A systematic review of controlled trials on visual stress using Intuitive Overlays or the Intuitive Colorimeter

Flicker and reading speed: Effects on individuals with visual sensitivity

Flicker and patterns of stripes in the modern environment can evoke visual illusions, discomfort migraine, and seizures. We measured reading speed while striped and less striped texts were illuminated with LED lights. In Experiment 1, the lights flickered at 60 Hz and 120 Hz compared to 60 kHz (perceived as steady light). In Experiment 2, the lights flickered at 60 Hz or 600 Hz (at which frequency the phantom array is most visible), and were compared to continuous light. Two types of text were used: one containing words with high horizontal autocorrelation (striped) and another containing words with low autocorrelation (less striped). We measured the number of illusions participants saw in the Pattern Glare (PG) Test. Overall, reading speed was slowest during the 60 Hz and 600 Hz flicker and was slower when reading the high autocorrelation text. Interestingly, the low PG group showed greater effects of flicker on reading speed than the high PG group, which tended to be slower overall. In addition, reading speed in the high PG group was reduced when the autocorrelation of the text was high. These findings suggest that uncomfortable visual environments reduce reading efficiency, the more so in individuals who are visually sensitive.

Colour-cued paragraph writing instruction for students with learning disabilities

Expository paragraph writing is difficult to learn and teach. For many students, particularly those with learning disabilities, it is difficult to manage the multiple, simultaneous complex processes required for success. And for their teachers, writing is the content area in which they feel least prepared to teach. This intervention applied the concept of reverse engineering to instructional design to teach expository paragraph writing using a color-cued graphic organizer. The study evaluated the effects of using a systematic color code to highlight the alignment of where ideas originate in a graphic organizer to their development into a sentence within a well-organized expository paragraph. Using a single case research design, with a pre- and post-intervention assessments, students (n = 5) with dyslexia improved their expository paragraph knowledge and skills. Percentage of non-overlapping data and Tau analyses indicate a large to very large effect of the 2-week intervention. Results, suggestions for further research, and implications for practice are discussed.

Dyslexia with and without Irlen syndrome: A study of influence on abilities and brain-derived neurotrophic factor level

The presence of comorbid Irlen syndrome (IS) in children with developmental dyslexia (DD) may have an impact on their reading and cognitive abilities. Furthermore, the brain-derived neurotrophic factor (BDNF) was reported to be expressed in brain areas involved in cognitive and visual processing. The aim of this study was to evaluate some cognitive abilities of a group of dyslexic children with IS and to measure and compare the plasma BDNF level to dyslexic children without IS and neurotypical (NT) children. The participants were 60 children with DD (30 in the DD + IS group; 30 in the DD group) and 30 NT children. The Irlen reading perceptual scale, the Stanford Binet intelligence scale, 4th ed, the dyslexia assessment test, and the Illinois test of psycholinguistic abilities were used. The BDNF level was measured using the enzyme-linked immunosorbent assay. One-minute writing and visual closure deficits were more prevalent, while phonemic segmentation deficits were less prevalent in the DD + IS group compared to the DD group. The BDNF level in the DD groups was lower than that in NT children (p < 0.001). Some reading and non-reading tasks were influenced by the presence of a coexisting IS. The reduced BDNF level could play a role in the deficits noticed in the abilities of children with DD.

Randomised controlled trial of an accommodative support lens designed for computer users

PURPOSE

Accommodative support (AS) lenses are a low add progressive addition spectacle lens designed to ease symptoms in computer vision syndrome (CVS). The study aims to investigate if (1) AS lenses improve CVS symptoms; (2) binocular/accommodative functions predict a benefit from AS lenses and (3) wearing AS lenses for six months impacts on binocular/accommodative functions.

METHODS

Pre-presbyopic adults with symptoms of CVS (Computer Vision Syndrome Questionnaire, CVS-Q^© , score ≥ 6) were randomly allocated to wear AS lenses or control single vision (SV) lenses. The CVS-Q^© and a battery of optometric tests were applied at baseline and after three and six months. Participants and researchers were masked to participant group. After six months, the SV group were unmasked and changed to AS lenses and one week later asked to choose which they preferred.

RESULTS

The change in CVS-Q^© scores from baseline to six months did not differ significantly in the two groups. At the end of the one week period, when the control group wore the AS lenses, control group participants were significantly more likely to prefer AS lenses to SV lenses. No optometric functions correlated with the benefit from AS lenses. AS lenses did not have any adverse effects on binocular or accommodative function.

CONCLUSIONS

In pre-presbyopic adults, there was no greater improvement in CVS-Q^© scores in the group wearing AS lenses than in the control group. No adverse effects on optometric function (including accommodation) are associated with wearing AS lenses.

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.

Distribution of Visual and Oculomotor Alterations in a Clinical Population of Children with and without Neurodevelopmental Disorders

A prospective, non-randomized comparative study was conducted to compare the distribution of oculomotor and visual alterations in children with neurodevelopmental disorders and healthy children without such disorders. Sixty-nine children (aged 6-13 years) were enrolled and divided into three groups: a control group (CG) of 23 healthy children; a group of 18 healthy children with oculomotor abnormalities (OAG); and a group of 28 children with a neurodevelopmental disorder (NDDG), with 15 cases of dyslexia, 7 cases of developmental coordination disorder (DCD) and 6 cases of attention deficit/hyperactivity disorder (ADHD). Significantly worse near stereopsis was found in NDDG compared with CG (p < 0.001) and OAG (p = 0.001). Likewise, a significantly lower amplitude of accommodation was found in NDDG compared with CG in both the right (p = 0.001) and left eyes (p < 0.001). No statistically significant differences between groups were found in the measurement of near and distance phoria (p ≥ 0.557), near point of convergence (p = 0.700) and fusional vergences (p ≥ 0.059). Significantly impaired oculomotor test scores were found in NDDG compared with CG (p < 0.001), with no significant differences between OAG and NDDG (p ≥ 0.063). The comparison between the three types of neurodevelopmental disorders included revealed the presence of a significantly lower amplitude of accommodation in children with DCD compared with dyslexics. Furthermore, less exophoria at near was present in children with dyslexia compared with children with ADHD (p = 0.018) and DCD (p = 0.054). In conclusion, children with dyslexia, ADHD and DCD show an altered oculomotor pattern and a more reduced amplitude of accommodation, not always compatible with the diagnostic criteria of an accommodative insufficiency. Accommodative and binocular vision problems are not always present in these children and cannot be considered an etiologic factor.

The Relation between Symptoms of Computer Vision Syndrome and Visual Display Terminal Utilization

  Introduction: The increased use of computers in the era of technological advances had an impact on the eye health called Computer Vision Syndrome (CVS), a compound eye problem caused by computer use. Almost every job could not be separated from the use of computers. Based on data from World Health Organization (WHO) in 2014, the incidence of asthenopia (eye fatigue) ranged from 40% to 90%. This research aimed to determine the relationship between symptoms of Computer Vision Syndrome and Visual Display Terminal utilization. Methods: This research was a quantitative with analytic survey method. Based on the data collection method, this research included as observational research type. This research was conducted with cross-sectional study design. Data collection was carried out with doctor's diagnosis guidelines, interviews, measurement using questionnaires, and observation. The population was 47 permanent workers and the sample taken was 42 respondents from the design division workers. The sampling technique used simple random sampling. The variables in this research were age, working period, distance to VDT, and general lighting intensity. Results: This research showed that the factors associated with symptoms of Computer Vision Syndrome were working period and eye distance to VDT. Conclusion: The longer the working period and the more distance between the eye and the VDT, the more symptoms of VDT would be.Keywords: computer use, symptoms of computer vision syndrome, visual display terminal

An investigation of low power convex lenses (adds) for eyestrain in the digital age (CLEDA)

INTRODUCTION

Digital eye strain (DES; computer vision syndrome) is a common cause of symptoms when viewing digital devices. Low-powered convex lenses (adds) have been recommended for the condition and "accommodative support" designs developed on this premise. The present research reports the extent to which dry eye is present in this population and the effect of convex lenses on symptoms and visual performance.

METHODS

The CVS-Q instrument was used to select pre-presbyopic adults with the symptoms of DES. Participants received a full eye examination including an assessment of dry eye with a modified SANDE questionnaire and using DEWS I criteria. The immediate effect of low-powered convex lenses (low adds: +0.50D, +0.75D, +1.25D) was investigated using subjective preference and a double-masked comparison with plano lenses with the Wilkins Rate of Reading Test (WRRT). Throughout this testing, participants wore their full distance refractive correction, based on non-cycloplegic retinoscopy and subjective refraction.

RESULTS

The signs and symptoms of dry eye were frequently present. Most participants reported a subjective preference for low adds, with +0.75D the most commonly preferred lens. Low adds (+0.50D and +0.75D; but not +1.25D) were associated with significantly improved performance at the WRRT. One quarter of participants read more than 10% faster with these additional convex lenses.

CONCLUSIONS

The study population was aged 20-40y and mostly worked on desktop computers. It is possible that +1.25D add may be more advantageous for people who are older or work more at closer viewing distances. Many symptomatic users of digital devices report a preference for low adds and use of these lenses is often associated with an improvement in reading performance.

Visual and non-visual properties of filters manipulating short-wavelength light

Purpose

Optical filters and tints manipulating short‐wavelength light (sometimes called ‘blue‐blocking’ or ‘blue‐attenuating’ filters) are used in the management of a range of ocular, retinal, neurological and psychiatric disorders. In many cases, the only available quantification of the optical effects of a given optical filter is the spectral transmittance, which specifies the amount of light transmitted as a function of wavelength.

Methods

We propose a novel physiologically relevant and retinally referenced framework for quantifying the visual and non‐visual effects of these filters, incorporating the attenuation of luminance (luminous transmittance), the attenuation of melanopsin activation (melanopsin transmittance), the colour shift, and the reduction of the colour gamut (gamut reduction). Using these criteria, we examined a novel database of spectral transmittance functions of optical filters (n = 121) which were digitally extracted from a variety of sources.

Results

We find a large diversity in the alteration of visual and non‐visual properties. The spectral transmittance properties of the examined filters vary widely, in terms of shapes and cut‐off wavelengths. All filters show relatively more melanopsin attenuation than luminance attenuation (lower melanopsin transmittance than luminous transmittance). Across the data set, we find that melanopsin transmittance and luminous transmittance are correlated.

Conclusions

We suggest that future studies and examinations of the physiological effects of optical filters quantify the visual and non‐visual effects of the filters beyond the spectral transmittance, which will eventually aid in developing a mechanistic understanding of how different filters affect physiology. We strongly discourage comparing the downstream effects of different filters on, e.g. sleep or circadian responses, without considering their effects on the retinal stimulus.

Effect of spectral overlays on visual parameters and reading ability: an integrative review

ABSTRACT Purpose: to provide an integrative review of indexed articles published from 2009 to 2019 on the effect of spectral overlays on visual parameters and reading ability. Methods: keywords were used to search seven databases. Duplicate entries, reviews, literature reviews, editor's comments, and congress abstracts were excluded, as well as papers that were not relevant, based on their titles and abstracts. A total of 52 articles, which were read in full, were eligible at this stage. Of these, 12 articles, published in Portuguese or English from 2009 to 2019, were included. Results: all 12 articles included evaluated the effect of overlays on the reading rate. There was an improvement in different visual parameters (ocular accommodation and eye movement), facial recognition, and reading (reading rate, relative efficiency, and comprehension). The use of overlays reduced visual stress regardless of refractive, orthoptic or cognitive disorders. The associated conditions investigated were autism spectrum disorder, Tourette syndrome, stroke, deafness, dyslexia, and auditory temporal processing disorder. Conclusion: the effectiveness of overlays in improving reading quality is consistently demonstrated in the literature. The reviewed articles showed that the overlays’ effect is more expressive when the visual stress is associated with conditions that present sensory alterations and cortical hyperactivity.

High level of pattern glare in major depressive disorder

BACKGROUND

Visual deficits have been reported in abundance by recent studies on major depressive disorder. Pattern glare manifests as visual distortions, such as the symptoms of headache, glare, eyestrain, illusions of shapes, colors, and motion when viewing repetitive striped patterns, of which some can be observed in major depressive disorder. Inspired by what mentioned, the present study aims to explore whether there exists association between pattern glare and major depressive disorder and further attempts to explore possible clinical diagnostic value of pattern glare in major depressive disorder.

METHODS

Twenty-four patients diagnosed with major depressive disorder (MDDs group) were compared with 30 age-, gender- and education level-matched healthy control subjects (HCs group) on their visual stress with black-and-white gratings of different spatial frequencies-0.3 (low-SF), 2.3 (mid-SF), and 9.4 (high-SF) cycles per degree (c/deg)-which was named pattern glare test. The MDDs group divided into first episode medication-free group (fMDD) and recurrent medicated group (rMDD), comparisons of pattern glare scores (PGS) were performed within the MDDs group. We used Pearson and Spearman analysis to explore the relationship between some clinical indexes and pattern glare scores. ROC (receiver operating characteristic) curve was used to evaluate whether pattern glare test was able to discriminate patients and healthy controls.

RESULTS

The mid-SF pattern glare score significantly elevated in patients with major depressive disorder compared to control subjects. No differences of pattern glare scores were found between fMDD and rMDD. A significant negative correlation between mid-high difference and age in HCs group was found. There were no correlations between other variables and pattern glare scores. The mid-SF score has limited value in the diagnosis of major depressive disorder.

CONCLUSIONS

We observed an increased level of pattern glare in patients with major depressive disorder, reflecting the existence of cortical hyper-excitability in major depressive disorder. The mid-SF score may have a value in understanding cortical excitability in major depressive disorder.

Spectral Overlays for Reading Difficulties: Oculomotor Function and Reading Efficiency Among Children and Adolescents With Visual Stress

This study analyzed the effects of spectral overlays on ocular motility during reading among a clinical group of children and adolescents experiencing visual–perceptual distortions of text. We reviewed the records of 323 eye-hospital patients diagnosed with visual stress and divided this participant sample into two age-based cohorts: children ( n =  184; Mean [ M] age = 10.1, standard deviation [ SD]  =  1.3 years) and adolescents ( n =  139; M age = 14.6, SD = 1.5 years). We used a Visagraph III Eye-Movement Recording System to record ocular motor efficiency while reading with and without spectral overlays, and we examined the following parameters: (a) Fixations, (b) Regressions, (c) Span of Recognition, (d) Reading Rate, (e) Relative Efficiency, and (f) Comprehension. Our results showed that using one or some combination of 10 participant-selected spectral overlays immediately and significantly ( p <  .001) reduced the number of Fixations and Regressions per 100 words, while there were significant ( p <  .001) gains in positive factors such as Span of Recognition, Reading Rate, Relative Efficiency, and Comprehension. Our findings indicate that spectral filtering can be an effective tool for helping many young patients who experience visual–perceptual distortions while reading. Future expanded research employing eye-tracking technology is clearly needed.

Dizziness in a Child With Irlen Syndrome: Differentiating Visual and Vestibular Complaints

PURPOSE

A case study of a 12-year-old boy with Irlen syndrome illustrates the overlapping symptoms of Irlen syndrome and vestibular-related dizziness.

SUMMARY OF KEY POINTS

Individuals with Irlen syndrome have eyestrain and headache, and often report visual perceptual distortions of blurring, doubling, and movement of print on the page. These symptoms can be relieved with the use of individually prescribed tinted lenses or overlays. Visually induced dizziness, also known as visual vertigo, is characterized by dizziness and/or unsteadiness that is triggered by complex, distorted, large field/moving visual stimuli. Visually induced dizziness can be effectively treated with progressive, controlled exposure to optokinetic visual stimuli. The child with Irlen syndrome had impaired balance, impaired gaze stability, and symptoms of visual vertigo. His complaint of visually induced dizziness resolved following vestibular rehabilitation.

CONCLUSIONS AND RECOMMENDATIONS FOR CLINICAL PRACTICE

When an individual with Irlen syndrome complains of dizziness, ruling out a concomitant diagnosis of a central and/or peripheral vestibular disorder is warranted.

WHAT THIS ADDS TO THE EVIDENCE

The visual symptoms associated with Irlen syndrome can overlap with those of visually induced dizziness. This case report is the first to describe overlapping visual and vestibular complaints of dizziness in an individual with Irlen syndrome.

Association between auditory temporal and visual processing in reading skill

ABSTRACT Purpose: to verify whether students screened with altered auditory temporal processing are more likely to present altered visual processing. Methods: the sample consisted of 68 children, aged from 9 to 12 years, 53% males, from the 5th and 6th grades of a public school. All children with alterations in the audiological or ophthalmological evaluation were excluded. The Duration Pattern Test (screening for auditory temporal skill), the Reading Perceptual Scale (visual stress symptom questionnaire and colored overlays selection) and the Rate of Reading Test (number of words correctly read per minute) were used. Appropriate statistical tests were applied adopting the significance level lower than 0.05. Results: participants screened with abnormal auditory processing had higher visual stress symptoms and lower reading rate, with a significant and moderate effect (p< 0.05; d< 0.71), when compared to their peers with normal auditory processing. Among the children with altered Duration Pattern Test, 58% improved the reading rate with the use of colored overlays, whereas 29% did so in the control group (Odds Ratio = 3.4, p = 0.017). Conclusion: children screened with altered auditory temporal processing presented a three times higher possibility of association with visual processing alterations, due to shared magnocellular system.

Practice makes the deficiency of global motion detection in people with pattern-related visual stress more apparent

Aims

Pattern-related visual stress (PRVS) refers to the perceptual difficulties experienced by some individuals when exposed to high contrast striped patterns. People with PRVS were reported to have reduced sensitivity to global motion at baseline testing and the difference disappears at a second estimate. The present study was to investigate the effect of practice on global motion threshold in adults with and without PRVS.

Methods

A total of 101 subjects were recruited and the Wilkins & Evans Pattern Glare Test was used to determine if a subject had PRVS. The threshold to detect global motion was measured with a random dot kinematogram. Each subject was measured 5 times at the first visit and again a month later. Receiver operating characteristic (ROC) curve analysis was applied to show the agreement between the two tests.

Results

Twenty-nine subjects were classified as having PRVS and 72 were classified as normal. At baseline, the threshold to detect global motion was significantly higher in subjects with PRVS (0.832 ± 0.098 vs. 0.618 ± 0.228, p < 0.001). After 5 sessions, the difference between the normal and subjects with PRVS increased (0.767 ± 0.170 vs. 0.291 ± 0.149, p < 0.001). In ROC analysis, the area under the curve (AUC) improved from 0.792 at baseline to 0.964 at the fifth session. After a one-month break, the difference between normal and subjects with PRVS was still significant (0.843 ± 0.169 vs. 0.407 ± 0.216, p < 0.001) and the AUC was 0.875.

Conclusion

The ability to detect global motion is impaired in persons with PRVS and the difference increased after additional sessions of practice.

Computer Vision Syndrome: Implications for the Occupational Health Nurse

Computers and other digital devices are commonly used both in the workplace and during leisure time. Computer vision syndrome (CVS) is a new health-related condition that negatively affects workers. This article reviews the pathology of and interventions for CVS with implications for the occupational health nurse.

A Delphi study to develop practical diagnostic guidelines for visual stress (pattern-related visual stress)

PURPOSE

Visual stress (VS) is characterised by symptoms of visual perceptual distortions and eyestrain when viewing text, symptoms that are alleviated by individually prescribed coloured filters. A recent review supports the existence of VS and its treatment, but noted that controversy remains, in part due to inconsistencies in the diagnosis of the condition. The present paper reviews the diagnostic criteria for VS in the literature and reports a Delphi analysis of the criteria currently used in clinical practice.

METHODS

Twenty-six eyecare practitioners were invited to participate in a Delphi study. They were selected because they were frequent prescribers of precision tinted lenses. In the first round they were sent a list of the indicators for which there is literature to suggest a relevance in the diagnosis of VS. The practitioners were invited to rank the indicators and add any additional criteria they use in diagnosis. In the second round a revised list was circulated, including items added from the responses in the first round.

RESULTS

The respondents included optometrists, orthoptists and opticians. In the first round the response rate was 85%. Ninety-one percent of those who participated in the first round also responded in the second round. Strong indicators in the second round included the symptom of words moving when reading, voluntary use of an overlay for a prolonged period, improved performance of ≥15% with an overlay on the Wilkins Rate of Reading test, and an abnormally high score on the Pattern Glare Test.

CONCLUSIONS

The strongest diagnostic criteria are combined in a diagnostic tool. This is proposed as a guide for clinical practice and further research.

Coloured overlays and precision-tinted lenses: poor repeatability in a sample of adults and children diagnosed with visual stress

PURPOSE

Visual stress consists of perceived distortions or discomfort while reading. It is claimed that these symptoms are alleviated by viewing through coloured lenses or overlays, with a specific colour required for each individual. This has been explained on the basis of altered visual cortex excitation as affected by the spectral content of the viewing light. If symptoms are indeed alleviated by a particular colour that has an impact on the individual's visual system, we would expect that selection of the most beneficial colour would be repeatable. The aim of this study was to determine whether this is the case.

METHODS

Twenty-one participants (mean age 26 years (range 8-55 years); 12 female, nine male) with visual stress and no other uncorrected ocular or visual anomaly were recruited. Each participant selected the colour most beneficial in alleviating their symptoms from a standard set of 10 coloured overlays, and underwent intuitive colorimetry in which the most beneficial of a wide range of chromatic illuminance settings was selected. Without prescribing an overlay at the first appointment, this process was repeated on a second occasion at a mean of 25 days later.

RESULTS

About half of the participants (n = 10) chose the same (n = 7) or similar (with one common colour in both choices; n = 3) coloured overlay on the two occasions, while 11 participants chose a completely different overlay colour. Across all participants, the colorimetry setting shifted by, on average, 9.6 just noticeable differences, indicating that the colours were perceptually very different.

CONCLUSION

These findings suggest that people with visual stress are unlikely to find exactly the same colour to be optimal on different occasions, and raise questions about the need for precise colour specification in tinted lenses for visual stress.

Does Gender Influence Colour Choice in the Treatment of Visual Stress?

Purpose

Visual Stress (VS) is a condition in which words appear blurred, in motion, or otherwise distorted when reading. Some people diagnosed with VS find that viewing black text on white paper through coloured overlays or precision tinted lenses (PTLs) reduces symptoms attributed to VS. The aim of the present study is to determine whether the choice of colour of overlays or PTLs is influenced by a patient’s gender.

Methods

Records of all patients attending a VS assessment in two optometry practices between 2009 and 2014 were reviewed retrospectively. Patients who reported a significant and consistent reduction in symptoms with either overlay and or PTL were included in the analysis. Overlays and PTLs were categorized as stereotypical male, female or neutral colours based on gender preferences as described in the literature. Chi-square analysis was carried out to determine whether gender (across all ages or within age groups) was associated with overlay or PTL colour choice.

Results

279 patients (133 males and 146 females, mean age 17 years) consistently showed a reduction in symptoms with an overlay and were included. Chi-square analysis revealed no significant association between the colour of overlay chosen and male or female gender (Chi-square 0.788, p = 0.674). 244 patients (120 males and 124 females, mean age 24.5 years) consistently showed a reduction in symptoms with PTLs and were included. Chi-square analysis revealed a significant association between stereotypical male/female/neutral colours of PTLs chosen and male/female gender (Chi-square 6.46, p = 0.040). More males preferred stereotypical male colour PTLs including blue and green while more females preferred stereotypical female colour PTLs including pink and purple.

Conclusions

For some VS patients, the choice of PTL colour is influenced not only by the alleviation of symptoms but also by other non-visual factors such as gender.