloplegic retinoscopy and subjective refraction. RESULTS: The signs and symptoms of dry eye were frequently present. Most participants reported a subjective preference for low adds, with +0.75D the most commonly preferred lens. Low adds (+0.50D and +0.75D; but not +1.25D) were associated with significantly improved performance at the WRRT. One quarter of participants read more than 10% faster with these additional convex lenses. CONCLUSIONS: The study population was aged 20-40y and mostly worked on desktop computers. It is possible that +1.25D add may be more advantageous for people who are older or work more at closer viewing distances. Many symptomatic users of digital devices report a preference for low adds and use of these lenses is often associated with an improvement in reading performance

INTRODUCCIÓN: La fatiga digital (DES; síndrome visual informático) es una causa común de síntomas, a causa de la visualización de dispositivos digitales. Se han recomendado lentes convexas de baja potencia para esta situación, así como diseños de "apoyo acomodativo" desarrollados sobre la base de este principio. Los informes de investigación actuales reportan el alcance de la presencia de ojo seco en esta población, así como el efecto de las lentes convexas en los síntomas y el desempeño visual. MÉTODOS: Se utilizó el instrumento CVS-Q para seleccionar adultos pre-presbiópicos con síntomas de DES. Se realizó un examen visual completo a los participantes, incluyendo valoración de ojo seco con un cuestionario SANDE modificado, y utilizando los criterios DEWS I. Se investigó el efecto inmediato de las lentes convexas de baja potencia (adiciones bajas: +0,50D, +0,75D, +1,25D) utilizando la preferencia subjetiva y una comparación doble ciego con lentes planas mediante la prueba Wilkins Rate of Reading Test (WRRT). A lo largo de esta prueba, los participantes utilizaban su corrección refractiva de distancia completa, basada en retinoscopia no ciclopéjica y refracción subjetiva. RESULTADOS: Los signos y síntomas del ojo seco estuvieron frecuentemente presentes. Muchos participantes reportaron una preferencia subjetiva de bajas adiciones, siendo las lentes de +0,75D las más comúnmente preferidas. Las bajas adiciones (+0,50D y +0,75D, pero no +1,25D) se asociaron a un desempeño significativamente mejorado en la prueba WRRT. Un 25% de los participantes leyeron un 10% más rápido con estas lentes convexas adicionales. CONCLUSIONES: La edad de la población de estudio fue de 20 a 40 años, trabajando la mayoría de dichos sujetos en ordenadores de mesa. Es posible que la adición de +1,25D sea más ventajosa para personas de mayor edad, o que trabajen más con distancias de visualización más próxima. Muchos usuarios de dispositivos digitales sintomáticos reportan una preferencia por bajas adiciones, asociándose a menudo el uso de estas lentes a una mejora del desempeño lector

An investigation of low power convex lenses (adds) for eyestrain in the digital age (CLEDA).

INTRODUCTION: Digital eye strain (DES; computer vision syndrome) is a common cause of symptoms when viewing digital devices. Low-powered convex lenses (adds) have been recommended for the condition and "accommodative support" designs developed on this premise. The present research reports the extent to which dry eye is present in this population and the effect of convex lenses on symptoms and visual performance. METHODS: The CVS-Q instrument was used to select pre-presbyopic adults with the symptoms of DES. Participants received a full eye examination including an assessment of dry eye with a modified SANDE questionnaire and using DEWS I criteria. The immediate effect of low-powered convex lenses (low adds: +0.50D, +0.75D, +1.25D) was investigated using subjective preference and a double-masked comparison with plano lenses with the Wilkins Rate of Reading Test (WRRT). Throughout this testing, participants wore their full distance refractive correction, based on non-cycloplegic retinoscopy and subjective refraction. RESULTS: The signs and symptoms of dry eye were frequently present. Most participants reported a subjective preference for low adds, with +0.75D the most commonly preferred lens. Low adds (+0.50D and +0.75D; but not +1.25D) were associated with significantly improved performance at the WRRT. One quarter of participants read more than 10% faster with these additional convex lenses. CONCLUSIONS: The study population was aged 20-40y and mostly worked on desktop computers. It is possible that +1.25D add may be more advantageous for people who are older or work more at closer viewing distances. Many symptomatic users of digital devices report a preference for low adds and use of these lenses is often associated with an improvement in reading performance.

Sources of error in clinical measurement of the amplitude of accommodation / Fuentes de error en la medición clínica de la amplitud de acomodación

Measurement of the amplitude of accommodation is established as a procedure in a routine optometric eye examination. However, clinical methods of measurement of this basic optical function have several sources of error. They are numerous and diverse, and include depth of focus, reaction time, instrument design, specification of the measurement end-point, specification of the reference point of measurement, measurement conditions, consideration of refractive error, and psychological factors. Several of these sources of inaccuracy are composed of multiple sub-sources, and many of the sub-sources influence the common methods of measurement of amplitude of accommodation. Consideration of these sources of measurement error casts doubt on the reliability of the results of measurement, on the validity of established normative values that have been produced using these methods, and on the value of reports of the results of surgery designed to restore accommodation. Clinicians can reduce the effects of some of the sources of error by modifying techniques of measurement with existing methods, but a new method may further improve accuracy

La medición de la amplitud de acomodación se ha establecido como un procedimiento del examen optométrico ocular rutinario. Sin embargo, los métodos clínicos de medición de esta función óptica básica tienen diversas fuentes de error. Estas son numerosas y diversas, e incluyen profundidad de foco, tiempo de reacción, diseño del instrumento, especificación del punto final de la medición, especificación del punto de referencia de la medición, condiciones de la medición, consideración del error refractivo, y factores psicológicos. Algunas de estas fuentes de imprecisión se componen de múltiples sub-fuentes, muchas de las cuales influyen en los métodos comunes de medición de la amplitud de acomodación. La consideración de estas fuentes de error en la medición plantea dudas sobre la fiabilidad de los resultados de dicha medición, la validez de los valores normativos establecidos que se han producido utilizando estos métodos, y el valor de los informes sobre resultados de la cirugía diseñada para restablecer la acomodación. Los clínicos pueden reducir los efectos de algunas de las fuentes de error, modificando las técnicas de medición con ayuda de los métodos existentes, aunque el desarrollo de un nuevo método podría mejorar la precisión

Does an iPad fixation disparity test give equivalent results to the Mallett near fixation disparity test? / ¿Puede aportar la prueba de disparidad de fijación en iPad unos resultados equivalentes a la prueba de disparidad de fijación de cerca de la unidad de Mallett?

BACKGROUND: Various instruments have been developed to measure aligning prism, the prism that eliminates a fixation disparity (associated heterophoria). This includes the established Mallett near vision unit and recently developed Thomson Vision Toolbox on the iPad. With no previous research investigating the agreement between these instruments, practitioners may question if they can be used interchangeably. METHODS: 80 participants underwent near vision testing with the Mallett unit and iPad fixation disparity test. Data were analysed in four ways to investigate the agreement of the two instruments. RESULTS: Many participants reported no fixation disparity (horizontally 46.25%, vertically 82.5%), or non-significant aligning prism (horizontally 70%, vertically 97.5%), on both instruments. The iPad revealed a larger range of aligning prism results horizontally, 6∆ base out to 15∆ base in; the Mallett unit produced a larger range of results vertically, 1∆ base up to 3.5∆ base down. More participants required a significant aligning prism on the Mallett unit horizontally and vertically. Wilcoxon signed rank analysis found that the difference in aligning prism was not statistically significant (p = 0.357 horizontally, p = 0.236 vertically), but 95% limits of agreement revealed clinically significant differences between the instruments. CONCLUSION: Although the measured differences between the instruments are not significant in a Wilcoxon analysis, a Bland & Altman approach shows them to be in some cases clinically unacceptable, therefore the instruments should not be used interchangeably. Previous research indicates that the Mallett unit performs reasonably well at detecting symptomatic individuals and determining a prismatic correction that is likely to be helpful. Further research is required to determine the performance of the iPad test in these functions and to assess the reproducibility of both instruments

ANTECEDENTES: Se han desarrollado diversos instrumentos para medir el prisma de alineamiento, que es el prisma que elimina la disparidad de fijación (heteroforia asociada). Entre estos instrumentos se incluyen la unidad de visión de cerca de Mallett y la recientemente desarrollada Thomson Vision Toolbox en el iPad. Como no existe investigación previa acerca del acuerdo entre estos instrumentos, los clínicos pueden cuestionarse si pueden usarse ambos tests de forma intercambiable. MÉTODOS: Se realizó una prueba de visión de cerca a 80 participantes, utilizando la unidad de Mallett y la prueba iPad de disparidad de fijación. Los datos fueron analizados de cuatro modos, para evaluar el acuerdo entre ambos instrumentos. RESULTADOS: Muchos participantes reportaron ausencia de disparidad de fijación (horizontalmente 46,25%, verticalmente 82,5%), o prisma de alineamiento no significativo (horizontalmente 70%, verticalmente 97,5%), con ambos instrumentos. El iPad reveló un mayor rango de resultados de prisma de alineamiento horizontalmente, 6∆ base externa con respecto a 15∆ base interna, y la unidad de Mallett produjo un rango mayor de resultados verticalmente, 1∆ base superior con respecto a 3,5∆ base inferior. Muchos participantes requirieron un prisma de alineamiento significativo en la unidad de Mallett horizontalmente y verticalmente. La prueba de rango con signo de Wilcoxon encontró que la diferencia en cuanto a prisma de alineamiento no era estadísticamente significativa (p = 0,357 horizontalmente, p = 0,236 verticalmente), pero el 95% de los límites de acuerdo revelaron diferencias clínicamente significativas entre los dos instrumentos. CONCLUSIÓN: Aunque las diferencias de las mediciones entre ambos instrumentos no son significativas con el analisis de Wilcoxon, los analisis con Bland & Altman muestran algunas casos clinicamente significativos, y por tanto los instrumentos no deberían usarse de manera intercambiable. La investigación previa indica que la unidad de Mallett tiene un rendimiento razonablemente bueno para detectar los individuos sintomáticos, y determinar una corrección prismática que pueda resultar útil. Es necesaria más investigación para determinar el rendimiento de la prueba iPad en estas funciones y para analizar la reproducibilidad de ambos instrumentos

A Delphi study to develop practical diagnostic guidelines for visual stress (pattern-related visual stress) / Estudio Delphi para el desarrollo de pautas diagnósticas para el estrés visual (estrés visual relacionado con patrones)

Purpose: Visual stress (VS) is characterised by symptoms of visual perceptual distortions and eyestrain when viewing text, symptoms that are alleviated by individually prescribed coloured filters. A recent review supports the existence of VS and its treatment, but noted that controversy remains, in part due to inconsistencies in the diagnosis of the condition. The present paper reviews the diagnostic criteria for VS in the literature and reports a Delphi analysis of the criteria currently used in clinical practice. Methods: Twenty-six eyecare practitioners were invited to participate in a Delphi study. They were selected because they were frequent prescribers of precision tinted lenses. In the first round they were sent a list of the indicators for which there is literature to suggest a relevance in the diagnosis of VS. The practitioners were invited to rank the indicators and add any additional criteria they use in diagnosis. In the second round a revised list was circulated, including items added from the responses in the first round. Results: The respondents included optometrists, orthoptists and opticians. In the first round the response rate was 85%. Ninety-one percent of those who participated in the first round also responded in the second round. Strong indicators in the second round included the symptom of words moving when reading, voluntary use of an overlay for a prolonged period, improved performance of 15% with an overlay on the Wilkins Rate of Reading test, and an abnormally high score on the Pattern Glare Test. Conclusions: The strongest diagnostic criteria are combined in a diagnostic tool. This is proposed as a guide for clinical practice and further research (AU)

Objetivo: El estrés visual (EV) se caracteriza por síntomas de distorsión perceptual visual y astenopía, que pueden aliviarse mediante filtros coloreados de prescripción individual. Una revisión reciente respalda la existencia de EV y su tratamiento, aunque hay que resaltar que persiste la controversia, debido en parte a las inconsistencias en cuanto a diagnóstico. El presente documento revisa los criterios diagnósticos del EV en la literatura, y reporta un análisis Delphi sobre los criterios utilizados en la actualidad en la práctica clínica. Métodos: Se invitó a participar en un estudio Delphi a veintiséis facultativos. Éstos fueron seleccionados debido a su elevada prescripción de lentes tintadas de precisión. En la primera ronda, se les envió un listado de los indicadores a los que la literatura aporta relevancia para el diagnóstico del EV. Se solicitó a los facultativos que clasificaran los indicadores, y que añadieran cualquier criterio adicional que ellos utilizaran en su diagnóstico. En la segunda ronda, se hizo circular un listado revisado, incluyendo los ítems añadidos a partir de las respuestas de la primera ronda. Resultados: Entre los facultativos participantes se hallaban optometristas, ortoptistas y ópticos. En la primera ronda el índice de respuesta fue del 85%. El 91% de los participantes en la primera ronda aportaron también sus respuestas en la segunda. Los indicadores sólidos en la segunda ronda incluyeron: síntoma de movimiento de las palabras al leer, uso voluntario de filtros durante un periodo prolongado, mejora del desempeño de 15% en el índice de la prueba de lectura de Wilkins con el uso de filtros, y puntuación anormalmente elevada en la prueba PatternGlare. Conclusiones: Se combinan los criterios diagnósticos más sólidos en una herramienta diagnóstica. Ello se propone como pauta en la práctica clínica y la investigación futura (AU)

Reply to Letter to the Editor by Griffiths et al. commenting on Evans & Allen: Letter to the Editor concerning «A systematic review of controlled trials on visual stress using intuitive overlays or colorimeter» / Respuesta a la carta al editor de Griffiths et al., como comentario al documento de Evans & Allen: Carta al Editor en relación a «Revisión sistemática de ensayos controlados sobre estrés visual utilizando filtros intuitivos o colorímetro»

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A systematic review of controlled trials on visual stress using Intuitive Overlays or the Intuitive Colorimeter / Revisión sistemática de los ensayos controlados sobre estrés visual utilizando filtros intuitivos o colorímetros

Claims that coloured filters aid reading date back 200 years and remain controversial. Some claims, for example, that more than 10% of the general population and 50% of people with dyslexia would benefit from coloured filters lack sound evidence and face validity. Publications with such claims typically cite research using methods that have not been described in the scientific literature and lack a sound aetiological framework. Notwithstanding these criticisms, some researchers have used more rigorous selection criteria and methods of prescribing coloured filters that were developed at a UK Medical Research Council unit and which have been fully described in the scientific literature. We review this research and disconfirm many of the more extreme claims surrounding this topic. This literature indicates that a minority subset of dyslexics (circa 20%) may have a condition described as visual stress which most likely results from a hyperexcitability of the visual cortex. Visual stress is characterised by symptoms of visual perceptual distortions, headaches, and eyestrain when viewing repetitive patterns, including lines of text. This review indicates that visual stress is distinct from, although sometimes co-occurs with, dyslexia. Individually prescribed coloured filters have been shown to improve reading performance in people with visual stress, but are unlikely to influence the phonological and memory deficits associated with dyslexia and therefore are not a treatment for dyslexia. This review concludes that larger and rigorous randomised controlled trials of interventions for visual stress are required. Improvements in the diagnosis of the condition are also a priority (AU)

Las aseveraciones acerca de que los filtros coloreados ayudan a la lectura se remontan 200 años atrás, y siguen siendo controvertidas. Por ejemplo, algunas afirmaciones relativas a que el 10% de la población general y el 50% de las personas disléxicas podrían beneficiarse de los filtros coloreados carecen de evidencia y de validez firmes. Las publicaciones que incluyen dichas afirmaciones citan, normalmente, investigaciones que hacen uso de métodos no descritos en la literatura científica y que carecen de marcos etiológicos sólidos. A pesar de estas críticas, algunos investigadores han utilizado unos criterios y métodos de selección más rigurosos para la prescripción de filtros coloreados, desarrollados en una unidad del Medical Research Council del Reino Unido y que se han descrito cuidadosamente en la literatura científica. Revisamos todas estas investigaciones que desmienten muchas de las aseveraciones más extremas que rodean a esta cuestión. Esta literatura científica consistente indica que un subgrupo minoritario de disléxicos (de alrededor del 20%) puede padecer una afección médica descrita como estrés visual, que deriva muy probablemente de la hiperexcitabilidad de la corteza visual. El estrés visual se caracteriza por síntomas de distorsión de la percepción visual, cefaleas, y fatiga visual al visualizar patrones repetitivos, incluyendo las líneas de texto. Esta revisión indica que el estrés visual es diferente a la dislexia, aunque a veces coexisten ambas situaciones. Se ha demostrado que los filtros coloreados individualmente prescritos mejoran el desempeño lector en personas con estrés visual, pero es improbable que mejoren los déficits fonológicos y de memoria que se asocian a la dislexia, por lo que no constituyen un tratamiento para la misma. Esta revisión concluye que se precisan más ensayos controlados y aleatorizados sobre intervenciones para el estrés visual. También son prioritarias las mejoras diagnósticas de dicha afección (AU)

Randomised controlled study comparing comfort-related outcomes between two rigid gas permeable (RGP) lenses with different sessile drop contact angles.

PURPOSE: To compare comfort-related outcomes when wearing rigid gas permeable (RGP) contact lenses made of two different materials and using two cleaning regimes. METHODS: In a double-masked lens material cross-over study, subjects (n = 28 who completed the study) were refitted with new lenses made from (A) Boston XO material in one eye and made from (B) ONSI-56 material in the other eye. The lenses made from materials A and B were worn on the right eye and the left eye following the pattern AB-BA-AB (or vice versa) during the first, second, and third 5 week trial periods respectively. Miraflow cleaner (1st and 2nd period) was replaced by Boston Advance cleaner in the 3rd period. Comfort-related outcomes were assessed by a numerical rating scale (NRS) after each period. Subjects rated six comfort-related factors: satisfaction, sharpness of vision, end of day comfort, maximum comfortable wearing time, maximum wearing time and foreign body feeling. Additionally we obtained subjects' preferences for type of lens and lens cleaner during an exit interview. The sessile drop method was used to measure static contact angles. RESULTS: The mean of the contact angle measured for the Boston XO material was 93.3° and for the ONSI-56 material was 75.8 °. Mean 'end of the day comfort', 'satisfaction' and 'lens feeling' scores reached statistical significance (anova periods 1, 2 and 3, p's: 0.005, 0.028, 0.046, n = 23) with marginal differences in favour of those eyes that had worn lenses made of the ONSI-56 material (differences in mean scores on a 1-10 NRS never exceeded 0.7, 0.5 and 0.2 points in periods 1, 2, 3 respectively). At the exit interview 60% of the subjects (n = 17) were not able to express a preference for wearing either of the lenses, while 29% reported some preference for lenses made of the ONSI-56 material (n = 8) and 11% for wearing lenses made of the Boston XO material (n = 3) within one or more periods. CONCLUSIONS: The differences in comfort-related outcomes between contact lenses made from two different materials, with sessile contact angles that differed by 17.5°, were small. Although some observed comfort differences reached statistical significance, none of these differences were sufficiently large to support a clinically significant difference in comfort between the two materials. We recommend that both the sessile drop and the captive bubble contact angles, measured according to current standards, are made available to practitioners.