Simultaneous Comparison of Relative Damage to Chromatic Pathways in Ocular Hypertension and Glaucoma: Correlation with Clinical Measures

Castelo‐Branco, Miguel; Faria, Pedro; Forjaz, V.; Kozák, Lajos R.; Azevedo, H.

doi:10.1167/iovs.03-0815

Cited by 55 publications

(55 citation statements)

References 45 publications

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“…Far vision refractive correction was worn by participants, and tinted contact/spectacle lenses were replaced by lenses in a trial frame when necessary. The test ended after 11 reversals of each adaptive staircase, and the mean of the last 7 reversals was obtained as the threshold expressed in confusion vector length for each protan, deutan, and tritan axes in CIE 1976 u'v' color space units (32,33).…”

Section: Psychophysicsmentioning

confidence: 99%

Neuroretinal Dysfunction With Intact Blood-Retinal Barrier and Absent Vasculopathy in Type 1 Diabetes

et al. 2014

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It is unknown whether independent neural damage may occur in the pre-/absent vascular diabetic retinopathy (DR). To exclude vasculopathy, it is important to measure the integrity of the blood-retinal barrier (BRB). This cross-sectional study addressed this problem in type 1 diabetic patients with normal ocular fundus and absent breakdown of the BRB (confirmed with vitreous fluorometry). These were compared with a group with disrupted BRB (with normal fundus or initial DR) and normal controls. Multifocal electroretinography and chromatic/achromatic contrast sensitivity were measured in these 42 patients with preserved visual acuity. Amplitudes of neurophysiological responses (multifocal electroretinogram) were decreased in all eccentricity rings in both clinical groups, when compared with controls, with sensitivity >78% for a specificity level of 90%. Implicit time changes were also found in the absence of initial DR. Impaired contrast sensitivity along chromatic axes was also observed, and achromatic thresholds were also different between controls and both clinical groups. The pattern of changes in the group without baseline BRB permeability alterations, as probed by psychophysical and electrophysiological measurements, does thereby confirm independent damage mechanisms. We conclude that retinal neuronal changes can be diagnosed in type 1 diabetes, independently of the breakdown of the BRB and onset of vasculopathy.

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Section: Psychophysicsmentioning

confidence: 99%

Neuroretinal Dysfunction With Intact Blood-Retinal Barrier and Absent Vasculopathy in Type 1 Diabetes

et al. 2014

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“…Although blue on yellow perimetry (Short Wave Automated Perimetry or SWAP) can detect early stage glaucoma in some patients before visual field loss can be detected using conventional perimetry (Johnson et al 1993b, Johnson et al 1993a, this increased sensitivity is associated with decreased specificity, and an increase in false positives (Jampel et al 2011). On the other hand, findings from earlier studies of glaucomatous patients, found preferential loss of the red-green chromatic sensitivity, but mostly in advanced stages of glaucoma (Adams et al 1982, Pacheco-Cutillas et al 1999, Castelo-Branco et al 2004. Our data are supportive of this reported tendency for preferential impairment of red-green over yellow-blue chromatic loss, although we demonstrated loss in all subjects and most notably, in mild cases in locations free from visual field loss.…”

Section: Figmentioning

confidence: 99%

Assessment of novel binocular colour, motion and contrast tests in glaucoma

et al. 2013

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This is the unspecified version of the paper.This version of the publication may differ from the final published version. The effects of glaucoma on binocular visual sensitivity for detection of different stimulus attributes were investigated at the fovea and in four paracentral retinal regions. The study employed a number of visual stimuli designed to isolate the processing of different stimulus attributes. We measured absolute contrast detection thresholds and functional contrast sensitivity using Landolt ring stimuli. This psychophysical Landolt C based contrast test of detection and gap discrimination allowed us to test parafoveally at 6° from fixation as well as foveally employing interleaved testing locations. First-order motion perception was examined using moving stimuli embedded in static luminance contrast noise. Red/green (RG) and yellow/blue (YB) colour thresholds were measured with the Colour Assessment and Diagnosis (CAD) test, which utilises random dynamic luminance contrast noise (±45%) to ensure that only colour and not luminance signals are available for target detection. Subjects were normal controls (n = 65) and glaucoma patients with binocular visual field defects (n = 15), classified based on their Humphrey Field Analyzer mean deviation (MD) scores. The impairment of visual function varied depending on the stimulus attribute and location tested. There was also a progression of loss for all tests as the degree of glaucoma increased. For subjects with mild glaucoma (MD -0.01dB to -6.00dB) significantly more data points fell outside the normal age-representative range for RG colour thresholds than for any other visual test, followed by Motion thresholds. This was particularly the case for the parafoveal data compared to the foveal data. The findings suggest that a multifaceted measure of binocular visual performance, incorporating RG colour and motion testing at multiple locations, may provide a better index for comparison with QOL measures in glaucoma. Permanent repository link

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“…We have studied chromatic contrast sensitivity using three parallel, randomly interleaved staircases, corresponding to the simultaneous assessment of the three cone confusion axes, modulated in the CIE 1976 u'v' colour space [12][13][14][15] (modified Cambridge Colour Test, CRS, Rochester, UK). Refractive correction for far vision conditions was worn by participants, and tinted contact or spectacle lenses were replaced by trial lenses in a trial frame, whenever necessary.…”

Section: Evaluation Of Visual Function-psychophysics and Electrophysimentioning

confidence: 99%

Independent patterns of damage to retinocortical pathways in multiple sclerosis without a previous episode of optic neuritis

et al. 2011

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Asymptomatic visual loss is a feature of multiple sclerosis (MS) but its relative impact on distinct retinocortical pathways is still unclear. The goal of this work was to investigate patterns of subclinical visual impairment in patients with MS with and without clinically associated previous optic neuritis (ON). We have used functional methods that assess parvo-, konio- and magnocellular pathways in order to compare pathophysiological mechanisms of damage in a population of 44 subjects with MS (87 eyes), with and without a previous episode of ON. These methods included chromatic contrast sensitivity across multiple chromatic axes (Cambridge Colour Test-parvo/konio pathways), perimetric achromatic contrast sensitivity for the magno pathway [frequency doubling technique (FDT)] and pattern visual evoked potentials (VEP). These measures were correlated with field sensitivity measures obtained using conventional automated static perimetry (ASP) and were also compared with conventional clinical chromatic/achromatic contrast sensitivity chart-based measures. We have found evidence for uncorrelated damage of all retinocortical pathways only in patients with MS without ON. VEP evidence for axonal damage was found in this group supporting the emerging notion of axonal damage even in sub-clinical stages of ON/MS pathophysiology. Only in this group was significant correlation of functional measures with disease stage observed, suggesting that distinct pathophysiological milestones are present before and after ON has occurred.

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Simultaneous Comparison of Relative Damage to Chromatic Pathways in Ocular Hypertension and Glaucoma: Correlation with Clinical Measures

Abstract: This psychophysical test can detect visual dysfunction in a significant subset of patients with long-term hypertension with preserved visual fields. Macular function is damaged earlier than previously believed, in both the blue-yellow and red-green pathways.

Cited by 55 publications

References 45 publications

Neuroretinal Dysfunction With Intact Blood-Retinal Barrier and Absent Vasculopathy in Type 1 Diabetes

Neuroretinal Dysfunction With Intact Blood-Retinal Barrier and Absent Vasculopathy in Type 1 Diabetes

Assessment of novel binocular colour, motion and contrast tests in glaucoma

Independent patterns of damage to retinocortical pathways in multiple sclerosis without a previous episode of optic neuritis

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