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.

Risk assessment of sudden visual loss following non-penetrating deep sclerectomy in severe and end-stage glaucoma.

BACKGROUND/OBJECTIVES: To assess the risk of immediate sudden visual loss ("wipe-out" phenomenon) following non-penetrating deep sclerectomy (NPDS) for end-stages glaucoma within the first 6-months postoperative period. SUBJECTS/METHODS: Monocenter database study. We reviewed the results for 73 eyes with severe or end-stage glaucoma that underwent NPDS. End-stage glaucoma (stage 5) was defined by the inability of patients to perform the Humphrey visual field test or by a visual acuity <20/200 due to glaucoma, according to the Glaucoma Staging System classification. Severe glaucoma (stage 4) was defined by a mean deviation (MD) <-20 dB by the preoperative 24-2 Humphrey visual field assessment. All eyes had a severe defect on the central 10° visual field: only a central island of vision remained. "Wipe-out" was defined as the permanent postoperative reduction of visual acuity to <20/200 or to "counting fingers" or less if preoperative visual acuity was <20/200. RESULTS: The mean age was 60 years (range 22-86). Before surgery, the average MD (Humphrey 24-2) was -25.6 ± 3.8 dB, the MD (Humphrey 10-2) -19.9 ± 7.0 dB, and the VFI 24.6 ± 13%. There were no cases of postoperative flat anterior chamber. No patients experienced "wipe-out" within the first 6 months following surgery. At the six-month visit, intraocular pressure (IOP) had decreased significantly from 22.0 ± 8.8 to 13.5 ± 4.5 mmHg (P<0.001). There were no significant changes in mean visual acuity after 6 months (P = 6). CONCLUSIONS: In our study, NPDS provided considerable IOP decrease with no occurrences of "wipe-out" and few other complications. Consideration of NPDS in end-stage and severe glaucoma is advisable given its low risk of intraoperative and postoperative complications and the low risk of wipe out. This surgery should probably be offered with less apprehension about the risk of "wipe-out" in end-stages glaucoma.

Cognitive load of walking in people who are blind: Subjective and objective measures for assessment.

BACKGROUND: Although walking without vision seems to carry a high cognitive cost, few studies have measured the cognitive load involved in this activity in blind people. The aim of this study was to assess the cognitive load of walking in blind people, using gait analysis, a dual task paradigm and a subjective assessment of cognitive load. METHODS: In a quantitative quasi-experimental design, 25 blind adults walked 40 meters. In one trial, participants walked normally (control condition). In another, they walked while performing an auditory simple reaction time task, and in the third trial they walked, performed the simple reaction time task and avoided obstacles. In addition to the simple reaction time task performance, walking speed was recorded, and participants provided a subjective assessment of cognitive load after each trial. Performance of participants aged less than 60 years were compared with those aged over than 60 years. RESULTS: Walking significantly reduced performance of the simple reaction time task; carrying out the simple reaction time task while walking significantly reduced walking performance and increased the subjective assessment of cognitive load; and simple reaction time task performance decreased and subjective assessment increased when obstacles were present. Few significant age effects were found. SIGNIFICANCE: Walking without vision involves a cognitive load that increases when the environment becomes complex. Each of the three methods used is relevant when assessing the cognitive load involved in walking in blind people, and could be useful in rehabilitation intervention. The results obtained allowed recommendations to be suggested for the design of technological mobility devices.

Rapid assessment of avoidable blindness: Prevalence of blindness, visual impairment and diabetes in nuevo leon, Mexico 2014.

PURPOSE: To estimate the prevalence of blindness, visual impairment, diabetes mellitus, and diabetic retinopathy in patients aged 50 years and older in the State of Nuevo León, Mexico. METHODS: Ninety-one clusters of 60 people aged 50+ were selected randomly and a rapid assessment of avoidable blindness (RAAB) was conducted. Participants had their visual acuity and cause of visual impairment assessed, underwent a random glucose test and fundoscopy under mydriasis if they had diabetes. The diabetic retinopathy (DR) degree was classified according to the Scottish diabetic retinopathy grading scheme. RESULTS: From the sample 5,055 (92.6%) people were examined. The blindness prevalence was 1.7% (95% Confidence Interval: 1.3-2.1%). Cataract (32.6%), DR (29.1%) and glaucoma (16.3%) were the leading causes of blindness. The prevalence of severe, moderate, and early visual impairment was 1.0%, 5.1%, and 7.7%, respectively. Among respondents, 31% had diabetes and 8.1% of them was not diagnosed prior to the study. Of all participants with diabetes, 50% had glucose levels of 200 mg/dl or higher and 15.7% had sight-threatening diabetic retinopathy. CONCLUSIONS: Besides strengthening of cataract intervention activities, more ophthalmic services for diabetic retinopathy and glaucoma control are needed in Nuevo León to provide timely intervention to prevent blindness.

The prevalence of vision loss due to ocular trauma in the Australian National Eye Health Survey.

BACKGROUND: To determine the prevalence of vision loss due to ocular trauma in Australia. METHODS: The National Eye Health Survey (NEHS) is a population-based cross-sectional study that examined 3098 non-Indigenous Australians (aged 50-98 years) and 1738 Indigenous Australians (aged 40-92 years) living in 30 randomly selected sites, stratified by remoteness. An eye was considered to have vision loss due to trauma if the best-corrected visual acuity was worse than 6/12 and the main cause was attributed to ocular trauma. This determination was made by two independent ophthalmologists and any disagreements were adjudicated by a third senior ophthalmologist. RESULTS: The sampling weight adjusted prevalence of vision loss due to ocular trauma in non-Indigenous Australians aged 50 years and older and Indigenous Australians aged 40 years and over was 0.24% (95%CI: 0.10, 0.52) and 0.79% (95%CI: 0.56, 1.13), respectively. Trauma was attributed as an underlying cause of bilateral vision loss in one Indigenous participant, with all other cases being monocular. Males displayed a higher prevalence of vision loss from ocular trauma than females in both the non-Indigenous (0.47% vs. 1.25%, p=0.03) and Indigenous populations (0.12% vs. 0.38%, p=0.02). After multivariate adjustments, residing in Very Remote geographical areas was associated with higher odds of vision loss from ocular trauma. CONCLUSIONS: We estimate that 2.4 per 1000 non-Indigenous and 7.9 per 1000 Indigenous Australian adults have monocular vision loss due to a previous severe ocular trauma. Our findings indicate that males, Indigenous Australians and those residing in Very Remote communities may benefit from targeted health promotion to improve awareness of trauma prevention strategies.

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.

Changing patterns of cataract services in North-West Nigeria: 2005-2016.

PURPOSE: This study was conducted to assess the impact of the eye care programme on cataract blindness and cataract surgical services in Sokoto, Nigeria over a 12 year period 2005-2016. METHODS: Data from the 2005 population based cross-sectional study of blindness in Sokoto state was re-analysed to obtain baseline estimates of the prevalence of cataract blindness and cataract surgical coverage for persons 50 years and over in Wurno health zone. A population based survey of a representative sample of persons 50 years and over in Wurno health zone was conducted in July 2016. Data on eye health workforce, infrastructure and cataract surgical services between 2005 and 2016 were analysed from relevant documents. RESULTS: In 2005 the unadjusted prevalence of bilateral cataract blindness (<3/60) in people 50 years and over in Wurno health zone was 5.6% (95% CI: 3.1, 10.1). By 2016 this had fallen to 2.1% (95% CI 1.5%, 2.7%), with the age-sex adjusted prevalence being 1.9% (95% CI 1.3%, 2.5%). The CSC for persons with visual acuity <3/60, <6/60, <6/18 for Wurno health zone was 9.1%, 7.1% and 5.5% respectively in 2005 and this had increased to 67.3%, 62.1% and 34.7% respectively in 2016. The CSR in Sokoto state increased from 272 (1005 operations) in 2006, to 596 (2799 operations) in 2014. In the 2005 survey, couching (a procedure used by traditional practitioners to dislocate the lens into the vitreous cavity) accounted for 87.5% of all cataract interventions, compared to 45.8% in the 2016 survey participants. In 2016 18% of eyes having a cataract operation with IOL implantation had a presenting visual acuity of <6/60 (poor outcome) with the main causes being postoperative complications (53%) and uncorrected refractive error (29%). CONCLUSION: Between 2005 and 2016 there was a doubling in cataract surgical rate, a 7 times increase in cataract surgical coverage (<3/60), and a decrease in cataract blindness and the proportion of eyes being couched. However, there remains a high prevalence of un-operated cataract in 2016 indicating a need to further improve access to affordable and good quality cataract surgical services.

A Global View on Output and Outcomes of Cataract Surgery With National Indices of Socioeconomic Development.

Purpose: Cataract blindness accounts for a substantial proportion of blindness worldwide. Understanding the correlations between national levels of socioeconomic development with the quantity and quality of cataract surgery may provide insight for the prioritization and resource allocation for blindness prevention programs. Methods: The relationships between human development index (HDI), gross domestic product (GDP) per capita, and cataract surgical coverage (CSC) and visual outcome of cataract surgery were examined in a multinational study utilizing secondary data from the repository for Rapid Assessment of Avoidable Blindness (RAAB), World Health Organization, Global Burden of Disease, United Nations, and the World Bank. Results: A total of 266 RAAB studies across 73 countries/territories were retrieved. Linear regression model results revealed strong associations of HDI with prevalence of cataract blindness (ß = -7.056, P < 0.001), CSC (ß = 60.808, P = 0.004), proportion of intraocular lens (IOL) implantation (ß = 87.040, P = 0.001), and proportion of cases with good vision outcomes among operated eyes (ß = 73.351, P < 0.001) in studies performed between 1995 and 2009. Similar associations were observed for studies performed between 2010 and 2015. In addition, countries with lower GDP per capita showed a higher rate of cataract blindness (ß = -0.527, P = 0.001), lower CSC (ß = 9.800, P < 0.001), lower percentage of IOL implantation (ß = 6.871, P = 0.001), and fewer patients with good vision outcomes after surgery (ß = 7.959, P < 0.001). After controlling survey year, country, and other factors, GDP per capita and HDI were also found to be significantly associated with CSC and visual outcomes after cataract surgery (all P < 0.05). Conclusions: We documented the strong associations of socioeconomic indices with quantity and quality of cataract surgery. These socioeconomic indicators should be considered as important factors for developing strategies aimed to improve worldwide cataract surgery service delivery.

Assessment of sleep in subjects with visual impairment: Comparison using subjective and objective methods.

The objective of the present study was to verify the agreement between objective and subjective measures of sleep in people with and without visual impairment. Thirty-seven subjects with visual impairment participated in the study (19 blind without light perception and 18 low-vision), as well as 34 subjects with normal vision, with paired age and gender characteristics. For the subjective sleep evaluation, we used the Sleep Quality Index-PSQI and for the objective evaluation we used the ActiGraph GT3X+. Among the three analyzed groups, the blind was the only ones who presented differences between subjective and objective sleep duration (p = 0.021). Furthermore, the concordance between subjective and objective sleep duration (ICC = 0.388; p = 0.108) was not observed in blind subjects, and a greater variability of differences in sleep duration between the two methods was observed by the Bland Altman scatter plot. We concluded that the sleep duration obtained by PSQI did not show agreement for the objective sleep duration in blind subjects without light perception.

Detecting Glaucoma With a Portable Brain-Computer Interface for Objective Assessment of Visual Function Loss.

Importance: The current assessment of visual field loss in diseases such as glaucoma is affected by the subjectivity of patient responses and the lack of portability of standard perimeters. Objective: To describe the development and initial validation of a portable brain-computer interface (BCI) for objectively assessing visual function loss. Design, Setting, and Participants: This case-control study involved 62 eyes of 33 patients with glaucoma and 30 eyes of 17 healthy participants. Glaucoma was diagnosed based on a masked grading of optic disc stereophotographs. All participants underwent testing with a BCI device and standard automated perimetry (SAP) within 3 months. The BCI device integrates wearable, wireless, dry electroencephalogram and electrooculogram systems and a cellphone-based head-mounted display to enable the detection of multifocal steady state visual-evoked potentials associated with visual field stimulation. The performances of global and sectoral multifocal steady state visual-evoked potentials metrics to discriminate glaucomatous from healthy eyes were compared with global and sectoral SAP parameters. The repeatability of the BCI device measurements was assessed by collecting results of repeated testing in 20 eyes of 10 participants with glaucoma for 3 sessions of measurements separated by weekly intervals. Main Outcomes and Measures: Receiver operating characteristic curves summarizing diagnostic accuracy. Intraclass correlation coefficients and coefficients of variation for assessing repeatability. Results: Among the 33 participants with glaucoma, 19 (58%) were white, 12 (36%) were black, and 2 (6%) were Asian, while among the 17 participants with healthy eyes, 9 (53%) were white, 8 (47%) were black, and none were Asian. The receiver operating characteristic curve area for the global BCI multifocal steady state visual-evoked potentials parameter was 0.92 (95% CI, 0.86-0.96), which was larger than for SAP mean deviation (area under the curve, 0.81; 95% CI, 0.72-0.90), SAP mean sensitivity (area under the curve, 0.80; 95% CI, 0.69-0.88; P = .03), and SAP pattern standard deviation (area under the curve, 0.77; 95% CI, 0.66-0.87; P = .01). No statistically significant differences were seen for the sectoral measurements between the BCI and SAP. Intraclass coefficients for global and sectoral parameters ranged from 0.74 to 0.92, and mean coefficients of variation ranged from 3.03% to 7.45%. Conclusions and Relevance: The BCI device may be useful for assessing the electrical brain responses associated with visual field stimulation. The device discriminated eyes with glaucomatous neuropathy from healthy eyes in a clinically based setting. Further studies should investigate the feasibility of the BCI device for home-based testing as well as for detecting visual function loss over time.

The Effect of Programmable Tactile Displays on Spatial Learning Skills in Children and Adolescents of Different Visual Disability.

Vision loss has severe impacts on physical, social and emotional well-being. The education of blind children poses issues as many scholar disciplines (e.g., geometry, mathematics) are normally taught by heavily relying on vision. Touch-based assistive technologies are potential tools to provide graphical contents to blind users, improving learning possibilities and social inclusion. Raised-lines drawings are still the golden standard, but stimuli cannot be reconfigured or adapted and the blind person constantly requires assistance. Although much research concerns technological development, little work concerned the assessment of programmable tactile graphics, in educative and rehabilitative contexts. Here we designed, on programmable tactile displays, tests aimed at assessing spatial memory skills and shapes recognition abilities. Tests involved a group of blind and a group of low vision children and adolescents in a four-week longitudinal schedule. After establishing subject-specific difficulty levels, we observed a significant enhancement of performance across sessions and for both groups. Learning effects were comparable to raised paper control tests: however, our setup required minimal external assistance. Overall, our results demonstrate that programmable maps are an effective way to display graphical contents in educative/rehabilitative contexts. They can be at least as effective as traditional paper tests yet providing superior flexibility and versatility.

Olfactory Function Assessment of Blind Subjects Using the Sniffin' Sticks Test.

OBJECTIVE: In recent years, a growing number of studies have focused on the olfactory abilities of blind individuals as well as their tactile and auditory senses. In this study, we aimed to investigate possible alterations in the sense of smell in early- and late-blind subjects as compared with sighted controls, using a Sniffin' Sticks test battery. STUDY DESIGN: Prospective clinical study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: A total of 66 subjects were included in the study. The subjects were divided into 2 groups: blind subjects-who were then subgrouped as subjects with congenital blindness (n = 17) and those with acquired blindness (n = 16)-and sighted subjects (n = 33). We compared both congenitally and acquired blind subjects with sighted counterparts using the Sniffin' Sticks test for odor threshold, odor discrimination, odor identification, and total odor scores. RESULTS: The blind subjects were more successful than their sighted counterparts in odor discrimination and odor threshold tasks. There was no statistically significant difference between the blind participants and the sighted individuals in terms of odor identification value. Another important finding was that the difference between individuals with congenital blindness and those with acquired blindness was not significant in any of the parameters. CONCLUSION: This finding may suggest that odor discrimination and odor threshold in blind people were superior to those of controls. There was no difference in any of the results of tasks among congenital and acquired blind subjects.

The effects of technological advances on outcomes for elderly persons with exudative age-related macular degeneration.

IMPORTANCE Exudative age-related macular degeneration (ARMD) is the major cause of blindness among US elderly. Developing effective therapies for this disease has been difficult. OBJECTIVES To assess the effects of introducing new therapies for treating exudative ARMD on vision of the affected population and other outcomes among Medicare beneficiaries newly diagnosed as having ARMD. DESIGN The study used data from a 5% sample of Medicare claims and enrollment data with a combination of a regression discontinuity design and propensity score matching to assess the effects on the introduction or receipt of new technologies on study outcomes during a 2-year follow-up period. SETTING AND PARTICIPANTS The analysis was based on longitudinal data for the United States, January 1, 1994, to December 31, 2011, for Medicare beneficiaries with fee-for-service coverage. The sample was limited to beneficiaries 68 years or older newly diagnosed as having exudative ARMD as indicated by beneficiaries having no claims with this diagnosis in a 3-year look-back period. EXPOSURES The comparisons with vision outcomes were after vs before the introduction of photodynamic therapy and anti-vascular endothelial growth factor (VEGF) therapy. The comparisons for depression and long-term care facility admission were between beneficiaries newly diagnosed as having exudative ARMD who received photodynamic therapy or anti-VEGF therapy compared with beneficiaries having the diagnosis who received no therapy for this disease. MAIN OUTCOMES AND MEASURES Onset of decrease in vision, vision loss or blindness, depression, and admission to a long-term care facility. RESULTS Among beneficiaries newly diagnosed as having exudative ARMD, the introduction of anti-VEGF therapy reduced vision loss by 41% (95% CI, 52%-68%) and onset of severe vision loss and blindness by 46% (95% CI, 47%-63%). Such beneficiaries who received anti-VEGF therapy and were not admitted to a long-term care facility during the look-back period were 19% (95% CI, 72%-91%) less likely on average to be admitted to a long-term care facility during the follow-up period. CONCLUSIONS AND RELEVANCE This study demonstrates gains in population vision from the introduction of anti-VEGF therapy for patients 68 years or older with an exudative ARMD diagnosis in community-based settings in the United States.

Sensory substitution: closing the gap between basic research and widespread practical visual rehabilitation.

Sensory substitution devices (SSDs) have come a long way since first developed for visual rehabilitation. They have produced exciting experimental results, and have furthered our understanding of the human brain. Unfortunately, they are still not used for practical visual rehabilitation, and are currently considered as reserved primarily for experiments in controlled settings. Over the past decade, our understanding of the neural mechanisms behind visual restoration has changed as a result of converging evidence, much of which was gathered with SSDs. This evidence suggests that the brain is more than a pure sensory-machine but rather is a highly flexible task-machine, i.e., brain regions can maintain or regain their function in vision even with input from other senses. This complements a recent set of more promising behavioral achievements using SSDs and new promising technologies and tools. All these changes strongly suggest that the time has come to revive the focus on practical visual rehabilitation with SSDs and we chart several key steps in this direction such as training protocols and self-train tools.

Assessment of the caudate nucleus and its relation to route learning in both congenital and late blind individuals.

BACKGROUND: In the absence of visual input, the question arises as to how complex spatial abilities develop and how the brain adapts to the absence of this modality. As such, the aim of the current study was to investigate the relationship between visual status and an important brain structure with a well established role in spatial cognition and navigation, the caudate nucleus. We conducted a volumetric analysis of the caudate nucleus in congenitally and late blind individuals, as well as in matched sighted control subjects. RESULTS: No differences in the volume of the structure were found either between congenitally blind (CB) and matched sighted controls or between late blind (LB) and matched sighted controls. Moreover, contrary to what was expected, no significant correlation was found between caudate volume and performance in a spatial navigation task. Finally, consistent with previously published reports, the volume of the caudate nucleus was found to be negatively correlated with age in the sighted; however such correlations were not significant in the blind groups. CONCLUSION: Although there were no group differences, the absence of an age-volume correlation in the blind suggests that visual deprivation may still have an effect on the developmental changes that occur in the caudate nucleus.