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The Effect of Colored Overlays on Reading Performance in Infantile Nystagmus
Ophthalmology Volume 121, Number 3, March 2014 of Ophthalmology, University Scientific Institute San Raffaele, Milan, Italy
References 1. Hogan MJ, Alvarado JA, Weddell JE. Histology of the Human Eye: An Atlas and Textbook. Philadelphia: Saunders; 1971: 393–522. 2. Chin EK, Kim DY, Hunter AA 3rd, et al. Staging of macular telangiectasia: power-Doppler optical coherence tomography and macular pigment optical density. Invest Ophthalmol Vis Sci 2013;54:4459–70. 3. Fruttiger M. Development of the retinal vasculature. Angiogenesis 2007;10:77–88. 4. Provis JM. Development of the primate retinal vasculature. Prog Retin Eye Res 2001;20:799–821. 5. Antcliff R, Marshall J. The pathogenesis of edema in diabetic maculopathy. Semin Ophthalmol 1999;14:223–32.
The Effect of Colored Overlays on Reading Performance in Infantile Nystagmus Infantile nystagmus (IN) is an involuntary oscillations of the eyes with onset within 6 months from birth. It can result in vision loss owing to constant retinal motion and lead to significant psychosocial problems.1 Recent studies have described reading deficits associated with IN and found that they can be relatively mild under optimal reading conditions, but are more apparent when reading smaller font sizes.2 Colored overlays have been tested in numerous diseases for improving reading performance but not in IN. Newman Wright et al3 have found them to be beneficial in multiple sclerosis, a condition associated with acquired pendular nystagmus and other visual symptoms such as optic neuritis. It has been suggested that colored filters might influence the magnocellular pathway contribution to reading by reducing inhibitory S-cone (blue) inputs and/or changing the relative balance of the L-cone (red) and M-cone (green) inputs.4 We postulated that colored filters could influence reading performance in IN based on the (i) increased retinal motion of images and reduced motion sensitivity in IN, which could change the role of the magnocellular pathway to reading, (ii) foveal hypoplasia, caused by associated conditions such as albinism, altering the relative contribution of high acuity parvocellular vision to reading, and (iii) photosensitivity, for example in albinism, because of hypopigmentation of the iris and fundus. The aim of this study was to compare the effects of colored overlays in IN testing reading performance under optimal and suboptimal conditions using the Radner reading chart. Twenty-five participants with albinism (mean age SD, 38.913.1 years), 20 idiopaths (35.114.6 years), and 20 agematched controls (34.613.5 years) were recruited from neuroophthalmology clinics in the Leicester Royal Infirmary, UK, or were contacted through a nystagmus patient database. The study received local ethical approval and was performed in accordance with the tenets of the Declaration of Helsinki. All participants with IN reported onset of nystagmus within the first 6 months of life with no history of persistent oscillopsia. Diagnosis of albinism was confirmed by the coexistence of
804
monocular visual evoked response asymmetry, foveal hypoplasia, and iris transillumination. Diagnosis of idiopaths was based on genetic testing and/or normal ophthalmologic examination. Participants with periodic alternating nystagmus were excluded. Reading performance was assessed using the Radner reading chart consisting of a series of short sentences read in descending order of font size under near viewing (40 cm). The reading parameters derived are described in Figure 1 (available at www.aaojournal.org). Participants chose from 5 different colored overlays (i.O.O. Sales Limited, London, UK): Aqua, lime green, mint green, pink, and yellow (the most popular choices in the Newman Wright et al study3) using 1 of the 3 paragraph series in the Radner chart. Each colored overlay is designed to be equidistant from white on the CIE u v map of color space. The tasks were performed under a standard white fluorescent light (Sylvania Osram, 3500CCT, 3750 lumens) and the overlay properties under this light source are described in Table 1 (available at www.aaojournal.org). The other 2 Radner series were used to test reading with and without the selected overlay (in random order). Subjective improvements made by the colored overlays were assessed by asking (1) whether they subjectively perceived that the overlay “helped,” and (2) if so how. The sample size was based on previously reported testeretest values for the Radner chart.5 The most popular overlay color choices were yellow and lime green for all participants, although idiopaths particularly favored yellow overlays (60% of all colors chosen; Table 1; available at www.aaojournal.org). On questioning, 60% of participants with albinism and 50% of idiopaths subjectively reported that overlays “helped” them read compared with 30% of control participants (chi square test: albinism versus controls, P ¼ 0.045; idiopaths versus controls, P ¼ 0.197). All of the 12 IN participants who chose the lime green overlay perceived that the overlay “helped” (albinism versus controls, P > 0.0001; idiopaths versus controls, P ¼ 0.005). The colored overlays made no significant differences to any objective reading parameters measured using the Radner reading chart for the idiopaths or albinism group (paired t test: P > 0.05 for all comparisons; Fig 1; available at www.aaojournal.org). For controls, the colored overlays resulted in worse reading acuity (P ¼ 0.010). Although the colored overlays did not significantly affect the number of mistakes made by any group (gamma statistic; P > 0.05; Fig 2; available at www.aaojournal.org), participants with albinism made significantly more errors than idiopaths (P ¼ 0.018 with colored overlay and P ¼ 0.009 without colored overlay) and control participants (P ¼ 0.01 with colored overlay and P ¼ 0.001 without colored overlay). We found no objective improvement in reading performance in IN when using colored overlays either for participants with albinism or with idiopathic IN. Subjectively, participants with IN reported that the colored filters assisted reading, particularly in albinism where the subjective effect was significant in comparison to controls. These subjective improvements may be owing to the colored filters improving asthenopia and photosensitivity through mechanisms such as a reduced chromatic aberration and contrast (Table 1; available at www.aaojournal.org). Alternatively, subjective improvements could be a placebo effect. Further studies may be needed before categorically ruling out the objective benefits of colored filters in IN altogether. These might include testing colored overlays over sustained periods of reading. Although the Radner test has been shown to correlate well with reading
Reports performance for longer paragraphs,5 sustained reading could lead to increased visual stress and fatigue in nystagmus. It would also be worthwhile to test reading performance using a wider range of color filter options or using precision-tinted lenses, where the preferred tint is specifically administered. The range of colors available to the participants was based on the most popular choices made by patients with multiple sclerosis,3 although these choices may be biased by the color desaturation caused by optic neuritis. Participants with IN particularly preferred the lime green overlay, which is close to the peak photopic spectral sensitivity for normal humans.
NIRAJ BAROT, BSC, MBCHB REBECCA J. MCLEAN, MSC IRENE GOTTLOB, FRCOPHTH, MD FRANK A. PROUDLOCK, MSC, PHD Ophthalmology Group, University of Leicester, Faculty of Medicine & Biological Sciences, Leicester Royal Infirmary, Leicester, UK
Presented at: the Annual Meeting for the Association for Research in Vision and Ophthalmology (ARVO), Fort Lauderdale, Florida, May 4e10, 2012.
References 1. McLean RJ, Windridge KC, Gottlob I. Living with nystagmus: a qualitative study. Br J Ophthalmol 2012;96:981–6. 2. Barot N, McLean RJ, Gottlob I, Proudlock FA. Reading performance in infantile nystagmus. Ophthalmology 2013;120:1232–8. 3. Newman Wright B, Wilkins AJ, Zoukos Y. Spectral filters can improve reading and visual search in patients with multiple sclerosis. J Neurol 2007;254:1729–35. 4. Chase C, Dougherty RF, Ray N, et al. L/M speed-matching ratio predicts reading in children. Optom Vis Sci 2007;84:229–36. 5. Stifter E, Konig F, Lang T, et al. Reliability of a standardized reading chart system: variance component analysis, test-retest and inter-chart reliability. Graefes Arch Clin Exp Ophthalmol 2004;242:31–9.
Corrigendum The authors of “Intravitreal Ranibizumab for Diabetic Macular Edema with Prompt versus Deferred Laser Treatment: Three Year Randomized Trial Results” (Ophthalmology 2012;119:2312e2318) would like to clarify the following statement, which applies throughout the manuscript: The percentage of eyes with a 10-letter or more gain was 42% in the ranibizumab plus prompt laser treatment group compared with 56% in the ranibizumab plus deferred laser treatment group (P ¼ 0.02), whereas the percentage of eyes with a 10-letter or more loss was 10% in the ranibizumab plus prompt laser treatment group compared with 5% in the ranibizumab plus deferred laser treatment group (P ¼ 0.12).
805
Ophthalmology Volume 121, Number 3, March 2014
Figure 1. The effect of the colored overlays made on objective reading parameters measured using the Radner reading chart. The difference made by the overlay on reading performance is plotted against the average value for each parameter with and without the colored overlay (i.e., a BlandeAltman plot) where values above abscissa indicate an improvement. Reading acuity (A) is the smallest font size reached (þ0.005 number of incorrectly read syllables from the last full line read). Maximum reading speed (B) is the average of the 3 fastest reading speeds recorded. Critical print size (C) is the point at which the reading speed drops below 80% of the maximum reading speed. Suboptimal reading range (D) is the range of font size read below 80% of the maximum reading speed. Yellow squares indicate individuals with albinism, blue circles idiopathic infantile nystagmus (IN), and red crosses control participants. Values above zero (green shaded area) indicate improved reading with the overlay. The colored overlays made no differences in any parameter for either the IN or albinism group (P > 0.05 for all paired comparisons).
805.e1
Reports Table 1. Filter Properties with Choice of Colored Overlay and Subjective Improvements Perceived by Participants with Albinism, Infantile Nystagmus, and Controls Color Properties of Chart Background CIE Space Color
Weber Contrast
Luminance
U
v
Yellow Lime green Aqua Pink Mint green No filter
0.68 0.77 0.76 0.45 0.70 0.85
34.7 30.5 21.9 23.6 23.3 39.5
0.226 0.211 0.212 0.255 0.208 0.227
0.511 0.480 0.477 0.574 0.467 0.510
Overlay Choice Color
Figure 2. Number of reading errors made during the Radner reading test (A) with and (B) without the colored overlays where data have been averaged for all font sizes in each participant relative to individual reading acuities recorded (i.e., smallest font read are the right hand bars). Yellow bars indicate albinism, blue bars indicate idiopathic infantile nystagmus, and green bars control participants.
Albinism Yellow Lime green Aqua Pink Mint green Total Idiopathic Yellow Lime green Aqua Pink Mint green Total Controls Yellow Lime green Aqua Pink Mint green Total
No. of participants (%)
Perceived Effect of Overlay Helped
Made Clearer
Less Glare
(32) (32) (28) (8) 0 25
5 8 2 0 0 15 (60%)
2 6 0 0 0 8 (32%)
3 1 2 0 0 6 (24%)
12 (60) 4 (20) 3 (15) 0 1 (5) 20
6 4 0 0 0 10 (50%)
5 2 0 0 0 7 (35)
1 2 0 0 0 3 (15)
5 0 1 0 0 6 (30)
4 0 1 0 0 5 (25)
1 0 0 0 0 1 (5)
8 8 7 2
9 6 2 2 1
(45) (3) (10) (10) (5) 20
The most commonly reported improvement made by the colored overlays in infantile nystagmus patients was that text was clearer/sharper/easier to see (60%) or that the colored overlay reduced glare (36%). “Helped” indicates that the patients perceived the overlay assisted reading, “made clearer” is where the filter was perceived to make the text clear, sharper or easier to see.
805.e2
References 1. Hogan MJ, Alvarado JA, Weddell JE. Histology of the Human Eye: An Atlas and Textbook. Philadelphia: Saunders; 1971: 393–522. 2. Chin EK, Kim DY, Hunter AA 3rd, et al. Staging of macular telangiectasia: power-Doppler optical coherence tomography and macular pigment optical density. Invest Ophthalmol Vis Sci 2013;54:4459–70. 3. Fruttiger M. Development of the retinal vasculature. Angiogenesis 2007;10:77–88. 4. Provis JM. Development of the primate retinal vasculature. Prog Retin Eye Res 2001;20:799–821. 5. Antcliff R, Marshall J. The pathogenesis of edema in diabetic maculopathy. Semin Ophthalmol 1999;14:223–32.
The Effect of Colored Overlays on Reading Performance in Infantile Nystagmus Infantile nystagmus (IN) is an involuntary oscillations of the eyes with onset within 6 months from birth. It can result in vision loss owing to constant retinal motion and lead to significant psychosocial problems.1 Recent studies have described reading deficits associated with IN and found that they can be relatively mild under optimal reading conditions, but are more apparent when reading smaller font sizes.2 Colored overlays have been tested in numerous diseases for improving reading performance but not in IN. Newman Wright et al3 have found them to be beneficial in multiple sclerosis, a condition associated with acquired pendular nystagmus and other visual symptoms such as optic neuritis. It has been suggested that colored filters might influence the magnocellular pathway contribution to reading by reducing inhibitory S-cone (blue) inputs and/or changing the relative balance of the L-cone (red) and M-cone (green) inputs.4 We postulated that colored filters could influence reading performance in IN based on the (i) increased retinal motion of images and reduced motion sensitivity in IN, which could change the role of the magnocellular pathway to reading, (ii) foveal hypoplasia, caused by associated conditions such as albinism, altering the relative contribution of high acuity parvocellular vision to reading, and (iii) photosensitivity, for example in albinism, because of hypopigmentation of the iris and fundus. The aim of this study was to compare the effects of colored overlays in IN testing reading performance under optimal and suboptimal conditions using the Radner reading chart. Twenty-five participants with albinism (mean age SD, 38.913.1 years), 20 idiopaths (35.114.6 years), and 20 agematched controls (34.613.5 years) were recruited from neuroophthalmology clinics in the Leicester Royal Infirmary, UK, or were contacted through a nystagmus patient database. The study received local ethical approval and was performed in accordance with the tenets of the Declaration of Helsinki. All participants with IN reported onset of nystagmus within the first 6 months of life with no history of persistent oscillopsia. Diagnosis of albinism was confirmed by the coexistence of
804
monocular visual evoked response asymmetry, foveal hypoplasia, and iris transillumination. Diagnosis of idiopaths was based on genetic testing and/or normal ophthalmologic examination. Participants with periodic alternating nystagmus were excluded. Reading performance was assessed using the Radner reading chart consisting of a series of short sentences read in descending order of font size under near viewing (40 cm). The reading parameters derived are described in Figure 1 (available at www.aaojournal.org). Participants chose from 5 different colored overlays (i.O.O. Sales Limited, London, UK): Aqua, lime green, mint green, pink, and yellow (the most popular choices in the Newman Wright et al study3) using 1 of the 3 paragraph series in the Radner chart. Each colored overlay is designed to be equidistant from white on the CIE u v map of color space. The tasks were performed under a standard white fluorescent light (Sylvania Osram, 3500CCT, 3750 lumens) and the overlay properties under this light source are described in Table 1 (available at www.aaojournal.org). The other 2 Radner series were used to test reading with and without the selected overlay (in random order). Subjective improvements made by the colored overlays were assessed by asking (1) whether they subjectively perceived that the overlay “helped,” and (2) if so how. The sample size was based on previously reported testeretest values for the Radner chart.5 The most popular overlay color choices were yellow and lime green for all participants, although idiopaths particularly favored yellow overlays (60% of all colors chosen; Table 1; available at www.aaojournal.org). On questioning, 60% of participants with albinism and 50% of idiopaths subjectively reported that overlays “helped” them read compared with 30% of control participants (chi square test: albinism versus controls, P ¼ 0.045; idiopaths versus controls, P ¼ 0.197). All of the 12 IN participants who chose the lime green overlay perceived that the overlay “helped” (albinism versus controls, P > 0.0001; idiopaths versus controls, P ¼ 0.005). The colored overlays made no significant differences to any objective reading parameters measured using the Radner reading chart for the idiopaths or albinism group (paired t test: P > 0.05 for all comparisons; Fig 1; available at www.aaojournal.org). For controls, the colored overlays resulted in worse reading acuity (P ¼ 0.010). Although the colored overlays did not significantly affect the number of mistakes made by any group (gamma statistic; P > 0.05; Fig 2; available at www.aaojournal.org), participants with albinism made significantly more errors than idiopaths (P ¼ 0.018 with colored overlay and P ¼ 0.009 without colored overlay) and control participants (P ¼ 0.01 with colored overlay and P ¼ 0.001 without colored overlay). We found no objective improvement in reading performance in IN when using colored overlays either for participants with albinism or with idiopathic IN. Subjectively, participants with IN reported that the colored filters assisted reading, particularly in albinism where the subjective effect was significant in comparison to controls. These subjective improvements may be owing to the colored filters improving asthenopia and photosensitivity through mechanisms such as a reduced chromatic aberration and contrast (Table 1; available at www.aaojournal.org). Alternatively, subjective improvements could be a placebo effect. Further studies may be needed before categorically ruling out the objective benefits of colored filters in IN altogether. These might include testing colored overlays over sustained periods of reading. Although the Radner test has been shown to correlate well with reading
Reports performance for longer paragraphs,5 sustained reading could lead to increased visual stress and fatigue in nystagmus. It would also be worthwhile to test reading performance using a wider range of color filter options or using precision-tinted lenses, where the preferred tint is specifically administered. The range of colors available to the participants was based on the most popular choices made by patients with multiple sclerosis,3 although these choices may be biased by the color desaturation caused by optic neuritis. Participants with IN particularly preferred the lime green overlay, which is close to the peak photopic spectral sensitivity for normal humans.
NIRAJ BAROT, BSC, MBCHB REBECCA J. MCLEAN, MSC IRENE GOTTLOB, FRCOPHTH, MD FRANK A. PROUDLOCK, MSC, PHD Ophthalmology Group, University of Leicester, Faculty of Medicine & Biological Sciences, Leicester Royal Infirmary, Leicester, UK
Presented at: the Annual Meeting for the Association for Research in Vision and Ophthalmology (ARVO), Fort Lauderdale, Florida, May 4e10, 2012.
References 1. McLean RJ, Windridge KC, Gottlob I. Living with nystagmus: a qualitative study. Br J Ophthalmol 2012;96:981–6. 2. Barot N, McLean RJ, Gottlob I, Proudlock FA. Reading performance in infantile nystagmus. Ophthalmology 2013;120:1232–8. 3. Newman Wright B, Wilkins AJ, Zoukos Y. Spectral filters can improve reading and visual search in patients with multiple sclerosis. J Neurol 2007;254:1729–35. 4. Chase C, Dougherty RF, Ray N, et al. L/M speed-matching ratio predicts reading in children. Optom Vis Sci 2007;84:229–36. 5. Stifter E, Konig F, Lang T, et al. Reliability of a standardized reading chart system: variance component analysis, test-retest and inter-chart reliability. Graefes Arch Clin Exp Ophthalmol 2004;242:31–9.
Corrigendum The authors of “Intravitreal Ranibizumab for Diabetic Macular Edema with Prompt versus Deferred Laser Treatment: Three Year Randomized Trial Results” (Ophthalmology 2012;119:2312e2318) would like to clarify the following statement, which applies throughout the manuscript: The percentage of eyes with a 10-letter or more gain was 42% in the ranibizumab plus prompt laser treatment group compared with 56% in the ranibizumab plus deferred laser treatment group (P ¼ 0.02), whereas the percentage of eyes with a 10-letter or more loss was 10% in the ranibizumab plus prompt laser treatment group compared with 5% in the ranibizumab plus deferred laser treatment group (P ¼ 0.12).
805
Ophthalmology Volume 121, Number 3, March 2014
Figure 1. The effect of the colored overlays made on objective reading parameters measured using the Radner reading chart. The difference made by the overlay on reading performance is plotted against the average value for each parameter with and without the colored overlay (i.e., a BlandeAltman plot) where values above abscissa indicate an improvement. Reading acuity (A) is the smallest font size reached (þ0.005 number of incorrectly read syllables from the last full line read). Maximum reading speed (B) is the average of the 3 fastest reading speeds recorded. Critical print size (C) is the point at which the reading speed drops below 80% of the maximum reading speed. Suboptimal reading range (D) is the range of font size read below 80% of the maximum reading speed. Yellow squares indicate individuals with albinism, blue circles idiopathic infantile nystagmus (IN), and red crosses control participants. Values above zero (green shaded area) indicate improved reading with the overlay. The colored overlays made no differences in any parameter for either the IN or albinism group (P > 0.05 for all paired comparisons).
805.e1
Reports Table 1. Filter Properties with Choice of Colored Overlay and Subjective Improvements Perceived by Participants with Albinism, Infantile Nystagmus, and Controls Color Properties of Chart Background CIE Space Color
Weber Contrast
Luminance
U
v
Yellow Lime green Aqua Pink Mint green No filter
0.68 0.77 0.76 0.45 0.70 0.85
34.7 30.5 21.9 23.6 23.3 39.5
0.226 0.211 0.212 0.255 0.208 0.227
0.511 0.480 0.477 0.574 0.467 0.510
Overlay Choice Color
Figure 2. Number of reading errors made during the Radner reading test (A) with and (B) without the colored overlays where data have been averaged for all font sizes in each participant relative to individual reading acuities recorded (i.e., smallest font read are the right hand bars). Yellow bars indicate albinism, blue bars indicate idiopathic infantile nystagmus, and green bars control participants.
Albinism Yellow Lime green Aqua Pink Mint green Total Idiopathic Yellow Lime green Aqua Pink Mint green Total Controls Yellow Lime green Aqua Pink Mint green Total
No. of participants (%)
Perceived Effect of Overlay Helped
Made Clearer
Less Glare
(32) (32) (28) (8) 0 25
5 8 2 0 0 15 (60%)
2 6 0 0 0 8 (32%)
3 1 2 0 0 6 (24%)
12 (60) 4 (20) 3 (15) 0 1 (5) 20
6 4 0 0 0 10 (50%)
5 2 0 0 0 7 (35)
1 2 0 0 0 3 (15)
5 0 1 0 0 6 (30)
4 0 1 0 0 5 (25)
1 0 0 0 0 1 (5)
8 8 7 2
9 6 2 2 1
(45) (3) (10) (10) (5) 20
The most commonly reported improvement made by the colored overlays in infantile nystagmus patients was that text was clearer/sharper/easier to see (60%) or that the colored overlay reduced glare (36%). “Helped” indicates that the patients perceived the overlay assisted reading, “made clearer” is where the filter was perceived to make the text clear, sharper or easier to see.
805.e2