Changes In Color Vision Research Articles

Investigating the effects of simulated high altitude on colour discrimination

PurposeTo quantify changes in colour vision immediately after exposure to different altitudes of low-pressure hypoxia.MethodsThe study involved 35 healthy participants (ages 20–26). Colour vision was assessed using the Farnsworth-Munsell 100-Hue...

Effect of brimonidine on visual indices in patients with acute optic neuritis: A single blind randomized clinical trial

PurposeThis study investigates brimonidine's potential effect on visual functions, particularly contrast sensitivity (CS), an indicator of retinal ganglion cell function. MethodsIn this single-blind, randomized clinical trial, 60 patients (aged 23–56) with first-episode acute optic neuritis within seven days of symptom onset were randomly assigned to brimonidine or control groups. The intervention group received brimonidine three times daily for three months, while the control group received synthetic tears with the same dosage and frequency. Primary outcomes were changes in CS, visual acuity (VA), and color vision at one and three months post-treatment. Repeated measures ANOVA was used to assess statistically significant and partial eta squared (η2) values, mean differences, and clinically significance important were reported. ResultsAll participants completed the study without complications. VA improved significantly in both groups by follow-up end (p < 0.001), with significant improvement from first to third month only in the brimonidine group (p < 0.001). The mean VA difference between groups was not statistically and clinically significant. CS showed statistically significant improvement within both groups (p < 0.001) and between groups (p < 0.001), with a large effect size (partial η2 = 0.28). The mean CS difference between groups (14.5) was clinically considerable. No significant changes in color vision were observed between groups (p = 0.96). ConclusionBrimonidine significantly improved contrast sensitivity compared to placebo and was well-tolerated. Its neuroprotective effects suggest it may be beneficial in treating optic neuritis and preserving retinal ganglion cell function. Trial registrationProspectively registered at Iranian Clinical Trial Registration; Registration date 3 December 2022; Registration number: IRCT20221127056631N1

Assessment of visual function in patients with posterior fossa tumours

Introduction. Posterior fossa tumours (PFTs) frequently present with ophthalmic complaints. The literature is mainly focused on PFTs affecting the pediatric age group, and the post-treatment visual outcomes (VOs) are scarcely reported. Objective. To evaluate the VOs at 6 months following the index surgery in patients with PFTs. Materials and methods. This retrospective study involved 50 patients of all age groups who underwent surgical resection of PFTs in the Department of Neurosurgery. The patients with PFTs, except those with low-grade tumours, received concurrent chemo-radiotherapy. Pre- and postoperative (6 months after the index surgery) ophthalmic examinations were done and compared. VOs included colour vision, night vision, visual acuity (VA), pupillary function (size, reactivity), papilledema grade, splinter haemorrhage, retinal venous dilatation, strabismus (esotropia and hypertropia), and nystagmus. Results. The patients were mainly aged 1–10 years (22%) with slight female predominance (52%). The most common PFTs were brainstem glioma and pilocytic astrocytoma (each 18%). At 6 months, there was no significant change in colour and night vision, pupil size and reactivity, splinter haemorrhage, and hypertropia (all p-values&gt;0.05). A significantly lesser proportion of patients had moderate VA (p-value=0.013), retinal venous dilatation (p-value=0.001), and grade 1 (p-value=0.005) as well as grade 4 papilledema (p-value=0.041). Moreover, a significantly greater proportion of patients had grade 0 papilledema (p-value&lt;0.0001). While the incidence of nystagmus and esotropia increased significantly (both p-values&lt;0.0001). Conclusion. At 6 months, the majority of the patients had good VOs, including significant improvement in moderate VA, papilledema, and retinal venous dilatation. While nystagmus and esotropia increased significantly.

General Approach to Optic Neuropathies and Routine Examinations

Optic neuropathies are neuro-ophthalmological disorders characterized by decreased visual acuity, visual field defects and color vision changes as a result of damage to the optic nerve. The underlying causes, clinical features and treatments of optic neuropathies vary. Clarifying the etiology is very important in terms of visual prognosis and patient follow-up. Clinical history, examination findings, visual field, electrophysiological tests and imaging methods are used in diagnosis. In this article, the general characteristics, examination and ancillary diagnostic methods of optic neuropathies that develop due to different etiological reasons will be discussed

Evaluation of colour vision impairment during acute hypobaric hypoxia in aviation medicine: a randomized controlled trial

The digitization of aircraft cockpits places high demands on the colour vision of pilots. The present study investigates colour vision changes upon acute exposure to hypobaric hypoxia. The digital Waggoner Computerized Color Vision Test and the Waggoner D-15 were performed by 54 healthy volunteers in a decompression chamber. Respective altitude levels were sea level, 10,000 or 15,000 ft for exposure periods of 15 and 60 min, respectively. As for 60 min of exposure a significant decrease in colour perception was found between subjects at 15,000 ft as compared to the control group as well as between subjects at 15,000 ft as compared to subjects at 10,000 ft. No significant difference was found in the comparison within the 15,000 ft groups across time points pre-, peri-, and post-exposure. Thus, pilots appear to experience only minor colour vision impairment up to an exposure altitude of 15,000 ft over 60 min of exposure.

Color vision of people with headaches

The aim of the study is to obtain new data on possible changes in color vision of people with headaches. The object of the study is people who periodically experience primary headaches of different nature. The subject of the study is the specificity of perception of chromatic parameters of the environment and color sensitivity of people with headaches of different nature, quality, intensity and frequency. The data were collected using the Farnsworth-Munsell standard clinical color vision test (FM-100). The study involved 65 people aged 17 to 66 years. The results of the assessment of color vision in the experimental group were compared with the normative indicators and data obtained in the age-matched control group (N=40). Special attention was paid to discussing the possible causes of the identified disorders and analyzing the correlation between various aspects of headache with individual indicators of color sensitivity. The data analysis included calculating the total error (TES), as well as partial errors (PES) along the blue-yellow (B-Y) and red-green (R-G) axes. We also identified partial errors for individual tones. The study revealed a noticeable specificity in the perception of blue-green and blue shades of patients with severe, chronic and non-localized headaches. Since the detected color vision disorders appear to be temporary and are most likely typical of the premonitory phase of headaches, the results of this study may contribute to understanding of headache predictors. Since the identified changes relate to only one group of (blue) shades, the findings of the study can be used in the development of alternative treatment methods. In particular, in choosing the optimal color of tinted lenses, which are offered to patients to relieve headaches and reduce their frequency.

Elamipretide Topical Ophthalmic Solution for the Treatment of Subjects with Leber Hereditary Optic Neuropathy: A Randomized Trial

PurposeThe purpose of this study was to assess the safety, tolerability, and potential efficacy of topical elamipretide in patients affected with Leber’s Hereditary Optic Neuropathy (LHON). DesignThis Phase 2, prospective, randomized, vehicle controlled, single-center clinical trial involved administration of elamipretide (MTP-131) topical ophthalmic solution to LHON patients over a 52-week double-masked treatment period (DMTP), followed by an open extension label (OLE) for up to 108 additional weeks of treatment. SubjectsTwelve patients affected with LHON were included in this study. Patients between ages 18 and 50 with decreased vision, for at least one year and no more than ten years, and a genetically confirmed diagnosis of m.11778G>A LHON were eligible for this trial. MethodsFor the first 52 weeks of the study, patients were randomized to one of two arms, elamipretide in both eyes or elamipretide in one eye and vehicle in the other eye, followed by an OLE where both eyes were treated with elamipretide. Main outcome measuresThe primary outcome measure was the assessment of adverse events from the administration of topical elamipretide 1% and the primary efficacy endpoint was change in best corrected visual acuity (BCVA). Secondary outcome measures included changes in color vision, visual field mean deviation, and electrophysiological outcomes. ResultsElamipretide was well tolerated with the majority of treatment-emergent adverse events (TEAEs) being mild to moderate and resolving spontaneously. The change from baseline in BCVA in elamipretide-treated eyes was not significantly different from the vehicle eyes at any time point. Six of 12 subjects met the criteria for clinically relevant benefit (CRB). In the post-hoc analysis, change from baseline in mean deviation in the central visual field was significantly greater in elamipretide treated eyes versus the vehicle eyes. Compared to baseline, both treatment groups showed improvement in color discrimination and contrast sensitivity in the OLE. ConclusionsElamipretide treatment was generally well tolerated with no serious adverse events reported. Although this study did not meet its primary BCVA efficacy endpoint, improvements across assessments on visual function during the OLE, and the post-hoc findings of the HVF central region, were encouraging and require further exploration.

Opsin Gene Duplication in Lepidoptera: Retrotransposition, Sex Linkage, and Gene Expression.

Color vision in insects is determined by signaling cascades, central to which are opsin proteins, resulting in sensitivity to light at different wavelengths. In certain insect groups, lineage-specific evolution of opsin genes, in terms of copy number, shifts in expression patterns, and functional amino acid substitutions, has resulted in changes in color vision with subsequent behavioral and niche adaptations. Lepidoptera are a fascinating model to address whether evolutionary change in opsin content and sequence evolution are associated with changes in vision phenotype. Until recently, the lack of high-quality genome data representing broad sampling across the lepidopteran phylogeny has greatly limited our ability to accurately address this question. Here, we annotate opsin genes in 219 lepidopteran genomes representing 33 families, reconstruct their evolutionary history, and analyze shifts in selective pressures and expression between genes and species. We discover 44 duplication events in opsin genes across ∼300 million years of lepidopteran evolution. While many duplication events are species or family specific, we find retention of an ancient long-wavelength-sensitive (LW) opsin duplication derived by retrotransposition within the speciose superfamily Noctuoidea (in the families Nolidae, Erebidae, and Noctuidae). This conserved LW retrogene shows life stage-specific expression suggesting visual sensitivities or other sensory functions specific to the early larval stage. This study provides a comprehensive order-wide view of opsin evolution across Lepidoptera, showcasing high rates of opsin duplications and changes in expression patterns.

The prevalence of red-green color vision deficiency and its related factors in an elderly population above 60 years of age.

To determine the prevalence of red-green (RG) color vision deficiency (CVD) in an elderly population and its related factors. This report is a part of the Tehran Geriatric Eye Study: a cross-sectional population-based study that was conducted on the elderly population (≥60y) of Tehran, Iran using multi-stage stratified random cluster sampling. All study participants underwent complete ocular examination, including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, and slit-lamp biomicroscopy. The color vision was tested using Ishihara plates with the near optical correction in place. Of the 3791 invitees, 3310 participated in the study. The data of 2164 individuals were analyzed after applying the exclusion criteria. The prevalence of R-G CVD was 3.73% (95%CI: 2.37%-5.09%) in the whole sample; the prevalence of protanomaly, protanopia, and deuteranopia was 1.51%, 1.76%, and 0.45%, respectively. The prevalence of R-G CVD was significantly higher in males than in females. The prevalence of RG CVD increased with advancing age from 2.91% in the age group 60-64y to 5.8% in the age group ≥80y (P=0.070). According to the multiple logistic regression model, male sex, and glaucoma were significantly related to RG CVD. Older age and hypertension also had a marginally significant relationship with RG CVD. Changes in color vision occur in the elderly due to the aging process and some physiological and pathological factors. Since the change in visual perception may affect the person's performance, this aspect of the visual system's function should also be taken into consideration in the examinations of the elderly.

Screening of Oral Tamoxifen Ocular Toxicity in Breast Cancer Patients

Background Breast cancer is one of the leading cancer types among females worldwide. Prevalence of breast cancer is reported to be the second most common among women. Several treatment lines were prescribed in treatment of breast cancer besides surgical, radiological interventions. Tamoxifen is one of the medical treatments used in postsurgical prophylaxis of breast cancer. Various visual problems were reported with tamoxifen therapy. These include posterior subcapsular cataracts, color vision changes, optic neuritis, and intra-retinal crystals. Aim of the Work The aim of the work was to screen for ocular toxicity of tamoxifen used for treatment of breast cancer patients having no ophthalmic complains and treated with tamoxifen for at least 2 years with dose (20mg per day). Patients and Methods We included 50 female patients with breast cancer treated with Tamoxifen therapy for at least 2 years then we divided them into two groups regarding duration of tamoxifen intake from (2-4) years group and from (5-8) years group, all subjects underwent complete careful history taking and full ophthalmological examination, BCVA was measured using Snellen chart with conversion to log. MAR notation for statistical analysis. Results There was significant correlation between duration of tamoxifen intake and RPE mottling, no other significant correlations were detected, there was no significant difference in mean of BCVA, IOP, cup values, disc parameters, GCC thickness, RNFL zones between the two groups except for (inferior quadrant), macular thickness except in (superior quadrant), OCT layers thinning shows RNFL affection in (34%) of cases, GCC affection in (48%) of cases and macula affection in (64%) of cases, color vision defects was found in (12%) and electrophysiological test changes found in few cases. Conclusion Tamoxifen therapy causes minimal affection on the ocular structure and function, OCT layers thinning (34-64% of cases) preceed the clinical changes this highlights the importance of OCT examination in those patients to evaluate tamoxifen toxicity and further studies will be needed to evaluate reversibility of these changes after stoppage of therapy, main ocular complications associated with tamoxifen therapy were correlated to duration of treatment.

Evaluation of color vision related quality of life changes due to cataract surgery.

Questionnaires have been used as research tools to provide a standardized approach to assess quality of life at various time periods and populations. However, literature shows only a few articles about self-reported color vision changes. Our aim was to evaluate the subjective patient feelings before and after cataract surgery and compare the results with a color vision test result. Our method was as follows: 80 cataract patients filled out a modified color vision questionnaire and performed the Farnsworth-Munsell 100 Hue Color Vision Test (FM100) before, two weeks, and six months after cataract surgery. We analyzed the correlations between these two types of results, which reveal that FM100 hue performance and subjective perception improved after surgery. Additionally, subjective patient questionnaire scores correlate well with the FM100 test results before and two weeks after the cataract surgery, but this effect decreased with longer follow-up times. We conclude that subjective color vision changes can only be noticed at longer periods after the cataract surgery. Health care professionals can use this questionnaire to better understand the subjective feelings of patients and monitor their color vision sensitivity changes.

Multiple sclerosis and glatiramer acetate: Risk factors for central retinal vein occlusion?

Multiple sclerosis may present an increased risk for venous thromboembolism. Ophthalmological symptoms include loss of vision, visual field loss, changes in color vision, diplopia and nystagmus. First-line treatments for multiple sclerosis are beta-interferon, glatiramer acetate, dimethyl fumarate and teriflunomide. To the best of our knowledge, no ophthalmologic side effects have been reported with glatiramer acetate. We present a woman with multiple sclerosis on glatiramer acetate therapy with a central retinal vein occlusion in the absence of other risk factors.

Medications Damaging Vascular Bed or Causing Microvasculopathy / Occlusion-1: Pathogenesis, Diagnosis, and Treatment (Interferon, IL2- Denileukin Diftitox, Tyrosine Kinase Inhibitor-Imatinib, Ergot Alkaloids, Talc)

Despite the presence of the blood-ocular barrier, the retina is susceptible to the toxic effects of systemic drugs due to dysfunction and retinal degeneration. This toxicity due to drugs can be categorized as follows; retinal pigment epithelium (RPE), photoreceptor complex damage, vascular bed damage, ganglion cell or optic nerve damage, cystoid macular edema, crystalline retinopathy, uveitis, changes in color vision and electroretinography (ERG), and various other effects. These drugs show their toxic effects by causing vascular damage or causing vasospasm with various effects.

Colour vision changes in patients with pressure differences across the lamina cribrosa

AbstractThe retinal nerve fibre layer (RNFL) thickness parameters describe the integrity of retinal ganglion cells (RGC) and their axons and can be affected in pathological processes involving the optic nerve. Glaucoma and papilledema are two conditions where RGCs and hence RNFL, are damaged due to the pressure differences across the lamina cribrosa. The latter separates the intraocular and intracranial pressure compartments. In glaucoma, the intraocular pressure (IOP) is elevated and in papilledema, the intracranial pressure is elevated. When intracranial pressure is managed, papilledema patients can recover without significant loss of RGC. Conversely irreversible RGC loss can occur in severe cases.Subtle, functional changes that are often not detected clinically can remain following recovery. The detection of such changes require sensitive functional tests and a knowledge of normal age limits for the stimulus attribute investigated.Results of preliminary studies designed to assess how colour vision and rod and cone mediated flicker sensitivity recover in papilledema will be reported for a number of patients. Following recovery, the results often reveal binocular summation effects, even when the differences between the two eyes remain significant. Patients classed clinically as fully recovered continue to show small differences between the two eyes, even when the measured binocular thresholds are within the expected age limits.In summary, the preliminary findings from this investigation show how various attributes of vision are affected during the early stages of the disease and after treatment and recovery from late stage of severe papilledema with loss of RGCs.

Visual disorders and driving ability in persons with dementia: A mini review.

Impaired driving ability in patients with Alzheimer's disease (AD) is associated with a decline in cognitive processes and a deterioration of their basic sensory visual functions. Although a variety of ocular abnormalities have been described in patients with AD, little is known about the impact of those visual disorders on their driving performance. Aim of this mini-review is to provide an update on the driving ability of patients with dementia and summarize the primary visual disorders affecting their driving behavior. Databases were screened for studies investigating dementia, associated visual abnormalities and driving ability. There is consistent evidence that dementia affects driving ability. Patients with dementia present with a variety of visual disorders, such as visual acuity reduction, visual field defects, impaired contrast sensitivity, decline in color vision and age-related pathological changes, that may have a negative impact on their driving ability. However, there is a paucity in studies describing the impact of oculovisual decline on the driving ability of AD subjects. A bidirectional association between cognitive and visual impairment (VI) has been described. Given the bidirectional association between VI and dementia, vision screening and cognitive assessment of the older driver should aim to identify at-risk individuals and employ timely strategies for treatment of both cognitive and ocular problems. Future studies should characterize the basic visual sensory status of AD patients participating in driving studies, and investigate the impact of vision abnormalities on their driving performance.

Fluoxetine for non-arteritic anterior ischemic optic neuropathy: A double-blind, randomized clinical trial

Introduction: Fluoxetine raises the levels of BDNF (brain-derived neurotrophic factor). BDNF is known to improve neurogenesis and plasticity, so it seems to improve Anterior Ischemic Optic Neuropathy (AION). The goal of this study was to find out how Fluoxetine affects the clinical outlook of people with AION. Methods: In this double-blind, placebo-controlled, randomized clinical trial, patients with AION split into two groups: the fluoxetine group (n=50), which took 20 mg of Fluoxetine every day, and the control group (n=50), which took a placebo pill instead. Both groups were followed for six months. Before and after the trial, patients were given clinical and non-clinical evaluations. Results: 100 people took part in this study and were evaluated. Subjects in the Fluoxetine group had better visual acuity than those in the placebo group. They had lower scores on the LogMAR scale (P: 0.008 and 0.002), better MD parameters of perimetry (P: 0.003 and 0.002), and shorter VEP latencies (P (in 1st minute): 0.001 and 0.001, P (in 15th minute): 0.038 and 0.011. After the trial of Fluoxetine therapy, there were no changes in color vision, Rnfl in all dimensions, PSD parameter of perimetry, or VEP amplitudes (Ps&gt; 0.05. Conclusion: Fluoxetine showed promise as a therapy for people with AION, and it was safe to use as a treatment option in addition to corticosteroids

The Association Between Acquired Color Deficiency and PET Imaging of Neurodegeneration in Mild Cognitive Impairment and Alzheimer Disease.

PurposeTo evaluate color vision changes and retinal processing of chromatic and luminance pathways in subjects with Alzheimer disease (AD) and mild cognitive impairment (MCI) compared with a matched control group and whether such changes are associated with impaired brain glucose metabolism and β-amyloid deposition in the brain.MethodsWe evaluated 13 patients with AD (72.4 ± 7.7 years), 23 patients with MCI (72.5 ± 5.5 years), and 18 controls of comparable age (P = 0.44) using Cambridge color test and the heterochromatic flicker ERG (HF-ERG). The Cambridge color test was performed using the trivector protocol to estimate the protan, deutan and tritan color confusion axes. HF-ERG responses were measured at a frequency of 12 Hz, which ERGs reflect chromatic activity, and at 36 Hz, reflecting luminance pathway. A study subsample was performed using neuropsychological assessments and positron emission tomography.ResultsPatients with AD presented higher mean values indicating poorer color discrimination for protan (P = 0.04) and deutan (P = 0.001) axes compared with the controls. Along the tritan axis, both patients with AD and patients with MCI showed decreased color vision (P = 0.001 and P = 0.001) compared with controls. The analyses from the HF-ERG protocol revealed no differences between the groups (P = 0.31 and P = 0.41). Diffuse color vision loss was found in individuals with signs of neurodegeneration (protan P = 0.002, deutan P = 0.003 and tritan P = 0.01), but not in individuals with signs of β-amyloid deposition only (protan P = 0.39, deutan P = 0.48, tritan P = 0.63), regardless of their clinical classification.ConclusionsHere, patients with AD and patients with MCI present acquired color vision deficiency that may be linked with impaired brain metabolism.

Basic Concept of Ophthalmology and Visual Disorder

The eye is a complex sensory organ that is responsible for vision. Within the protective sheath, each eye has receptors, a lens system for focusing light on receptors, and a nervous system for transmitting impulses from the receptors to the brain. Visual dysfunction can be caused by abnormal eye movements or changes in visual acuity, refraction, color vision, or accommodation. Visual dysfunction may also be a secondary effect of other neurological disorders. This narrative review aims to describe the structure of the eye in general and visual disturbances caused by the aging process and disorders of the protective structure of the eye.

Deficits in color detection in patients with Alzheimer disease.

Deficits in color vision and related retinal changes hold promise as early screening biomarkers in patients with Alzheimer’s disease. This study aimed to determine a cut-off score that can screen for Alzheimer’s dementia using a novel color vision threshold test named the red, green, and blue (RGB) modified color vision plate test (RGB-vision plate). We developed the RGB-vision plate consisting of 30 plates in which the red and green hues of Ishihara Plate No.22 were sequentially adjusted. A total of 108 older people participated in the mini-mental state examination (MMSE), Ishihara plate, and RGB-vision plate. For the analyses, the participants were divided into two groups: Alzheimer’s dementia (n = 42) and healthy controls (n = 38). K-means cluster analysis and ROC curve analysis were performed to identify the most appropriate cut-off score. As a result, the cut-off screening score for Alzheimer’s dementia on the RGB-vision plate was set at 25, with an area under the curve of 0.773 (p<0.001). Moreover, there was a negative correlation between the RGB-vision plate thresholds and MMSE scores (r = -0.36, p = 0.02). In conclusion, patients with Alzheimer’s dementia had a deficit in color vision. The RGB-vision plate is a potential early biomarker that may adequately detect Alzheimer’s dementia.

Structural and Functional Characteristics of Color Vision Changes in Choroideremia.

Color vision is considered a marker of cone function and its assessment in patients with retinal pathology is complementary to the assessments of spatial vision [best-corrected visual acuity (BCVA)] and contrast detection (perimetry). Rod-cone and chorioretinal dystrophies—such as choroideremia—typically cause alterations to color vision, making its assessment a potential outcome measure in clinical trials. However, clinical evaluation of color vision may be compromised by pathological changes to spatial vision and the visual field. The low vision Cambridge Color Test (lvCCT) was developed specifically to address these latter issues. We used the trivector version of the lvCCT to quantify color discrimination in a cohort of 53 patients with choroideremia. This test enables rapid and precise characterization of color discrimination along protan, deutan, and tritan axes more reliably than the historically preferred test for clinical trials, namely the Farnsworth Munsell 100 Hue test. The lvCCT demonstrates that color vision defects—particularly along the tritan axis—are seen early in choroideremia, and that this occurs independent of changes in visual acuity, pattern electroretinography and ellipsoid zone area on optical coherence tomography (OCT). We argue that the selective loss of tritan color discrimination can be explained by our current understanding of the machinery of color vision and the pathophysiology of choroideremia.