Vision-related quality of life in adults with severe peripheral vision loss: a qualitative interview study

Understanding data visualization techniques in qualitative studies used to develop and validate patient-reported outcome measures: a targeted literature review

PURPOSE

Qualitative data that reflects patients' experiences are the foundation of any patient-reported outcome measure (PROM) development and validation study; however, there is limited understanding of the type of data visualization techniques that facilitate communication of this data. The goal of this targeted literature review was to investigate data visualization methods that have been used in published PROM development and validation literature to report qualitative results.

METHODS

A literature search in OVID via MEDLINE was conducted among the top 10 non-disease-specific journals publishing PROM qualitative development and validation studies. Studies that reported qualitative methods to develop/validate a PROM and included data visualization in the form of tables or figures were included. Article characteristics and data visualization types were extracted.

RESULTS

A total of 185 articles were included in data extraction. Most articles (n = 109, 59.1%) included figures (n = 172, average 2 relevant figures per article) in the form of hierarchy/flowcharts (n = 124, 72.1%) and bar charts (n = 29, 16.9%). Information reported in figures included depiction of conceptual frameworks (n = 112, 65.1%) and concept frequency (n = 40, 24.4%). Most articles (n = 152, 81.7%) included tables (n = 307, average 2 relevant tables per article). Information reported in tables included concept frequency (n = 133, 43.3%) and cognitive debriefing and revisions (n = 91, 29.6%).

CONCLUSION

Data visualization techniques used to report qualitative results in the identified PROM qualitative development and validation studies were heterogeneous, and many studies did not utilize any data visualization techniques. This study will inform the development of guidance for using data visualizations to report qualitative PROM research.

Natural remedies proposed for the management of diabetic retinopathy (DR): diabetic complications

Diabetic retinopathy (DR) represents a significant and serious complication associated with diabetes mellitus (DM), often resulting in considerable visual impairment or even blindness. The intricate pathological processes underlying DR complicate the effectiveness of current treatment modalities. Studies have highlighted the potential of natural products in the treatment of DR via several beneficial effects including anti-inflammatory, antioxidant, anti-neovascular, and anti-apoptotic properties. Flavonoids, saponins, saccharides, and alkaloids exhibited various beneficial effects in DR in in vivo and in vitro studies. However, the clinical utilization of these natural compounds is hindered by issues such as inadequate specificity, low bioavailability, and potential toxicity. Therefore, there is a pressing need for rigorous clinical studies to confirm the efficacy of natural products in preventing or mitigating the progression of DR.

Association of Quality of Life and Visual Function in Glaucoma With Tests of Structure and Function

PRCIS

In addition to standard automated perimetry tests, contrast sensitivity (CS) testing and macular analyses may predict changes in the quality of life (QOL) in patients at different stages of glaucoma.

OBJECTIVE

To examine the relationship between functional and structural tests of visual function and the 25-item National Eye Institute-Visual Function Questionnaire (NEI-VFQ-25) and the 36-item Short Form (SF-36) Health Survey in patients with different stages of glaucoma.

MATERIALS AND METHODS

Standard automated perimetry tests, optical coherence tomography scans, and CS testing were prospectively performed in 160 patients with glaucoma. The Hoddap-Parrish-Anderson staging system was used for glaucoma staging. Health-related QOL questionnaires (NEI-VFQ-25, SF-36) were also administered to all patients.

RESULTS

The study group comprised 29 patients with suspected glaucoma, 104 with mild glaucoma, 15 with moderate glaucoma, and 12 with severe glaucoma. The mean total score of the NEI-VFQ-25 was 88.8 ± 8.2. The SF-36 did not show a significant correlation with the data on functional and structural tests of visual function, whereas the NEI-VFQ-25 showed a low to moderate correlation ( r = 0.212 to -0.492). Vision parameters can explain up to 18.6% of the total score of the NEI-VFQ-25. CS was the only function significantly correlated with glaucoma suspects, whereas, in the early stages, visual acuity was the strongest correlated function with the NEI-VFQ-25 total score ( P = 0.003 and r = 0.551; P = 0.001 and r = 0.343, respectively). The impact of the visual field on vision-related QOL increased in the advanced stages ( P = 0.013, r = 0.688). The macular retinal ganglion cell plus inner plexiform layer thickness remained associated with NEI-VFQ-25 at all stages of glaucoma ( r = 0.335 to 0.802). The NEI-VFQ-25 total score and most of the subscales were correlated with the physical and mental component summary scores of the SF-36 ( r = 0.159 to 0.587).

CONCLUSION

Visual acuity correlated the most with QOL in patients with glaucoma, as measured with the NEI-VFQ-25 to assess QOL in glaucoma. The impact of visual functions on QOL varies at different stages of glaucoma.

Patient-reported visual function outcomes agree with visual acuity and ophthalmologist-graded scoring of visual function among patients with long-chain 3-hydroxyacylcoA dehydrogenase deficiency (LCHADD)

Patients with LCHADD develop progressive chorioretinopathy with vision loss over time. To date, no data on the impact of vision loss on patient vision-specific activities of daily living or quality of life have been reported. We used validated ophthalmic patient-reported outcome measures (PROMs) to compare the impact of patient-perceived visual function to visual acuity and an ophthalmologist-graded stage of LCHADD chorioretinopathy. There was a strong correlation between the patient-reported visual function scores, visual acuity and the ophthalmologist's assigned stage. Adult patients reported lower driving and mental health scores compared to other visual subscales in the VFQ-25. Both children and their parents report a similar impact of their child's eye condition to their quality of life and worry about their vision. These validated PROMs captured functional vision in a group of 40 patients with LCHADD/TFPD that closely correlated with visual acuity and ophthalmologist-graded visual function.

Visual activities of daily living survey for retinitis pigmentosa

PURPOSE

To gauge the value of low-vision-specific function and activities of daily living measures (LVFAM) in the assessment of Patient Reported Outcomes (PRO) of Retinitis Pigmentosa (RP).

STUDY DESIGN

Prospective observation study.

METHODS

The May-July 2023 Visual activities of daily living (ADL) Survey of the low-vision-specific function and activities of daily living measure (LVFAM) was conducted on 15 RP patients attending our Ophthalmology outpatient clinic. We used the better corrected visual acuity, and the better Mean Deviation (MD) values of the central 10 degrees of Humphrey's visual field as macular sensitivity, and examined the total scores after Rasch Analysis for each of the low-vision-specific function of Daily Living (LVFDL) and the low-vision-specific activities of Daily Living (LVADL) among LVFAM, as well as the relationship between the items.

RESULTS

Age 26-78 (mean 60.8), 5 men and 10 women, corrected visual acuity of 0.01-1.0 (mean 0.45) in the better eye, macular sensitivity of 3.47-40.00 (mean 18.60) dB, mean 52.2 for LVFDL and 66.4 for LVADL. The correlations were positive for visual acuity and LVFDL and LVADL, and negative for macular sensitivity, LVFDL and LVADL. In addition, four items were scored 0 by at least 5 (33%) of the LVFDL respondents, and two items were scored 1 by at least 5 (33%) of the LVADL respondents, suggesting that the results differed by question items.

CONCLUSION

The LVFAM was useful not only for the total score but also for each question item in the development strategy of PROs in RP with no treatment.

Risk of pedestrian collision for persons with peripheral field loss: A computational analysis

SIGNIFICANCE

People with peripheral field loss report colliding with other pedestrians on their blind side(s). We show that, in dyadic collision scenarios between persons, one with field loss, such as homonymous hemianopia, and the other normally sighted pedestrian, collisions occur only if the persons with homonymous hemianopia are overtaking the pedestrians, and the collision risk is concentrated at farther bearing angles than previously suggested.

PURPOSE

Prior work computed the risk of collision while simulating both pedestrians as points and did not consider the ability of the other pedestrian's normal vision to avoid the collision. We extended the model to better characterize the open space collision risk posed for persons with homonymous hemianopia by normally sighted pedestrians where both have volume.

METHODS

We computed the risk of collision with approaching pedestrians using a model that simulates approaching pedestrians as volumetric entities without vision, volumetric entities with vision, and as points for comparison with the prior work. Collision risk of approaching pedestrians is characterized for all three conditions through spatial collision risk maps and collision risk densities as a function of bearing and radial distances.

RESULTS

The collision risk for volumetric pedestrians is slightly different from that of point pedestrians. For volumetric pedestrians simulated with normal vision, the risk of collision was reduced substantially, as the other pedestrians could detect and avoid most impending collisions. The remaining collision risk is from pedestrians approaching at higher bearing angles (>50°) and from shorter radial distances (<2 m). Thus, collisions occurred when the pedestrians started in front of the person with homonymous hemianopia that was overtaking the pedestrian.

CONCLUSIONS

The probability of collisions between pedestrians and the person with peripheral field loss is low and occurs only when the person with peripheral field loss is walking from behind the pedestrian at faster speed, thereby overtaking them. Such collisions occur with pedestrians at higher bearing angles, which should be monitored by assistive aids to avoid collisions. The same collision risk applies not only in homonymous hemianopia but also in other peripheral field loss such as monocular vision loss or concentric field loss, as common in retinitis pigmentosa and glaucoma.

Current Status of Clinical Trials Design and Outcomes in Retinal Gene Therapy

With the rapid expansion of methods encompassed by the term gene therapy, new trials exploring the safety and efficacy of these methods are initiated more frequently. As a result, important questions arise pertaining the design of these trials and patient participation. One of the most important aspects of any clinical trial is the ability to measure the trial's outcome in a manner that will reflect the effect of the treatment and allow its quantification, whether the trial is aimed at preservation or restoration of retinal cells (photoreceptors and others), vision, or both. Here we will review the existing methods for quantification of trial outcomes, stressing the importance of assessing the participant's visual function and not just visual acuity. We will also describe the key considerations in trial design. Finally, as patient safety remains the primary concern in any trial participation, we will outline the key principles in that regard.

Development and Validation of the Low Vision Severely Constricted Peripheral Eyesight (LV-SCOPE) Questionnaire

PURPOSE

To develop and validate a novel patient-reported outcome (PRO) measure to assess vision-related functioning in individuals with severe peripheral field loss (PFL).

DESIGN

Prospective outcome measure development/validation study.

METHODS

A 127-item questionnaire was developed based on a prior qualitative interview study. A total of 116 participants with severe PFL due to retinitis pigmentosa (RP) or glaucoma were recruited at the Kellogg Eye Center and completed the Likert-scaled telephone-administered questionnaire. Included participants had a horizontal extent of their visual field <20 degrees (RP) or a mixed or generalized stage 4 to 5 defect using the Enhanced Glaucoma Staging System (glaucoma) in the better seeing eye (or in 1 eye if the fellow eye visual acuity was <20/200). Response data were analyzed using exploratory factor analysis and Rasch modeling. Poorly functioning items were eliminated, confirmatory factor analysis was used to ensure scale unidimensionality, and the model was refit to produce the final instrument.

RESULTS

The final Low Vision Severely Constricted Peripheral Eyesight (LV-SCOPE) Questionnaire contains 53 items across 6 domains: mobility, object localization, object recognition, reading, social functioning, and technology. There were 74 items removed because of high missingness, poor factor loadings, low internal consistency, high local dependency, low item information, item redundancy, or differential item functioning. Using Rasch item calibrations, person ability scores could be calculated for each of the 6 unidimensional LV-SCOPE domains with good test-retest stability.

CONCLUSIONS

The LV-SCOPE Questionnaire provides a valid and reliable measure of vision-related functioning across 6 key domains relevant to individuals with severe PFL. Findings support the clinical utility of this psychometrically valid instrument.

Experiences of people with dual sensory loss in various areas of life: A qualitative study

Individuals with dual sensory loss (DSL) appear to have limited ability to compensate for their visual impairment with residual hearing, or for their hearing impairment with residual vision, resulting in challenges in various areas of life. The aim of this qualitative study was to explore the diverse experiences facing individuals with DSL as well as to determine how they experience sensory compensation. Semi-structured interviews were carried out in twenty adults with DSL (13 females and 7 males, mean age 47 years). The causes of DSL severity varied amongst participants. Sensory compensation and experiences in regards to access to information, mobility, communication and fatigue were discussed. Interviews were audio recorded and transcribed verbatim. Framework analysis was used to summarize and interpret the data. In relation to access to information, our results show that, despite various challenges, the use of assistive technology such as voice command functions, enabled participants to operate effectively. Regarding mobility, most participants were capable of finding their way in familiar environments. However, if the setting was unfamiliar, assistance from others or reliance on navigation applications was necessary. Participants experienced little issues with having conversations in quiet settings, however, crowded settings were considered very difficult. The final results showed that most participants suffered from fatigue. Carefully considering which daily activities were feasible and having a daily routine helped to cope with fatigue. This study revealed the experiences of individuals with DSL in important areas of life. The results suggest that, even though many challenges are experienced, individuals with DSL are resourceful in finding compensation strategies. However, capturing participants' sensory compensation experiences was challenging.

A multidisciplinary approach to inherited retinal dystrophies from diagnosis to initial care: a narrative review with inputs from clinical practice

BACKGROUND

Non-syndromic inherited retinal dystrophies (IRDs) such as retinitis pigmentosa or Leber congenital amaurosis generally manifest between early childhood and late adolescence, imposing profound long-term impacts as a result of vision impairment or blindness. IRDs are highly heterogeneous, with often overlapping symptoms among different IRDs, and achieving a definite diagnosis is challenging. This narrative review provides a clinical overview of the non-syndromic generalized photoreceptor dystrophies, particularly retinitis pigmentosa and Leber congenital amaurosis. The clinical investigations and genetic testing needed to establish a diagnosis are outlined, and current management approaches are discussed, focusing on the importance of the involvement of an interdisciplinary team from diagnosis and initial care to long-term follow-up and support.

RESULTS

The effective management of IRDs requires a multidisciplinary, and ideally interdisciplinary, team of experts knowledgeable about IRDs, with experienced professionals from fields as diverse as ophthalmology, neuropsychiatry, psychology, neurology, genetics, orthoptics, developmental therapy, typhlology, occupational therapy, otolaryngology, and orientation and mobility specialties. Accurate clinical diagnosis encompasses a range of objective and subjective assessments as a prerequisite for the genetic testing essential in establishing an accurate diagnosis necessary for the effective management of IRDs, particularly in the era of gene therapies. Improvements in genome sequencing techniques, such as next-generation sequencing, have greatly facilitated the complex process of determining IRD-causing gene variants and establishing a molecular diagnosis. Genetic counseling is essential to help the individual and their family understand the condition, the potential risk for offspring, and the implications of a diagnosis on visual prognosis and treatment options. Psychological support for patients and caregivers is important at all stages of diagnosis, care, and rehabilitation and is an essential part of the multidisciplinary approach to managing IRDs. Effective communication throughout is essential, and the patient and caregivers' needs and expectations must be acknowledged and discussed.

CONCLUSION

As IRDs can present at an early age, clinicians need to be aware of the clinical signs suggesting visual impairment and follow up with multidisciplinary support for timely diagnoses to facilitate appropriate therapeutic or rehabilitation intervention to minimize vision loss.

Beyond the NEI-VFQ: Recent Experience in the Development and Utilization of Patient-Reported Outcomes for Inherited Retinal Diseases

Patient-reported outcome measures (PROMs) are tools designed to capture how a patient feels or functions, without the input or interpretation of anyone else. The earliest PROMs used in studies of inherited retinal diseases (IRDs) lack the validity required for therapy development today. The NEI-VFQ was one of the earliest PROMs developed using concept elicitation and cognitive debriefing of patients, but it lacks items that are common to patients with IRDs and it has poor measurement properties. Recent advances in PROM development include the Michigan Retinal Degeneration Questionnaire (MRDQ) and the ViSIO-PRO for nonsyndromic retinitis pigmentosa (RP), both of which have been qualitatively and quantitatively validated. As these new tools are used in clinical studies, they will generate additional evidence about their measurement characteristics. With the latest advances in PROM development for IRDs, it is now possible to move beyond the NEI-VFQ to measure what is truly important to patients.

Vision rehabilitation in glaucoma patients

PURPOSE OF REVIEW

Vision rehabilitation services are important but underutilized resources for patients with glaucoma. Glaucoma and its impact on vision can affect patients' abilities to read and drive, two activities of daily living that are associated with quality of life and functional independence. In this review, we provide an overview of low vision, discuss barriers to vision rehabilitation, and outline various strategies and interventions to optimize visual function and quality of life in patients with glaucoma.

RECENT FINDINGS

Studies have shown that glaucoma negatively impacts reading, driving and overall quality of life. Decreased visual acuity, visual field loss and reduced contrast sensitivity play a role. Low vision services and interventions can help patients maximize visual function and improve their quality of life. Barriers to receiving these services exist at multiple levels and an increased awareness and integration into routine ophthalmic care are needed to deliver comprehensive care.

SUMMARY

Glaucoma is one of the leading causes of low vision. Ophthalmologists who treat glaucoma often tend to focus on objective measures to monitor progression and disease severity, but the functional impact of glaucoma should also be addressed. Low vision services can benefit patients, particularly for reading and driving, and should be considered as an essential component of patient care.

Elicitation of Health State Utility Values in Retinitis Pigmentosa by Time Trade-off in the United Kingdom

Introduction

Retinitis pigmentosa (RP) is an inherited retinal pathology associated with "night blindness" and progressive loss of peripheral vision, in some cases leading to complete blindness. Health state utility values are required for activities such as modelling disease burden or the cost-effectiveness of new interventions. The current study aimed to generate utility values for health states of varying levels of functional vision in RP, with members of the general public in the UK.

Methods

Five health states were defined according to standard clinical measures of visual ability. Health state descriptions were developed following interviews with patients with RP in the UK (n=5). Further interviews were conducted for confirmation with healthcare professionals with specific experience of managing patients with RP in the UK (n=2). Interviews with members of the general public in the UK were conducted to value health states. A time trade-off (TTO) process based on the established Measurement and Valuation of Health (MVH) protocol was used. Due to the ongoing COVID-19 pandemic, all interviews were web-enabled and conducted 1:1 by a trained moderator.

Results

In total, n=110 TTO interviews were conducted with members of the UK general public. Mean TTO utility values followed the logical and expected order, with increasing visual impairment leading to decreased utility. Mean values varied between 0.78 ± 0.20 ("moderate impairment"), and 0.33 ± 0.26 ("hand motion" to "no light perception"). Supplementary visual analogue scale (VAS) scores also followed the logical and expected order: mean VAS values varied between 47.95 ± 15.38 ("moderate impairment") and 17.22 ± 12.49 in ("hand motion" to "no light perception").

Discussion

These data suggest that individuals living with RP have substantially impaired quality of life. Utility values for RP have been elicited here using a method and sample that is suitable for economic modelling and health technology assessment purposes.

The impact of low vision on social function: The potential importance of lost visual social cues

Visual cues usually play a vital role in social interaction. As well as being the primary cue for identifying other people, visual cues also provide crucial non-verbal social information via both facial expressions and body language. One consequence of vision loss is the need to rely on non-visual cues during social interaction. Although verbal cues can carry a significant amount of information, this information is often not available to an untrained listener. Here, we review the current literature examining potential ways that the loss of social information due to vision loss might impact social functioning. A large number of studies suggest that low vision and blindness is a risk factor for anxiety and depression. This relationship has been attributed to multiple factors, including anxiety about disease progression, and impairments to quality of life that include difficulties reading, and a lack of access to work and social activities. However, our review suggests a potential additional contributing factor to reduced quality of life that has been hitherto overlooked: blindness may make it more difficult to effectively engage in social interactions, due to a loss of visual information. The current literature suggests it might be worth considering training in voice discrimination and/or recognition when carrying out rehabilitative training in late blind individuals.

Patient-Reported Measures of the Effects of Vision Impairments and Low Vision Rehabilitation on Functioning in Daily Life

The quantification of vision impairments dates to the mid-nineteenth century with standardization of visual acuity and visual field measures in the eye clinic. Attempts to quantify the impact of vision impairments on patients' lives did not receive clinical attention until the close of the twentieth century. Although formal psychometric theories and measurement instruments were well developed and commonplace in educational testing, as well as in various areas in psychology and rehabilitation medicine, the late start applying them to clinical vision research created a vacuum that invited poorly developed and poorly functioning instruments and analytic methods. Although this research is still burdened with legacy instruments, mandates by regulatory agencies to include the patients' perspectives and preferences in the evaluation of clinical outcomes have stimulated the development and validation of self-report instruments grounded in modern psychometric theory and methods. Here I review the progress and accomplishments of applying modern psychometrics to clinical vision research. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Wearable System to Guide Crosswalk Navigation for People With Visual Impairment

Independent travelling is a significant challenge for visually impaired people in urban settings. Traditional and widely used aids such as guide dogs and long canes provide basic guidance and obstacle avoidance but are not sufficient for complex situations such as street crossing. We propose a new wearable system that can safely guide a user with visual impairment at a signalized crosswalk. Safe street crossing is an important element of fully independent travelling for people who are blind or visually impaired (BVI), but street crossing is challenging for BVI because it involves several steps reliant on vision, including scene understanding, localization, object detection, path planning, and path following. Street crossing also requires timely completion. Prior solutions for guiding BVI in crosswalks have focused on either detection of crosswalks or classifying crosswalks signs. In this paper, we demonstrate a system that performs all the functions necessary to safely guide BVI at a signalized crosswalk. Our system utilizes prior maps, similar to how autonomous vehicles are guided. The hardware components are lightweight such that they can be wearable and mobile, and all are commercially available. The system operates in real-time. Computer vision algorithms (Orbslam2) localize the user in the map and orient them to the crosswalk. The state of the crosswalk signal (don’t walk or walk) is detected (using a convolutional neural network), the user is notified (via verbal instructions) when it is safe to cross, and the user is guided (via verbal instructions) along a path towards a destination on the prior map. The system continually updates user position relative to the path and corrects the user’s trajectory with simple verbal commands. We demonstrate the system functionality in three BVI participants. With brief training, all three were able to use the system to successfully navigate a crosswalk in a safe manner.

Visual Difficulty, Race and Ethnicity, and Activity Limitation Trajectories Among Older Adults in the United States: Findings From the National Health and Aging Trends Study

OBJECTIVES

To characterize the influence of visual difficulty on activity limitation trajectories in older U.S. adults and investigate whether this varied across racial/ethnic groups.

METHODS

We used data from 8,077 participants in the nationally representative National Health and Aging Trends Study from 2011 to 2019. Using mixed-effects regression models, we investigated the association of self-reported visual difficulty and race/ethnicity with activity limitation trajectories.

RESULTS

Higher levels of visual difficulty and belonging to a minority racial/ethnic group were associated with greater mobility, self-care, and household activity limitations. Visual difficulty was associated with mobility and self-care activity limitation trajectories, and race/ethnicity was significantly associated with mobility and household activity limitation trajectories. Among those with the highest levels of visual difficulty, non-Hispanic Black participants experienced a faster rate of decline in self-care activities compared to non-Hispanic White participants.

DISCUSSION

Promoting optimal aging for all requires an understanding of the factors that influence disparities in key outcomes. Our study provides evidence from a diverse national sample that visual difficulty appears to disproportionately affect activity limitation trajectories among older adults from minority racial/ethnic groups and particularly among non-Hispanic "Black individuals." Further research is needed to determine whether interventions to promote healthy vision may positively affect overall activity and independence and ameliorate disparities in late-life activity limitation trajectories.

Assessing optimal colour and illumination to facilitate reading: an analysis of print size

PURPOSE

This study examined how optimal colour/illumination conditions and the efficacy of the iPad, LuxIQ and Smart Bulb varied as a function of print size in younger, older and visually impaired adults.

METHODS

Participants with visual impairments and simulated low vision (SLV) read the MNRead using the iPad, LuxIQ and Smart Bulb.

RESULTS

In the impairment condition at 1.20 logMAR, the iPad (M = 9.49, 95% CI [3.18, 19.42]) and LuxIQ (M = 15.95, 95% CI [9.54, 24.86]) improved the reading speeds. At 0.80 logMAR (SLV), all devices improved reading speeds of older adults (iPad (M = 28.70, 95% CI [14.65, 42.51]); LuxIQ (M = 49.63, 95% CI [30.04, 69.68]); Smart Bulb (M = 23.11, 95% CI [3.33, 42.11])), but in younger adults only the LuxIQ (M = 13.04, 95% CI [3.21, 21.27]) did so. In the impairment condition, the iPad (M = 5.54, 95% CI [0.31, 12.13]) and LuxIQ (M = 13.90, 95% CI [7.88, 23.49]) improved reading speeds. In the SLV condition, age was a significant predictor of reading speed at 1.20 logMAR (F_3,164  = 10.74, p < 0.001, Adj. R²  = 0.16). At 0.80 logMAR, age and luminance, but not colour, were significant predictors (F_3,164  = 52.52, p < 0.001, Adj. R²  = 0.49). In the impairment condition, both age and lux were significant predictors of reading speed at 1.20 (F_3,85  = 7.14, p < 0.001, Adj. R²  = 0.20) and 0.80 logMAR (F_3,85  = 7.97, p < 0.001, Adj. R²  = 0.22), but colour was not.

CONCLUSIONS

Light source effectiveness and optimal colour/illumination vary as a function of print size. It appears that print size is the most important factor for improving reading speed. As print size decreases, luminance becomes crucial, and only at the smallest print sizes does the effect of colour become useful.