Fonts Designed for Macular Degeneration: Impact on Reading

Seeing in crowds: Averaging first, then max

Crowding, a fundamental limit in object recognition, is believed to result from excessive integration of nearby items in peripheral vision. To understand its pooling mechanisms, we measured subjects' internal response distributions in an orientation crowding task. Contrary to the prediction of an averaging model, we observed a pattern suggesting that the perceptual judgement is made based on choosing the largest response across the noise-perturbed items. A model featuring first-stage averaging and second-stage signed-max operation predicts the diverse errors made by human observers under various signal strength levels. These findings suggest that different rules operate to resolve the bottleneck at early and high-level stages of visual processing, implementing a combination of linear and nonlinear pooling strategies.

Toward an internationally accepted standard for reading charts

Patients who suffer from sight-threatening eye diseases share a desire to regain a comfortable reading ability. In light of the modern advances achieved in ophthalmic diagnosis and therapy, and because a significant lack of comparability between reading charts still exists, there is an increasing need for a worldwide standard in the form of a norm for diagnostic reading charts. Already, applied advancements such as digital print, which allow a calibration of the print sizes of reading charts in correctly progressing geometric proportions by using the actual height of a lower case "x" in millimeters (x-height), and psychophysically standardizing reading charts and their test items by applying modern statistical methods have significantly contributed to establishing a norm for reading charts. In 2020, a proposal of the British delegation was accepted by the International Organization for Standardization (ISO) group "Visual Optics and Optical Instruments," and a working group was established. Bearing in mind the efforts of the ISO with regard to an international norm, this review article is intended to (a) give an overview of the historical background and related normative approaches for diagnostic reading tests used in ophthalmology and optometry, (b) explain psychophysical and technical concerns, and (c) discuss the possibilities and limits of concepts that seem relevant to developing a modern standard for reading charts.

Luciole, a new font for people with low vision

Low vision affects the ability to read and can be a major barrier to educational success and insertion into the workplace. We designed a new font (Luciole) to improve the readability and comfort for people with low vision. In this study, we analyze the effect of the font type on readability. Luciole was compared to five other fonts (Arial, OpenDyslexic, Verdana, Eido and Frutiger) in 145 French readers (73 with low vision, and 72 normal sighted), aged 6 to 35 years old and divided into four reading expertise groups. Participants completed two tasks, first reading texts on paper and then reading false-words on screen using eye tracking. About half of the participants with low vision had a subjective preference for Luciole when reading on paper and on the screen; lower preference is noted for participants with normal vision. Other readability criteria show a slight advantage of the Luciole font over some fonts (e.g., Eido and OpenDyslexic) in both groups. The results obtained when taking into consideration the level of reading expertise confirm this trend.

Is learning a logographic script easier than reading an alphabetic script for German children with dyslexia?

PURPOSE

Developmental dyslexia in alphabetic languages (DD) is characterized by a phonological deficit. Since logographic scripts rely predominantly on visual and morphological processing, reading performance in DD can be assumed to be less impaired when reading logographic scripts.

METHODS

40 German-speaking children (18 with DD, 22 not reading-impaired-group C; 9-11 years) received Chinese lessons. Eye movements (EM) were recorded during naming single alphabetic words, pictures (confrontational) and Chinese characters to be named in German and Chinese. The main outcome variables were: Articulation latency, numbers and durations of fixations. Quality of life (QoL) was assessed by questionnaires.

RESULTS

While reading alphabetic words, articulation latencies and numbers of fixations were significantly higher for group DD than for group C (AL-DD = 1.13, AL-C = 0.84, p< .001; FN-DD = 3.50; FN-C = 2.00, p< .001). For naming pictures and Chinese characters in German and in Chinese, no significant group differences were found for any of the EM variables. The percentage of correct answers was high for German naming (DD = 86.67%, C = 95.24%; p = .015) and lower for Chinese naming in both groups, but significantly lower in group DD, especially for Chinese naming (DD = 56.67%, C: 83.77%; p = .003). QoL differed between groups from the children's perspective only at posttest. Parents of group DD perceived their children`s QoL to be lower compared with parents of group C at pre- and posttest.

CONCLUSIONS

Children with dyslexia performed as well as group C during naming Chinese characters in German and in Chinese regarding their EM variables, presumably because they processed Chinese characters by the visuo-spatial pathway with direct access to the semantic system. However, the significantly lower percentage of correct answers especially during Chinese naming showed that group DD had more difficulties naming Chinese characters than group C, which could be attributed to their phonological deficit, among other factors.

TRIAL REGISTRATION

German clinical trials register (DRKS00015697).

The effect of serifs and stroke contrast on low vision reading

PURPOSE

Patients with low vision are generally recommended to use the same fonts as individuals with normal vision. However, we are yet to fully understand whether stroke width and serifs (small ornamentations at stroke endings) can increase readability. This study's purpose was to characterize the interaction between two factors (end-of-stroke and stroke width) in a well-defined and homogenous group of patients with low vision.

METHODS

Font legibility was assessed by measuring word identification performance of 19 patients with low vision (autosomal dominant optic atrophy [ADOA] with a best-corrected average visual acuity 20/110) and a two-interval, forced-choice task was implemented. Word stimuli were presented with four different fonts designed to isolate the stylistic features of serif and stroke width.

RESULTS

Font-size threshold and sensitivity data revealed that using a single measure (i.e., font-size threshold) is insufficient for detecting significant effects but triangulation is possible when combined with signal detection theory. Specifically, low stroke contrast (smaller variation in stroke width) yielded significantly lower thresholds and higher sensitivity when a font contained serifs (331 points; d' = 1.47) relative to no serifs (345 points; d' = 1.15), E(μ_{sans, low} - μ_{serif, low}) = -14 points, 95 % Cr. I. = [-24, -5], P(δ > 0) = 0.99 and E(μ_{serif, low} - μ_{sans, low}) = 0.32, 95 % Cr. I. = [0.16, 0.49], P(δ > 0) = 0.99.

CONCLUSION

In people with low visual acuity caused by ADOA, the combination of serifs and a uniform stroke width resulted in better text legibility than other combinations of uniform/variable stroke widths and presence/absence of serifs.

Towards a standardisation of reading charts: Font effects on reading performance-Times New Roman with serifs versus the sans serif font Helvetica

PURPOSE

The purpose was to compare systematically the legibility of a font without serifs (Helvetica) and one with serifs (Times New Roman).

METHODS

Three paragraphs that were equal in the number of words, syllables, characters, difficulty and reading length were printed at equal size, with equal spacing between the lines and equal layout (paperback style), in either the sans serif typeface Helvetica Neue T1 55 Roman (Adobe) or the serif typeface Times New Roman PS Roman (Adobe). They were also printed in newspaper format in the serif font. The paragraphs were presented in random order (Latin square design) to 36 participants between 18 and 38 years of age (wearing their best-corrected visual acuity). Reading duration was measured with a stopwatch. Reading time, reading speed and the number of reading errors were compared.

RESULTS

For the paperback layout, no significant difference in reading time (p = 0.50) or reading speed (p = 0.56) was found between the two fonts. The correlation between the two fonts was high for both reading time and speed (r = 0.93). The mean number of reading errors was the same (0.31 ± 0.58 errors/text) for both fonts. There was a significant difference in reading time and speed between the paperback and the newspaper layout.

CONCLUSION

The legibility of Helvetica and Times New Roman is similar when investigated under equivalent conditions. Thus, these two font types can be used as interchangeable standard typefaces.

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.

Font effects on reading parameters: comparing Radner Reading Charts printed in Helvetica and Times Roman

Purpose

To investigate the effect of font choice on reading parameters by using the RADNER Reading Charts printed in two fonts (Helvetica vs. Times Roman) equalized in terms of x-height.

Methods

This is a cross-sectional study of 40 participants with healthy eyes (18 to 60 years of age; mean: 42.13 ± 12.28 years). Reading performance was evaluated binocularly with RADNER Reading Charts printed in either Helvetica Neue (T1) Roman sans serif (Adobe) or Times New Roman PS Roman serif (Adobe). The test distance was 40 cm. Reading charts were presented in random order. Reading acuity (RA), mean reading speed of all sentences read (MEAN-ALL RS), mean reading speed from 0.8 logRAD to 0.3 logRAD (MEAN-RS), maximum reading speed (MAX-RS), and critical print size (CPS) were compared.

Results

The RA values obtained for the Helvetica and Times Roman fonts (in full logarithmic units of 0.1 logRAD) did not differ between the two fonts (mean for both fonts: − 0.128 ± 0.064 logRAD; 95% CI for both: − 0.148; − 0.107 logRAD). The differences in all other reading parameters between the two fonts were small and not statistically significant. The analyses revealed narrow confidence intervals and good coefficients of reliability. Except for the CPS (r = 0.49) and RA (equal for Helvetica and Times Roman), the correlations for all parameters were high, ranging from r = 0.92 to r = 0.98.

Conclusion

The equivalent reading performance obtained with Helvetica and Times Roman (when equalized in x-height and layout) makes these font types interchangeable as standards for reading charts.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-022-05665-y.

Comparison of Logarithmic Reading Charts for Visual Assessment in Normally Sighted Participants

SIGNIFICANCE

Logarithmic reading charts provide standardized measures of reading performance. Here we show that existing charts provide equivalent assessments of visual aspects of reading that are in good agreement with traditional measures of visual acuity and seem uninfluenced by cognitive (linguistic) factors.

PURPOSE

The aims of this study were to (1) determine the equivalence of logarithmic charts of sentence and word reading, (2) evaluate the relationship between reading chart performance and more traditional measures of visual assessment, and (3) establish the influence of linguistic factors on reading chart performance.

METHODS

In a sample of 82 normally sighted participants, we determined performance on the reading measures (e.g., reading acuity, reading speed, critical print size) of the following logarithmic charts of sentence and word reading: The Colenbrander English Continuous Text Near Vision Card, Radner Reading Chart, Minnesota Reading Acuity Chart, and Smith-Kettlewell Reading Chart. In doing so, we compared performance on reading measures between charts and with performance on more traditional measures of visual assessment (uncrowded and crowded letter acuity, stereoacuity, accommodation) and cognitive measures of word knowledge and ability (Wechsler Adult Intelligence Scale Vocabulary Subtest, National Adult Reading Test).

RESULTS

Factor analysis confirmed that performance on the reading measures (reading acuity, reading speed, critical print size) was equivalent across charts. Reading test performance was also related to more traditional measures of vision, the most consistent of which were significant associations between reading acuity and acuity for single-letter optotypes. There were no significant associations between reading chart performance and cognitive measures of word knowledge and ability.

CONCLUSIONS

The findings presented here suggest that logarithmic charts composed of sentences and words represent an alternative to traditional letter acuity testing. This is particularly the case for measures of reading acuity.

The effect of font width on eye movements during reading

Certain font features (e.g., letter width) can change the amount of space occupied by text in published works. Font styles/features are also known to affect reading eye movements (EM); however, few studies have examined these effects - and none used high-resolution displays. We examined the effects of font width on EMs by utilizing four fonts, from the Univers family, which varied in letter-width magnitude. Participants' (n = 25) reading speed, saccade velocity, and the duration/number of fixations and saccades were recorded. The Ultra Condensed font significantly influenced readability and yielded: fewer fixations and saccades; longer fixation durations than the Roman and Extended fonts; and shorter saccade durations, relative to the other fonts. Readers efficiently adjusted their EMs such that no reading-speed differences were observed. The eye-tracking metrics revealed two trade-off effects: (1) fewer and shorter EMs and (2) more and longer EMs, which were revealed by the font-width manipulation.

Training to improve temporal processing of letters benefits reading speed for people with central vision loss

Reading is slow and difficult for many people with central vision loss. A previous study showed that the temporal threshold for letter recognition is a major factor limiting reading speed for people with central vision loss. Here, we asked whether the temporal threshold for letter recognition for people with central vision loss could be improved through training and, if so, whether that would benefit reading. Training consisted of six sessions (3000 trials) of recognizing letter trigrams presented at fixation. Trigrams were initially presented at a baseline temporal threshold that was decreased by 0.1 log step when observers' letter recognition accuracies reached 80% or higher for four consecutive blocks. Before and after training, we measured observers' visual acuity, preferred retinal locus for fixation, fixation stability, reading speeds using the rapid serial visual presentation (RSVP) paradigm, the MNREAD Acuity Chart and 100-word passages, the baseline temporal threshold for letter recognition at 80% accuracy, and a visual-span profile. After training, the temporal threshold was decreased by 68%. This improvement was accompanied by a higher RSVP maximum reading speed (but no change in MNREAD and passage reading speeds) and a larger visual span. A mediation analysis showed that the relationship between the temporal threshold and RSVP maximum reading speed was mainly mediated by the information transfer rate (size of visual span/temporal duration). Our results showed that the temporal threshold for letter recognition is amenable to training and can improve RSVP reading speeds, offering a practical means to improve reading speed for people with central vision loss.

Reconciling print-size and display-size constraints on reading

Two fundamental constraints limit the number of characters in text that can be displayed at one time-print size and display size. These dual constraints conflict in two important situations-when people with normal vision read text on small digital displays, and when people with low vision read magnified text. Here, we describe a unified framework for evaluating the joint impact of these constraints on reading performance. We measured reading speed as a function of print size for three digital formats (laptop, tablet, and cellphone) for 30 normally sighted and 10 low-vision participants. Our results showed that a minimum number of characters per line is required to achieve a criterion of 80% of maximum reading speed: 13 characters for normally sighted and eight characters for low-vision readers. This critical number of characters is nearly constant across font and display format. Possible reasons for this required number of characters are discussed. Combining these character count constraints with the requirements for adequate print size reveals that an individual's use of a small digital display or the need for magnified print can shrink or entirely eliminate the range of print size necessary for achieving maximum reading speed.

Online Survey of Digital Reading by Adults with Low Vision

SIGNIFICANCE

Access to digital text is increasingly widespread, but its impact on low-vision reading is not well understood.

PURPOSE

We conducted an online survey of people with low vision to determine what assistive technologies they use for visual reading, their preferred text characteristics, and the time they devote to reading digital and hard-copy text.

METHODS

One hundred thirty-three low-vision participants completed an online survey. Participants reported the nature and history of their low vision, their usage of different assistive technologies, and time devoted to five visual reading activities.

RESULTS

The three largest diagnostic categories were albinism (n = 36), retinitis pigmentosa (n = 20), and glaucoma (n = 15). Mean self-reported acuity was 0.93 logMAR (range, 0.1 to 1.6 logMAR). Mean age was 46 years (range, 18 to 98 years). Participants reported on percentage time spent reading using vision, audio, or touch (braille). Seventy-five percent of our participants did more than 50% of their reading visually. Across five categories of reading activities-work or education, news, pleasure, spot reading, and social networking-participants reported more time spent on digital reading than hard-copy reading. Eighty-nine percent of our participants used at least one technology from each of our two major categories of assistive technologies (digital content magnifiers and hard-copy content magnifiers) for visual reading.

CONCLUSIONS

Despite the growing availability of digital text in audio or braille formats, our findings from an online sample of people with low vision indicate the continuing importance of visual reading. Our participants continue to use technology to access both hard-copy and digital text, but more time is devoted to digital reading. Our findings highlight the need for continued research and development of technology to enhance visual reading accessibility.

Reading in the presence of macular disease: a mini-review

Purpose

Reading is vital to full participation in modern society. To millions of people suffering from macular disease that results in a central scotoma, reading is difficult and inefficient, rendering reading as the primary goal for most patients seeking low vision rehabilitation. The goals of this review paper are to summarize the dependence of reading speed on several key visual and typographical factors and the current methods or technologies for improving reading performance for people with macular disease.

Important findings

In general, reading speed for people with macular disease depends on print size, text contrast, size of the visual span, temporal processing of letters and oculomotor control. Attempts at improving reading speed by reducing the crowding effect between letters, words or lines; or optimizing properties of typeface such as the presence of serifs or stroke‐width thickness proved to be futile, with any improvement being modest at best. Currently, the most promising method to improve reading speed for people with macular disease is training, including perceptual learning or oculomotor training.

Summary

The limitation on reading speed for people with macular disease is likely to be multi‐factorial. Future studies should try to understand how different factors interact to limit reading speed, and whether different methods could be combined to produce a much greater benefit.

Typeface features and legibility research

In the early 20th century, reading researchers expressed optimism that scientific study of reading would improve the legibility of typefaces. Font-making was, however, complex, expensive and impractical for reading research, which was therefore restricted to standard commercial fonts. The adoption of computer typography in legibility studies makes the measurement, modification and creation of experimental fonts easier, while display of text on computer screens facilitates reading studies. These technical advances have spurred innovative research. Some studies continue to test fonts for efficient reading in low vision as well as normal vision, while others use novel fonts to investigate visual mechanisms in reading. Some experimental fonts incorporate color and animation features that were impractical or impossible in traditional typography. While it is not clear that such innovations will achieve the optimistic goals of a century ago, they extend the investigation and understanding of the nature of reading.

Extending the MNREAD sentence corpus: Computer-generated sentences for measuring visual performance in reading

The MNREAD chart consists of standardized sentences printed at 19 sizes in 0.1 logMAR steps. There are 95 sentences distributed across the five English versions of the chart. However, there is a demand for a much larger number of sentences: for clinical research requiring repeated measures, and for new vision tests that use multiple trials at each print size. This paper describes a new sentence generator that has produced over nine million sentences that fit the MNREAD constraints, and demonstrates that reading performance with these new sentences is comparable to that obtained with the original MNREAD sentences. We measured reading performance with the original MNREAD sentences, two sets of our new sentences, and sentences with shuffled word order. Reading-speed versus print-size curves were obtained for each sentence set from 14 readers with normal vision at two levels of blur (intended to simulate acuity loss in low vision) and with unblurred text. We found no significant differences between the new and original sentences in reading acuity and critical print size across all levels of blur. Maximum reading speed was 7% slower with the new sentences than with the original sentences. Shuffled sentences yielded slower maximum reading speeds and larger reading acuities than the other sentences. Overall, measures of reading performance with the new sentences are similar to those obtained with the original MNREAD sentences. Our sentence generator substantially expands the reading materials for clinical research on reading vision using the MNREAD test, and opens up new possibilities for measuring how text parameters affect reading.