Eccentric Viewing Training for Age-Related Macular Disease: Results of a Randomized Controlled Trial (the EFFECT Study)

Purpose

Eccentric viewing training for macular disease has been performed for > 40 years, but no large studies including control groups have assessed the benefits of this training. The EFFECT (Eccentric Fixation From Enhanced Clinical Training) study is a large randomized controlled trial of 2 types of eccentric viewing training.

Design

Randomized controlled trial.

Participants

Two hundred adults with age-related macular disease.

Methods

Participants were randomized to either of the following: (1) a control group; (2) a group receiving supervised reading support; (3) a group receiving 3 sessions of training to optimize the use of their own preferred retinal locus; or (4) a group receiving 3 sessions of biofeedback training of a theoretically optimal trained retinal locus. All participants received standard low-vision rehabilitation.

Main Outcome Measures

The primary outcome was patient-reported visual task ability measured on the Activity Inventory instrument at goal level. Secondary outcomes included reading performance and fixation stability.

Results

There was no difference between groups on change in task ability (F(3,174) = 1.48, P = 0.22) or on any of the secondary outcome measures. Visual acuity and contrast sensitivity fell in all groups, suggesting that disease progression outweighed any benefit of training.

Conclusions

Eccentric viewing training did not systematically improve task ability, reading performance, or fixation stability in this study. Our results do not support the routine use of eccentric viewing training for people with progressing age-related macular disease, although this training may help people with end-stage disease. Rehabilitation of an inherently progressive condition is challenging.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Evidence-based Classification in Track Athletics for Athletes with a Vision Impairment: A Delphi Study

SIGNIFICANCE

The Delphi analysis presented here highlights the need for a sport-specific evidence-based classification system for track athletics for athletes with a vision impairment (VI). This system may differ for different race distances. Further research is required to develop a useful test battery of vision tests for classification. The issue of intentional misrepresentation during classification needs particular attention.

PURPOSE

At present, athletes with VI are placed into competition classes developed on the basis of legal definitions of VI. The International Paralympic Committee Athlete Classification Code states that all sports should have their own classification system designed to reflect the (visual) demands of that individual sport. This project gathered expert opinion on the specific requirements for an evidence-based sport-specific classification system for VI track athletics and to identify any particular issues within track athletics that require further research into their impact on sport performance.

METHODS

A three-round Delphi review was conducted with a panel of 17 people with expertise in VI track athletics.

RESULTS

The panel agreed that the current classification system in VI track athletics does not completely minimize the impact of impairment on competition outcome, highlighting the need for improvements. There was clear agreement that the existing measures of vision may fail to adequately reflect the type of vision loss that would impact running performance, with additional measures required. Intentional misrepresentation, where athletes "cheat" on classification tests, remains a serious concern.

CONCLUSIONS

The panel has identified measures of vision and performance that will inform the development of an evidence-based classification system by better understanding the relationship between VI and performance in track athletics. Issues such as the use of guides and whether the current class system was equitable gave rise to differing opinions within the panel, with these varying across the different running distances.

The effect of low light levels on postural stability in older adults with age-related macular degeneration

PURPOSE

To investigate the effect of low light levels on postural stability in older adults with and without age-related macular degeneration (AMD).

METHODS

Participants included 28 older adults [14 with AMD (mean age ± S.D., 83.4 ± 6.7 years) and 14 controls with normal vision (74.6 ± 3.3 years)]. Postural stability was assessed with eyes open on both a firm and foam surface under four lighting conditions in a randomised order: photopic (~436 lux, vertically at the eye), sudden reduction to mesopic (~436 to ~1 lux), adapted mesopic (~1 lux) and adapted mesopic with a light emitting diode (LED) door frame lighting system (~1.3 lux), using the root mean square (RMS) of the centre of pressure measures derived from an electronic force plate in the anterior-posterior (AP) and medio-lateral (ML) directions. Visual function was assessed binocularly (visual acuity, contrast sensitivity and visual fields), physical function was assessed using standardised measures (sit-to-stand, grip strength and the timed walk test) and self-reported difficulties under low light levels were recorded using the Low Luminance Questionnaire. Data were analysed using linear mixed models.

RESULTS

For all participants, low light levels significantly increased postural sway on the foam surface in the AP (p = 0.01) but not ML (p = 0.80) direction, but had no effect on postural stability on the firm surface. On the foam surface, while AP-RMS sway was significantly greater in the sudden (p < 0.001) and adapted (p = 0.02) mesopic compared to the photopic condition, sway for the adapted mesopic with the LED lighting system was not significantly different to the photopic condition (p = 0.20). On the foam surface, AP-RMS (p = 0.02) and ML-RMS (p < 0.001) sway were significantly greater in the AMD compared to the control group. None of the measures of visual function was significantly associated with AP- or ML-RMS sway.

CONCLUSIONS

On the foam surface, low light levels significantly reduced postural stability in older adults with and without AMD, and postural stability was significantly reduced for the AMD group compared to controls, regardless of light level. Importantly, the LED lighting system reduced sway under mesopic conditions, which was not significantly greater than that measured under photopic conditions in either group. These findings have important implications for enhancing the visual environment for older adults with and without AMD to improve postural stability and reduce the risk of falls in low lighting environments.

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.

Determinants of concern about falling in adults with age-related macular degeneration

PURPOSE

To investigate the prevalence and level of concern about falling (CF) among older people with vision impairment due to age-related macular degeneration (AMD) compared to a visually normal control group, and to identify determinants of CF for the AMD group.

METHODS

Participants included 133 older people: 77 with AMD (mean age = 80.5 ± 6.2 years), and 56 controls (mean age = 75.4 ± 5.3 years). Binocular visual acuity, contrast sensitivity and visual fields were measured, and CF was assessed using the Falls Efficacy Scale - International (FES-I). Data were also collected for sensorimotor function (postural sway, sit-to-stand, knee extensions, walking speed, proprioception), and neuropsychological function (reaction time, symptoms of anxiety and depression) using validated tests and scales.

RESULTS

Concern about falling scores were higher for AMD participants compared to control participants (mean ± S.D. 24.6 ± 8.0 vs 21.6 ± 5.7, p = 0.02, respectively), although these findings failed to reach significance when adjusted for age (p = 0.16). Among AMD participants, multivariable models showed that greater CF was associated with reduced contrast sensitivity (p = 0.02), slower sit-to-stand times (p < 0.001) and higher anxiety scores (p < 0.001); these factors explained 40% of the variance in CF (p < 0.01).

CONCLUSION

Levels of CF in older people with AMD were not found to be elevated by their disease status alone, but rather by the extent of vision loss. Levels of CF in those with AMD were associated with various visual, sensorimotor and neuropsychological factors. These findings will assist clinicians in identifying those at greatest risk of developing high CF and inform the design of future intervention programmes for this population.

Assessing Functional Disability in Glaucoma: The Relative Importance of Central Versus Far Peripheral Visual Fields

Purpose

To evaluate the importance of central versus far peripheral visual field (VF) loss in assessing disability in glaucoma.

Methods

In total, 231 patients with glaucoma or suspected glaucoma completed 24-2 VF testing and automated peripheral VFs using the suprathreshold 30- to 60-degree pattern. Questionnaires assessed fear of falling (FoF), quality of life (QOL), instrumental activities of daily living (IADLs), and driving habits; nonsedentary time, reading speed, and gait were objectively measured. Multivariable regression models analyzed the effect of central VF and/or peripheral VF damage on each outcome.

Results

In models including both central and peripheral VF damage (independent effects), greater central, but not peripheral, VF damage was associated with greater FoF, worse QOL, fewer daily steps, and difficulty with IADLs (P < 0.02 for central; P > 0.5 for peripheral). For gait measures, greater peripheral, but not central, damage was associated with shorter steps and shorter strides, as well as greater variability in step length (P < 0.03 for peripheral; P > 0.14 for central). Model R² values were not substantially higher (less than 5% additional explained variability) for models including both central and peripheral VF damage as compared to the best models incorporating only one region of VF damage (i.e., central or peripheral).

Conclusions

The relative importance of central 24 degrees versus more peripheral VF damage differs across functional domains in patients with glaucoma. Central damage is more strongly associated with most disability outcomes, although peripheral damage is more associated with specific gait measures. Studies examining the relative importance of various VF regions should assess functional domain separately and eschew integrated measures of quality of life/activity limitation.

Context Association in Glaucoma Patients Using a Touch Screen

PRECIS

The results showed that people with glaucoma are able to perform with high accuracy a context-association task on a touch screen. This device could be a new possibility for communication and for clinical assessment.

BACKGROUND

The present study was designed to investigate the ability of patients with glaucoma to use a touch screen to find and associate pictures with limited text.

METHODS

Eighty-four volunteers were recruited in 3 groups and tested binocularly or monocularly. Twenty-eight patients with binocular glaucoma (M=68.5 y) were selected with a visual acuity of 0.4 log MAR or better in each eye and visual field defects, with a mean deviation equal to or less than -6 dB in each eye. Twenty-eight age-matched controls (M=68.8 y) and 28 young controls (M=22.1 y) were also recruited (normal acuity; exclusion of ocular disease). The participants had to associate, by moving their index on a 22″ touch screen, a target on the unique scene (between 3 other distractor images) with a consistent background related to the target (eg, to match a fish with the sea).

RESULTS

The performances of the glaucomatous patients were significantly (P<0.01) impaired in monocular vision compared with binocular vision with regard to the exploration duration (+2 s), accuracy (-3% of correct response), and peak speed (-10 cm/s). However, with binocular vision, representing daily life conditions, exploration duration, deviation, movement duration, peak speed, and accuracy were not affected by glaucoma, as demonstrated by comparison with the age-matched group.

CONCLUSIONS

People with glaucoma are able to perform with high accuracy a context-association task on a touch screen. Many applications involving touch screen devices should provide new tools with limited text to help patients with visual disabilities.

Benefits of low vision aids to reading accessibility

The Reading Accessibility Index (ACC) has been proposed as a single-value reading parameter that can capture information on both reading speed and print sizes that can be read. It is defined as the average reading speed across a relevant range of print sizes (1.3-0.4logMAR), normalised by typical young-adult reading speed of 200 wpm, and with values typically in the range of 0-1. This study determines the impact of low vision aids (LVAs) on reading by evaluating ACC values for visually impaired observers reading both without and with an optical LVA. A secondary analysis of previously published data obtained from 100 visually impaired observers attending low vision assessments was undertaken. Observers had mixed causes of visual impairment but predominantly macular degeneration. All used an LVA for reading, with 88% using it 'often' or 'very often'. MNREAD reading parameters, including ACC, were determined both for reading without an LVA (clinical function) and with the LVA habitually used for reading (aided function). There was a significant improvement in ACC from clinical (0.31) to aided conditions (0.47). Average improvement in ACC with an LVA was 0.16, but the benefits of LVAs in terms of improvement in ACC could not be predicted from clinical visual function. Even with an LVA reading accessibility is, on average, markedly reduced from normal levels. The ACC is a potentially valuable outcome measure for reading rehabilitation interventions.

A New Graphical Tool for Assessing Visual Field Progression in Clinical Populations

Purpose

We demonstrate a new approach for assessing and visualizing visual field (VF) progression in clinics.

Methods

Two summary measures for VF progression, Rate of Progression (RP) and Loss of Sight Years (LSY), are combined with a novel visualization (Hedgehog Plots). RP is calculated per eye using linear regression of mean deviation (MD) against time of follow-up. LSY is a novel parameter, linked to actuarial data, which estimates the number of years that a patient will have advanced bilateral VF loss in their predicted remaining lifetime. Every eye is given a rank within the sample based on RP and LSY allowing for “priority” patients to be identified. We illustrate differences between the parameters with an experiment comparing the cases flagged as “priority” by each method using data from 1263 VF records.

Results

RP for every eye in a “clinic” can be visualized and assessed using a Hedgehog Plot. Eyes are ranked against all other eyes by RP and LSY; these parameters provide different and complementary information on a patient's VF progression status. A purpose written interactive application demonstrating the techniques is available in the public domain at https://crabblab.shinyapps.io/hedgehog.

Conclusion

Hedgehog Plots provide a tool for visualizing VF progression in groups of patients and can be used potentially to prioritize monitoring resources.

Translational Relevance

This study illustrates a novel visualization technique and an interactive application that can be used to help determine VF progression in large groups of patients.

Functional visual fields: a cross-sectional UK study to determine which visual field paradigms best reflect difficulty with mobility function

OBJECTIVES

To develop an appropriate method of assessing visual field (VF) loss which reflects its functional consequences, this study aims to determine which method(s) of assessing VF best reflect mobility difficulty.

SETTING

This cross-sectional observational study took place within a single primary care setting. Participants attended a single session at a University Eye Clinic, Cambridge, UK, with data collected by a single researcher (HS), a qualified optometrist.

PARTICIPANTS

50 adult participants with peripheral field impairment were recruited for this study. Individuals with conditions not primarily affecting peripheral visual function, such as macular degeneration, were excluded from the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Participants undertook three custom and one standard binocular VF tests assessing VF to 60°, and also integrated monocular threshold 24-2 visual fields (IVF). Primary VF outcomes were average mean threshold, percentage of stimuli seen and VF area. VF outcomes were compared with self-reported mobility function assessed with the Independent Mobility Questionnaire, and time taken and patient acceptability were also considered. Receiver operating characteristic (ROC) curves determined which tests best predicted difficulty with mobility tasks.

RESULTS

Greater VF loss was associated with greater self-reported mobility difficulty with all field paradigms (R² 0.38-0.48, all P<0.001). All four binocular tests were better than the IVF at predicting difficulty with at least three mobility tasks in ROC analysis. Mean duration of the tests ranged from 1 min 26 s (±9 s) for kinetic assessment to 9 min 23 s (±24 s) for IVF.

CONCLUSIONS

The binocular VF tests extending to 60° eccentricity all relate similarly to self-reported mobility function, and slightly better than integrated monocular VFs. A kinetic assessment of VF area is quicker than and as effective at predicting mobility function as static threshold assessment.

Functional visual fields: relationship of visual field areas to self-reported function

PURPOSE

The aim of this study is to relate areas of the visual field to functional difficulties to inform the development of a binocular visual field assessment that can reflect the functional consequences of visual field loss.

METHODS

Fifty-two participants with peripheral visual field loss undertook binocular assessment of visual fields using the 30-2 and 60-4 SITA Fast programs on the Humphrey Field Analyser, and mean thresholds were derived. Binocular visual acuity, contrast sensitivity and near reading performance were also determined. Self-reported overall and mobility function were assessed using the Dutch ICF Activity Inventory.

RESULTS

Greater visual field loss (0-60°) was associated with worse self-reported function both overall (R² = 0.50; p < 0.0001), and for mobility (R² = 0.64; p < 0.0001). Central (0-30°) and peripheral (30-60°) visual field areas were similarly related to mobility function (R² = 0.61, p < 0.0001 and R² = 0.63, p < 0.0001 respectively), although the peripheral (30-60°) visual field was the best predictor of mobility self-reported function in multiple regression analyses. Superior and inferior visual field areas related similarly to mobility function (R² = 0.56, p < 0.0001 and R² = 0.67, p < 0.0001 respectively). The inferior field was found to be the best predictor of mobility function in multiple regression analysis.

CONCLUSION

Mean threshold of the binocular visual field to 60° eccentricity is a good predictor of self-reported function overall, and particularly of mobility function. Both the central (0-30°) and peripheral (30-60°) mean threshold are good predictors of self-reported function, but the peripheral (30-0°) field is a slightly better predictor of mobility function, and should not be ignored when considering functional consequences of field loss. The inferior visual field is a slightly stronger predictor of perceived overall and mobility function than the superior field.

What rates of glaucoma progression are clinically significant?

Clinically important rates of glaucoma progression (worsening) are ones that put a patient at risk of future functional impairment or reduction of vision-related quality of life. Rates of progression can be evaluated through measuring structural or functional changes of the optic nerve. Most treated eyes do not progress at rates that will lead to future visual impairment, but there are a significant proportion (3-17%) of eyes, that are at risk of impairment even under clinical care. While very fast rates of progression (e.g. MD progression of -1.5 dB/year) are generally problematic, much slower rates also may be deleterious for young patients, particularly those diagnosed with late disease. As a result, it is important to consider life expectancy, disease severity and vision-related quality of life based treatment targets to estimate future prognosis when evaluating whether a rate of glaucoma progression can be clinically relevant.

Visual impairment and vision-related quality of life in the Early Manifest Glaucoma Trial after 20 years of follow-up

Purpose

To determine the association between vision‐related quality of life (VRQOL) and levels of visual function loss in the Early Manifest Glaucoma Trial (EMGT).

Methods

Two hundred and fifty‐five patients were included in the EMGT between 1993 and 1997 and followed regularly by ophthalmic examinations. A Swedish translation of the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ‐25) was self‐administered at several follow‐up visits until 2014. We analysed the association between Rasch‐calibrated NEI VFQ‐25 scores and visual function in the best eye at the final follow‐up visit.

Results

Ninety‐one per cent (233/255) of all participants completed the NEI VFQ‐25 at least once. In univariate logistic regression analysis, NEI VFQ‐25 scores were modestly associated with visual acuity (VA) (r² = 0.330, p < 0.001), visual field index (VFI) (r² = 0.200, p < 0.001) and perimetric mean deviation (MD) (r² = 0.193, p < 0.001). In multivariate analysis, VA and VFI together accounted for approximately 40% (r² = 0.380) of the NEI VFQ‐25 scores. NEI VFQ‐25 scores were significantly higher for patients with no visual impairment (mean 73 ± 22) than for visually impaired patients (mean 31 ± 15, p < 0.001). VFI worse than 50% or MD worse than −18 dB was significantly associated with low VRQOL scores (p < 0.001).

Conclusions

Our results support the widespread, albeit arbitrary, use of a better‐eye visual field of <50% as an important threshold for a significant reduction in VRQOL.

The effect of trial frames on adaptive gait

PURPOSE

Research investigating how vision affects adaptive gait typically tests participants whilst wearing their own spectacles or whilst wearing trial case lenses mounted in a trial frame. Trial frames are temporary frames allowing different lenses to be inserted, permitting different visual conditions to be simulated. Trial frames occlude part of the wearer's peripheral visual field. The current study investigated how use of trial frames affects adaptive gait.

METHODS

Fifteen participants (age 25 ± 5 years) with normal uncorrected vision negotiated a single floor based obstacle habitually (not wearing a trial frame) or wearing trial frames which occluded part of the lower visual field (half-eye) or circumferential peripheral visual field (full aperture). No lenses were used in the trial frames. Analysis assessed visual field occlusion and the kinematics of obstacle crossing.

RESULTS

Visual field was reduced wearing either trial frame. Compared to the habitual condition, participants wearing either type of trial frame lifted their foot significantly higher over the obstacle and increased the time taken to step over the obstacle; a result of uncertainty regarding the precise location (height) of the obstacle due to the occlusion of visual information from the inferior visual field. There were no differences in obstacle crossing between trial frame conditions.

CONCLUSIONS

Wearing either full or half eye trial frames can in itself influence adaptive gait. Whilst consideration needs to be given to the visual correction that participants wear during gait research, the method of mounting these lenses also requires consideration.

Areas of the visual field important during reading in patients with glaucoma

PURPOSE

To determine the areas of the binocular visual field (VF) associated with reading speed in glaucomatous patients with preserved visual acuity (VA).

MATERIALS AND METHODS

Fifty-four patients with glaucoma (mean age ± standard deviation 70 ± 8 years) and 38 visually healthy controls (mean age 66 ± 9 years) had silent reading speeds measured using non-scrolling text on a computer setup. Participants completed three cognitive tests and tests of visual function, including the Humphrey 24-2 threshold VF test in each eye; the results were combined to produce binocular integrated VFs (IVFs). Regression analyses using the control group to correct for cognitive test scores, age and VA were conducted to obtain the IVF mean deviation (MD) and total deviation (TD) value from each IVF test location. Concordance between reading speed and TD, assessed using R (2) statistics, was ranked in order of importance to explore the parts of the IVF most likely to be linked with reading speed.

RESULTS

No significant association between IVF MD value and reading speed was observed (p = 0.38). Ranking individual thresholds indicated that the inferior left section of the IVF was most likely to be associated with reading speed.

CONCLUSIONS

Certain regions of the binocular VF impairment may be associated with reading performance even in patients with preserved VA. The inferior left region of patient IVFs may be important for changing lines during reading.