Near prescribing trends in two low vision rehabilitation clinics over a ten-year period.

CLINICAL RELEVANCE: Optical magnification (OM), electronic magnification (EM), and assistive technology (AT) can be prescribed in low vision rehabilitation (LVR) clinics for near vision goals of patients. This study shows the prescription of OM has not decreased with increased availability of EM and AT. BACKGROUND: Near visual goals are a primary concern for patients with visual impairment. LVR providers can prescribe OM, EM and/or AT to help. With the rapid evolution and availability of EM and AT, we aim to evaluate if there have been changes in the prescription patterns of clinicians with respect to OM over time. We hypothesise that the increased availability of technology may result in declining prescriptions of OM and increasing prescription of EM and AT over time. METHODS: This retrospective study investigated near prescribing between 2008-2017 for 530 new patients to the LVR clinics. Examinations were performed by optometrists specialising in low vision. Near devices prescribed included OM and EM and AT. RESULTS: Most patients attending the LVR clinics were female, over 60 years old and had age related macular degeneration. Near visual goals were a primary concern of 97.2% of the patients. OM was most prescribed in the 0-19 and >60-year-old age groups. Within the 20-39-year-old age group there was the greatest number of both EM and AT prescriptions. OM was most prescribed in patients with visual acuity better than 6/60. EM and AT showed a trend of increasing prescription as visual acuity decreased. EM prescription peaked in <6/60 to 6/240 category while AT trended upwards from <6/21 to no light perception and peaked in patients with no light perception. Referral rates for additional rehabilitation services were 75.7%. CONCLUSIONS: This study shows that the prescription of OM is not declining even as the prescription and the breadth of electronic magnification and assistive technology available is expanding. OM continues to be a viable option for patients, especially in the youngest and oldest cohorts.

Retrospective analysis of low vision assistive products - A 6-year review.

PURPOSE: The purpose of the study was to analyze the demographics, visual acuity (VA), etiologies, recommended low vision assistive products (LVAP), and the acceptance rates of LVAP in various age groups. METHODS: This was a long-term retrospective review of all the patients presenting to the low vision clinic of our tertiary eye care hospital from January 2011 to December 2016. Data obtained included age, gender, VA, visual fields, ocular pathology causing the low vision, and types of LVAP advised. The primary outcome was to analyze the type of LVAP prescribed in different age groups, and the secondary outcome was the acceptance rate of LVAP. RESULTS: We analyzed the results of 8309 patients, out of which 2844 (34%. 2) were <15 years of age, 2425 (29.5%) were between 16-40 years, and 3013 (36.3%) were above 40 years. A total of 5522 (66.4%) had best-corrected visual acuity (BCVA) ranging from 6/18-3/60, and 2796 (33.6%) had BCVA from 3/60-No PL. Approximately 38% improved with LVAPs. The most common etiology was retinitis pigmentosa in 1545 (18.6%) patients, followed by congenital nystagmus in 1482 (17.8%), and the least was albinism 383 (4.6%). Maximum prescribed and accepted LVAP were hand and stand magnifiers among 1017 (44.3%) and 512 (52.6%) patients, respectively. CONCLUSION: Products that are easy to use, require lesser adaptability, are cheap, and require lower maintenance have maximum acceptance rates. We suggest that great emphasis should be laid on training, education, and guidance for low vision rehabilitation centers.

Towards Making Videos Accessible for Low Vision Screen Magnifier Users.

People with low vision who use screen magnifiers to interact with computing devices find it very challenging to interact with dynamically changing digital content such as videos, since they do not have the luxury of time to manually move, i.e., pan the magnifier lens to different regions of interest (ROIs) or zoom into these ROIs before the content changes across frames. In this paper, we present SViM, a first of its kind screen-magnifier interface for such users that leverages advances in computer vision, particularly video saliency models, to identify salient ROIs in videos. SViM's interface allows users to zoom in/out of any point of interest, switch between ROIs via mouse clicks and provides assistive panning with the added flexibility that lets the user explore other regions of the video besides the ROIs identified by SViM. Subjective and objective evaluation of a user study with 13 low vision screen magnifier users revealed that overall the participants had a better user experience with SViM over extant screen magnifiers, indicative of the former's promise and potential for making videos accessible to low vision screen magnifier users.

Stand magnifiers for low vision: description, prescription, assessment.

Stand magnifiers are still one of the most commonly prescribed classes of low vision devices. Their performance can be difficult to understand because stand magnifiers usually do not give an image at infinity. This review summarises the methods of describing image enlargement for stand magnifiers, emphasising their relationship to equivalent viewing distance (EVD). This is done in terms of the underlying optical equations, and measurement methods, and methods of prescribing. In the past, methods of determining EVD have been somewhat indirect, requiring accurate measurement of lens power, and image position. The use of digital photography provides an alternative, more direct, simpler method of determining EVD, which can be accomplished in-office. This method is described and it is demonstrated how it gives comparable results to older methods with small, clinically non-meaningful differences, that may be due to differences in image distance reference planes. Describing the performance of stand magnifiers in terms of their dioptric power, or in terms of 'nominal magnification' or 'trade magnification', is imprecise and misleading. It is better to use indices such as equivalent viewing power and EVD, which take into account the magnifier dioptric power, the image position of the magnifier and the distance a patient is from the magnifier. While EVD is a useful index for prescribing stand magnifiers, manufacturers do not always provide sufficient technical details to determine EVD for their stand magnifiers, and available tables of EVDs are more than a decade old and are likely to need updating. Photographic comparison provides a method for determining EVD, and this method can also be applied to other low vision devices.

Dynamics of the accommodative response under artificially-induced aniseikonia.

Aniseikonia has demonstrated to deteriorate the binocular function, however its impact on the accommodative response remains unknown. The present study aimed to analyze the effects of artificially-induced aniseikonia, using afocal magnifiers, on the dynamics of the accommodative response. The magnitude and variability of the accommodative response were objectively measured in 20 young healthy subjects by a binocular open-field autorefractometer. Participants observed a static stimulus for 90 s, under seven degrees of aniseikonia (0%, 1%, 3%, 5%, 8%, 10% and 12%), and at three distances (500 cm, 40 cm and 20 cm). Complementarily, near stereoacuity, and perceived levels of fatigue and visual discomfort were assessed. The degree of induced aniseikonia was associated with the magnitude of the accommodative response (p < 0.001, ηp2 = 0.329), obtaining a statistically significant reduced accommodative lag for the induced aniseikonia conditions of 8%, 10% and 12% in comparison to the control condition at 40 cm (p-corrected = 0.019, <0.001 and 0.013, respectively) and at 20 cm (p-corrected < 0.001, <0.001 and 0.003, respectively). However, the degree of induced aniseikonia did not reveal any effect on the variability of accommodation (p > 0.05). We also found a decline in near stereoacuity and an increment of visual symptomatology when inducing aniseikonia (p < 0.05). Our data evidenced that greater degrees of induced aniseikonia cause a heightened accommodative response. These preliminary findings may be of relevance for patients undergoing cataract or refractive surgery procedures in which aniseikonia can be induced.

Ayudas ópticas y no ópticas en la baja visión / Visual and not visual aid in low vision

Este estudio se propone conocer la ayuda visual mejor aceptada por pacientes de visión baja, para lo cual se realizó una revisión bibliográfica con el fin de contribuir al ejercicio optométrico. Se revisaron un total de 28 artículos del año 2007 a la fecha actual. En las diferentes patologías en estudio se encontró que la ayuda visual mejor aceptada para la visión cercana fueron las lupas, y para la visión lejana eran más usados los telescopios(AU)

The aim of this study is to determine which is the most frequent visual aid use in low vision. Twenty-eight articles were consulted in a period from 2007 until now. It was observed that for near vision the hans spectacles were the best aid and for far vision telescope were more used(AU)

Ayudas ópticas y no ópticas en la baja visión / Visual and not visual aid in low vision

Este estudio se propone conocer la ayuda visual mejor aceptada por pacientes de visión baja, para lo cual se realizó una revisión bibliográfica con el fin de contribuir al ejercicio optométrico. Se revisaron un total de 28 artículos del año 2007 a la fecha actual. En las diferentes patologías en estudio se encontró que la ayuda visual mejor aceptada para la visión cercana fueron las lupas, y para la visión lejana eran más usados los telescopios(AU)

The aim of this study is to determine which is the most frequent visual aid use in low vision. Twenty-eight articles were consulted in a period from 2007 until now. It was observed that for near vision the hans spectacles were the best aid and for far vision telescope were more used(AU)

Profile of the Australian College of Optometry low vision clinic.

BACKGROUND: The number of Australians living with vision impairment or blindness is expected to increase substantially due to the ageing population and prevalence of age-related eye disease. In response, the Australian College of Optometry (ACO) commenced a low vision clinic in 2013. The ACO is a not-for-profit organisation providing eye-care services to more than 60,000 Victorians per year experiencing economic or social disadvantage. Consultation fees are bulk-billed to the Australian national health care scheme - Medicare - while spectacles and visual aids are subsidised through the state government-funded Victorian Eyecare Service. The aim of this study was to determine the profile and prescribing patterns of the new optometry-led low vision clinic, and report the findings of a short-term loan magnifier pilot study. METHODS: A retrospective audit of 270 patient records was conducted. Additionally, a short-term loan magnifier program was pilot tested to ascertain the demand for, and benefits of, such a program among this cohort. RESULTS: The median age was 77 years (interquartile range 64 to 85 years), with 52 per cent being female. The main cause of vision impairment was age-related macular degeneration (40 per cent). At least one-third primarily spoke a language other than English. The majority (75 per cent) were referred by the optometrist to the onsite consultant occupational therapist for immediate assistance with activities of daily living and onward referral for additional comprehensive services, as required. Of the 49 participants who completed the loan magnifier study, only nine exchanged the magnifier/s initially prescribed. CONCLUSIONS: The ACO has established a low vision service within a large optometry clinic for people experiencing social and economic disadvantage. Where a program of subsidised low-cost magnifiers is available, there is little benefit to short-term loans of magnifiers. Providing basic affordable low vision aids and rehabilitation within a large primary care optometry setting can facilitate acceptability and uptake of low vision services that increase quality of life.

The p-EVES study design and methodology: a randomised controlled trial to compare portable electronic vision enhancement systems (p-EVES) to optical magnifiers for near vision activities in visual impairment.

PURPOSE: To describe the study design and methodology for the p-EVES study, a trial designed to determine the effectiveness, cost-effectiveness and acceptability of portable Electronic Vision Enhancement System (p-EVES) devices and conventional optical low vision aids (LVAs) for near tasks in people with low vision. METHODS: The p-EVES study is a prospective two-arm randomised cross-over trial to test the hypothesis that, in comparison to optical LVAs, p-EVES can be: used for longer duration; used for a wider range of tasks than a single optical LVA and/or enable users to do tasks that they were not able to do with optical LVAs; allow faster performance of instrumental activities of daily living; and allow faster reading. A total of 100 adult participants with visual impairment are currently being recruited from Manchester Royal Eye Hospital and randomised into either Group 1 (receiving the two interventions A and B in the order AB), or Group 2 (receiving the two interventions in the order BA). Intervention A is a 2-month period with conventional optical LVAs and a p-EVES device, and intervention B is a 2-month period with conventional optical LVAs only. RESULTS: The study adopts a mixed methods approach encompassing a broad range of outcome measures. The results will be obtained from the following primary outcome measures: Manchester Low Vision Questionnaire, capturing device 'usage' data (which devices are used, number of times, for what purposes, and for how long) and the MNRead test, measuring threshold print size, critical print size, and acuity reserve in addition to reading speed at high (≈90%) contrast. Results will also be obtained from a series of secondary outcome measures which include: assessment of timed instrumental activities of daily living and a 'near vision' visual functioning questionnaire. A companion qualitative study will permit comparison of results on how, where, and under what circumstances, p-EVES devices and LVAs are used in daily life. A health economic evaluation will provide results on: the incremental cost-effectiveness of p-EVES compared to optical magnifiers; cost-effectiveness; and cost-utility. CONCLUSIONS: The evidence base in low vision rehabilitation is modest and further high quality clinical trials are required to inform decisions on healthcare provision. The p-EVES study findings are anticipated to contribute to this broader evidence requirement, with the methodological issues evident here being relevant to other trials within the field.