Usability of smartphone apps as reading aids for low vision patients.

PURPOSE: Reading is one of the main complaints of low vision patients referred for visual rehabilitation, since it is fundamental for full participation in modern society. The purpose of this study was to analyse the usability of free smartphone apps with magnification tools as digital aids for reading visual rehabilitation in low vision patients. METHODS: Low vision adult patients were included regarding the following criteria: best-corrected visual acuity in the better-seeing eye from 0.6 to 1.3logMAR, previous habit of smartphone use, without former aid adaptation. Android system was used for the selection of three applications (apps) to be tested as digital reading aids. Visual acuity (VA) for near, reading acuity (RA) and reading speed (RS) using each app were measured. The participants were also asked about apps usability concerning accessibility, focus adjustment and text tracking. RESULTS: Seventeen participants (10 females - 58.8%) with ages ranging from 26 to 73 years (mean = 45.2 ± 13.1 years) were included. Mean binocular VA, RA and RS without the apps were respectively 1.00 ± 0.22 logMAR, 1.01 ± 0.28 logMAR and 41.7 ± 28.6 words/minute. Statistically better visual and RA results through the apps were found with a mean ≥9-line gain for both, and no significant difference for RS was found. All apps achieved good usability scores (means > 7). CONCLUSIONS: All tested apps provided improvement in VA and reading performance, with proven usability. Free smartphone apps for magnification should be considered in reading rehabilitation programmes for low vision patients.Implications for rehabilitationReading is essential for performing productive daily activities and for full participation in modern society, being a clinical indicator of visual function and quality of life.Difficulty in reading is one of the main complaints of low vision patients referred for visual rehabilitation.Smartphone apps for magnification and readability optimization of printed texts may provide improvement in visual acuity and reading performance of low vision patients.Digital technologies should be considered in the low vision reading rehabilitation programme since they provide additional advantages such as accessibility, cost, portability and social acceptance.Usability is the user's experience when interacting with a software application and associated with pleasantness, usefulness, ease of use, safety and efficiency. Low vision patient's feedback on the usability of assistive technologies is important for a successful visual rehabilitation which meets his/her needs and expectations.

Impaired Ganglion Cell Function Objectively Assessed by the Photopic Negative Response in Affected and Asymptomatic Members From Brazilian Families With Leber's Hereditary Optic Neuropathy.

Purpose: The photopic negative response (PhNR) is an electrophysiological method that provides retinal ganglion cell function assessment using full-field stimulation that does not require clear optics or refractive correction. The purpose of this study was to assess ganglion cell function by PhNR in affected and asymptomatic carriers from Brazilian families with LHON. Methods: Individuals either under suspicion or previously diagnosed with LHON and their family members were invited to participate in this cross-sectional study. Screening for the most frequent LHON mtDNA mutations was performed. Visual acuity, color discrimination, visual fields, pattern-reversal visual evoked potentials (PRVEP), full-field electroretinography and PhNR were tested. A control group of healthy subjects was included. Full-field ERG PhNR were recorded using red (640 nm) flashes at 1 cd.s/m2, on blue (470 nm) rod saturating background. PhNR amplitude (µV) was measured using baseline-to-trough (BT). Optical coherence tomography scans of both the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) were measured. PhNR amplitudes among affected, carriers and controls were compared by Kruskal-Wallis test followed by post-hoc Dunn test. The associations between PhNR amplitude and OCT parameters were analyzed by Spearman rank correlation. Results: Participants were 24 LHON affected patients (23 males, mean age=30.5 ± 11.4 yrs) from 19 families with the following genotype: m.11778G>A [N = 15 (62%), 14 males]; m.14484T>C [N = 5 (21%), all males] and m.3460G>A [N = 4 (17%), all males] and 14 carriers [13 females, mean age: 43.2 ± 13.3 yrs; m.11778G>A (N = 11); m.3460G>A (N = 2) and m.14484T>C (N = 1)]. Controls were eight females and seven males (mean age: 32.6 ± 11.5 yrs). PhNR amplitudes were significantly reduced (p = 0.0001) in LHON affected (-5.96 ± 3.37 µV) compared to carriers (-16.53 ± 3.40 µV) and controls (-23.91 ± 4.83; p < 0.0001) and in carriers compared to controls (p = 0.01). A significant negative correlation was found between PhNR amplitude and total macular ganglion cell thickness (r = -0.62, p < 0.05). Severe abnormalities in color discrimination, visual fields and PRVEPs were found in affected and subclinical abnormalities in carriers. Conclusions: In this cohort of Brazilian families with LHON the photopic negative response was severely reduced in affected patients and mildly reduced in asymptomatic carriers suggesting possible subclinical abnormalities in the latter. These findings were similar among pathogenic mutations.