Cone structure and retinal sensitivity assessment in patients with red-green colour vision deficiency using multimodal imaging.

The purpose of this study was to report a case of acute zonal occult outer retinopathy (AZOOR) with spontaneous remission that was followed up using adaptive optics scanning laser ophthalmoscopy (AO-SLO). The right eye of a 31-year old myopic man diagnosed with AZOOR was followed up. The patient underwent a full ophthalmologic examination, spectral-domain optical coherence tomography (SD-OCT), multifocal electroretinography (mfERG) and imaging with prototype AO-SLO systems (Canon Inc) at the first visit, 1 month after, and 2 months after. Images focused on the photoreceptor layer were recorded in the area, and a montage of AO-SLO images was created. The patient presented with acute onset of a blind spot and photopsia in his right eye. On AO-SLO, focal dark areas could be observed on the right eye but not on the left eye at the first examination (cone density 8,589/mm(2), mosaic regularity of cone photoreceptors 38.5 %, cone spacing 0.567). The dark areas on AO-SLO corresponded to areas of disrupted inner segments and outer segments (IS/OS) line or ellipsoid of the IS and abnormal area in mfERG. After 1 and 2 months, his symptoms tended to disappear gradually without any treatment. IS/OS line and mfERG could be nearly normalized. Furthermore, normal cone mosaic could be observed in areas where some focal dark spots could be observed at the first examination (cone density 10,112/mm(2), mosaic regularity of cone photoreceptors 39.9 %, cone spacing 0.606). AO-SLO is a useful tool of diagnosis and follow-up of AZOOR. This study might suggest reversible cone damage could occur in some cases of AZOOR with spontaneous remission.

High-Resolution Imaging of Resolved Central Serous Chorioretinopathy Using Adaptive Optics Scanning Laser Ophthalmoscopy

Red-green colour vision deficiency (CVD) affects ~ 4% of Caucasians. Notch filters exist to simulate CVD when worn by colour vision normal (CVN) observers (simulation tools), or to improve colour discrimination when worn by CVD observers (compensation tools). The current study assesses effects of simulation (Variantor) and compensation (EnChroma) filters on performance in a variety of tasks. Experiments were conducted on 20 CVN and 16 CVD participants under no-filter and filter conditions (5 CVN used Variantor; 15 CVN and 16 CVD used EnChroma). Participants were tested on Ishihara and Farnsworth-Munsell 100 hue tests, CVA-UMinho colour discrimination and colour naming tasks and a board-game colour-sorting task. Repeated-measures ANOVAs found Variantor filters to significantly worsen CVN performance, mimicking protanopia. Mixed-model and repeated-measures ANOVAs demonstrate that EnChroma filters do not significantly enhance performance in CVD observers. Key EnChroma results were replicated in 8 CVD children (Ishihara test) and a sub-sample of 6 CVD adults (CVA-UMinho colour discrimination and colour naming tasks) for a smaller stimulus size. Pattern similarity exists across hue for discrimination thresholds and naming errors. Variantor filters are effective at mimicking congenital colour vision defects in CVN observers for all tasks, however EnChroma filters do not significantly compensate for CVD in any.

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.

Purpose: To observe retinal sensitivity (RS) and microvasculature changes in preoperative and postoperative idiopathic macular epiretinal membrane (iERM) with optical coherence tomography (OCT) classification by microperimetry (MP) and optical coherence tomography angiography (OCTA). Methods: In this retrospective study, 53 eyes of 53 patients affected with iERM were enrolled and 35 iERM eyes underwent pars plana vitrectomy associated with internal limiting membrane peeling. All iERM eyes were evaluated and graded by OCT. According to the thickness of the fovea relative to the surrounding macula from OCT radial line scans, we classified iERM into 3 grades. MP was used to measure RS of macular within 20° centered on the fovea and fixation stability (FS). OCTA was used to measure the superficial and deep capillary plexus (DCP) layers using 6 mm × 6 mm scans. Measurements were taken at the baseline visit and 3-month postoperation. Evaluated factors included: best corrected visual acuity, RS, FS, vessel density. Results: Eyes with iERM had worse RS than control eyes (p < 0.0001), especially in higher grade iERM eyes. And higher grade iERM eyes had a marked increase foveal vessel density (FVD) (p < 0.0001) in superficial capillary plexus (SCP) and DCP, and a significant decrease parafoveal vessel density (Para VD) in DCP. After surgery, there was no difference in RS and FS than preoperation (p > 0.05), whether in grade 1 or 2 iERM eyes. However, in OCTA analyses, grade 1 iERM eyes had less whole vessel density (WVD) and perifoveal vessel density (Peri VD) in SCP, than preoperation (p < 0.05). And grade 1 iERM eyes had higher Para VD and Peri VD in DCP (p < 0.05), than preoperative OCTA results. Grade 2 iERM eyes had less WVD, FVD, and Peri VD in SCP, than preoperation (p < 0.05). After surgery, in grade 2 iERM eyes, there was a positive correlation between whole retinal sensitivity and WVD (p < 0.05) in SCP. And there were positive correlations between Para RS and Para VD (p < 0.05), Peri RS and Peri VD (p < 0.05) in SCP. Conclusions: Classification helps to reveal different changes in iERM eyes. Higher grade iERM eyes had worse RS and microvasculature changes. MP and OCTA play an important role in assessing iERM and help surgical decisions for patients with iERM.

Although color vision deficiencies are very prevalent, there are no ideal methods for assessing color vision in all environments. We compared a new digital and automated method that quantifies color perception for the three protan, deutan, and tritan axes with two of the most commonly used color tests in daily practice: the Ishihara 38 plates test and the Farnsworth-Munsell 100-Hue test. One hundred patients underwent a triple examination composed of the new DIVE Color Test, the Ishihara test, and the Farnsworth-Munsell 100-Hue test. The DIVE Color Test was performed twice in forty participants to assess its repeatability. In the trichromatic group, the mean age stood at 20.57 ± 9.22 years compared with 25.99 ± 15.86 years in the dyschromatic group. The DIVE and Ishihara tests exhibited excellent agreement in identifying participants with color deficiency (Cohen's kappa = 1.00), while it was 0.81 when comparing DIVE and Farnsworth. The correlation between the global perception values of Farnsworth (TES) and DIVE (GCS) was 0.80. The repeatability of the DIVE Color Test was high according to Bland-Altman analysis with an intraclass correlation coefficient of 0.83. According to Ishihara, the DIVE Color Test proved to be an effective and reproducible tool for red-green color vision deficiency detection, capable of determining the severity of the defect in each of the three axes faster and more accurately than both Ishihara and Farnsworth.

Background: We aimed to measure and correlate inner retinal layer (IRL) thickness and macular sensitivity by optical coherence tomography (OCT) and by microperimetry, respectively, in type 1 diabetes mellitus patients (DM1) without diabetic retinopathy (DR). Methods: Fifty-one DM1 patients and 81 age-matched healthy subjects underwent measurement of the axial length (AL), retinal thickness in the macular ETDRS areas by swept source (SS)-OCT and macular sensitivity by microperimeter. Results: The total retinal and IRL thicknesses were thicker in the DM1 group (p < 0.05) in practically all ETDRS areas, and they had a generalized decrease in sensitivity (p < 0.05) in 9 areas between both groups. There was a significant negative correlation between retinal sensitivity and age in all areas and in visual acuity (VA) in 5 out of the 9 areas for DM1 patients. Only a mild negative correlation was observed between retinal sensitivity in the 5° nasal inner (5NI) area and in IRL thickness in the temporal inner (TI) area (−0.309 with p = 0.029) in the DM1 group. Conclusion: Aging and disease evolution in DM1 patients without DR signs generate a decrease in retinal sensitivity. There was a direct relationship between retinal sensitivity and macular thickness in the DM1 group.

In this study, our goal was to deepen the understanding of the clinical significance and underlying pathogenic mechanisms of the hyperreflective ganglion cell layer (HGB) observed in optical coherence tomography (OCT) scans of patients with retinitis pigmentosa (RP). The study was designed as observational, cross-sectional. RP patients with and without HGB were recruited and underwent complete multimodal retinal imaging assessment, including OCT, OCT angiography (OCTA) and Dense Automatic-RealTime (DART) OCTA. Morphological outcome measures included OCTA vessel density (VD), foveal avascular zone area and ellipsoid zone (EZ) width. Functional outcome measures were LogMAR best-corrected visual acuity (BCVA) and retinal sensitivity. Twenty eyes with HGB (20 RP patients) and 20 eyes without HGB (20 RP patients) were included. A reference control group was included as well. RP eyes with HGB were characterized by significantly worse LogMAR BCVA and retinal sensitivity, compared with RP eyes without HGB. Moreover, HGB subgroup showed significantly worse VD values of intraretinal capillary networks. The main superficial capillary plexus (SCP) VD reduction was detected in the extrafoveal region. DART OCTA allowed to support the SCP perivascular gliosis pathogenic origin of HGB. DART OCTA was able to detect (I) SCP perivascular hyperreflectivity; (II) SCP perfusion signal reduction and (III) peripheral SCP capillaries closure. The presence of HGB is identified as an adverse finding in a subset of eyes affected by RP. HGB correlates with markedly deteriorated retinal morphology and function. The possible pathogenic mechanism underlying HGB manifestation is the perivascular gliosis of the SCP.

Macular oedema is a common complication and vision-limiting factor in uveitis. The aim of this study was to compare retinal thickness as measured by optical coherence tomography and photoreceptor function as measured by fundus-related microperimetry with respect to their correlation with visual acuity. Prospective observational monocentre study. Thirty-one patients (53 eyes) with endogenous uveitis and fluorescein angiographically confirmed macular oedema were evaluated. Foveal thickness was analysed using spectral-domain (Spectralis(TM) ; Heidelberg Engineering, Heidelberg, Germany) OCT and retinal sensitivity was assessed using fundus-related microperimetry (MP1; Nidek Technologies, Padova, Italy). All findings were correlated with best-corrected visual acuity (BCVA). Foveal thickness was correlated with BCVA [p = 0.005, r = 0.38, 95% confidence interval (CI) 0.12-0.59]. For microperimetry measurements, a negative correlation with logMAR visual acuity was found. Fixation abnormalities were not associated with poor visual acuity, increased foveal thickness or retinal sensitivity. In eyes with cystoid changes in the outer plexiform and inner nuclear layer, foveal thickness was increased (p < 0.0001). Epiretinal membrane formation was present in 70%. In these eyes, foveal thickness was significantly increased (p = 0.003) and visual acuity was worse (p = 0.08). Foveal thickness and fundus-related microperimetry were correlated with visual acuity. Cystoid changes in the outer plexiform and inner nuclear layer and the presence of epiretinal membrane were associated with poor visual acuity. Fixation abnormalities were not associated with poor visual acuity.

Color vision deficiency (CVD) affects more than 4% of the population and leads to a different visual perception of colors. Though this has been known for decades, colormaps with many colors across the visual spectra are often used to represent data, leading to the potential for misinterpretation or difficulty with interpretation by someone with this deficiency. Until the creation of the module presented here, there were no colormaps mathematically optimized for CVD using modern color appearance models. While there have been some attempts to make aesthetically pleasing or subjectively tolerable colormaps for those with CVD, our goal was to make optimized colormaps for the most accurate perception of scientific data by as many viewers as possible. We developed a Python module, cmaputil, to create CVD-optimized colormaps, which imports colormaps and modifies them to be perceptually uniform in CVD-safe colorspace while linearizing and maximizing the brightness range. The module is made available to the science community to enable others to easily create their own CVD-optimized colormaps. Here, we present an example CVD-optimized colormap created with this module that is optimized for viewing by those without a CVD as well as those with red-green colorblindness. This colormap, cividis, enables nearly-identical visual-data interpretation to both groups, is perceptually uniform in hue and brightness, and increases in brightness linearly.

Color vision deficiency (CVD), a common visual impairment, affects individuals' ability to differentiate between various colors due to malfunctioning or absent color photoreceptors in the retina. Currently available diagnostic tests require a behavioral response, rendering them unsuitable for individuals with limited physical and communication abilities, such as those with locked-in syndrome. This study introduces a novel, non-invasive method that employs brain signals, specifically Steady-State Visually Evoked Potentials (SSVEPs), along with Ishihara plates to diagnose CVD. This method aims to provide an alternative diagnostic tool that addresses the limitations of current tests. Electroencephalography (EEG) recordings were obtained from 16 subjects, including 5 with CVD (specifically Deuteranomaly), using channels O1, O2, Pz, and Cz. The subjects were exposed to visual stimuli at frequencies of 15 Hz and 18 Hz to assess the proposed method. The subjects focused on specific visual stimuli in response to questions related to the Ishihara plates. Their responses were analyzed to determine the presence of CVD. Feature extraction was performed using Power Spectral Density (PSD), Canonical Correlation Analysis (CCA), and a combined PSD + CCA, followed by classification to categorize subjects into two classes: normal vision and CVD. The results indicate that the proposed method effectively diagnoses CVD in individuals with limited communication abilities. The classification accuracy of SSVEP exceeded 75% across the three classifiers: Decision Tree (DT), K-Nearest Neighbors (KNN), and Support Vector Machine (SVM). The SVM classifier demonstrated higher accuracy compared to the other classifiers, exceeding 90%. These observations suggest that the SVM classifier, utilizing the combined feature set of PSD + CCA, may be the most effective in this classification task. These findings demonstrate that the proposed method is an accurate and reliable diagnostic tool for CVD, particularly for individuals unable to communicate.

PurposeAdaptive optics scanning light ophthalmoscopy (AOSLO) imaging in patients with achromatopsia (ACHM) and albinism is not always successful. Here, we tested whether optical coherence tomography (OCT) measures of foveal structure differed between patients for whom AOSLO images were either quantifiable or unquantifiable.MethodsThe study included 166 subjects (84 with ACHM; 82 with albinism) with previously acquired OCT scans, AOSLO images, and best-corrected visual acuity (BCVA, if available). Foveal OCT scans were assessed for outer retinal structure, outer nuclear layer thickness, and hypoplasia. AOSLO images were graded as quantifiable if a peak cone density could be measured and/or usable if the location of peak density could be identified and the parafoveal mosaic was quantifiable.ResultsForty-nine percent of subjects with ACHM and 57% of subjects with albinism had quantifiable AOSLO images. Older age and better BCVA were found in subjects with quantifiable AOSLO images for both ACHM (P = 0.0214 and P = 0.0276, respectively) and albinism (P = 0.0073 and P < 0.0004, respectively). There was a significant trend between ellipsoid zone appearance and ability to quantify AOSLO (P = 0.0028). In albinism, OCT metrics of cone structure did not differ between groups.ConclusionsPreviously reported AOSLO-based cone density measures in ACHM may not necessarily reflect the degree of remnant cone structure in these patients.Translational RelevanceUntil AOSLO is successful in all patients with ACHM and albinism, the possibility of the reported data from a particular cohort not being representative of the entire population remains an important issue to consider when interpreting results from AOSLO studies.

Hahn's New Pseudoisochromatic Colour Vision Test contains provision for screening red-green and blue-yellow colour vision deficiencies, a qualitative diagnosis as protan and deutan, and a quantitative diagnosis of red-green deficiencies. In this study 58 colour vision deficient and 68 colour vision normal subjects were examined using a battery of colour vision tests. The screening and classification ability of the Hahn test was compared with Ishihara's Test and the Standard Pseudoisochromatic Plates (SPP). The quantitative diagnosis ability was assessed by comparison with the Farnsworth—Munsell D-15 Test, the Farnsworth Lantern, and the Anomaloscope range. The Hahn proved to have a colour vision screening performance comparable with the two other PIC tests. Its classification ability was poor compared with the other PIC tests, one design in the SPP plates was markedly superior. The Hahn's quantitative diagnosis plates did not produce a useful classification; more than 50% of subjects made the full six errors and only 3 of 58 colour vision deficient subjects made less than 3 errors out of the 6 plates. The colorimetric measurements are used to illustrate the design features and are consistent with these performances. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 69–77 1998

Diabetic Macular Edema With and Without Subfoveal Neuroretinal Detachment: Two Different Morphologic and Functional Entities

Dysflective cones: Visual function and cone reflectivity in long-term follow-up of acute bilateral foveolitis