Photopic and Mesopic Contrast Sensitivity Function in the Presence of Glare and the Effect of Filters in Young Healthy Adults.

Purpose: The aim of this study was to evaluate the effect of four different filters on contrast sensitivity under photopic and mesopic conditions with and without glare. Methods: A forced choice algorithm in a Bayesian psychophysical procedure was utilized to evaluate the spatial luminance contrast sensitivity. Five different spatial frequencies were evaluated: 1.5, 3, 6, 12, and 18 cycles per degree (cpd). The measurements were performed under 4 settings: photopic and mesopic luminance with glare and no glare. Two long pass filters (LED light reduction and 511nm filter) and two selective absorption filters (ML41 and emerald filter) and a no filter condition were evaluated. The measurements were performed in 9 young subjects with healthy eyes. Results: For the no filter condition, there was no difference between glare and no glare settings for the photopic contrast sensitivity measurements whereas in the mesopic setting, glare reduced the contrast sensitivity significantly at all spatial frequencies. There was no statistically significant difference between contrast sensitivity measurements obtained with different filters under both photopic conditions and the mesopic glare condition. In the mesopic no glare condition, the contrast sensitivity at 6 cpd with 511, ML41 and emerald filters was significantly reduced compared to no filter condition (p = 0.045, 0.045, and 0.071, respectively). Similarly, with these filters the area under the contrast sensitivity function in the mesopic no glare condition was also reduced. A significant positive correlation was seen between the filter light transmission and the average AULCSF in the mesopic non-glare condition. Conclusion: The contrast sensitivity measured with the filters was not significantly different than the no filter condition in photopic glare and no glare setting as well as in mesopic glare setting. In mesopic setting with no glare, filters reduced contrast sensitivity.

Retinal nerve fiber layer thickness associates with cognitive impairment and physical disability in multiple sclerosis.

BACKGROUND: Reductions of the peripapillary retinal nerve fiber layer (pRNFL) thickness has been indicated even in early-stages of multiple sclerosis (MS). The aim was to investigate the association between pRNFL thickness, measured with optical coherence tomography (OCT), and physical disability and cognitive impairment in MS. METHODS: 465 MS patients and 168 healthy controls (HCs) were included. MS subjects were divided into subgroups according to disease subtype. All subjects underwent OCT examination of all pRNFL quadrants using Canon OCT-HS100. Associations were tested using linear mixed effect models. Physical disability was assessed with the Expanded Disability Status Scale (EDSS) and cognitive function with the Symbol Digit Modalities Test (SDMT). RESULTS: The average pRNFL, inferior pRNFL and temporal pRNFL thicknesses were significantly correlated to both EDSS (-1.0 µm, p < 0.01; -1.2 µm, p < 0.05; -1.2 µm, p < 0.01) and SDMT (0.1 µm, p < 0.05; 0.2 µm, p < 0.05; 0.2 µm, p < 0.01). A significant thickness loss compared with HCs was seen in the average pRNFL and in all quadrants except for the superior quadrant of primary progressive MS. The largest reduction compared with HCs was seen in the temporal pRNFL of PPMS eyes (-15.8 µm; p < 0.001). CONCLUSION: The reduction of average pRNFL, inferior pRNFL and temporal pRNFL thickness is associated with physical and cognitive disability in MS. We suggest the use of temporal pRNFL as a more sensitive outcome as it showed the strongest association to both EDSS and SDMT.

The Temporal Retinal Nerve Fiber Layer Thickness Is the Most Important Optical Coherence Tomography Estimate in Multiple Sclerosis.

BACKGROUND: Reduced peripapillary retinal nerve fiber layer (pRNFL) and combined ganglion cell and inner plexiform layer (GCIP) thicknesses as measured by optical coherence tomography (OCT) have been observed in multiple sclerosis (MS) patients. The purpose was to determine the most associative OCT measure to level of cognitive and physical disability in MS. METHODS: Data were collected from 546 MS patients and 175 healthy controls (HCs). We compared the average pRNFL, temporal pRNFL (T-pRNFL), overall inner ganglion cell/inner plexiform layer (GCIP), and the overall ganglion cell complex (GCC) including macular RNFL and GCIP thicknesses measurements in differentiating MS subtypes from HCs. The association between OCT measures, Expanded Disability Status Scale (EDSS), and Symbol Digit Modalities Test (SDMT) were assessed using generalized estimating equations models. RESULTS: Both peripapillary and macular OCT measurements could differentiate all MS subtypes from HCs. The SDMT score was significantly associated with reduced thickness of all OCT measures, mostly in average pRNFL (0.14 µm, P = 0.001) and T-pRNFL (0.17 µm, P < 0.001). The EDSS score was significantly associated with reduced inner retinal layer thickness. The largest reduction was seen in T-pRNFL (-1.52 µm, P < 0.001) and inner GCC (-1.78 µm, P < 0.001). CONCLUSION: The T-pRNFL is highly sensitive and associated with level of both cognitive and physical disability.

Evaluation of aspects of binocular vision in children with dyslexia.

BACKGROUND: Prevalence of dyslexia is 5%-10% of the population. Opinions differ on how binocular function affects dyslexia. The aim of the present study was to evaluate the binocular function in dyslexic children and compare it with a group of age-matched control children. METHODS: The study was performed at Ängkärrskolan and at Kungsholmen elementary schools in Stockholm, Sweden. Sixty-three children with dyslexia and 60 control children between fourth and ninth grade participated. Monocular and binocular visual acuity, refractive error, best corrected visual acuity at distance and near, near point of convergence, amplitude of accommodation, stereopsis, phorias, and fusional reserves were evaluated in all of the children. RESULTS: The results show that there was no difference in the visual functions tested except for the amplitude of accommodation, which was found to be reduced both monocularly and binocularly in the dyslexic children. CONCLUSION: This study showed that only the amplitude of accommodation seems to differ in children with dyslexia as compared with the control children; however, the ability to accommodate was still good and is unlikely to hamper reading and learning ability. The results therefore support that the recent findings of binocular deficits in dyslexic children are a result of the phonological deficit of dyslexia and not an underlying cause of dyslexia.