Clinical performance and Willingness To Pay for soft toric contact lenses in low and moderate astigmats.

PURPOSE: To determine clinical performance and the 'Willingness To Pay' for toric vs. spherical soft contact lenses in an astigmatic population. METHODS: In the clinical study, subjects with binocular low to moderate astigmatism (-0.75DC to -1.50DC) wore pairs of soft toric (Biofinity toric) and spherical (Biofinity) contact lenses in random sequence. Visual acuity (high and low contrast, monocular and binocular), subjective comfort and subjective vision were recorded. In the economics study, first subjects who had participated in the clinical study were presented with a series of randomised economic scenarios in order to determine their Willingness To Pay a premium (i.e. an increase) for toric lenses. Then, a similar set of scenarios were presented to a much larger group of online respondents and again, Willingness To Pay was established. RESULTS: For the four measures of visual acuity, the Biofinity toric lens out-performed the Biofinity spherical lens by 0.6 to 1.1 lines.. Subjective vision performance was statistically significantly better with the toric lens for the distance task only. Comfort scores were not significantly different. Similar findings for Willingness To Pay were established for the clinical subjects and for the online respondents. The Willingness To Pay premium (additional fee) for a monthly supply of toric lenses (over spherical lenses) was between £13 and £16, if a toric lens provides better vision and similar comfort, as shown in the clinical study. CONCLUSION: Consumers are willing to pay a monthly premium of around 50% to benefit from the typical experience of better vision and similar comfort for toric vs. spherical lenses. The level of additional cost for toric lenses compared to their spherical equivalents is less than this in the market, so eye care professionals should consider that toric lenses are delivering a greater clinical return than anticipated by wearers for the relatively small increase in price.

Investigating eye examination-related anxiety in autistic adults.

CLINICAL RELEVANCE: It is important to investigate whether anxiety is a barrier to accessing eye examinations for autistic adults, because existing research suggests this population are more likely to develop ophthalmic abnormalities. BACKGROUND: Anxiety influences healthcare accessibility for autistic people without learning disabilities. Previous qualitative studies by the research team, with a small sample of autistic adults, have indicated several aspects of eyecare services which cause anxiety. Considering the limited existing research suggesting autistic individuals are more likely to develop ophthalmic abnormalities, this study explored whether this population more widely experiences anxiety when accessing eye examinations. METHODS: A total of 322 UK-based autistic adults completed the Optometric Patient Anxiety Scale (OPAS) online, between July and December 2020. Rasch analysis was used to validate this questionnaire for an autistic adult population, and compare optometric anxiety levels to the general population. RESULTS: Item infit (0.77 to 1.39) and outfit (0.78 to 1.33) values, the person separation index (2.64), and item (0.99) and person (0.97) reliability coefficients suggested that all 10 items in the OPAS are useful to assess optometric anxiety in an autistic adult population. Item probability curves confirmed the response scale to be appropriate. A comparison of optometric anxiety between the autistic population in the current study and a general population in previous work found no statistically significant difference. CONCLUSION: The OPAS is a statistically valid tool for use in the autistic adult population. It appears to suggest no significant difference in optometric anxiety between the autistic adult and general population. However, it is possible that it underestimates the true optometric anxiety of autistic adults since the items do not include some of the anxiety provoking factors for this population which have been indicated in previous studies by the research team.

Autism-friendly eyecare: Developing recommendations for service providers based on the experiences of autistic adults.

PURPOSE: People with autism face significant barriers when accessing healthcare services. Eye examinations present unique challenges. Accessibility of this healthcare sector for people with autism has not been investigated previously. The aim of this research was to investigate eye examination accessibility for autistic adults and produce recommendations for autism-friendly eyecare. METHODS: Two qualitative studies were conducted. In Study 1, 18 autistic adults took part in focus groups to elicit their eye examination experiences. Transcripts of the recorded discussions were thematically analysed. Study 1 findings were used to design autism-friendly eye examinations for autistic adults. These were conducted in Study 2. Twenty-four autistic adults participated in these examinations, during which they were interviewed about their experience and how it might be improved by reasonable modifications. Audio recordings of the interviews were content analysed. RESULTS: Knowledge of what to expect, in advance of the eye examination, could greatly reduce anxiety. Participants liked the logical structure of the examination, and the interesting instrumentation used. However, the examination and practice environment did include sensory challenges, due to lights, sound and touch. Changes in practice layout, and interacting with multiple staff members, was anxiety provoking. Participants expressed a need for thorough explanations from the optometrist that outlined the significance of each test, and what the patient was expected to do. CONCLUSION: A number of accessiblity barriers were identified. These suggested that UK eye examinations are not very accessible for autistic adults. Barriers began at the point of booking the appointment and continued through to the dispensing of spectacles. These caused anxiety and stress for this population, but could be reduced with easy-to-implement adaptations. Based on the findings, recommendations are presented here for the whole eyecare team which suggest how more autism-friendly eye examinations can be provided.

Visual Sensory Experiences From the Viewpoint of Autistic Adults.

Although previous research has investigated altered sensory reactivity in autistic individuals, there has been no specific focus on visual sensory experiences, particularly in adults. Using qualitative methods, this study aimed to characterize autistic visual sensory symptoms, contextualize their impact and document any associated coping strategies. A total of 18 autistic adults took part in four focus groups which involved questions around visual experiences, the impact of these on daily life, and strategies for their reduction. Transcripts of each session were thematically analyzed allocating six key themes. Participants described a range of visual hypersensitivities, including to light, motion, patterns and particular colors, which contributed to distraction and were frequently part of a wider multisensory issue. Such experiences had significant negative impacts on personal wellbeing and daily life with participants describing fatigue, stress and hindrances on day-to-day activities (e.g., travel and social activities). However, the degree of understanding that participants had about their visual experiences influenced their emotional response, with greater understanding reducing concern. Participants employed a variety of coping strategies to overcome visual sensory experiences but with varied success. Discussions also highlighted that there may be a poor public understanding of sensory issues in autism affecting how well autistic individuals are able manage their sensory symptoms. In summary, autistic adults expressed significant concern about their visual experiences and there is a need to improve understanding of visual experiences on a personal and public level as well as for developing potential support.

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

Does an iPad fixation disparity test give equivalent results to the Mallett near fixation disparity test?

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, 6Δ base out to 15Δ base in; the Mallett unit produced a larger range of results vertically, 1Δ base up to 3.5Δ 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.