A clinical method to assess the effect of visual loss on the ability to perform activities of daily living

Evaluation of a Retinal Projection Laser Eyeware in Patients with Visual Impairment Caused by Corneal Diseases in a Randomized Trial

PURPOSE

Patients with incurable corneal diseases experience visual impairment (VI) despite having a healthy retina and optic pathway. Low-vision aids (LVAs) can optimize the use of remaining vision through magnification and contrast enhancement, but do not harness the full visual capacity because they rely on the optic media. Therefore, we investigated a novel laser eyewear (LEW) technology that bypasses the anterior segment of the eye. Images captured by an integrated camera are projected directly onto the retina using a low-energy laser. The patient is able to view a full-color video, realized as augmented reality. We aimed to evaluate the efficacy of the LEW to enhance the vision of individuals with corneal diseases.

DESIGN

Prospective, randomized, crossover clinical trial.

PARTICIPANTS

We examined the retinal projection glasses in 21 patients (25-69 years) with VI (0.7 logarithm of the minimum angle of resolution [logMAR] or worse) resulting from corneal diseases. Patients with comorbidities that impact vision, such as retinal disorders, were excluded.

METHODS

Standardized measurements of visual acuity (VA) for near vision (NV) and distance vision (DV) were conducted using ETDRS charts with the respective best correction (BC) and then with LEW. In addition reading speed, vision-related quality of life (QoL) and capacity to carry out daily tasks were assessed at an initial visit and at 2 subsequent visits after a home phase with and without the device. Six weeks after last use of the LEW, an ophthalmologic examination including spectral-domain-OCT or full-field-electroretinography was conducted and compared with baseline findings to evaluate the safety of the device. Four patients participated and completed a subsequent 12-month follow-up phase.

MAIN OUTCOME MEASURES

Improvement of VA using the LEW. Secondary objectives included safety, reading speed, QoL, and usability in daily activities.

RESULTS

The mean VA in patients with VI was improved by 0.43 logMAR in DV using the LEW compared with BC (P < 0.0001). Using the ×2 magnification mode of the LEW resulted in an average improvement of 0.66 logMAR compared with BC (P < 0.0001). In NV, an increase of 0.47 logMAR was achieved compared with BC (P < 0.0001). Although only 4 of 21 participants were able to read with BC, 17 of 21 participants were able to read with the LEW. Quality of life significantly improved in the 17 participants who completed all visits.

CONCLUSIONS

We demonstrated that the retinal projection glasses resulted in enhanced VA for all participants by directly projecting images onto the intact retina. In future, the LEW could represent a new option as an LVA for patients with corneal diseases. No pathological alterations were observed in the safety assessments.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Converting LEA to Pelli-Robson contrast sensitivity score in neuro-ophthalmology patients

PURPOSE

The Pelli-Robson and LEA contrast sensitivity charts are commonly used in clinical settings to measure contrast sensitivity. Although the Pelli-Robson chart is considered the gold standard, it is limited by its bulky size. The LEA chart, on the contrary, offers a more practical and portable option that is still reliable. This has led to questions about whether we can predict Pelli-Robson scores based on LEA scores. This study developed a conversion method to help transition from the LEA chart to the Pelli-Robson chart and validate the conversion score.

METHODS

In this retrospective study, we analyzed the relationship between LEA and the Pelli-Robson contrast sensitivity test. Our study examined a total of 120 eyes. We developed a conversion table through the equipercentile equating method. Subsequently, we assessed the reliability and accuracy of this algorithm for converting LEA results into Pelli-Robson contrast sensitivity scores.

RESULTS

The study used a conversion table to convert LEA scores to Pelli-Robson scores. The conversion table achieved a reliability of 0.91 based on intraclass correlation, and the algorithm had an accuracy of 81.6% within a 1-point difference from the raw score.

CONCLUSIONS

This study reported a reliable and comparable conversion algorithm for transforming LEA scores into converted estimated Pelli-Robson scores, thereby improving the usefulness of existing data in both clinical and research contexts.

Visual function tests for glaucoma practice - What is relevant?

Glaucoma represents one of the most important ocular diseases causing irreversible ganglion cell death. It is one of the most common causes of visual impairment and morbidity in the elderly population. There are various tests for measuring visual function in glaucoma. While visual field remains the undisputed method for screening, diagnosis, and monitoring disease progression, other tests have been studied for their utility in glaucoma practice. This review discusses some of the commonly used tests of visual function that can be routinely used in clinics for glaucoma management. Among the various modalities of testing visual function in glaucoma, this review highlights the tests that are most clinically relevant.

Use of Virtual Reality Simulation to Identify Vision-Related Disability in Patients With Glaucoma

Importance

Clinical assessment of vision-related disability is hampered by the lack of instruments to assess visual performance in real-world situations. Interactive virtual reality (VR) environments displayed in a binocular stereoscopic VR headset have been designed, presumably simulating day-to-day activities to evaluate vision-related disability.

Objective

To investigate the application of VR to identify vision-related disability in patients with glaucoma.

Design, Setting, and Participants

In a cross-sectional study, 98 patients with glaucoma and 50 healthy individuals were consecutively recruited from a university eye clinic; all participants were Chinese. The study was conducted between August 30, 2016, and July 31, 2017; data analysis was performed from December 1, 2017, to October 30, 2018.

Exposures

Measurements of visual acuity, contrast sensitivity, visual field (VF), National Eye Institute 25-item Visual Function Questionnaire Rasch score, and VR disability scores determined from 5 VR simulations: supermarket shopping, stair and city navigations in daytime, and stair and city navigations in nighttime. Duration required to complete the simulation, number of items incorrectly identified, and number of collisions were measured to compute task-specific and overall VR disability scores. Vision-related disability was identified when the VR disability score was outside the normal age-adjusted 95% confidence region.

Main Outcomes and Measures

Virtual reality disability score.

Results

In the 98 patients with glaucoma, mean (SD) age was 49.8 (11.6) years and 60 were men (61.2%); in the 50 healthy individuals, mean (SD) age was 48.3 (14.8) years and 16 were men (32.0%). The patients with glaucoma had different degrees of VF loss (122 eyes [62.2%] had moderate or advanced VF defects). The time required to complete the activities by patients with glaucoma vs healthy individuals was longer by 15.2 seconds (95% CI, 5.5-24.9 seconds) or 34.1% (95% CI, 12.4%-55.7%) for the shopping simulation, 72.8 seconds (95% CI, 23.0-122.6 seconds) or 33.8% (95% CI, 10.7%-56.9%) for the nighttime stair navigation, and 38.1 seconds (95% CI, 10.9-65.2 seconds) or 30.8% (95% CI, 8.8%-52.8%) for the nighttime city navigation. The mean (SD) duration was not significantly different between the glaucoma and healthy groups in daytime stair (203.7 [93.7] vs 192.9 [89.1] seconds, P = .52) and city (118.7 [41.5] vs 117.0 [52.3] seconds, P = .85) navigation. For each decibel decrease in binocular VF sensitivity, the risk of collision increased by 15% in nighttime stair (hazard ratio [HR], 1.15; 95% CI, 1.08-1.22) and city (HR, 1.15; 95% CI, 1.08-1.23) navigations. Fifty-eight patients (59.1%) with glaucoma had vision-related disability in at least 1 simulated daily task; a higher proportion of patients had vision-related disability in nighttime city (27 of 88 [30.7%]) and stair (27 of 90 [30.0%]) navigation than in daytime city (7 of 88 [8.0%]) and stair (19 of 96 [19.8%]) navigation. The overall VR disability score was associated with the National Eye Institute 25-item Visual Function Questionnaire Rasch score (R2 = 0.207).

Conclusions and Relevance

These findings suggest that vision-related disability is associated with lighting condition and task in patients with glaucoma. Virtual reality may allow eye care professionals to understand the patients' perspectives on how visual impairment imparts disability in daily living and provide a new paradigm to augment the assessment of vision-related disability.

Glaucoma-Associated Visual Task Performance and Vision-Related Quality of Life in South India

OBJECTIVE/PURPOSE

Performance-based measures may provide an objective assessment of how glaucoma affects daily functioning. We sought to validate a clinically-applicable performance-based measure of visual ability for patients with glaucoma in south India and to describe its relationship to clinical and patient-reported outcomes.

DESIGN

Cross-sectional validation study.

SUBJECTS/PARTICIPANTS/CONTROLS

145 participants with glaucoma were recruited at Aravind Eye Hospital.

METHODS/INTERVENTION/TESTING

We modified the compressed assessment of activities related to vision (CAARV), a performance-based measure validated in the U.S., to be culturally relevant in south India. Participants underwent a series of tests, including the Indian CAARV (I-CAARV), Indian Visual Functioning Questionnaire (IND-VFQ), Spaeth/Richman Contrast Sensitivity (SPARCS) test, standard automated perimetry, and visual acuity (VA). Factor analysis and Rasch modeling were used to validate the I-CAARV. Correlations between the I-CAARV and other outcomes were evaluated.

MAIN OUTCOME MEASURE

Psychometric properties of the I-CAARV for individuals with glaucoma in south India.

RESULTS

The study included 142 participants (51.7% female, mean age 56.4 years). Average presenting visual acuity and visual field mean deviation (MD) in the better-seeing eye were 0.26 logMAR and -6.57 dB, respectively. The four tasks of the I-CAARV were found to measure a single underlying construct. Rasch analysis of the I-CAARV revealed that the outcome measure had moderate reliability, good construct and content validity, and fair measurement precision. Tasks were well-targeted to the study sample. Rasch-calibrated scores on the I-CAARV were significantly correlated with Rasch-calibrated IND-VFQ scores (r=-0.54) and with visual field MD, presenting VA, best-corrected VA, and SPARCS contrast sensitivity in both the better-seeing eye (r=0.60, -0.51, -0.53, 0.76, respectively) and worse-seeing eye (r=0.48, -0.61, -0.46, 0.69, respectively).

CONCLUSIONS

The I-CAARV is a valid performance-based measure of vision-dependent functioning in glaucoma in south India. This study also found that I-CAARV task performance was strongly correlated with contrast sensitivity and suggests that performance-based and patient-reported outcomes are related but distinct measures of the impact of glaucoma on functioning and vision-related quality of life. Future studies are needed to determine the sensitivity of the I-CAARV to detect changes due to disease progression that are relevant to functioning and vision-related quality of life.

Novel Means of Clinical Visual Function Testing among Glaucoma Patients, Including Virtual Reality

Computed perimetry remains the gold standard of visual field measurement among glaucoma patients. However, several emerging technologies, made possible by advances in computer programming, smartphone, tablet, or virtual reality, allow alternative means of visual function assessment. These new visual tests may one day have a useful complementary role in visual field testing and to bridge the gap between perimetry and daily experience. Many of these emerging technologies have distinct practical advantages over Ganzfield bowl-based computed perimetry. This paper outlines a discussion of some of these emerging techniques in visual function assessment in glaucoma.

Visual Defects and Ageing

Many diseases are related to age, among these neurodegeneration is particularly important. Alzheimer's disease Parkinson's and Glaucoma have many common pathogenic events including oxidative damage, Mitochondrial dysfunction, endothelial alterations and changes in the visual field. These are well known in the case of glaucoma, less in the case of neurodegeneration of the brain. Many other molecular aspects are common, such as the role of endoplasmic reticulum autophagy and neuronal apoptosis while others have been neglected due to lack of space such as inflammatory cytokine or miRNA. Moreover, the loss of specific neuronal populations, the induction of similar mechanisms of cell injury and the deposition of protein aggregates in specific anatomical areas are very similar events between these diseases. Intracellular and/or extracellular accumulation of protein aggregates is a key feature of many neurodegenerative disorders. The existence of abnormal protein aggregates has been documented in the RGCs of glaucomatous patients such as the anomalous Tau protein or the β-amyloid accumulations. Intra-cell catabolic processes also appear to be common in both glaucoma and neurodegeneration. They also help us to understand how the basis between these diseases is common and how the visual aspects can be a serious problem for those who are affected.

The Impact of Visual Field Clusters on Performance-based Measures and Vision-Related Quality of Life in Patients With Glaucoma

PURPOSE

To investigate how visual field (VF) clusters affect performance-based measures of the ability to perform activities of daily living and subjective measures of vision-related quality of life (QoL) in patients with glaucoma.

DESIGN

Prospective, cross-sectional study.

METHODS

setting: Institutional - Wills Eye Hospital.

STUDY POPULATION

322 eyes of 161 patients with moderate-stage glaucoma.

OBSERVATION

VF tests were conducted using the Humphrey 24-2 Swedish Interactive Thresholding Algorithm standard perimeter. The VFs of each patient were divided into 5 clusters: nasal, temporal, central, paracentral, and peripheral. The score for each cluster was the averaged total deviation scores of all tested points within the cluster. Each cluster score was correlated with performance-based measures of visual function and subjective assessment of vision-related QoL.

MAIN OUTCOME MEASURES

The Compressed Assessment of Ability Related to Vision, the National Eye Institute Visual Functioning Questionnaire 25 (NEI VFQ-25), and the Modified Glaucoma Symptom Scale.

RESULTS

The central VF cluster in the better eye was positively correlated with all Compressed Assessment of Ability Related to Vision (performance-based measure) subscales. The strongest correlation for the better eye was between the central VF cluster and total Compressed Assessment of Ability Related to Vision score (0.39, P < .001). The inferior VF hemisphere in both eyes was positively correlated with most Compressed Assessment of Ability Related to Vision subscales. Central VF clusters in the better eye were positively correlated with a majority of the NEI VFQ-25 subscales. There were no significant correlations between VF clusters and Modified Glaucoma Symptom Scale subscales.

CONCLUSIONS

Scores of central VF defects in the better eye and inferior hemisphere defects in both eyes were positively correlated with performance-based measures of the ability to perform activities of daily living. Glaucoma patients with central defects in the better eye were more likely to have reduced scores on assessments of vision-related QoL.

Family Board: A new means for people with visual impairment to communicate inner pictures of social relations

Visual impairment often entails changes in social relations. In order to identify supportive needs and provide tailored support, it is helpful to analyse these changes. Non-verbal methods have proven useful to facilitate this process but had so far not been available for visually impaired people. The Family Board, an established method of depicting social relations, was adapted for use by blind people and pilot-tested in this study. After adaptation and pretest, seven visually impaired adults undergoing rehabilitative treatment volunteered to participate in this qualitative pilot-study. Results showed that the method of the Family Board was well accepted and that the adapted board provides a feasible new non-verbal medium of communication for visually impaired people. The Family Board could be used to complement qualitative methods in further research on changes of social relations due to the loss of eyesight, to follow changes during coping and adaptation and to monitor effects of counselling.

A view on glaucoma--are we seeing it clearly?

Successful clinical management of glaucoma should not simply be about control of intraocular pressure, but must equate to correct decisions about intensifying treatment when patients are at risk of developing 'visual disability'. Yet little is known about what visual field defects, at different stages of glaucoma, specifically affect patients' abilities to perform everyday visual tasks. One way to do this is to measure patient performance in tasks in a lab setting. Another way is to ask patients themselves. The latter can be revealing and demystify views about how patients perceive the world. This short commentary highlights some of the current research in this area.

A prospective, longitudinal, observational cohort study examining how glaucoma affects quality of life and visually-related function over 4 years: design and methodology

Background

The aim of this study is to summarize the design and methodology of a prospective, longitudinal, observational cohort study to investigate how glaucoma affects patients’ quality of life and visually-related function over a 4-year period.

Methods/Design

One hundred sixty-one (161) subjects were enrolled in this ongoing study. Patients between the ages of 21–85 years with a minimum 2-year diagnosis of primary open-angle glaucoma, chronic primary angle-closure glaucoma or pseudoexfoliation glaucoma were included. Each patient visited Wills Eye Hospital for a baseline visit. Follow-up is planned for a minimum of 4 years, with annual visits. Each visit includes (1) Clinical evaluation: a slit lamp examination, fundoscopy, intraocular pressure measurement, visual field examination, spectral domain optical coherence tomography, Pelli-Robson Contrast Sensitivity test and the Spaeth-Richman Contrast Sensitivity test; (2) a performance based measure: the Compressed Assessment of Ability Related to Vision; and (3) Subjective measures of vision-related quality of life (the National Eye Institute Visual Functioning Questionnaire 25 and the Modified Glaucoma Symptom Scale).

Discussion

The results of this ongoing, prospective, longitudinal study are expected to shed light on the relationships between clinical measures, performance-based measures and subjective measures of well-being, in order to assess changes in the quality of life and the ability to function of patients with glaucoma over time.