Novel computer-based assessments of everyday visual function in people with age-related macular degeneration

Functional vision tests as clinical trial outcome measures in ophthalmology: a scoping review

OBJECTIVES

To identify currently available functional vision tests and evaluate their use as clinical trial outcome measures in ophthalmology.

DESIGN

Scoping review using the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-analysis Extension for Scoping Reviews) guidelines.

METHODS

A literature search was conducted in MEDLINE and Embase (via Ovid) for articles published between 1 January 2003 and 1 August 2024. Additional grey literature was sourced from institutional repositories, conference proceedings and a manual citation search. Article screening was conducted against a predefined inclusion criteria by two independent, masked reviewers, with a third reviewer acting as arbiter. The inclusion criteria were English language articles which feature a test assessing functional vision in patients with an ophthalmological disease. Details of source characteristics, test methodology and accessibility and evidence of test validation were collected.

RESULTS

Of 2665 articles returned by the search, 73 were included and 45 unique tests of functional vision were identified. Diseases affecting the peripheral retina were mainly affected, accounting for 77% (56 out of 73) of the diseases featured in all included studies. Overall, 82% (37 out of 45) functional vision tests reported evidence of statistical validation with varying robustness. Functional vision tests were mapped to domains of orientation and mobility, facial recognition, observer-rated task performance, visual search and driving. Obstacle courses assess vision-guided orientation and mobility, correlate highly with clinical measures of visual function in severe peripheral retinal disease and have been validated for use in clinical trials. Their requirement of physical space and time limits utility in multicentre trials; equivalent tests leveraging virtual reality and eye tracking technologies are in development. Early iterations of visual search tests to simulated realistic scenes have demonstrated discriminative ability, even in paediatric patients.

CONCLUSIONS

Functional vision tests can facilitate research into future novel ophthalmological treatments that prioritise patients in terms of how clinical benefit is defined. The principal barriers to the uptake of these tests are lack of accessibility, low quality validation and that many tests remain early in their development stage. This review captures the current landscape of functional vision tests and serves as a reference for investigators and regulatory bodies to evaluate the suitability of these tests for ophthalmic clinical trials.

An overview of quality of life and visual outcomes in AMD

Age-related macular degeneration (AMD) is the leading cause of blindness in high income countries and third most common cause of blindness worldwide. This chapter provides an overview of existing literature pertaining to the ways in which AMD impacts clinical measures of visual function, quality of life, and performance of everyday tasks. As well as being used in clinics, some of the tests described in this chapter have the potential to be piloted in patients' homes as self-monitoring tools, or as patient-centred outcome measures in clinical trials for new treatments in AMD. Moreover, the research findings reported in this literature review should help clinicians with patient management and expectations, and should to inform future patient, public and professional education on AMD.

Neural and Perceptual Adaptations in Bilateral Macular Degeneration: An Integrative Review

Bilateral age-related macular degeneration (AMD) results in central vision loss, affecting the fovea-associated cortical regions. This review examines neuroimaging and psychophysical evidence of spontaneous neural adaptation in acquired bilateral central scotoma. Early visual brain areas show reduced cortical thickness and axonal integrity due to postsynaptic (anterograde) degeneration. Contrary to animal models, evidence for spontaneous adaptation in the primary visual cortex (V1) is limited. Activity in the lesion projection zone (LPZ), previously seen as extensive cortical remapping, may result from non-retinotopic peripheral-to-foveal feedback, sharing substrates with healthy retinal feedforward processes. Preferred retinal loci (PRLs) are influenced more by location and task than by residual vision quality. Reduced lateral masking in the PRL may reflect decreased contrast sensitivity from retinal damage, rather than genuine adaptive mechanisms. Weakened crowding in the PRL is explained by transient adaptation in healthy subjects to artificial scotomas, not by long-term plasticity. Higher visual areas may show compensatory mechanisms enhancing complex tasks like symmetry, face, and motion discrimination. Leveraging spontaneous adaptation through perceptual learning-based treatments can preserve residual visual abilities. Because of limited evidence for spontaneous reorganization in AMD, behavioural training and emerging techniques are crucial for optimal treatment efficacy.

Utilisation of patient-centred outcome measures in age-related macular degeneration research and clinical practice: A systematic review

BACKGROUND

To identify the utilisation, type, and psychometric properties of patient-centered outcome measures (PCOMs) associated with the performance-based assessment of visual function (VF) in age-related macular degeneration (AMD) in clinical care and research.

METHODS

A systematic literature search identified studies, available in English, that used PCOMs to assess VF in patients with any AMD severity, published from January 2015 to November 2023. Two researchers screened studies for quality using the Mixed Methods Appraisal Tool (MMAT) 2018 and assessed the psychometric properties of the PCOMs with the guidance of Consensus-based Standards for the selection of health Measurement Instruments (COSMIN).

RESULTS

Of 514 studies shortlisted in the literature, 31 were eligible with the majority (77.4%) fulfilling all the MMAT criteria, indicating good quality. The most used PCOM was reading (14/31 = 45.1%), with 5 of the 14 studies (35.7%) showing that the increasing severity and/or progression of AMD were associated with a worsening reading ability. AMD also negatively affected mobility and physical activity levels (7/31 = 22.6%), and visual search and exploration (4/31 = 12.9%). Based on the COSMIN checklist, apart from reading and physical activity measured with the accelerometer, the other PCOMs had 'inadequate' psychometric properties.

CONCLUSIONS

Limited published studies include PCOMs as an assessment of VF in AMD patients. Apart from reading, there is a lack of robust validation data to support the widespread use of other PCOMs. Hence, well-designed, robustly validated, and simple to use PCOMs are required for more widespread implementation in AMD clinical care and research.

Retinal sensitivity changes in early/intermediate AMD: a systematic review and meta-analysis of visual field testing under mesopic and scotopic lighting

Visual fields under mesopic and scotopic lighting are increasingly being used for macular functional assessment. This review evaluates its statistical significance and clinical relevance, and the optimal testing protocol for early/intermediate age-related macular degeneration (AMD). PubMed and Embase were searched from inception to 14/05/2022. All quality assessments were performed according to GRADE guidelines. The primary outcome was global mean sensitivity (MS), further meta-analysed by: AMD classification scheme, device, test pattern, mesopic/scotopic lighting, stimuli size/chromaticity, pupil dilation, testing radius (area), background luminance, adaptation time, AMD severity, reticular pseudodrusen presence, and follow-up visit. From 1489 studies screened, 42 observational study results contributed to the primary meta-analysis. Supported by moderate GRADE certainty of the evidence, global MS was significantly reduced across all devices under mesopic and scotopic lighting with large effect size (-0.9 [-1.04, -0.75] Hedge's g, P < 0.0001). The device (P < 0.01) and lighting (P < 0.05) used were the only modifiable factors affecting global MS, whereby the mesopic MP-1 and MAIA produced the largest effect sizes and exceeded test-retest variabilities. Global MS was significantly affected by AMD severity (intermediate versus early AMD; -0.58 [-0.88, -0.29] Hedge's g or -2.55 [3.62, -1.47] MAIA-dB) and at follow-up visit (versus baseline; -0.62 [-0.84, -0.41] Hedge's g or -1.61[-2.69, -0.54] MAIA-dB). Magnitudes of retinal sensitivity changes in early/intermediate AMD are clinically relevant for the MP-1 and MAIA devices under mesopic lighting within the central 10° radius. Other factors including pupil dilation and dark adaptation did not significantly affect global MS in early/intermediate AMD.

Humanistic and Economic Burden of Geographic Atrophy: A Systematic Literature Review

PURPOSE

Geographic atrophy (GA), the advanced form of dry age-related macular degeneration, can result in irreversible blindness over time. We performed a systematic literature review to assess the humanistic and economic burden of GA.

METHODS

Predefined search terms were used to identify studies in PubMed, Embase, and Cochrane Library; conference abstracts also were searched.

RESULTS

Of 1111 unique studies identified, 25 studies on humanistic burden, 4 on economic burden, and 3 on both humanistic and economic burden of GA were included. Vision-related functioning and health-related quality of life (HRQOL) are poor in patients with GA. HRQOL is commonly measured using the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25); patients with GA have significantly lower composite and subscale scores for near activities, distance activities, dependency, driving, social functioning, mental health, role difficulties, color vision, and peripheral vision than individuals without GA. Driving is a particular concern, and inability to drive affects dependency. Vision-related quality of life (VRQOL) declines as GA progresses. While we identified only 7 reports describing the economic burden of GA, its direct costs may be substantial. In a US study, mean cost to the payer per patient with GA was $11,533 in the year after diagnosis. A multinational study estimated annualized total direct costs of €1772 per patient with GA, mainly driven by diagnostic tests and procedures (€1071). Patients with GA are at increased risk of falls and fractures, potentially increasing direct costs. Only one study evaluated indirect costs, estimating ~$24.4 billion in yearly lost wages among people with severe vision loss due to GA or drusen ≥125 μm.

CONCLUSION

GA represents a significant humanistic burden. Evidence on the economic impact of GA is limited; characterizing the economic burden of GA requires further research. Interventions that reduce GA-related disability may improve HRQOL and reduce indirect costs.