Topical Review: Assessment of Binocular Sensory Processes in Low Vision.

SIGNIFICANCE: This article summarizes the evidence for a higher prevalence of binocular vision dysfunctions in individuals with vision impairment. Assessment for and identification of binocular vision dysfunctions can detect individuals experiencing difficulties in activities including reading, object placement tasks, and mobility.Comprehensive vision assessment in low vision populations is necessary to identify the extent of remaining vision and to enable directed rehabilitation efforts. In patients with vision impairment, little attention is typically paid to assessments of binocular vision, including ocular vergence, stereopsis, and binocular summation characteristics. In addition, binocular measurements of threshold automated visual fields are not routinely performed in clinical practice, leading to an incomplete understanding of individuals' binocular visual field and may affect rehabilitation outcomes.First, this review summarizes the prevalence of dysfunctions in ocular vergence, stereopsis, and binocular summation characteristics across a variety of ocular pathologies causing vision impairment. Second, this review examines the links between clinical measurements of binocular visual functions and outcome measures including quality of life and performance in functional tasks. There is an increased prevalence of dysfunctions in ocular alignment, stereopsis, and binocular summation across low vision cohorts compared with those with normal vision. The identification of binocular vision dysfunctions during routine low vision assessments is especially important in patients experiencing difficulties in activities of daily living, including but not limited to reading, object placement tasks, and mobility. However, further research is required to determine whether addressing the identified deficits in binocular vision in low vision rehabilitative efforts directly impacts patient outcomes.

Comparison of Two Lighting Assessment Methods when Reading with Low Vision.

SIGNIFICANCE: Lighting assessments are an important component of low-vision rehabilitation but are rarely studied systematically. Our study indicates that preferred lighting levels support improvements in reading ease and enjoyment, independently of the evaluation technique. To determine preferred illumination level and color temperature, the LuxIQ is quicker to administer and covers broad options of settings. PURPOSE: The purpose of this study was to determine if preferred lighting, as assessed by the LuxIQ versus a standard lighting assessment, leads to better reading outcomes in individuals with low vision. METHODS: Preferred lighting was assessed at home with visually impaired persons (mean age, 75.3 years), using the LuxIQ (n = 18) or a standard technique based on trying out light bulbs of various intensity and color temperature (n = 16). Maximum reading speed and reading acuity were measured before the lighting intervention and then under the preferred lighting conditions. A 1-month telephone follow-up evaluated the (1) compliance with the lighting recommendations and, for those who modified their lighting, (2) their level of satisfaction with the length of reading time and eye strain felt during reading. RESULTS: Compared with usual lighting conditions, most participants preferred a cooler temperature at a higher illuminance level. Neither lighting assessment type appeared to lead to substantially improved objectively measurable reading outcomes. At the 1-month follow-up, 56% of the participants had modified their lighting, having a significant effect on satisfaction (P < .01), independent of assessment method. Of 18 respondents, 16 (87.5%) mentioned that reading was more enjoyable or easier with the lighting modifications. CONCLUSIONS: Both lighting assessment methods lead to comparable results, but the LuxIQ is easier and faster to use. More research is needed to determine whether the LuxIQ is suitable to be incorporated into clinical practice.

Occupational Therapy Practice Guidelines for Older Adults With Low Vision.

IMPORTANCE: The aging of the population is generating increased demand for occupational therapy practitioners to address the occupational performance of those experiencing low vision. OBJECTIVE: This Practice Guideline, which is informed by systematic reviews on interventions for older adults with low vision, is meant to serve as a reference for occupational therapy practitioners to guide best practice in service delivery, improve quality of care, enhance consumer satisfaction, and justify occupational therapy services to external stakeholders. Interventions included in this guideline address performance of activities of daily living (ADLs) and instrumental activities of daily living (IADLs), reading, and leisure and social participation. METHOD: We examined, synthesized, and integrated the results of three systematic reviews into recommendations for practice, education, and research. RESULTS: Thirty-eight articles were included in the systematic reviews, which served as the basis for clinical recommendations. A case study describes translation and application of the recommendations to clinical practice. CONCLUSIONS AND RECOMMENDATIONS: Strong evidence supports the role of occupational therapy for older adults with low vision. On the basis of the evidence, we recommend routine use of low vision rehabilitation for ADL and IADL impairments, multicomponent interventions to improve ADL and IADL performance and leisure and social participation, stand-based electronic magnification to enhance reading, and visual skills training to enhance reading for clients with a central field impairment. We recommend using client-centered problem-solving training to enhance ADL and IADL performance, reading, and leisure and social participation. Mainstream technology may be considered for use on a case-by-case basis to enhance reading performance. Finally, adapted tango may be considered for use on a case-by-case basis to enhance ADL and IADL performance and leisure and social participation. WHAT THIS ARTICLE ADDS: This Practice Guideline provides a summary of the current evidence supporting occupational therapy intervention for older adults with low vision. It summarizes the emerging literature supporting the use of mainstream technology and provides additional support for the use of multicomponent intervention strategies.

Cost-effectiveness of basic vision rehabilitation (The basic VRS-effect study): study protocol for a randomised controlled trial.

PURPOSE: To investigate the cost-effectiveness of a basic vision rehabilitation service (basic-VRS) in Portugal. We designed a parallel group, randomised controlled trial whose aim is to compare the effects and costs of 'usual low vision care' with a 'basic-VRS intervention' on self-reported visual ability and other psychosocial and health-related quality-of-life outcomes. METHODS: The trial will recruit participants that meet the following inclusion criteria: (1) visual acuity between 0.4-1.0 logMAR in the better-seeing eye, (2) cause of vision loss is diabetic retinopathy or age-related macular degeneration, (3) 18 years or older and iv) live in the community (not in nursing homes or other type of institution). Participants will be randomised to one of the study arms consisting of immediate intervention and delayed intervention. The delayed intervention group will receive 'usual care' or no intervention in the first 12 weeks. Visual acuity, contrast sensitivity and retinal structure will be assessed during the study. RESULTS: The primary outcome measure is visual ability, which will be evaluated with the Massof Activity Inventory, we expect that the intervention will raise the overall person measure or visual ability. Reading, health-related quality-of-life, anxiety and depression and social support will be also assessed. The analysis will be undertaken on an intention-to-treat basis. A cost-effectiveness analysis will be performed to provide information about the cost per unit of utility. To evaluate the cost-effectiveness of the intervention we will adopt the perspective of the healthcare system. CONCLUSION: This study will provide additional evidence about the effects of basic-VRS on self-reported visual ability. Findings from this study should also contribute to better planning of low vision provision and, consequently, may contribute to reduce barriers to basic-VRS.

A low-cost 2-D video system can accurately and reliably assess adaptive gait kinematics in healthy and low vision subjects.

3-D gait analysis is the gold standard but many healthcare clinics and research institutes would benefit from a system that is inexpensive and simple but just as accurate. The present study examines whether a low-cost 2-D motion capture system can accurately and reliably assess adaptive gait kinematics in subjects with central vision loss, older controls, and younger controls. Subjects were requested to walk up and step over a 10 cm high obstacle that was positioned in the middle of a 4.5 m walkway. Four trials were simultaneously recorded with the Vicon motion capture system (3-D system) and a video camera that was positioned perpendicular to the obstacle (2-D system). The kinematic parameters (crossing height, crossing velocity, foot placement, single support time) were calculated offline. Strong Pearson's correlations were found between the two systems for all parameters (average r = 0.944, all p < 0.001). Bland-Altman analysis showed that the agreement between the two systems was good in all three groups after correcting for systematic biases related to the 2-D marker positions. The test-retest reliability for both systems was high (average ICC = 0.959). These results show that a low-cost 2-D video system can reliably and accurately assess adaptive gait kinematics in healthy and low vision subjects.

Assessment of the visual function of partially sighted and blind Canadian youth using the VFQ-25 questionnaire: a preliminary study.

OBJECTIVE: Young people are a relatively underrepresented group in literature on poor vision and blindness. This study assessed the quality of life and function of young people who have poor vision or blindness by asking directly about their personal experiences. METHODS: A modified version of the VFQ-25 was administered to 47 students at a school for blind youth. All students who received the test had visual acuity scores of 20/100 or worse. The VFQ-25 scoring system was used, and results from additional qualitative questions were themed and ranked. Further analysis was performed, using Spearman's rank correlation coefficient to check for correlation between duration of blindness and VFQ score. RESULTS: Participants recorded a composite VFQ score of 65, showing that poor vision had a self-perceived moderate effect on their daily function. Proportion of participant's life spent with visual impairment correlated with higher composite scores. In general, lower scores were reported by participants with worse visual acuity. However, variations were observed in the mental health category. CONCLUSIONS: Young people have a more optimistic and nuanced view of their function than expected based on VFQ scores of other groups. Larger studies, particularly ones including youth in non-specialized schools would be useful to expand these findings.

[Vision-related Quality of Life with Low Vision - Assessment and Instruments]. / Visuelle Lebensqualität bei starker Sehbehinderung ­ Messung und Messinstrumente.

Patient-reported outcome measures have been met with increasing interest, particularly in clinical research. They are used to capture the patient-relevant impact of an intervention or a loss of function. In patients with loss of vision, vision-related quality of life is assessed in order to quantify the impact of visual impairment in everyday life. When using quality of life instruments, psychometric characteristics - such as reliability, validity and responsiveness - are of great importance to ensure that the collected data are robust. There are various questionnaires to assess health-related quality of life, vision-related quality of life or visual function, but not all of these are suitable for patients with very low vision. The IVI and NEI VFQ questionnaires are available in German and can be used to assess vision-related quality of life. However, additional studies to evaluate these instruments and refinement or development of novel tools are needed to better meet the growing interest in using patient-reported outcomes as clinical study endpoints.

The key informant strategy to determine the prevalence and causes of functional low vision among children in South India.

PURPOSE: To report the prevalence and causes of functional low vision (FLV) in school-age children in Coimbatore District, Tamil Nadu, India and to report our experience using the key informant (KI) method in this setting. METHODS: Children suspected of having low vision were identified by KIs or Aravind Eye Hospital personnel in Coimbatore District. All identified children underwent a cycloplegic refraction and full eye exam. A primary cause of decreased vision was determined for each child. The prevalence of FLV was calculated for children 6-14 years old. Spectacles and low vision devices were provided free of charge. RESULTS: 345 children aged 6-14 years were referred and 231 had FLV. The positive-predictive value of KI referrals was 64.5%. The prevalence of FLV was 0.071% (7.1 per 10,000; 95% CI 0.062-0.080%) and ranged from 0.026% to 0.141% across the district's blocks. Older children (age 11-14 years; OR 1.41; 95% CI 1.09-1.82) and males (OR 1.52; 95% CI 1.16-1.98) had greater odds of being diagnosed with FLV. The most common causes of FLV were retinal disorders (30.0%) and amblyopia (25.5%). Low vision devices were provided to 169 children who had a mean near and distance visual acuity improvement of 0.31 and 0.63 logMAR, respectively (p < 0.001). CONCLUSIONS: This study reports a moderate prevalence of FLV and demonstrates the ability of KIs to identify school-age children with FLV in South India. The provision of basic low vision services can improve visual outcomes in this population.

23G pars plana vitrectomy for vitreal floaters: prospective assessment of subjective self-reported visual impairment and surgery-related risks during the course of treatment.

PURPOSE: Quantifying the subjective impairment due to floaters based on an indication-specific questionnaire and setting its change between prior to and 3/12 months after elective vitrectomy in relation to surgical risks. METHODS: Single-arm longitudinal observational multicenter study. Sixty-four floater patients underwent 23G pars plana vitrectomy; simultaneous phacoemulsification was excluded. An overall self-rated impairment index (SRI) and sub-indices SRI were calculated on the basis of a modified Visual Quality of Life questionnaire (VQoL), which addresses general vision, glare, near-sight problems and mobility of floaters. SRI ranged from 0 to 100% (maximum impairment). Secondary endpoints included corrected visual acuity and complications. RESULTS: Data were collected prior to and 3 (n = 64) and 12 (n = 62) months after surgery. The median overall SRI improved (44, 12, 11%) with a statistically significant median reduction of 69% (95% confidence interval 50-89%) 3 months postop. The median sub-SRIs improved for glare (50, 17, 17%), near sight problems (50, 17, 8%), and mobility of floaters (43, 5, 0%). Sixteen eyes needed cataract surgery during follow-up (10 showed cataract already prior to vitrectomy). Eight complications were reported (6 intra-operative retinal holes, 2 post-operative retinal detachments). CONCLUSION: For the majority of floater patients, subjective impairment was profoundly reduced by vitrectomy. Benefits of surgery prevailed despite complications.

Hospital anxiety and depression scale assessment of 100 patients before and after using low vision care: A prospective study in a tertiary eye-care setting.

PURPOSE: Assessment of anxiety and depression in patients attending low vision care (LVC) using Hospital Anxiety and Depression Scale (HADS). METHODS: In this prospective, observational study, 100 patients with best-corrected visual acuity (BCVA) worse than 6/18 in the better eye or limitation of field of vision to <10° from center of fixation were assessed on the depression and anxiety subscales of HADS questionnaire before and after LVC. HADS is a 14-item scale with seven items each for anxiety and depression subscales. Scoring for each item ranges from zero to three. A subscale score >8 denotes anxiety or depression. RESULTS: Mean age at presentation was 38.2 years. Mean duration of symptoms was 9.6 years. Underlying etiology of visual impairment included retinal dystrophy/degeneration (n = 35), disorders of the optic nerve (n = 17), glaucoma (n = 10), diabetic retinopathy (n = 9), age-related macular degeneration (n = 5), uncorrected refractive errors (n = 5), and miscellaneous diseases (n = 19). Mean presenting BCVA in the better eye was 0.83 (±0.64) which improved significantly to 0.78 (±0.63) after LVC (P < 0.001). The HADS-Depression subscale score was comparable for severity of visual impairment for both distance (P = 0.57) and near vision (P = 0.61). Similarly, HADS-Anxiety scores were also comparable for severity of distance (P = 0.34) and near-visual impairment (NVI; P = 0.50). At baseline, mean HADS-Depression and HADS-Anxiety scores were 8.4 (±3.7) and 9.6 (±4.3) points, which improved significantly to 6.0 (±3.4) and 6.7 (±3.7), respectively, after low-vision correction (P < 0.001). CONCLUSION: Low vision correction can significantly improve anxiety and depression indicators in visually impaired patients.

Trends in Visual Health Inequalities in Childhood Through Associations of Visual Function With Sex and Social Position Across 3 UK Birth Cohorts.

Importance: Despite the existing country-specific strategies tackling social inequalities in visual health in adults, little is known about trends in visual function in childhood and its association with social position. Objective: To investigate the distribution of childhood visual function in the United Kingdom and associations with early-life social position between 1961 and 1986, a period of significant social change. Design, Setting, and Participants: Longitudinal cohort study using harmonized data sets from the British 1946, 1958, and 1970 national birth cohorts. In total, 14 283 cohort members with complete data on visual acuity at age 15 or 16 years, measured in 1961, 1974, and 1986, respectively, for each cohort, and social position were assessed. Main Outcomes and Measures: Using habitual distance visual acuity (with correction if prescribed), participants were assigned to a visual function category ranging from bilateral normal to visual impairment/severe visual impairment/blindness (International Statistical Classification of Diseases, Tenth Revision, Clinical Modification). Distribution of visual function over time and associations with social position (risk ratios [RRs] and 95% confidence intervals) were analyzed. Results: Complete data were available for 3152 participants (aged 15 years; 53% boys [n = 1660]) in the 1946 Medical Research Council National Survey of Health and Development, 6683 participants (aged 16 years; 51% boys [n = 3420]) in the 1958 National Child Development Study, and 4448 participants (aged 16 years; 48% boys [n = 2156]) in the 1970 British Birth Cohort Study. The proportion of children with bilateral normal vision decreased by 1.3% (95% CI, -5.1% to 2.7%) in 1974 and 1.7% (95% CI, -5.9% to 2.7%) in 1986. The risk of overall impaired vision increased by 1.20 times (95% CI, 1.01-1.43) and the risk of visual impairment/severe visual impairment/blindness by 1.75 times (95% CI, 1.03-2.98) during this period. Girls were consistently at increased risk of all vision impairment categories. Higher social position at birth and in childhood was associated with reduced risk of visual impairment/severe visual impairment/blindness (RR, 0.58; 95% CI, 0.20-1.68) and unilateral impairment (RR, 0.89; 95% CI, 0.72-1.11), respectively. Conclusions and Relevance: Our study provides evidence of temporal decline in childhood visual function between 1961 and 1986. Despite the limited power of the analysis owing to the small sample size of those with impaired vision, we found an emergence of a contribution of sociodemographic status to the cohort effect that may be the antecedent of the current picture of childhood blindness. Equally, early-life social position may also have contributed to the current social patterning in visual function in older adults in the United Kingdom. These findings highlight the potential value of targeting children in national ophthalmic public policies tackling inequalities.

Assessment of the Apple iPad as a low-vision reading aid.

PurposeLow-vision clients frequently report having problems with reading. Using magnification, reading performance (as measured by reading speed) can be improved by up to 200%. Current magnification aids can be expensive or bulky; therefore, we explored if the Apple iPad offers comparable performance in improving reading speeds, in comparison with a closed-circuit television (CCTV) video magnifier, or other magnification devices.MethodsWe recruited 100 participants between the ages of 24-97 years, with low vision who were literate and cognitively capable, of whom 57 had age-related macular degeneration. To assess reading, participants read standardized iReST texts and were tested for comprehension. We compared reading speed on the Apple iPad (10 inch) with that of the CCTV, home magnification devices, and baseline measures.ResultsAll assistive devices improved reading rates in comparison to baseline (P<0.001, Hedge's g>1), however, there was no difference in improvement across devices (P>0.05, Hedge's g<0.1). When experience was taken into account, those with iPad experience read, on average, 30 words per minute faster than first time iPad users, whereas CCTV experience did not influence reading speed.ConclusionsIn our sample, the Apple iPad was as effective as currently used technologies for improving reading rates. Moreover, exposure to, and experience with the Apple iPad might increase reading speed with that device. A larger sample size, however, is needed to do subgroup analysis on who would optimally benefit from each type of magnification device.

Effect of rehabilitation worker input on visual function outcomes in individuals with low vision: study protocol for a randomised controlled trial.

BACKGROUND: Visual Rehabilitation Officers help people with a visual impairment maintain their independence. This intervention adopts a flexible, goal-centred approach, which may include training in mobility, use of optical and non-optical aids, and performance of activities of daily living. Although Visual Rehabilitation Officers are an integral part of the low vision service in the United Kingdom, evidence that they are effective is lacking. The purpose of this exploratory trial is to estimate the impact of a Visual Rehabilitation Officer on self-reported visual function, psychosocial and quality-of-life outcomes in individuals with low vision. METHODS/DESIGN: In this exploratory, assessor-masked, parallel group, randomised controlled trial, participants will be allocated either to receive home visits from a Visual Rehabilitation Officer (n = 30) or to a waiting list control group (n = 30) in a 1:1 ratio. Adult volunteers with a visual impairment, who have been identified as needing rehabilitation officer input by a social worker, will take part. Those with an urgent need for a Visual Rehabilitation Officer or who have a cognitive impairment will be excluded. The primary outcome measure will be self-reported visual function (48-item Veterans Affairs Low Vision Visual Functioning Questionnaire). Secondary outcome measures will include psychological and quality-of-life metrics: the Patient Health Questionnaire (PHQ-9), the Warwick-Edinburgh Mental Well-being Scale (WEMWBS), the Adjustment to Age-related Visual Loss Scale (AVL-12), the Standardised Health-related Quality of Life Questionnaire (EQ-5D) and the UCLA Loneliness Scale. The interviewer collecting the outcomes will be masked to the group allocations. The analysis will be undertaken on a complete case and intention-to-treat basis. Analysis of covariance (ANCOVA) will be applied to follow-up questionnaire scores, with the baseline score as a covariate. DISCUSSION: This trial is expected to provide robust effect size estimates of the intervention effect. The data will be used to design a large-scale randomised controlled trial to evaluate fully the Visual Rehabilitation Officer intervention. A rigorous evaluation of Rehabilitation Officer input is vital to direct a future low vision rehabilitation strategy and to help direct government resources. TRIAL REGISTRATION: The trial was registered with ( ISRCTN44807874 ) on 9 March 2015.

Equating Visual Function Scales to Facilitate Reporting of Medicare Functional G-Code Severity/Complexity Modifiers for Low-Vision Patients.

OBJECTIVE: To present a method of estimating and equating scales across functional assessment instruments that appropriately represents changes in a patient's functional ability and can be meaningfully mapped to changes in Medicare G-code severity modifiers. DESIGN: Previously published measures of patients' overall visual ability, estimated from low-vision patient responses to 7 different visual function rating scale questionnaires, are equated and mapped onto Medicare G-code severity modifiers. SETTING: Outpatient low-vision rehabilitation clinics. PARTICIPANTS: The analyses presented in this article were performed on raw or summarized low-vision patient ratings of visual function questionnaire (VFQ) items obtained from previously published research studies. INTERVENTIONS: Previously published visual ability measures from Rasch analysis of low-vision patient ratings of items in different VFQs (National Eye Institute Visual Functioning Questionnaire, Index of Visual Functioning, Activities of Daily Vision Scale, Visual Activities Questionnaire) were equated with the Activity Inventory (AI) scale. The 39 items in the Self-Report Assessment of Functional Visual Performance (SRAFVP) and the 48 items in the Veterans Affairs Low Vision Visual Functioning Questionnaire (VA LV VFQ) were paired with similar items in the AI in order to equate the scales. MAIN OUTCOME MEASURES: Tests using different observation methods and indicators cannot be directly compared on the same scale. All test results would have to be transformed to measures of the same functional ability variable on a common scale as described here, before a single measure could be estimated from the multiple measures. RESULTS: Bivariate regression analysis was performed to linearly transform the SRAFVP and VA LV VFQ item measures to the AI item measure scale. The nonlinear relationship between person measures of visual ability on a logit scale and item response raw scores was approximated with a logistic function, and the 2 regression coefficients were estimated for each of the 7 VFQs. These coefficients can be used with the logistic function to estimate functional ability on the same interval scale for each VFQ and for transforming raw VFQ responses to Medicare's G-code severity modifier categories. CONCLUSIONS: The principle of using equated interval scales allows for comparison across measurement instruments of low-vision functional status and outcomes, but can be applied to any area of rehabilitation.

Random word recognition chart helps scotoma assessment in low vision.

PURPOSE: To evaluate the use of SKread, a vision test based on random word sequences that prevents the prediction of upcoming words by linguistic criteria and is simple to score in a clinical setting. METHODS: SKread combines the standardized format of the MNread test with sequences of random words and letters like the Pepper Visual Skills for Reading test. A total of 231 subjects (aged 16 to 97 years) participated. We report data from 136 eyes of subjects with a maculopathy and 65 with normal or near-normal vision. Test reliability was investigated on an additional 30 eye-healthy subjects. We tested visual acuity and reading performance for continuous text and random words monocularly. Reading speed and all errors made are reported. RESULTS: Reading speed was always higher for continuous text than for random word sequences, even in normally sighted subjects for whom the median reading times per paragraph were 2.4 s (MNread) vs. 6.8 s (SKread). In patients with maculopathies, the medians were 4.2 s vs. 12.25 s. These differences were statistically significant. Number and type of errors made depended only negligibly on age and visual acuity. Patients with a dense scotoma right of fixation made more "right errors" by missing letters at the end of words, whereas those with a scotoma left of fixation made more "left errors" by missing letters at the beginning of words. The SKread test showed good test-retest repeatability. CONCLUSIONS: The unpredictability of random word and letter sequences renders reading performance highly dependent on eyesight and less dependent on reading skill and educational level. Recurrent right or left errors can indicate the presence and location of a scotoma without expensive equipment. This knowledge can be used to teach patients about how the scotoma can interfere with their vision.

Developing an instrumental activities of daily living tool as part of the low vision assessment of daily activities protocol.

PURPOSE: To determine the validity, reliability, and measurement characteristics using factor and Rasch analysis of the Very Low Vision Instrumental Activities of Daily Living (IADL-VLV) in persons with severe vision loss. METHODS: From an initial pool of 296 tasks, 25 were shortlisted after conducting a Delphi survey with persons designated legally blind. Using further input from occupational therapy and low-vision professionals, 11 activities were chosen to be pilot tested. Forty legally blind participants (better eye visual acuity < 20/200) underwent clinical assessments and functional tests as well as the 53 IADL tasks related to the 11 activities. The task pool was refined and condensed using factor and Rasch analysis. RESULTS: Based on iterative principal component analyses, tasks were grouped together into the following domains: reading signs/information access, signature placement, clothes sorting, shelf search, gesture recognition, clock reading, and table search. A final selection of 23 tasks yielded satisfactory measurement characteristics, differentiated between at least four different levels of IADL performance (person separation of 3.8), and had adequate task difficulty for the tested sample (person mean -0.61). In multivariate analyses, only visual acuity (VA) and percent of remaining visual field (VF) were associated with IADL performance. CONCLUSIONS: Using a large item pool, participant, and expert input, as well as factor and Rasch analysis, we designed a valid and reliable assessment to measure vision-related IADL performance in persons with severe vision loss. This assessment tool can be used in clinical sight restoration trials.

Mental health state and quality of life questionnaire in low vision assessment: a case report.

BACKGROUND: Vision impairment associated with diabetic retinopathy, is well known and low vision rehabilitation is always recommended. In this report, the importance of objective measure of mental health and quality of life screening in diabetic retinopathy low-vision assessment is discussed. CASE PRESENTATION: We describe the case of a 43-year-old Asian female who has mild vision impairment due to tractional retinal detachment secondary to diabetic retinopathy and how mental health screening and quality of life screening during low vision rehabilitation can improve in the management of this patient. CONCLUSION: Although vision impairment was mild, the psychological impact was enormous and affected her quality of life substantially. This case report illustrates that recognition of the mental health and quality of life impact on visual impairment is critical to the rehabilitation management of low vision patients with diabetic retinopathy.

A standardized obstacle course for assessment of visual function in ultra low vision and artificial vision.

We describe an indoor, portable, standardized course that can be used to evaluate obstacle avoidance in persons who have ultralow vision. Six sighted controls and 36 completely blind but otherwise healthy adult male (n=29) and female (n=13) subjects (age range 19-85 years), were enrolled in one of three studies involving testing of the BrainPort sensory substitution device. Subjects were asked to navigate the course prior to, and after, BrainPort training. They completed a total of 837 course runs in two different locations. Means and standard deviations were calculated across control types, courses, lights, and visits. We used a linear mixed effects model to compare different categories in the PPWS (percent preferred walking speed) and error percent data to show that the course iterations were properly designed. The course is relatively inexpensive, simple to administer, and has been shown to be a feasible way to test mobility function. Data analysis demonstrates that for the outcome of percent error as well as for percentage preferred walking speed, that each of the three courses is different, and that within each level, each of the three iterations are equal. This allows for randomization of the courses during administration.

Impact of colour in the assessment of potential visual acuity in patients with age-related macular degeneration.

OBJECTIVE: To compare chromatic and achromatic potential visual acuity (PVA) in patients with bilateral low vision caused by age-related macular degeneration (AMD). DESIGN: Prospective, nonrandomized, observational case series. PARTICIPANTS: Fifty-five patients, representing a consecutive series of patients all presenting with bilateral AMD. METHODS: Best-corrected visual acuity of each eye was measured using an Early Treatment in Diabetic Retinopathy Study (ETDRS) chart with appropriate near correction. Included were cases with visual acuity of 0.4 logMAR (20/50) or worse in both eyes. Achromatic and chromatic PVA were measured in each eye using white on black and red on yellow flooding E charts at 50 cm in controlled lighting conditions. RESULTS: One hundred and seven eyes from 55 patients were included in the analysis. Mean achromatic and chromatic PVA were 0.69 ± 0.26 and 0.65 ± 0.22 logMAR, respectively. Overall, patients had a significantly higher chromatic than achromatic PVA, with a median difference of 0.1 logMAR (p<0.05). Patients with ETDRS visual acuity worse than 0.9 logMAR also had a significantly higher chromatic than achromatic PVA, with a median difference of 0.1 logMAR (p<0.05). Patients with ETDRS visual acuity between 0.4 and 0.9 logMAR had a trend toward a higher chromatic than achromatic visual acuity that was not significant, with a median difference of 0.1 logMAR (p = 0.8539). CONCLUSIONS: Patients with low vision caused by AMD can discern smaller targets when a red on yellow colour scheme is used than when using achromatic white on black charts.

Visual impairment and subsequent use of support services among older people: longitudinal findings from the Blue Mountains Eye Study.

PURPOSE: To assess the impact of visual impairment and blindness on the incident use of community support services in the Blue Mountains Eye Study. DESIGN: Population-based cohort. METHODS: Of 3654 baseline participants (1992-1994), 2334, 1952, and 1149 were re-examined after 5, 10, and 15 years, respectively. Incident visual impairment was defined as subsequent development of visual impairment (visual acuity <20/40) in the better eye of subjects with best-corrected visual acuity ≥20/40 at baseline. Community support service use included regular use of Meals on Wheels, Home Care, or community nurse services. Informal support included assistance from family or friends. Discrete logistic regression models with time-dependent study and outcome variables were used to assess associations between visual impairment and subsequent use of support, adjusted for potential confounders. RESULTS: Among participants with bilateral visual impairment at baseline, incident use of community services over 5-15 years was 41.7% compared to 19.4% in those without visual impairment at baseline (odds ratio, 1.39; 95% confidence interval, 0.54-3.60). Persons with incident bilateral visual impairment were more likely to subsequently need community support (odds ratio, 3.32; confidence interval 1.96-5.59) in 5 years, compared to persons without visual impairment during the entire follow-up period. Baseline older age, walking disability, receiving pension, and having 2+ hospital admissions within 12 months were also significantly associated with incident use of support services. CONCLUSIONS: Development of bilateral visual impairment in this cohort was associated with greater likelihood of subsequent use of community or informal support services in 5 years, independent of physical comorbidities.