Vision loss and 12-year risk of dementia in older adults: the 3C cohort study.

To analyze the longitudinal relationships between vision loss and the risk of dementia in the first 2 years, from 2 to 4 years and beyond 4 years after inclusion and to determine the roles of depressive symptomatology and engagement in cognitively stimulating activities in these associations. This study is based on the Three-City (3C) study, a population-based cohort of 7736 initially dementia-free participants aged 65 years and over with 12 years of follow-up. Near visual impairment (VI) was measured and distance visual function (VF) loss was self-reported. Dementia was diagnosed and screened over the 12-year period. At baseline, 8.7% had mild near VI, 4.2% had moderate to severe near VI, and 5.3% had distance VF loss. Among the 882 dementia cases diagnosed over the 12-year follow-up period, 140 cases occurred in the first 2 years, 149 from 2 to 4 years and 593 beyond 4 years after inclusion. In Cox multivariate analysis, moderate to severe near VI was associated with an increased risk of dementia in the first 2 years (HR 2.0, 95% CI 1.2-3.3) and from 2 to 4 years (HR 1.8, 95% CI 1.1-3.1) but the association was not significant beyond 4 years after inclusion even if pointing in similar direction (HR 1.3, 95% CI 0.95-1.9). Mild near VI was associated with an increased risk of dementia only in the first 2 years (HR 1.6, 95% CI 1.1-2.5). Moreover, self-reported distance VF loss was associated with an increased risk beyond 4 years after inclusion (HR 1.5, 95% CI 1.1-2.0) but the association was no longer significant after taking into account baseline cognitive performances. Further adjustment for engagement in cognitively stimulating activities only slightly decreased these associations. However, there was an interaction between vision loss and depressive symptomatology, with vision loss associated with dementia only among participants with depressive symptomatology. These results suggest that poor vision, in particular near vision loss, may represent an indicator of dementia risk at short and middle-term, mostly in depressed elderly people.

Fixation Stability and Viewing Distance in Patients with AMD.

PURPOSE: People with normal vision perform activities of daily living binocularly, while changing viewing distance frequently and effortlessly. Typically, in patients with age-related macular degeneration (AMD), fixation stability is recorded with monocular instruments at a fixed viewing distance (i.e. optical infinity) to determine the location and precision of the preferred retinal loci (PRLs)-the part of the functional retina that fulfills the role of a pseudo-fovea. Fixation stability recorded with these instruments has been related to performance on visual tasks at shorter viewing distances, although it is not known how viewing distance affects the precision of ocular motor control in these patients. This study examined whether viewing distance affects fixation stability during binocular and monocular viewing. METHODS: Thirty patients with bilateral AMD, 10 older controls, and 10 younger controls participated. Each patient's better eye (BE) and worse eye (WE) were identified based on their visual acuity. Fixation stability was recorded with a binocular eye-tracker at three viewing distances (40 cm, 1 m, 6 m) in binocular and monocular (with BE and with WE) viewing conditions. Fixation stability was evaluated with a bivariate contour ellipse area. RESULTS: For the AMD group, there was no effect of viewing distance on fixation stability, regardless of viewing condition (i.e. binocular, monocular with the BE or with the WE). The same pattern of results was found for the two control groups. CONCLUSIONS: Viewing distance does not affect fixation stability in patients with AMD. Fixation stability data recorded with an instrument at a fixed viewing distance can be related to performance on visual tasks at other viewing distances.

Prevalence and Associated Factors of Uncorrected Refractive Error in Older Adults in a Population-Based Study in France.

Importance: Uncorrected refractive error (URE) is a common cause of visual impairment, but its prevalence in groups of older adults who could be pragmatic targets for improving optical correction remains unknown. Objectives: To estimate the prevalence of URE in older adults, particularly in those with age-related eye disease and those who are unable to attend an outpatient clinic, and to identify the factors associated with URE. Design, Setting, and Participants: This population-based cross-sectional analysis included 707 adults 78 years or older from the Alienor Study in Bordeaux, France. Data were collected from February 12, 2011, through December 21, 2012, and analyzed from November 1, 2017, through July 7, 2018. Main Outcomes and Measures: Uncorrected refractive error was defined as the presenting distance visual acuity in the better-seeing eye improved by at least 5 letters on the Early Treatment Diabetic Retinopathy Study chart (≥1 line on the logMAR chart) using the best-achieved optical correction. Multivariate logistic regressions were used to determine the factors associated with URE. Results: The study population of 707 adults 78 years or older (64.8% women; mean [SD] age, 84.3 [4.4] years) had a prevalence of URE of 38.8% (95% CI, 35.2%-42.5%). Prevalence was high for participants with eye disease (range, 35.0% [95% CI, 28.4%-42.0%] to 44.1% [95% CI, 27.2%-62.1%], depending on the disease) and those without eye disease (30.1%; 95% CI, 24.0%-36.7%). Prevalence was higher in participants who were examined at home (because they could not come to the clinic) than in those examined at the clinic (49.4% [95% CI, 42.8%-55.9%] vs 33.5% [95% CI, 29.2%-37.9%]; P < .001). Having an eye examination performed at home (odds ratio [OR], 1.64; 95% CI, 1.13-2.37), living alone (OR, 0.65; 95% CI, 0.47-0.90), and having the perceptions that the ophthalmologist consultation fees are too expensive (OR, 1.94; 95% CI, 1.12-3.36) and that declining visual acuity is normal with aging (OR, 1.47; 95% CI, 1.04-2.08) were all associated with URE. Conclusions and Relevance: These study results show that the prevalence of URE was high in this population and suggest that preventive strategies aimed at enhancing optical correction could be directed to all older adults and to specific groups by implementing at-home eye examinations for those who have difficulties attending an outpatient clinic and by focusing on those with eye disease who probably already have a regular ophthalmologic follow-up. More studies are needed to evaluate prevalence of URE in different populations and countries with various eye care systems.

Page mode reading with simulated scotomas: oculo-motor patterns.

This study investigated the relationship between reading speed and oculo-motor parameters when normally sighted observers had to read single sentences with an artificial macular scotoma. Using multiple regression analysis, our main result shows that two significant predictors, number of saccades per sentence followed by average fixation duration, account for 94% of reading speed variance: reading speed decreases when number of saccades and fixation duration increase. The number of letters per forward saccade (L/FS), which was measured directly in contrast to previous studies, is not a significant predictor. The results suggest that, independently of the size of saccades, some or all portions of a sentence are temporally integrated across an increasing number of fixations as reading speed is reduced.

Page mode reading with simulated scotomas: a modest effect of interline spacing on reading speed.

Crowding is thought to be one potent limiting factor of reading in peripheral vision. While several studies investigated how crowding between horizontally adjacent letters or words can influence eccentric reading, little attention has been paid to the influence of vertically adjacent lines of text. The goal of this study was to examine the dependence of page mode reading performance (speed and accuracy) on interline spacing. A gaze-contingent visual display was used to simulate a visual central scotoma while normally sighted observers read meaningful French sentences following MNREAD principles. The sensitivity of this new material to low-level factors was confirmed by showing strong effects of perceptual learning, print size and scotoma size on reading performance. In contrast, reading speed was only slightly modulated by interline spacing even for the largest range tested: a 26% gain for a 178% increase in spacing. This modest effect sharply contrasts with the dramatic influence of vertical word spacing found in a recent RSVP study. This discrepancy suggests either that vertical crowding is minimized when reading meaningful sentences, or that the interaction between crowding and other factors such as attention and/or visuo-motor control is dependent on the paradigm used to assess reading speed (page vs. RSVP mode).

Visual Impairment, Undercorrected Refractive Errors, and Activity Limitations in Older Adults: Findings From the Three-City Alienor Study.

Purpose: As vision is required in almost all activities of daily living, visual impairment (VI) may be one of the major treatable factors for preventing activity limitations. We aimed to evaluate the attributable risk of VI associated with activity limitations and the extent to which limitations are avoidable with optimal optical correction of undercorrected refractive errors. Methods: We analyzed 709 older adults from the Three-City-Alienor population-based study. VI was defined by presenting distance visual acuity in the better-seeing eye. Multivariate modified Poisson regressions were used to estimate the associations between vision, activity limitations, and social participation restrictions. Population attributable risk (PAR) and generalized impact fraction (GIF) were estimated. Bootstrapping was used to estimate 95% confidence intervals (CI). Results: After adjustment for potential confounders, VI was associated with each domain of activity limitations, except basic activities of daily living (ADL) limitations. These associations were found for even minimal levels of VI. PAR was estimated at 10.1% (95% CI: 5.2-10.6) for mobility limitations, at 26.0% (95% CI: 13.5-41.2) for instrumental ADL (IADL) limitations, and at 24.9% (95% CI: 10.5-47.1) for social participation restrictions. GIF for improvement of undercorrected refractive errors was 6.1% (95% CI: 3.8-8.5) for mobility limitations, 15.8% (95% CI: 11.5-20.1) for IADL limitations and 21.4% (95% CI: 13.8-28.5) for social participation restrictions. Conclusions: About one-sixth of IADL limitations and one-fifth of social participation restrictions could be prevented by an optimal optical correction. These results underline the importance of eye examinations in older adults to prevent disability.

Sensorimotor and cognitive factors associated with the age-related increase of visual field dependence: a cross-sectional study.

Reliance on the visual frame of reference for spatial orientation (or visual field dependence) has been reported to increase with age. This has implications on old adults' daily living tasks as it affects stability, attention, and adaptation capacities. However, the nature and underlying mechanisms of this increase are not well defined. We investigated sensorimotor and cognitive factors possibly associated with increased visual field dependence in old age, by considering functions that are both known to degrade with age and important for spatial orientation and sensorimotor control: reliance on the (somatosensory-based) egocentric frame of reference, visual fixation stability, and attentional processing of complex visual scenes (useful field of view, UFOV). Twenty young, 18 middle-aged, and 20 old adults completed a visual examination, three tests of visual field dependence (RFT, RDT, and GEFT), a test of egocentric dependence (subjective vertical estimation with the body erect and tilted at 70°), a visual fixation task, and a test of visual attentional processing (UFOV®). Increased visual field dependence with age was associated with reduced egocentric dependence, visual fixation stability, and visual attentional processing. In addition, visual fixation instability and reduced UFOV were correlated. Results of middle-aged adults fell between those of the young and old, revealing the progressive nature of the age effects we evaluated. We discuss results in terms of reference frame selection with respect to ageing as well as visual and non-visual information processing. Inter-individual differences amongst old adults are highlighted and discussed with respect to the functionality of increased visual field dependence.

"RecognizeCane" : The new concept of a cane which recognizes the most common objects and safety clues.

This paper introduces the new concept of an electronic cane for blind people. While some systems inform the subject only of the presence of the object and its relative distance, RecognizeCane is also able to recognize most common objects and environment clues to increase the safety and confidence of the navigation process. The originality of RecognizeCane is the use of simple sensors, such as infrared, brilliance or water sensors to inform the subject of the presence, for example, of a stairway, a water puddle, a zebra crossing or a trash can. This cane does not use an embedded vision system. RecognizeCane is equipped with several sensors and microprocessors to collect sensor data and extract the desired information about the close environment by means of a dynamic analysis of output signals.