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Vision Testing (vision + testing)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopia

HUMAN BRAIN MAPPING, Issue 2 2005
Janine D. Mendola
Abstract Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7,12 years and 18,35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia. Hum Brain Mapp 25:222,236, 2005. © 2005 Wiley-Liss, Inc. [source]

Technical Note: The effect of refractive blur on colour vision evaluated using the Cambridge Colour Test, the Ishihara Pseudoisochromatic Plates and the Farnsworth Munsell 100 Hue Test

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2007
Sri Thyagarajan
Abstract The results of a prospective study examining the effect of refractive blur on colour vision performance in normal subjects measured with three different colour vision tests are reported. The Farnsworth Munsell 100 Hue (FM100) and Cambridge Colour Test (CCT) results were significantly affected at +6 D of spherical refractive blur, whereas those from the Ishihara Pseudoisochromatic Plate (IPP) test were not. In a clinical setting, correction of refractive error up to 3 D for colour vision testing with these tests may not be required. Poor colour vision should not be attributed solely to refractive causes of poor visual acuity (Snellen equivalent: >6/36). Fastest test times were achieved using IPP, followed by CCT. [source]

2466: Blue cone nonochromacy gene mutation in Asia: phenotype variability

ACTA OPHTHALMOLOGICA, Issue 2010
P BITOUN
Purpose A far East asian family with 4 affected maternal cousin males with congenital nystagmus, low vision and dyschromatopsia was investigated for a genetic cause after informed consent. Blue cone monochromacy is a rare form of X-linked visual handicap with dyschromatopsia. Methods Family members had ophthalmologic examination including visual acuity, fundoscopy , slit lamp, biomicroscopy,colour vision testing and ERG and VEP recordings.DNA analysis of the composition of the cone ospin gene cluster was performed by PCR and PCR/RFLP as well as direct sequencing of LWS opsin gene. Results A novel nonsense Mutation in the single Long wave sensitive opsin gene was identified in all affected males and carrier females. The variability of the phenotype as well as the added role of parental myopia transmission in the phenotype will be discussed. Conclusion This is the first reported molecular diagnosis of blue cone monochromacy in the Asian population. The compound effect of dominantly inherited myopia offers insight of the effect of the added mutational load in these patients. [source]

Which color vision test should be used in progressive cone dystrophy?

ACTA OPHTHALMOLOGICA, Issue 2007
AAHJ THIADENS
Purpose: The early manifestation of progressive cone dystrophy (COD) can remain unrecognized due to the relatively normal macular appearance. Color vision testing can be very useful as a first diagnostic step. The many available color vision tests have different benefits and shortcomings. We aimed to identify which test would be preferred to use in a clinical setting as a first step towards diagnosis of COD. Methods: We compared patients (n=18) derived from the ophthalmogenetic unit of Erasmus Medical Center and University Medical Center Nijmegen, with various levels of cone dysfunction. Golden Standard for diagnosis of COD was a diminished photopic ERG and a relative central scotoma on Goldmann perimetry. Controls (n=33) were patients from these clinics with other diagnoses or healthy companions of COD patients. We estimated sensitivity and specificity of the Ishihara test, Lanthony Desaturated and Saturated Panel D15 test, the Hardy-Rand-Rittler (HRR) pseudo-isochromatic plates, and the Nagel anomaloscope. We analyzed sensitivity, specificity and the predictive value with receiver operating characteristic curve (ROC). Results: The HRR test had the highest sensitivity and specificity for protan and deutan axes. HRR and Ishihara had the highest predictive value. Lanthony Panel D15 test did not have an additional predictive value for severe color vision defects. The Nagel anomaloscope was not reliable due to low specificity. Its results showed high variations among both healthy and afflicted individuals. Conclusions: The HRR test was the most useful for COD. This test had the highest sensitivity in detecting early dysfunction of all three cone types, and it adequately quantifies the level of cone dysfunction in the course of the disease. [source]

Visual neurophysiological dysfunction in infants exposed to hydroxychloroquine in utero

ACTA PAEDIATRICA, Issue 9 2009
F Renault
Abstract Aim:, Hydroxychloroquine therapy during pregnancy is thought to be safe for foetuses. Normal visual function has been showed on clinical grounds in infants exposed in utero to hydroxychloroquine, but there are few visual neurophysiological data. Our study was designed to assess retina and visual pathways using electroretinogram and visual evoked potentials in a series of infants born to mothers treated by hydroxychloroquine for connective tissue diseases. Methods:, Twenty-one infants (3,7 months of age) were consecutively examined between June 2002 and May 2007. Full-field electroretinogram was recorded by contact lens electrodes and visual evoked potentials were recorded by occipital surface electrodes using flash stimulation in mesopic condition. Analysis was focused on the amplitudes and latencies of the a - and b -waves of electroretinogram and the latency of the P100 component of visual evoked potentials. Results:, Electroretinogram abnormalities were detected in six infants, associated with delayed visual evoked potentials in four of them. Conclusion:, Early electroretinogram and visual evoked potentials testing evidenced neurophysiological visual disturbances in a subset of infants born to mothers treated by hydroxychloroquine. Systematic clinical and neurophysiological vision testing during childhood is needed to detect possible consequences of antenatal exposure to hydroxychloroquine. [source]