Contrast Sensitivity Evaluation in a Population-Based Study in Shahroud, Iran

Hashemi, Hassan; Khabazkhoob, Mehdi; Jafarzadehpur, Ebrahim; Emamian, Mohammad Hassan; Shariati, Mohammad; Fotouhi, Akbar

doi:10.1016/j.ophtha.2011.08.030

Cited by 38 publications

(40 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Consistent with the literature (e.g., Hashemi et al, 2012;Robson, 1966), Contrast Sensitivity measured by the Sensory Station was significantly better at 6 cpd than at 18 cpd, (t(229) = 35.289, p b 0.001). It should be noted, however, that for 43% of participants, performance reached the ceiling of stimulus contrasts levels available at the 6 cpd condition (maximum value = 2.4) on the Sensory Station Contrast Sensitivity assessment.…”

Section: Contrast Sensitivity (Cs)supporting

confidence: 88%

Mapping the structure of perceptual and visual–motor abilities in healthy young adults

et al. 2015

View full text Add to dashboard Cite

The ability to quickly detect and respond to visual stimuli in the environment is critical to many human activities. While such perceptual and visual-motor skills are important in a myriad of contexts, considerable variability exists between individuals in these abilities. To better understand the sources of this variability, we assessed perceptual and visual-motor skills in a large sample of 230 healthy individuals via the Nike SPARQ Sensory Station, and compared variability in their behavioral performance to demographic, state, sleep and consumption characteristics. Dimension reduction and regression analyses indicated three underlying factors: Visual-Motor Control, Visual Sensitivity, and Eye Quickness, which accounted for roughly half of the overall population variance in performance on this battery. Inter-individual variability in Visual-Motor Control was correlated with gender and circadian patters such that performance on this factor was better for males and for those who had been awake for a longer period of time before assessment. The current findings indicate that abilities involving coordinated hand movements in response to stimuli are subject to greater individual variability, while visual sensitivity and occulomotor control are largely stable across individuals.

show abstract

Section: Contrast Sensitivity (Cs)supporting

confidence: 88%

Mapping the structure of perceptual and visual–motor abilities in healthy young adults

et al. 2015

View full text Add to dashboard Cite

show abstract

“…14 Contrast VA is a more sensitive measurement of central visual function than conventional VA. 15 However, contrast VA did not correlate with OCT findings in the current study. Both contrast VA and conventional VA measurements involve staring at the Landolt chart, in contrast to the FVA system, in which a series of charts is presented on which the optotypes must be identified within 2 s. Thus, contrast VA and FVA may reflect different aspects of visual ability.…”

Section: Discussioncontrasting

confidence: 81%

Functional Visual Acuity in Age-Related Macular Degeneration

2016

Optometry and Vision Science

View full text Add to dashboard Cite

Purpose. We evaluated whether a functional visual acuity (FVA) system can detect subtle changes in central visual acuity that reflect pathological findings associated with age-related macular degeneration (AMD). Methods. Twenty-eight patients with unilateral AMD and logMAR monocular best corrected VA better than 0 in both eyes, as measured by conventional chart examination, were analyzed between November 2012 and April 2013. After measuring conventional VA, FVA, and contrast VA with best correction, routine eye examinations including spectral domainYoptical coherence tomography were performed. Standard Schirmer test was performed, and corneal and lens densities were measured. Results. The FVA score (p G 0.001) and visual maintenance ratio (p G 0.001) measured by the FVA system, contrast VA (p G 0. 01), and conventional VA (p G 0.01) were significantly worse in the AMD-affected eyes than in the fellow eyes. No significant differences were observed in the anterior segment conditions. Forward stepwise regression analysis demonstrated that the length of interdigitation zone disruption, as visualized by optical coherence tomography imaging, correlated with the FVA score (p G 0.01) but not with any other parameters investigated. Conclusions. The FVA system detects subtle changes in best corrected VA in AMD-affected eyes and reflects interdigitation zone disruption, an anatomical change in the retina recorded by optical coherence tomography. Further studies are required to understand the value of the FVA system in detecting subtle changes in AMD. (Optom Vis Sci 2016;93:70Y76) Key Words: functional visual acuity, interdigitation zone, optical coherence tomography, age-related macular degeneration, retina R ecent progress in medical technology and science has facilitated the development of effective treatments for retinal diseases, such as molecular targeted drugs, and antiYvascular endothelial growth factor (anti-VEGF) drugs for age-related macular degeneration (AMD), as well as pars plana vitrectomy. With the improvement in prognosis, treatment is extended to patients who have better visual function at baseline. Thus, a sensitive method for detecting subtle changes in central visual acuity (VA) that reflects pathological findings of AMD and other retinal diseases is warranted. One method proposed for this purpose is the functional VA (FVA) system. The FVA system can detect subtle visual dysfunction caused by epiretinal membrane in eyes with good VA as measured by conventional Landolt C charts.1 However, whether this method is able to detect the subtle impairment of visual function caused by AMD and reflect the retinal clinical findings remains obscure.The FVA system uses a series of charts shown continuously and requires patient responses within 2 s of each chart display, which is in contrast to the conventional Landolt C chart examination, in which patients can stare at the chart before responding. Contrast VA testing involves the use of a lower-contrast Landolt C chart than conventional VA measurement, but...

show abstract

“…Acuity and contrast sensitivity reflect different aspects of visual functioning, and contrast sensitivity deficits at low spatial frequency have been reported without comparable deficits in spatial acuity measured at high contrast-for example, in humans with aging, diabetes, or glaucoma. [93][94][95] Moreover, contrast sensitivity loss without commensurate high contrast spatial acuity loss is often an early sign of optic nerve injury and ganglion cell loss. [96][97][98] This may also explain why we did not detect left eye acuity deficits in 30-40 psi blast mice, although many degenerating axons were present in the left optic nerve, especially in 40-psi mice.…”

Section: Discussionmentioning

confidence: 99%

A Novel Closed-Head Model of Mild Traumatic Brain Injury Using Focal Primary Overpressure Blast to the Cranium in Mice

Guley

Rogers

Mar

et al. 2016

Journal of Neurotrauma

View full text Add to dashboard Cite

Mild traumatic brain injury (TBI) from focal head impact is the most common form of TBI in humans. Animal models, however, typically use direct impact to the exposed dura or skull, or blast to the entire head. We present a detailed characterization of a novel overpressure blast system to create focal closed-head mild TBI in mice. A high-pressure air pulse limited to a 7.5 mm diameter area on the left side of the head overlying the forebrain is delivered to anesthetized mice. The mouse eyes and ears are shielded, and its head and body are cushioned to minimize movement. This approach creates mild TBI by a pressure wave that acts on the brain, with minimal accompanying head acceleration-deceleration. A single 20-psi blast yields no functional deficits or brain injury, while a single 25-40 psi blast yields only slight motor deficits and brain damage. By contrast, a single 50-60 psi blast produces significant visual, motor, and neuropsychiatric impairments and axonal damage and microglial activation in major fiber tracts, but no contusive brain injury. This model thus reproduces the widespread axonal injury and functional impairments characteristic of closed-head mild TBI, without the complications of systemic or ocular blast effects or head acceleration that typically occur in other blast or impact models of closed-skull mild TBI. Accordingly, our model provides a simple way to examine the biomechanics, pathophysiology, and functional deficits that result from TBI and can serve as a reliable platform for testing therapies that reduce brain pathology and deficits.

show abstract

Contrast Sensitivity Evaluation in a Population-Based Study in Shahroud, Iran

Cited by 38 publications

References 34 publications

Mapping the structure of perceptual and visual–motor abilities in healthy young adults

Mapping the structure of perceptual and visual–motor abilities in healthy young adults

Functional Visual Acuity in Age-Related Macular Degeneration

A Novel Closed-Head Model of Mild Traumatic Brain Injury Using Focal Primary Overpressure Blast to the Cranium in Mice

Contact Info

Product

Resources

About