Color Vision Testing Research Articles

Ocular Biomarkers of Riboflavin Transporter Deficiency.

To describe the clinical presentation with a focus on ocular manifestations and response to riboflavin supplementation of 3 patients with riboflavin transporter deficiency (RTD) caused by mutations in SLC52A2 ( SLC52A2- RTD). This is a retrospective review of records of 3 children (aged 18, n = 2 and age = 8, n = 1) with SLC52A2- RTD. Patients underwent comprehensive ophthalmic evaluations including color vision testing, pattern visual-evoked potentials (pVEPs, 1 patient) and spectral domain optical coherence tomography (SD-OCT) imaging. Patients received riboflavin supplements from the time of the molecular diagnosis of RTD. Two unrelated 18-year-old patients with SLC52A2- RTD had a symptomatic onset with sensorineural hearing loss and auditory neuropathy/dys-synchrony since age 3 and 11, respectively. On examination 7 years after symptomatic onset, they showed subnormal visual acuities (20/30 and 20/60, both eyes, respectively), preserved color vision, and a thin but measurable retinal ganglion cell layer (GCL) and nerve fiber (RNFL). The inner and outer nuclear layers were normal. The asymptomatic SLC52A2- positive brother of one of these patients started riboflavin supplementation right after the molecular diagnosis and had normal vision and SD-OCTs 7 years later. Onset of riboflavin supplementation in one of the 2 symptomatic cases resulted in acute improvement of the pattern visual-evoked potential and vision. Retinal ganglion cells and their axons are uniquely susceptible to RTD compared with other highly energy-dependent retinal neurons, such as photoreceptors, raising the possibility for alternative mechanisms of disease or protection. Riboflavin supplementation results in acute functional improvement of vision and long-term preservation of GCL and RNFL if initiated early.

Compressive Optic Neuropathy Caused by Internal Carotid Artery Aneurysm Presenting with Concurrent Neuromyelitis Optica

Purpose: To report a case of compressive optic neuropathy caused by an internal carotid artery aneurysm accompanied by concurrent neuromyelitis optica (NMO).Case summary: A 48-year-old female presented with sudden painless blurry vision in the inferior visual field of her right eye for 2 days. The corrected visual acuity was 0.7 in the right eye, and a relative afferent pupillary defect was observed. The visual field test demonstrated an inferior altitudinal defect in the right eye, while the color vision test was normal. However, after 5 days, she developed decreased color vision. Optic nerve enhancement in the right eye was observed on orbital magnetic resonance imaging, and anti-aquaporin-4 antibody was positive. She was diagnosed with NMO, and high-dose steroids were administered intravenously. In addition, brain magnetic resonance angiography showed a 5-mm aneurysm in the ophthalmic segment of the right internal carotid artery, which was compressing the optic nerve. Coil embolization of the aneurysm was performed. On the fourth day of steroid therapy and the first day after coiling, the corrected visual acuity in the right eye improved to 1.0. At 6-week follow-up, color vision and visual field defect also showed complete recovery.Conclusions: In this rare case of internal carotid artery aneurysm combined with NMO, early active treatment led to complete recovery of visual acuity and field defects.

Ophthalmic and Genetic Features of Bardet Biedl Syndrome in a German Cohort.

The aim of this study was to characterize the ophthalmic and genetic features of Bardet Biedl (BBS) syndrome in a cohort of patients from a German specialized ophthalmic care center. Sixty-one patients, aged 5–56 years, underwent a detailed ophthalmic examination including visual acuity and color vision testing, electroretinography (ERG), visually evoked potential recording (VEP), fundus examination, and spectral domain optical coherence tomography (SD-OCT). Adaptive optics flood illumination ophthalmoscopy was performed in five patients. All patients had received diagnostic genetic testing and were selected upon the presence of apparent biallelic variants in known BBS-associated genes. All patients had retinal dystrophy with morphologic changes of the retina. Visual acuity decreased from ~0.2 (decimal) at age 5 to blindness 0 at 50 years. Visual field examination could be performed in only half of the patients and showed a concentric constriction with remaining islands of function in the periphery. ERG recordings were mostly extinguished whereas VEP recordings were reduced in about half of the patients. The cohort of patients showed 51 different likely biallelic mutations—of which 11 are novel—in 12 different BBS-associated genes. The most common associated genes were BBS10 (32.8%) and BBS1 (24.6%), and by far the most commonly observed variants were BBS10 c.271dup;p.C91Lfs*5 (21 alleles) and BBS1 c.1169T>G;p.M390R (18 alleles). The phenotype associated with the different BBS-associated genes and genotypes in our cohort is heterogeneous, with diverse features without genotype–phenotype correlation. The results confirm and expand our knowledge of this rare disease.

Ocular Survey in Kathmandu University Medical Students

Background Medical students spend long time in academic activities that increases the risk of developing refractive errors and dry eyes that can affect their learning and social abilities. Only a few studies are available regarding ocular problems and its contribution to visual impairment among medical students in Nepal.
 Objective To evaluate the ocular problems among the medical students in a University hospital.
 Method An observational, descriptive, cross-sectional study was conducted among five batches undergraduate medical students until 2022 of Kathmandu University School of Medical Sciences, Dhulikhel, Kavre. A self-administered questionnaire was used to obtain demographic data and information on visual problems followed by a detailed ocular examination that included refraction, color vision and Schirmer test.
 Result Total of 284 medical students (with 568 eyes) with mean age of 22.8 years, 179 males and 105 females were enrolled. Among them, 270 (47.5%) eyes were emmetropic. Simple Myopia was the commonest followed by Compound Myopic Astigmatism. The mean spherical equivalent in right and left eye were -0.914 ± 1.54 and -0.886 ± 1.53 respectively. Approximately 18% students had some form of dry eye. Nineteen students (6.7%) had color vision deficiency and 13 (4.6%) had deuteranomalia, 3(1.1%) had deuteranopia and 3(1.1%) had protanomalia.
 Conclusion Eye defects, like refractive errors, dry eyes and color blindness, are common among medical students. They need to be advised for frequent eye check up in order to diagnose eye defects timely and arrest visual impairment at early stage.

Diagnosis of colour vision deficits using eye movements

We set out to develop a simple objective test of functional colour vision based on eye movements made in response to moving patterns. We exploit the finding that while the motion of a colour-defined stimulus can be cancelled by adding a low-contrast luminance-defined stimulus moving in the opposite direction, the “equivalent luminance contrast” required for such cancellation is reduced when colour vision is abnormal. We used a consumer-grade infrared eye-tracker to measure eye movements made in response to coloured patterns drifting at different speeds. An automated analysis of these movements estimated individuals’ red-green equiluminant point and their equivalent luminance contrast. We tested 34 participants: 23 colour vision normal controls, 9 deuteranomalous and 2 protanomalous individuals. We obtained reliable estimates of strength of directed eye movements (i.e. combined optokinetic and voluntary tracking) for stimuli moving at 16 deg/s and could use these data to classify participants’ colour vision status with a sensitivity rate of 90.9% and a specificity rate of 91.3%. We conclude that an objective test of functional colour vision combining a motion-nulling technique with an automated analysis of eye movements can diagnose and assess the severity of protanopia and deuteranopia. The test places minimal demands on patients (who simply view a series of moving patterns for less than 90 s), requires modest operator expertise, and can be run on affordable hardware.

Central Visual Function and Genotype–Phenotype Correlations in PDE6A-Associated Retinitis Pigmentosa

PurposeAutosomal recessive retinitis pigmentosa (arRP) can be caused by mutations in the phosphodiesterase 6A (PDE6A) gene. Here, we describe the natural course of disease progression with respect to central retinal function (i.e., visual acuity, contrast sensitivity, and color vision) and establish a detailed genotype-–phenotype correlation.MethodsForty-four patients (26 females; mean age ± SD, 43 ± 13 years) with a confirmed genetic diagnosis of PDE6A-associated arRP underwent comprehensive ophthalmological examinations including best-corrected visual acuity (BCVA) with Early Treatment Diabetic Retinopathy Study charts, contrast sensitivity (CS) with Pelli–Robson charts at distances of 3 m and 1 m, and color vision testing using Roth 28-Hue and Panel D-15 saturated color cups.ResultsThe most frequently observed variants were c.998+1G>A/p.?, c.304C>A/p.R102S, and c.2053G>A/p.V685M. Central retinal function in patients homozygous for variant c.304C>A/p.R102S was better when compared to patients homozygous for variant c.998+1G>A/p.?, although the former were older at baseline. Central retinal function was similar in patients homozygous for variant c.304C>A/p.R102S and patients heterozygous for variants c.304C>A/p.R102S and c.2053G>A/p.V685M, although the latter were younger at baseline. Annual decline rates in central retinal function were small.ConclusionsWe conclude that the severity of the different disease-causing PDE6A mutations in humans with respect to central visual function may be ranked as follows: c.2053G>A/p.V685M in homozygous state (most severe) > c.998+1G>A/p.? in homozygous state > c.304C>A/p.R102S and c.2053G>A/p.V685M in compound-heterozygous state > c.304C>A/p.R102S in homozygous state (mildest). The assessment of treatment efficacy in interventional trials will remain challenging due to small annual decline rates in central retinal function.

Profile of ocular conditions from school eye screening in Southern India.

Purpose:To profile the presentation of ocular conditions among school children aged 6 to 17 years from the south Indian state of Tamil Nadu.Methods:The study was conducted as part of a school eye health program in Kanchipuram district, Tamil Nadu that aimed to address the refractive needs of children (6–17 years) between July 2016 and June 2019. The study followed a three-phase protocol, which included visual acuity test, modified clinical test, color vision test, binocular vision assessment, objective and subjective refraction, dispensing spectacles, posterior segment evaluation using direct ophthalmoscopy, and referral to the base hospital. The demographics, clinical details, and ocular conditions (classified under 16 categories) were analyzed. Profiling and association of ocular conditions among different locations, types of schools, class grades, and gender were presented.Results:Data of 2,45,565 children were analyzed from 1,047 schools, of which 4,816 (1.96%) children were identified with ocular conditions other than refractive errors. The common reasons for referral were high myopia 901 (0.37%), strabismus 819 (0.33%), and amblyopia 691 (0.28%). Retinal problems (odds ratio [OR]: 1.65, 95% confidence interval [CI]: 1.22–2.22, P = 0.001) and strabismus (OR: 1.41, 95% CI: 1.21–1.65, P < 0.001) were the conditions prevalent in the rural location. Cataract and related conditions (OR: 5.73, 95% CI: 4.10–8.01, P < 0.001) and retinal problems (OR: 4.76, 95% CI: 3.37–6.72, P < 0.001) were common in children studying in public schools. Of the 16 categories, 13 conditions were seen among primary school children. Vernal keratoconjunctivitis (OR: 3.64 95% CI: 2.12–6.23 P < 0.001) was common among males.Conclusion:The study profiled ocular conditions among school children. Most ocular conditions warrant prolonged care and specialty eye care services. Ensuring the availability of such services and follow-up after school eye screening would safeguard the visual development of these children.

Evolution of Prodromal Multiple System Atrophy from REM Sleep Behavior Disorder: A Descriptive Study.

Prodromal multiple system atrophy (MSA) has been characterized mainly by retrospective chart reviews. Direct observation and tracking of prodromal markers in MSA have been very limitedObjective:To report the baseline characteristics and evolution of prodromal markers of MSA as they were prospectively measured in patients with idiopathic/isolated REM sleep behavior disorder (iRBD)Methods:Patients with iRBD were evaluated as part of a comprehensive protocol repeated annually. The protocol included assessment of motor, sleep, psychiatric, and autonomic symptoms supplemented by motor examination, quantitative motor testing, neuropsychological examination, orthostatic blood pressure measurement, and tests of olfaction and color vision. Patients who eventually developed MSA were described and compared with those who phenoconverted to Lewy body disease (Parkinson's disease and dementia with Lewy bodies). Of 67 phenocoverters, 4 developed MSA-P and 63 developed Lewy body disease. An additional 2 MSA-C patients were seen at baseline, already with cerebellar signs. Compared to those with Lewy body disease, those with MSA-P were younger, had less severe loss of tonic REM sleep atonia, more insomnia symptoms, and better olfaction. Clinically-evident autonomic dysfunction was not invariable in prodromal stages, often developing proximate to or after motor phenoconversion. Of the autonomic symptoms, genitourinary dysfunction was the first to develop in all cases. Olfaction and cognition remained normal throughout the prodromal and clinical disease course, in clear contrast to patients with Lewy body disease. Prodromal MSA progresses rapidly, often without substantial autonomic dysfunction, and with preserved olfaction and cognition throughout its prodromal course.

Chromatic discrimination in fixed saturation levels from trichromats and subjects with congenital color vision deficiency

Color vision tests use estimative of threshold color discrimination or number of correct responses to evaluate performance in chromatic discrimination tasks. Both approaches have advantages and disadvantages. In the present investigation, we compared the number of errors during color discrimination task in normal trichromats and participants with color vision deficiency (CVD) using pseudoisochromatic stimuli at fixed saturation levels. We recruited 28 normal trichromats and eight participants with CVD. Cambridge Color Test was used to categorize their color vision phenotype, and those with a phenotype suggestive of color vision deficiency had their L- and M-opsin genes genotyped. Pseudoisochromatic stimuli were shown with target chromaticity in 20 vectors radiating from the background chromaticity and saturation of 0.06, 0.04, 0.03, 0.02, 0.01, and 0.005 u’v' units. Each stimulus condition appeared in four trials. The number of errors for each stimulus condition was considered an indicator of the participant's performance. At high chromatic saturation, there were fewer errors from both phenotypes. The errors of the normal trichromats had no systematic variation for high saturated stimuli, but below 0.02 u’v' units, there was a discrete prevalence of tritan errors. For participants with CVD, the errors happened mainly in red-green chromatic vectors. A three-way ANOVA showed that all factors (color vision phenotype, stimulus saturation, and chromatic vector) had statistically significant effects on the number of errors and that stimulus saturation was the most important main effect. ROC analysis indicated that the performance of the fixed saturation levels to identify CVD was better between 0.02 and 0.06 u’v’ units reaching 100%, while saturation of 0.01 and 0.005 u’v’ units decreased the accuracy of the screening of the test. We concluded that the color discrimination task using high saturated stimuli separated normal trichromats and participants with red-green color vision deficiencies with high performance, which can be considered a promising method for new color vision tests based in frequency of errors.

Extending the color discrimination metric with consideration of illuminance level.

Color discrimination is a crucial dimension for the visual assessment of white light sources. In this Letter, we took full advantage of data comparability among Farnsworth-Munsell 100 Hue (FM-100) color vision tests and modified our recent proposed color discrimination metric [Opt. Lett.45, 6062 (2020)10.1364/OL.400422] to make it effective in quantifying the color discrimination capability of lighting under multiple illuminance levels. The updated metric was developed based on a meta-analysis of 100 sets of combined visual data derived from three groups of visual studies containing 29 FM-100 trials and its superiority was comprehensively validated by 140 sets of combined data from five groups of studies with 42 FM-100 trials.

Color Vision Testing, Standards, and Visual Performance of the U.S. Military.

Color vision deficiency (CVD) is a disqualifying condition for military special duty occupations. Color vision testing and standards vary slightly among the U.S. military branches. Paper-based pseudoisochromatic plates (PIPs) remain a screening tool. Computer-based color vision tests (CVTs), i.e., the Cone Contrast Test (CCT), the Colour Assessment and Diagnosis (CAD) test, and the Waggoner Computerized Color Vision Test (WCCVT), are now replacing the Farnsworth Lantern Test (FALANT) and its variants to serve as a primary or secondary test in the U.S. Armed Forces. To maintain consistency in recruitment, performance, and safety, the study objectives were to examine military color vision testing, passing criteria, and color discrimination performance. Study participants were 191 (17% female) students, faculty, and staff of the U.S. Air Force Academy and the Naval Aerospace Medical Institute. All subjects performed six CVTs, and 141 participants completed two additional military relevant color discrimination tasks. Friedman non-parametric test and Wilcoxon signed-rank post hoc test with Bonferroni adjusted P values were used to compare CVTs and standards. Analysis of variance and Bonferroni adjusted post hoc test were used to describe effects on color discrimination performance. The Heidelberg Multicolor-Moreland and Rayleigh (HMC-MR) anomaloscope diagnosed 58 CVD (30.4%). There were no statistically significant differences in identifying red-green CVD by the HMC-MR, CCT, CAD, WCCVT, and PIP tests (P = .18), or classifying deutan, protan, and normal color vision (CVN) by the HMC-MR and the CVT (P = .25). Classification of tritan CVD was significantly different depending on which CVT was used (P < .001). Second, overall passing rates were 79.1% on the CAD (≤6 standard normal unit (SNU)), 78.5% on the combined PIP/FALANT, 78.0% on the CCT (≥55%), and 75.4% on the WCCVT (mild) military standards. The CVTs and the PIP/FALANT standards were not significantly different in number of personnel selected, but CAD and CCT passed significantly more individuals than WCCVT (P = .011 and P = .004, respectively). The previous U.S. Air Force standard (CCT score ≥75%) passed significantly fewer individuals relative the U.S. Navy pre-2017 PIP/FALANT or the current CVT standards (P ≤ .001). Furthermore, for those who failed the PIP (<12/14), the FALANT (9/9 or ≥16/18) agreed with the CVTs on passing the same CVN (n = 5); however, it also passed moderate-to-severe CVD who did not pass WCCVT (n = 6), CCT (n = 3), and CAD (n = 1). Lastly, moderate/severe CVD were significantly slower and less accurate than the "mild" CVD or CVN in the two color discrimination tasks (P < .001). In comparison to CVN in the in-cockpit display color discrimination task, mild CVD (CCT ≥55% and <75%) were significantly slower by 1,424 ± 290 milliseconds in reaction time (P < .001) while maintaining accuracy. CVTs are superior to paper-based PIP in diagnosing, classifying, and grading CVD. Relative to the PIP/FALANT standard in personnel selection, the current U.S. military CVT passing criteria offer comparable passing rates but are more accurate in selecting mild CVD. Nevertheless, military commanders should also consider specific operational requirements in selecting mild CVD for duty as reduced job performance may occur in a complex color critical environment.

Inverse-Designed Aid Lenses for Precise Correction of Color Vision Deficiency.

Color vision deficiency (CVD) is a common ocular disorder affecting more than 300 million people on the earth. Although no clinical cure for the disorder currently exists, some specialized color filtering glasses/lenses based on dyes, metasurfaces, or nanocomposites have been employed for CVD management. However, as CVD patients usually diversify in their classification and severity, none of the current lenses provides a customized correction for various CVD patients, resulting in undesirable correction effects. Here, we present an inverse-designed approach for the precise correction of CVD. The wavelength shift of a patient's abnormal cone photoreceptors was measured to inversely design the best blocking wavelength and blocking rate of the lens. Then the customized aid lenses were fabricated using silica-coated gold nanoparticles with appropriate sizes and concentrations, verified by the simulated color vision and human tests. This study demonstrates the potential of the inverse-designed aid lenses in precise color filtering and customized CVD management.

Association Between Color Vision Deficiency and Myopia in Chinese Children Over a Five-Year Period.

PurposeTo explore the relationship of color vision deficiency with myopia progression and axial elongation in Chinese primary school children during a five-year cohort study.MethodsA total of 2849 grade 1 students (aged 7.1 ± 0.4 years) from 11 primary schools were enrolled and followed up for five years. Cycloplegic autorefraction and axial length were measured annually. Color vision testing was performed using Ishihara's test and the City University color vision test.ResultsThe prevalence of color vision deficiency was 1.68%, with 2.81% in boys and 0.16% in girls. Color-deficient cases consisted of 91.6% deutan and 8.3% protan. Over the five years, the cumulative incidence of myopia was 35.4% (17/48) in the color-vision deficiency group, which was lower than the 56.7% (1017/1794) in the color normal group (P = 0.004). Over the five-year study period, the change in spherical equivalent refraction in the color vision–deficiency group (−1.81 D) was also significantly lower than that in the color normal group (−2.41 D) (P = 0.002).ConclusionsThe lower incidence and slower progression of myopia in children with color-vision deficiency over the five-year follow-up period suggest that color-deficient individuals are less susceptible to myopia onset and development.

Electrophysiological and psychophysical studies in assessment of visual functions in patients with hereditary optic neuropathy

To study the capabilities of electrophysiological and psychophysical examination methods for assessment of the functional state of ganglion cells, retina and optic nerve in patients with hereditary optic neuropathy (HON). The study included 60 patients (118 eyes) with a genetically confirmed diagnosis of HON. All study patients underwent visual field test (VFT), spectral optical coherence tomography (OCT), flash and pattern visual evoked potentials (VEP) (Flash-VEP, FVEP; Pattern-VEP, PVEP), photopic electroretinography with photonegative response (PhNR) registration and the color vision test. In 24 patients (46 eyes), these parameters were assessed before the start of treatment and one year later. The treatment involved the mitochondria-targeted antioxidant SkQ1 - plastoquinonyl-decyl-triphenylphosphonium bromide (PDTP) in the form of eye drops. The main PVEP components for 1.0° and 0.3° were registered in 20% and in 14% of patient eyes with HON and high visual functions, respectively. After one year of PDTP use, a significant decrease in P100 peak latency was found only in the group with disease duration of ≤1.5 years as of the time of treatment start (p<0.05). Significant differences were observed in the PhNR amplitude (p<0.004) between patients of the main and the control groups, as well as in the PhNR amplitude between patients with visual acuity of ≤0.1 and ≥0.13 (p<0.01). Patients with high visual functions were found to have a correlation between the PhNR amplitude, GCC thickness and the global loss index (GLV). Along with VFT, OCT and color vision tests, electrophysiological studies are one of the main methods of examining patients with HON. After one year of PDTP use, there was a significant decrease in the FVEP P2 peak latency in the group with a disease duration of ≤1.5 years as of the time of treatment start. The PhNR amplitude in patients with high visual functions was found to correlate with structural changes in the ganglion cell layer and the retinal nerve fiber layer.

Impact of Eyes and Visual Functions in Safe Driving

Driving is a high level of visual functions demanding occupation. The relationship of good visual function and driving safety are innately and unarguably linked and have a direct bearing on the incidence of road traffic accidents. A more practical approach to improve the efficacy of vision screening at licensure is to examine visual acuity screening test supplemented by other types of screening tests like contrast sensitivity, visual field, binocularity, color vision, processing speed, light and dark adaptation etc. These clinical tests have a large evidence basis for their relevance to driver safety and should be mandatory for obtaining and renewing the driving license. The individual who failed the initial screening should undergo a protocol based comprehensive evaluation by an Ophthalmologist or Optometrist if fit to drive in future. Visual acuity and other visual functions requirements for driving vary from country to country though most countries mandate visual acuity of 20/40 in the better eye with horizontal visual field of 120 degrees. But there is variation regarding provision of color vision, binocularity, contrast sensitivity and night vision tests. Nepal yet , has not strict rules regarding evaluation of visual functions for safe driving. But indeed, a local expert review board should determine the suitability to issue a normal driving license or a restricted driving license, a temporary or a permanent denial for those who partially or completely failed the vision specific requirements. Moreover appropriate modification of the existing laws and expedited implementation are mandatory to minimize visual functions related road traffic accidents which is an avoidable cause of mortality and morbidity.

Color Vision in the Gas Station Workers of Isfahan City: A Quantitative Analysis With the Farnsworth D15 Color Test

Background and Objectives: The color vision evaluation of gas station workers in Isfahan City. Methods: This cross-sectional comparative study was performed on workers at gas stations in Isfahan; all the workers were men. The participants were divided into two 40-people groups of exposure and non-exposure (the members of the fuel sales department). The participants had better vision than 8/10 and no underlying problems or eye disease. Besides, examination, including color vision was performed for all subjects. Color vision was assessed using the D15 test under high to medium light conditions. Also, the color vision test was performed monocularly. Then, the obtained data were analyzed using SPSS V. 22. Results: The two study groups significantly differed in terms of color vision impairment index (P &lt;0.001). Also, more color vision defects were seen in the group exposed to gasoline. The color confusion index (as the indicator of color vision defects) were 1.485 and 1.129 in exposure and non-exposure to gasoline groups, respectively. Thus, color vision defects were significantly higher in the exposure to gasoline group, compared with the control group. Conclusion: The results of this study showed a difference in color vision index between the two groups. Therefore, long-term exposure to organic solvents, such as gasoline in fuel stations may cause color vision loss.

Dissociation between red and white stimulus perception: A perimetric quantification of protanopic color vision deficiencies.

SignificanceHorizontal visual field extension was assessed for red and white stimuli in subjects with protanopia using semi-automated kinetic perimetry. In contrast to a conventional anomaloscope, the “red/white dissociation ratio” (RWR) allows to describe protanopia numerically. For the majority of subjects with protanopia a restriction for faint red stimuli was found.PurposeComparing the horizontal visual field extensions for red and white stimuli in subjects with protanopia and those with normal trichromacy and assessing the related intra-subject intra-session repeatability.MethodsThe subjects were divided into groups with protanopia and with normal trichromacy, based on color vision testing (HMC anomaloscope, Oculus, Wetzlar/FRG). Two stimulus characteristics, III4e and III1e, according to the Goldmann-classification, were presented with semi-automated kinetic perimetry (Octopus 900 perimeter, Haag-Streit, Köniz/CH). They moved along the horizontal meridian, with an angular velocity of 3°/s towards the visual field center, starting from either the temporal or nasal periphery. If necessary, a 20° nasal fixation point offset was chosen to capture the temporal periphery of the visual field. For each condition the red/white dissociation ratio (RWR); Pat Appl. DPMA DRN 43200082D) between the extent of the isopter for red (RG610, Schott, Mainz/ FRG) and white stimuli along the horizontal meridian was determined.ResultsAll data are listed as median/interquartile range: Five males with protanopia (age 22.1/4.5 years) and six males with normal trichromacy (control group, age 30.5/15.2 years) were enrolled. The RWR is listed for the right eye, as no clinically relevant difference between right and left eye occurred. Protanopes’ RWR for mark III4e (in brackets: control group) was 0.941/0.013 (0.977/0.019) and for mark III1e 0.496/0.062 (0.805/0.051), respectively.ConclusionsIn this exploratory “proof-of-concept study” red/white dissociation ratio perimetry is introduced as a novel technique aiming at assessing and quantifying the severity of protanopia. Further effort is needed to understand the magnitude of the observed red-/white dissociation and to extend this methodology to a wider age range of the sample and to anomalous trichromacies (protanomalia) with varying magnitude.

Comparing The Validity Of Electronic Color Vision Test With Conventional Ishihara Pseudoisochromatic Plate Test

Many ocular diseases can affect color vision of a patient which will ultimately reduce many daily based activities. Measuring color vision of a patient can help deciding any management plan for that patient. Objectives:To compare the validity of electronic color vision test with conventional pseudoisochromaticishihara plates and to find out easiest and appropriate method of color vision testing.Methods: This was a cross-sectional study involving the use of structured proforma and questionnaire to evaluate the validity of electronic color vision test and conventional ishihara plate test. A sample size of 80 individuals with normal and mild degree of refractive error was examined and results were recorded in self-designed proforma. Results: Eighty individuals were enlisted; 35 were males (43.8%) and 45 (56.3) were female; age ranged from 14 to 56 (average 34.2+ 12.2) years. By conventional ishihara testing 68 patients gave 100% results (n = 68; 85%) and 12 gave 75% (n = 12; 15%) results. In electronic color vision test 69 individuals gave 100% ( n = 69; 86.3%) results and 11 gave 75% (n = 11; 13.7%) results. 45% peoples are satisfied with their electronic color vision test, 20% satisfied with both methods however 35% are satisfied with conventional method. Prevalence of color vision defect is higher in males as compared to females. Conclusions: This study found that the sensitivity and specificity of electronic color vision test and conventional ishihara test is nearly similar (p&lt; 0.05). Electronic Ishihara color vision test is also a way of self assesment and also has the advantage of reducing the cost through decreasing resources and the time to analyze the results.

Automated vision screening of children using a mobile graphic device

Background/ObjectiveCan measuring interocular brightness disparity, acuity, and colour vision classify children with amblyopia?Subjects/MethodsTwo hundred eight subjects (3–14 years) were recruited for a prospective, observational protocol to measure interocular brightness disparity, uniocular acuities with and without a pinhole, and colour vision using an iPad. Subjects looked through polarizing filters and chose the brighter of two spaceships to measure interocular brightness disparity. The differential brightness of image pairs was varied through a staircase algorithm until equal brightness was perceived. Acuities and colour vision were tested with tumbling Es and AO-HRR colour plates, respectively. Unilateral amblyopia was later confirmed in two subjects.ResultsBinocular brightness balance on the iPad detected amblyopes with 100% sensitivity and specificity. Using 20/30 as cutoff for normal acuity, 1 of the amblyopes was detected, and non-amblyopes were excluded by visual acuity pinhole testing. The mean difference between iPad and E-Chart visual acuities with pinhole was 0.02 logMAR with limits of agreement from −0.08 to +0.11 logMAR. iPad and printed plates Colour vision testing produced identical results. Testing times were brief and exit pleasure responses were positive. Mean and range testing times for Brightness Sense, Colour vision, and Visual Acuity were 32.7 s (range = 12–63 s), 52.8 min (range = 17–95 s), and 88.75 s (range = 41–188 s), respectively.ConclusionsInterocular brightness disparity, acuity, and colour vision can be measured in children as young as 3 years old solely through playing a game on a mobile device. Interocular brightness disparity is a sensitive and specific method to detect unilateral amblyopia.

Neuro-Ophthalmological Optic Nerve Cupping: An Overview

Optic nerve cupping or enlargement of the cup-to-disc ratio is widely recognized as a feature of glaucoma, however it may also occur in non-glaucomatous optic neuropathies. The most well-recognized non-glaucomatous optic neuropathies that cause cupping include compressive optic neuropathies, arteritic anterior ischemic optic neuropathies, hereditary optic neuropathies, and optic neuritis. Cupping is thought to consist of two main components: prelaminar and laminar thinning. The former is a shallow form of cupping and related to loss of retinal ganglion cells, whereas the latter involves damage to the lamina cribrosa and peripapillary scleral connective tissue. Differentiating glaucomatous and non-glaucomatous optic nerve cupping remains challenging even for experienced observers. Classically, the optic nerve in non-glaucomatous causes has pallor of the neuroretinal rim, but the optic nerve should not be examined in isolation. The patient’s medical history, history of presenting illness, visual function (visual acuity, color vision and visual field testing) and ocular examination also need to be considered. Ancillary testing such as optical coherence tomography of the retinal nerve fiber layer and ganglion cell layer-inner plexiform layer may also be helpful in localizing the disease. In this review, we review the non-glaucomatous causes of cupping and provide an approach to evaluating a patient that presents with an enlarged cup-to-disc ratio.