Digital Reading with Low Vision: Principles for Selecting Display Size.

SIGNIFICANCE: Digital reading devices have become increasingly popular among people with low vision. Because displays come in many sizes ranging from smart watches to large desktop computer displays, it is important to have principles to guide people with low vision in selecting suitable displays for reading. PURPOSE: The selection of effective digital displays for reading by people with low vision focuses attention on the interacting effects of print size, display size, font, visual acuity, and reading distance. This technical report aims to provide principles for identifying the minimum size of digital displays required for fluent reading by people with low vision. METHODS: We emphasize two critical factors in selecting an appropriate reading display: angular print size, which should exceed the individual's critical print size, and display size, which should allow at least 13 characters to be presented on each line. Our approach considers a low-vision individual's acuity and preferences for viewing distance and fonts. RESULTS: Through an illustrative example, we demonstrate how our approach can be used to determine display size for a low-vision individual with 20/200 acuity and central field loss who wants to read at 30-cm viewing distance with the Times Roman font. We have developed a web application based on our recommended approach to provide easy access to our algorithm. CONCLUSIONS: We provide a procedure to guide the selection of appropriate displays for a wide range of acuities. Our approach can help clinicians in making recommendations for their patients, digital product designers in developing more accessible devices, and low-vision individuals in selecting digital displays for reading.

Stickler Syndrome (SS): Laser Prophylaxis for Retinal Detachment (Modified Ora Secunda Cerclage, OSC/SS).

PURPOSE: To introduce a novel technique of encircling laser prophylaxis (ora secunda cerclage Stickler syndrome, OSC/SS) to prevent rhegmatogenous retinal detachment (RRD) in Stickler syndrome eyes. PATIENTS AND METHODS: After first eye RRD at age 50 and at age 18, respectively, a 53-year-old father and his 22-year-old son with type 2 SS (STL2) gave informed consent and underwent OSC/SS prophylaxis, performed in each fellow eye. A 26-year-old STL2 daughter then suffered first eye retinal detachment and similarly chose fellow eye OSC/SS prophylaxis. A second son, 28 years of age with STL2, chose OSC/SS prophylaxis in both eyes. RESULTS: The three OSC/SS treated fellow eyes have gone 12 years, 11 years, and 8 years without RRD. STL1 and less common STL2 eyes are known to have a similar rate of RRD, and 80% of STL1 fellow eyes develop RRD at a median of 4 years in the absence of prophylaxis. Moreover, five of six (83%) known STL2 family members suffered RRD, only the STL2 son with bilateral OSC/SS remaining bilaterally attached. All five OSC/SS treated eyes (average 8.7 years post-prophylaxis) retained preoperative visual acuity of 20/20 to 20/30, with an average, asymptomatic reduction of meridional field in each eye to 50 degrees. In contrast, in the three eyes having suffered RRD prior to presentation, visual acuity ranged from 20/125 to 8/200 and average meridional field was 29 degrees. CONCLUSION: Encircling grid laser (OSC) modified in Stickler eyes to encompass the ora serrata and extend posteriorly to and between the vortex vein ampullae (OSC/SS) is a reasonable RRD prophylaxis option to offer STL1 and STL2 patients as an alternative to no treatment or less effective prophylaxis. Because of rarity and severity, the ultimate proof of safety and efficacy will likely come not from randomized trials, but from a non-randomized, prospective, cohort comparison study of such individual efforts.

Effect of fluocinolone acetonide 0.2 µg/day implant on the decision to drive in patients with diabetic macular oedema: a report from the FAME study.

OBJECTIVE: This study aimed to determine whether treatment with the 0.2 µg/day fluocinolone acetone implant (FAc; ILUVIEN, Alimera Sciences) and the associated improvements in best-corrected visual acuity (BCVA) and central subfield thickness (CST) demonstrated in the Fluocinolone Acetonide in Diabetic Macular Edema (FAME) study have an impact on the patient's decision to drive as measured by the National Eye Institute Visual Functioning Questionnaire-25 (NEI-VFQ-25). METHODS: This was a post hoc analysis of up to 3 years of NEI-VFQ-25 data collected during the phase III FAME trial. Patients were divided into four quartiles according to baseline NEI-VFQ-25 driving subscale (DSS) score. Patients who had never driven were excluded. Patients received either the 0.2 µg/day FAc implant or sham (dummy injection). Change in the DSS score of the NEI-VFQ-25 questionnaire over 3 years in FAc-treated versus sham-treated patients was analysed by BCVA, CST and baseline DSS score. RESULTS: The proportion of patients achieving BCVA≥20/40 was similar between the FAc and sham groups throughout the study, while improvements in CST were significantly greater in the quartile of FAc-treated patients with the lowest baseline DSS score (quartile 1; p=0.04). Significant improvements in DSS score were also observed in quartile 1 (p=0.024), while numerical-but not significant-improvements in DSS score were observed in the full cohort. CONCLUSION: This post hoc analysis demonstrates a significant association between clinical outcomes in diabetic macular oedema and improvement in quality of life measures following a single FAc implant.

Depth Perception and Grasp in Central Field Loss.

PURPOSE: We set out to determine whether individuals with central field loss benefit from using two eyes to perform a grasping task. Specifically, we tested the hypothesis that this advantage is correlated with coarse stereopsis, in addition to binocular summation indices of visual acuity, contrast sensitivity, and binocular visual field. METHODS: Sixteen participants with macular degeneration and nine age-matched controls placed pegs on a pegboard, while their eye and hand movements were recorded. Importantly, the pegboard was placed near eye height, to minimize the contribution of monocular cues to peg position. All participants performed this task binocularly and monocularly. Before the experiment, we performed microperimetry to determine the profile of field loss in each eye and the locations of eccentric fixation (if applicable). In addition, we measured both acuity and contrast sensitivity monocularly and binocularly, and stereopsis by using both a RanDot test and a custom stereo test. RESULTS: Peg-placement time was significantly shorter and participants made significantly fewer errors with binocular than with monocular viewing in both the patient and control groups. Among participants with measurable stereopsis, binocular advantage in peg-placement time was significantly correlated with stereoacuity (ρ = -0.78; P = 0.003). In patients without measurable stereopsis, the binocular advantage was related significantly to the overlap in the scotoma between the two eyes (ρ = -0.81; P = 0.032). CONCLUSIONS: The high correlation between grasp performance and stereoacuity indicates that coarse stereopsis may benefit tasks of daily living for individuals with central field loss.

SKread predicts handwriting performance in patients with low vision.

OBJECTIVE: To assess whether performance on the Smith-Kettlewell Reading (SKread) test is a reliable predictor of handwriting performance in patients with low vision. DESIGN: Cross-sectional study. PARTICIPANTS: Sixty-six patients at their initial low-vision rehabilitation evaluation. METHODS: The patients completed all components of a routine low-vision appointment including logMAR acuity, performed the SKread test, and performed a handwriting task. Patients were timed while performing each task and their accuracy was recorded. The handwriting task was performed by having patients write 5 5-letter words into sets of boxes where each letter is separated by a box. The boxes were 15 × 15 mm, and accuracy was scored with 50 points possible from 25 letters: 1 point for each letter within the confines of a box and 1 point if the letter was legible. Correlation analysis was then performed. RESULTS: Median age of participants was 84 (range 54-97) years. Fifty-seven patients (86%) had age-related macular degeneration or some other maculopathy, whereas 9 patients (14%) had visual impairment from media opacity or neurologic impairment. Median Early Treatment Diabetic Retinopathy Study acuity was 20/133 (range 20/22 to 20/1000), and median logMAR acuity was 0.82 (range 0.04-1.70). SKread errors per block correlated with logMAR acuity (r = 0.6), and SKread time per block correlated with logMAR acuity (r = 0.51). SKread errors per block correlated with handwriting task time/accuracy ratio (r = 0.61). SKread time per block correlated with handwriting task time/accuracy ratio (r = 0.7). LogMAR acuity score correlated with handwriting task time/accuracy ratio (r = 0.42). All p values were < 0.01. CONCLUSIONS: SKread scores predict handwriting performance in patients with low vision better than logMAR acuity.

Random word recognition chart helps scotoma assessment in low vision.

PURPOSE: To evaluate the use of SKread, a vision test based on random word sequences that prevents the prediction of upcoming words by linguistic criteria and is simple to score in a clinical setting. METHODS: SKread combines the standardized format of the MNread test with sequences of random words and letters like the Pepper Visual Skills for Reading test. A total of 231 subjects (aged 16 to 97 years) participated. We report data from 136 eyes of subjects with a maculopathy and 65 with normal or near-normal vision. Test reliability was investigated on an additional 30 eye-healthy subjects. We tested visual acuity and reading performance for continuous text and random words monocularly. Reading speed and all errors made are reported. RESULTS: Reading speed was always higher for continuous text than for random word sequences, even in normally sighted subjects for whom the median reading times per paragraph were 2.4 s (MNread) vs. 6.8 s (SKread). In patients with maculopathies, the medians were 4.2 s vs. 12.25 s. These differences were statistically significant. Number and type of errors made depended only negligibly on age and visual acuity. Patients with a dense scotoma right of fixation made more "right errors" by missing letters at the end of words, whereas those with a scotoma left of fixation made more "left errors" by missing letters at the beginning of words. The SKread test showed good test-retest repeatability. CONCLUSIONS: The unpredictability of random word and letter sequences renders reading performance highly dependent on eyesight and less dependent on reading skill and educational level. Recurrent right or left errors can indicate the presence and location of a scotoma without expensive equipment. This knowledge can be used to teach patients about how the scotoma can interfere with their vision.

Visual ability of patients seeking outpatient low vision services in the United States.

IMPORTANCE: Most patients with low vision are elderly and have functional limitations from other health problems that could add to the functional limitations caused by their visual impairments. OBJECTIVE: To identify factors that contribute to visual ability measures in patients who present for outpatient low vision rehabilitation (LVR) services. DESIGN, SETTING, AND PARTICIPANTS: As part of a prospective, observational study of new patients seeking outpatient LVR, 779 patients from 28 clinical centers in the United States were enrolled in the Low Vision Rehabilitation Outcomes Study (LVROS) from April 25, 2008, through May 2, 2011. The Activity Inventory (AI), an adaptive visual function questionnaire, was administered to measure overall visual ability and visual ability in 4 functional domains (reading, mobility, visual motor function, and visual information processing) at baseline before LVR. The Geriatric Depression Scale, Telephone Interview for Cognitive Status, and Medical Outcomes Study 36-Item Short-Form Health Survey physical functioning questionnaires were also administered to measure patients' psychological, cognitive, and physical health states, respectively. MAIN OUTCOMES AND MEASURES: Predictors of visual ability and functional domains as measured by the AI. RESULTS: Among the 779 patients in the LVROS sample, the mean age was 76.4 years, 33% were male, and the median logMAR visual acuity score was 0.60 (0.40-0.90 interquartile range). Correlations were observed between logMAR visual acuity and baseline visual ability overall (r = -0.42) and for all functional domains. Visual acuity was the strongest predictor of visual ability (P < .001) and reading ability (P < .001) and had a significant independent effect on the other functional domains. Physical ability was independently associated with (P < .001) overall visual ability as well as mobility and visual motor function. Depression had a consistent independent effect (P < .001) on overall visual ability and on all functional domains, whereas cognition had an effect on only reading and mobility (P < .001). CONCLUSIONS AND RELEVANCE: Visual ability is a multidimensional construct, with visual acuity, depression, physical ability, and cognition explaining more than one-third of the variance in visual ability as measured by the AI. The significant contributions of the nonvisual factors to visual ability measures and the rehabilitation potential (ie, ceiling) effects they may impose on LVR are important considerations when measuring baseline visual ability and ultimately LVR outcomes in ongoing clinical research.

Patient awareness of binocular central scotoma in age-related macular degeneration.

PURPOSE: To assess whether age-related macular degeneration (AMD) patients are aware of binocular central visual field defects. METHODS: One hundred fifty-three consecutive AMD patients in their initial low-vision rehabilitation evaluation were immediately asked at the beginning of their visit (1) whether they were able to see any blind spots or defects in their field of vision and (2) whether they had any evidence or experiences that led them to believe that they had defects in their field of vision. They then had their vision assessed by binocular central visual field testing using the California Central Visual Field Test, binocular reading performance evaluated using the Smith-Kettlewell Reading Test (SK Read) and MN Read charts, and visual acuity measured using the ETDRS chart at 1 meter. Mean diameters of the scotomas with borders near fixation were noted. RESULTS: Visual acuity median was 20/253 (range 20/40 to hand movements). Binocular scotomas were present in 88% of patients (66% had dense scotoma). Of patients with binocular scotomas, 56% were totally unaware of their presence, even with dense scotomas measuring up to 30° in diameter; 1.5% could fleetingly see a defect in their visual field on waking; and 44% related experiences of things "disappearing" on them. The median and range of scotoma diameters for those unaware vs. those with some awareness of their scotomas were comparable. There was no significant relationship of awareness of the scotoma with age, acuity, scotoma size, density, or duration of onset. Awareness of scotoma was associated with fewer errors on the SK Read (p < 0.01). CONCLUSIONS: Low vision clinicians cannot depend on patients to report the presence of significant scotomas; thus, appropriate testing must be performed. Presence of scotomas decreased reading accuracy, but some awareness of the scotomas had a tendency to improve accuracy. The value of rehabilitation programs aimed at increasing patient awareness of their scotomas may be supported by this evidence.

Target search and identification performance in low vision patients.

PURPOSE: To introduce a novel approach to topographic function assessment in visual impairment that requires neither fixation nor reading. METHODS: One hundred thirty-five consecutive low vision patients with varying diagnoses and 30 control subjects of comparable median age participated. Performance was measured in a search task that required finding and identifying visual targets which appeared consecutively on a monitor in 32 locations of the central field of gaze. The task specifically discourages steady fixation and the subjects could make eye movements as needed to locate targets. Target size was always double the size threshold, and no manual action was required. The best attainable reading speed at any size was routinely measured (MNread). Main outcome measure was response latency necessary to solve the task. Data were median latencies and sums of all latencies. RESULTS: Measurements yielded a wide variety of performance levels, with a factor of 14 to 16 between best and worst performers. The highest correlation existed between median response latency in the search task and best attainable reading speed. Only a weak correlation was found between performance and visual acuity. No statistically significant correlations were found with age or diagnosis. CONCLUSIONS: The "search-and-identify" paradigm and continuous text reading share an important mechanism that determines performance in both tasks. The authors hypothesize that the factor enabling patients to perform well in both paradigms is oculomotor skill and/or eye movement strategy. Results show that the search test is a useful tool for the easy assessment of impaired vision independent of language, level of literacy, and reading habits.

Cognitive appraisals, distress and disability among persons in low vision rehabilitation.

OBJECTIVE: Examined cognitive appraisals of interference and tolerance in the prediction of distress and self-reported disability among persons presenting for low vision rehabilitation. DESIGN: Cross-sectional; correlational and path analyses. METHODS: One-hundred and thirteen patients (mean age, 71 years; 52 men and 61 women) presenting for low vision rehabilitation at a university-based centre for low vision rehabilitation participated in an initial clinical vision examination and completed several questionnaires to evaluate cognitive appraisals, emotional distress and self-reported disability. RESULTS: Path analyses indicated that greater tolerance was associated with less interference imposed by vision loss. Greater tolerance was also associated with less emotional distress and symptom severity (visual acuity) was associated with self-reported disability. Cognitive appraisals (tolerance and interference) indirectly influenced self-reported disability through emotional distress. CONCLUSIONS: The data indicate that appraisals of personal ability to tolerate vision loss and the perceived interference of vision loss on goal-directed behaviour and expected activities have greater influence on distress and are subsequently predictive of disability in comparison with objective symptoms (visual acuity). Implications for clinical interventions and further research are discussed.

Visual function in patients with choroidal neovascularization resulting from age-related macular degeneration: the importance of looking beyond visual acuity.

PURPOSE: A detailed understanding of overall quality of vision may help primary care physicians, optometrists, and general ophthalmologists to improve the care of patients with choroidal neovascularization (CNV) resulting from age-related macular degeneration (AMD). METHODS: Published literature was reviewed using Medline searches and the authors' knowledge of the field. RESULTS: Both visual acuity and contrast sensitivity are strongly associated with the ability to perform vision-related activities of daily living. CNV resulting from AMD often leads to scotoma, which is also strongly associated with the ability to perform everyday activities such as reading and driving. Contrast sensitivity and visual field extent may be better predictors of many abilities than visual acuity. Laser photocoagulation, verteporfin therapy, and pegaptanib sodium have been proven to reduce the risk of visual acuity loss in patients with CNV resulting from AMD. Laser photocoagulation frequently causes scotoma, but data on its effects on other aspects of overall quality of vision are scarce. Verteporfin therapy has been shown to also reduce the risk of contrast sensitivity loss and has been associated with stabilization or reduction of scotoma size. Treatment effects beyond visual acuity have not been investigated for pegaptanib. Detailed assessment of overall quality of vision also aids the design of vision rehabilitation programs tailored to the needs of individual patients. CONCLUSIONS: Understanding the impact of vision loss on patients with CNV resulting from AMD and assessing treatment benefits requires assessment of overall quality of vision. Primary care physicians and optometrists have an important role in ensuring that patients receive the best possible care, which can be aided by prompt referral to an ophthalmologist or retina specialist and collaboration with low-vision specialists and optometrists who together can make detailed assessments of overall quality of vision, implement appropriate treatment, and design effective rehabilitation strategies.

Counseling and rehabilitation.

Counseling is an art learned over a lifetime, from other physicians during formal training and from one's personal counseling experiences. The effort to develop this art will be greatly appreciated and richly awarded with personal satisfaction. The importance of counseling and rehabilitation for the ocular trauma victim is in treating the whole patient, not only the injured eye. Every effort should be made to help a patient achieve a positive attitude about his or her capabilities to successfully use residual vision and live a full and enjoyable life as a visually impaired person.