Category Archives: Invest Ophthalmol Vis Sci

Visual Performance as a Function of Luminance in Glaucoma: The De Vries-Rose, Weber’s, and Ferry-Porter’s Law.

Invest Ophthalmol Vis Sci. 2018 Jul 02;59(8):3416-3423

Authors: Bierings RAJM, de Boer MH, Jansonius NM

Abstract
Purpose: To determine whether the De Vries-Rose, Weber’s, and Ferry-Porter’s law, which describe visual performance as a function of luminance, also hold in patients with glaucoma.
Methods: A case-control study with 19 glaucoma patients and 45 controls, all with normal visual acuity. We measured foveal and peripheral contrast sensitivity (CS) using static perimetry and foveal and peripheral critical fusion frequency (CFF; stimulus diameter 1°) as a function of luminance (0.02 to 200 cd/m2). ANOVA was used to analyze the effect of glaucoma and luminance on CS and CFF; analyses were adjusted for age and sex.
Results: Foveally, logCS was proportional to log luminance at lower luminances (de Vries-Rose) and saturated at higher luminances (Weber); glaucoma patients had a 0.4 log unit lower logCS than controls (P < 0.001), independent of luminance. Peripherally, the difference was more pronounced at lower luminances (P = 0.007). CFF was linearly related to log luminance (Ferry-Porter). Glaucoma patients had a lower CFF compared with controls (P < 0.001), with a smaller slope of the CFF versus log luminance curve, for both the fovea (6.8 vs. 8.7 Hz/log unit; P < 0.001) and the periphery (2.5 vs. 3.4 Hz/log unit; P = 0.012).
Conclusions: Even in apparently intact areas of the visual field, visual performance is worse in glaucoma patients than in healthy subjects for a wide range of luminances, without a clear luminance dependency that is consistent across the various experiments. This indicates impaired signal processing downstream in the retina and beyond, rather than an impaired light adaptation in the strictest sense.

PMID: 30025071 [PubMed – in process]

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Substrate Elastic Modulus Regulates the Morphology, Focal Adhesions, and α-Smooth Muscle Actin Expression of Retinal Müller Cells.

Invest Ophthalmol Vis Sci. 2015 Sep 1;56(10):5974-82

Authors: Bu SC, Kuijer R, van der Worp RJ, van Putten SM, Wouters O, Li XR, Hooymans JM, Los LI

Abstract
PURPOSE: The stiffness of the extracellular matrix has been shown to regulate cell adhesion, migration, and transdifferentiation in fibrotic processes. Retinal Müller cells have been shown to be mechanosensitive; they are involved in fibrotic vitreoretinal diseases. Since fibrosis increases the rigidity of the extracellular matrix, our aim was to develop an in vitro model for studying Müller cell morphology and differentiation state in relation to matrix stiffness.
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PMID: 26377083 [PubMed – in process]

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