Allen, Hussain, Usherwood, and Wilkins (2010) |
Pattern-related visual stress, chromaticity, and accommodation |
Cambridge, England N = 11 + 11 Visual stress |
Favorable. Adults with visual stress, using spectral overlays, improved their reading rate by 9.9% and reduced the accommodation delay, which did not happen with the asymptomatic control group. |
Ritchie, Della Sala, and McIntosh (2011) |
Irlen colored overlays do not alleviate reading difficulties |
Port Glasgow, Scotland N = 47 + 14 Visual stress |
Unfavorable. There was no difference in reading performance regarding the type of overlay (ideal, not-ideal, transparent) nor between the screened group with visual stress and children in the control group. 32% of the sample had gains greater than ≥5% in the reading rate. |
Allen, Dedi, Kumar, Patel, Aloo, and Wilkins (2012) |
Accommodation, pattern glare, and coloured overlays |
Cambridge, England N = 18 +18 Visual stress |
Favorable. Adults with visual stress, when using spectral overlays, improved their reading rate by 10.4% ± 4.8% and reduced by 45% the ocular accommodation delay (from 0.95 D to 0.52 D, p = 0.0001), leveling their results with those from the control group. |
Ludlow, Taylor-Whiffen, and Wilkins (2012) |
Coloured filters enhance the visual perception of social cues in children with autism spectrum disorders |
Birmingham, England N = 15 + 15 Visual stress and Autism Spectrum Disorder |
Favorable. More words per minute were read with overlays than without them (p < 0.001). More participants in the group with autism spectrum disorder (80%), when using overlays, obtained gains of at least ≥5% in reading rate, when compared with the control group (33%). When using overlays, the autistic children improved in 18% the recognition of facial expressions of emotion, with no significant improvement in the control group. |
Beasley and Davies (2013) |
Visual stress symptoms secondary to stroke alleviated with spectral filters and precision tinted ophthalmic lenses: a case report |
Birmingham, England N = 1 Visual stress secondary to stroke |
Favorable. Case study of visual stress secondary to stroke, treated with the use of overlays and spectral filters, whose initial chromaticity was changed after the second stroke. There was an increase of 40% in reading rate with the use of overlays, and of 32% after one month had passed. |
Henderson, Tsogka, and Snowling (2013) |
Questioning the benefits that coloured overlays can have for reading in students with and without dyslexia |
York, England N = 16 + 26 Visual stress and Dyslexia |
Partially Favorable. Both the group of dyslexic college students and the control group read faster with the use of overlays. More participants of the dyslexic group (75%, 63% and 44%), when compared with the control group (48%, 46%, 35%), increased in at least ≥5%, ≥8% and ≥10% the reading rate, respectively. There was no improvement with overlays in connected text reading and text comprehension. |
Hollingsworth, Ludlow, Wilkins, Calver, and Allen (2015) |
Visual performance and the use of colored filters in children who are deaf |
Cambridge, England N = 31 + 39 Visual stress and profound deafness |
Favorable. All the deaf youths chose at least one overlay, of which Yellow was the most frequent (45%). In its turn, in the hearing control group, 67% chose at least one overlay, though none opted for the Yellow. Deaf people that chose Yellow increased in 14% their reading rate in the reading rate test and 9% in the deaf-adapted version, with no statistical difference in the other deaf people and the hearing control group. |
Monger, Wilkins and Allen (2015) |
Identifying visual stress during a routine eye examination |
Cambridge, England N = 73 Visual stress |
Favorable. 36% and 14% of the college students had a gain of at least ≥5% and ≥10% in their reading rate when using overlays, respectively. |
Ludlow and Wilkins (2016) |
Atypical Sensory behaviours in children with Tourette’s Syndrome and children with Autism Spectrum Disorders |
Midlands and London, England N = 12 + 12 + 12 Visual stress, Tourette Syndrome, Autism Spectrum Disorder |
Favorable. Gain greater than ≥15% in reading rate with the use of overlays was verified in Tourette syndrome (50%) and autism spectrum disorder (33%), though not in the control group (0%). |
Garcia, Momensohn-Santos, Vilhena (2017) |
Effects of Spectral Overlays on Reading Performance of Brazilian Elementary School Children |
Jacareí, São Paulo, Brazil N = 68 Visual stress in typical schoolchildren with no problems of visual or auditory acuity |
Favorable. 31%, 22%, 18% and 13% of 5th- and 6th-grade students of an elementary school had gains greater than ≥5%, ≥8%, ≥10% and ≥15% in reading rate with the use of overlays, respectively. Students with severe visual discomfort in reading (n = 11) were three times more likely to improve their reading rate with an overlay when compared with the less uncomfortable participants. |
Garcia, Vilhena, Guimarães, Pinheiro and Momensohn-Santos (2019) |
Relation between auditory and visual temporal processing in reading ability |
Jacareí, São Paulo, Brazil N = 26 + 42 Visual stress and auditory temporal processing disorder |
Favorable. Participants with auditory temporal processing disorder (n = 26) had more visual stress symptoms, lower reading rate, and were three times more likely to improve their reading rate with the use of spectral overlays when compared with the control group (n = 42). |
Guimarães, Vilhena, Loew, Guimarães (2019) |
Spectral overlays for reading difficulties: Oculomotor function and reading efficiency among children and adolescents with visual stress |
Belo Horizonte, Minas Gerais, Brazil N = 323 Visual stress |
Favorable. Eight- to seventeen-year-old participants with visual stress, when using overlays and evaluated with an eye tracker, reduced the number of eye fixations and regressions (p < 0.001), with an increase in perceptual reach, number of words read per minute, relative efficiency, and text comprehension (p < 0.001). The effect of the overlays is significantly higher in children when compared with adolescents (p < 0.01). The most frequent overlays were the Purple, Gray and Turquoise. |