The reading accessibility index and quality of reading grid of patients with central vision loss

Age-related changes in reading performance in normally sighted Arabic-speaking adults

CLINICAL RELEVANCE

Reading performance is important for evaluating near vision and predicting and prescribing near-vision correction. There is a significant gap in the literature on Arabic reading performance and its associated effects.

BACKGROUND

Normative data from control participants serve as the baseline for future studies involving groups with specific characteristics. This study aimed to assess baseline measures of Arabic reading performance.

METHODS

In total, 428 normally sighted adults aged 19-83 years read the Balsam Alabdulkader - Leat chart to measure their reading performance. The participants were divided into five age groups. The outcome measures were the maximum reading speed in standard-length words per minute, critical print size, reading acuity, and reading accessibility index.

RESULTS

The average reading performance measures were as follows: 171 ± 27 standard-length words per minute for maximum reading speed, 0.01 logarithm of the minimum angle of resolution for critical print size, -0.17 logarithm of the minimum angle of resolution for reading acuity, and 1.02 for the accessibility index. There were significant differences among the age groups, indicating a dependency on age and showing a plateau for the young adult group and a decline with age. The accessibility index had an almost perfect correlation with maximum reading speed and a weak but significant relationship with reading acuity and critical print size.

CONCLUSION

Arabic exhibits an age-dependent trend in reading speed. However, owing to differences in orthography, visual demands, and reading strategies, the magnitude of the decrease and increase differs, potentially accounting for the variations between languages, especially when compared to English. This study serves as a foundation for future studies on Arabic reading performance. Future studies should examine the reading performance in patients with low vision, study the effects of common diseases on reading ability, evaluate the effectiveness of reading devices, and assess improvements in vision rehabilitation.

Structure-function relationship of reading performance in patients with early to moderate glaucoma

PURPOSE

To assess reading performance in patients with mild to moderate primary open-angle glaucoma (POAG), and to determine the relationship between reading ability and visual field (VF), microperimetry, and optical coherence tomography (OCT) parameters.

METHODS

Reading performance of 30 POAG patients examined by the Minnesota Reading Acuity Chart (MNREAD) was compared to that of 21 age-matched controls collected from Ankara University in Turkey. Humphrey Field Analyzer (HFA) 24-2 SITA Standard and 10-2 patterns, and microperimetry were used for VF measurements. All subjects underwent OCT analysis for retinal nerve fiber layer thickness (RNFLT), optic nerve head (ONH) measurements, and ganglion cell inner plexiform layer thickness (GCIPLT). The linear relationship between reading parameters and VF, microperimetry, and OCT parameters was investigated. Univariate and multiple logistic regression models were used to identify the risk factors for glaucoma.

RESULTS

In POAG patients, maximum reading speed (MRS) had a significant association with average rim area, mean cup-to-disc ratio (CDR), and cup volume (p < 0.05, for all). Decreased MRS was associated with thinner average GCIPLT and inferotemporal, superior, and inferior GCIPLT quadrants (p < 0.05, for all). Global index values for the HFA 24-2/10-2 tests, microperimetry, and ONH/RNFLT parameters had no correlation with reading performance. After accounting for the better and worse eyes, gender, education, age, and visual acuity of the glaucoma patients, MRS score was 23 units lower in the worse eye (p = 0.009), critical print size (CPS) was 0.21 units larger in the better eye (p = 0.03) and 0.25 units larger in the worse eye (p < 0.001), reading accesibility index (ACC) was 0.11 units lower in the better eye (p = 0.02) and 0.13 units lower in the worse eye (p = 0.002), and RA was 0.13 units higher in the worse eye (p = 0.003) of POAG patients.

CONCLUSION

POAG had significantly lower reading performance when compared to healthy subjects. Reading speed was associated with decreased macular GCIPLT indicating that reading performance may be affected in the earlier stages of the disease.

What Is a Preferred Retinal Locus?

This review examines the concept of the preferred retinal locus (PRL) in patients with macular diseases. Considering monocular and binocular viewing, we (a) explain how to identify the PRL and discuss the pitfalls associated with its measurement, (b) review the current hypotheses for PRL development, (c) assess whether the PRL is the new reference point of the ocular motor system, and discuss (d) the functional and (e) the clinical implications of the PRL. We conclude that the current definition of the PRL is probably incomplete and should incorporate the need to evaluate the PRL in the framework of binocular viewing. We emphasize the need for more research.

Reading Performance in Blue Cone Monochromacy: Defining an Outcome Measure for a Clinical Trial

Purpose

Blue cone monochromacy (BCM), a congenital X-linked retinal disease caused by mutations in the OPN1LW/OPN1MW gene cluster, is under consideration for intravitreal gene therapy. Difficulties with near vision tasks experienced by these patients prompted this study of reading performance as a potential outcome measure for a future clinical trial.

Methods

Clinically and molecularly diagnosed patients with BCM (n = 17; ages 15–63 years) and subjects with normal vision (n = 22; ages 18–72 years) were examined with the MNREAD acuity chart for both uniocular and binocular conditions. Parameters derived from the measurements in patients were compared with normal data and also within the group of patients. Intersession, interocular and between-subject variabilities were determined. The frequent complaint of light sensitivity in BCM was examined by comparing results from black text on a white background (regular polarity) versus white on black (reverse polarity) conditions.

Results

MNREAD curves of print size versus reading speed were right-shifted compared with normal in all patients with BCM. All parameters in patients with BCM indicated abnormal reading performance. Intersession variability was slightly higher in BCM than in normal, but comparable with results previously reported for other patients with maculopathies. There was a high degree of disease symmetry in reading performance in this BCM cohort. Reverse polarity showed better reading parameters than regular polarity in 82% of the patients.

Conclusions

MNREAD measures of reading performance in patients with BCM would be a worthy and robust secondary outcome in a clinical trial protocol, given its dual purpose of quantifying macular vision and addressing an important quality of life issue.

Translational Relevance

Assessment of an outcome for a clinical trial.

Reading with central vision loss: binocular summation and inhibition

Purpose

There are conflicting reports as to whether there is a binocular advantage or disadvantage when reading with central vision loss. This study examined binocular reading summation in patients with macular degeneration.

Methods

Seventy‐one patients with bilateral central vision loss [mean age: 63 (S.D. = 21) years] participated. Reading performances during binocular and monocular viewing with the better eye (i.e., the eye with the best monocular visual acuity) were evaluated using different versions of the Italian MNREAD reading chart (www.precision‐vision.com). Fixation stability and preferred retinal loci (PRLs) were recorded monocularly for each eye. The overall sample was split into inhibition, equality, and summation groups based on the binocular ratio (i.e., binocular/monocular) of the maximum reading speed.

Results

41% of patients experienced binocular inhibition, 42% summation, and 17% equality. Binocular reading speed of the inhibition group was approximately 30 words per minute slower than those of the equality and summation groups, although the inhibition group had the best visual acuity. These patients generally had monocular PRLs in non‐corresponding locations temporal or nasal to the scotoma, had the largest interocular acuity difference and lacked residual stereopsis. The three groups did not differ in fixational control, contrast sensitivity or critical print size.

Conclusions

Equal proportions of patients with central vision loss show binocular reading summation and inhibition. Patients with binocular reading inhibition have poorer reading performance and different clinical characteristics than those with binocular reading summation and equality.

Impact of simulated micro-scotomas on reading performance in central and peripheral retina

Observers with central field loss typically fixate within a non-foveal region called the preferred retinal locus, which can include localized sensitivity losses, or micro-scotomas (Krishnan and Bedell, 2018). In this study, we simulated micro-scotomas at the fovea and in the peripheral retina to assess their impact on reading speed. Ten younger (<36 years old) and 8 older (>50 years old) naïve observers with normal vision monocularly read high and/or low contrast sentences, presented at or above the critical print size for young observers at the fovea and at 5 and 10 deg in the inferior visual field. Reading material comprised MNREAD sentences and sentences taken from novels that were presented in rapid serial visual presentation (RSVP) format. Randomly distributed 13 × 13 arc min blocks corresponding to 0-78% of the text area (corresponding to ∼0-17 micro-scotomas/deg2) were set to the background luminance to simulate micro-scotomas. A staircase algorithm estimated maximum reading speed from the threshold exposure duration for each combination of retinal eccentricity, contrast and micro-scotoma density in both age groups. Log10(RSVP reading speed) decreased significantly with simulated micro-scotoma density and eccentricity. Across conditions, reading speed was slower with low-compared to high-contrast text and was faster in younger than older normal observers. For a given eccentricity and contrast, a higher density of random element losses maximally affected older observers with normal vision. These outcomes may explain some of the reading deficits observed in older observers with central field loss.

Rehabilitation needs and activity limitations of adults with a visual impairment entering a low vision rehabilitation service in England

PURPOSE

To evaluate outcome measures of the Participation and Activity Inventory (PAI) in a sample of adults with acquired visual impairment entering vision rehabilitation. Both Priority Scores, indicating level of rehabilitative need, and Person Measures, indicating goal difficulty, were considered.

METHODS

Participants were newly registered adults with visual impairment within Leicestershire, United Kingdom. The importance and difficulty of 48 goals of the PAI were assessed, as were demographic factors, clinical visual function (visual acuity, contrast sensitivity, reading function) and psychosocial function (adjustment to visual loss, depression, anxiety and fear of falling). Priority scores were calculated as the product of importance and difficulty of each goal. All questionnaires were Rasch analysed, and person and item measures of perceived difficulty with goals were derived.

RESULTS

Sixty people (mean age ± S.D. = 75.8 ± 13.8 years) took part. PAI goals with greatest rehabilitative need were reading (6.82 ± 2.91), mobility outdoors (6.55 ± 3.92), mobility indoors within an unfamiliar environment (5.52 ± 3.93) and writing (5.27 ± 3.02). Greater rehabilitative need was associated with younger age (β = -0.46, p < 0.001), and with higher depressive symptomatology (β = 0.35, p < 0.01; model R² 34%). Goals with greatest difficulty were mending clothing (-1.95 ± 0.35 logits) and hobbies and crafts (-1.32 ± 0.23 logits). Greater difficulty was associated with higher depressive symptomatology (β = 0.39, p < 0.001), lower visual acuity (β = 0.42, p < 0.001) and lower adjustment of visual loss (β = 0.31, p < 0.01; model R² 53%).

CONCLUSIONS

Key rehabilitation needs for adults at entry to services require both optical and non-optical interventions. As rehabilitative need was not associated with the level of visual impairment, eyecare professionals should not wait until the end of medical treatment before referral for support. Similarly, rehabilitative need was associated with younger age, indicating the importance to refer younger people with sight loss at an early stage. The use of structured assessment, such as the PAI, ensures goals that have an impact upon quality of life are specifically identified. Depression screening on entry to rehabilitation is relevant as it predicts both perceived difficulty and rehabilitative need.

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.