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

Abstract

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

Altered Spontaneous Brain Activity in Primary Open Angle Glaucoma: A Resting-State Functional Magnetic Resonance Imaging Study

“…Obviously, the most affected area of functional connectivity was located in the ventral pathway in Dai’s study; the dorsal pathway changed little. However, clinical features indicate injury to both visual pathways [27]. This contradiction arises from the method by which functional connectivity is measured.…”

Evaluation of Acquired Color Vision Deficiency in Glaucoma Using the Rabin Cone Contrast Test

“…In addition, the current study shows statistically significant correlations between L CCTs and M CCTs (r ¼ 0.42, P < 0.05) and M CCTs and S CCTs (r¼ 0.48, P < 0.05) in eyes affected by glaucoma. Using the Color Assessment Test by Birch et al, 16 Rauscher et al 23 found that redgreen loss is almost as common as blue-yellow loss in glaucoma patients. Our current results also imply a correlation between red-green and blue-yellow loss in glaucoma patients.…”

Color vision changes in normal aging

“…The most obvious is the greater reduction in the contribution short-wavelength light makes to retinal illuminance with increasing age and hence the more rapid increase in YB thresholds above 40 years of age. If the loss of RGC axons during the life span accounts for much of the increase in RG and YB thresholds observed in normal aging, accelerated loss of RGC axons and cell bodies as documented in glaucoma (Marvasti, Tatham, Zangwill, Girkin, Liebmann, Weinreb, and Medeiros, 2013]) may be directly linked to the corresponding increase in color thresholds that has also been shown to depend on retinal topography (Rauscher et al, 2013). Further work is needed to establish whether the severity of localized RG and YB color loss in glaucoma can be used to estimate directly the percentage of ganglion cells lost or the rate of progression in glaucoma.…”