Geoff P. Sampson

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AIMS To investigate the relationship between retinal nerve fibre layer thickness and peripheral neuropathy in patients with Type 2 diabetes, particularly in those who are at higher risk of foot ulceration. METHODS Global and sectoral retinal nerve fibre layer thicknesses were measured at 3.45 mm diameter around the optic nerve head using optical coherence(More)
We have compared visual search under conditions that tend to isolate the magnocellular, parvocellular and koniocellular channels of the human visual system. We used isoluminant red–green stimuli that do not modulate short-wavelength sensitive (SWS) cones to isolate the parvocellular pathway, isoluminant SWS-cone isolating stimuli to stimulate only the(More)
To develop a rapid optimized technique of wide-field imaging of the human corneal subbasal nerve plexus. A dynamic fixation target was developed and, coupled with semiautomated tiling software, a rapid method of capturing and montaging multiple corneal confocal microscopy images was created. To illustrate the utility of this technique, wide-field maps of(More)
AIMS Corneal nerve morphology and corneal sensation threshold have recently been explored as potential surrogate markers for the evaluation of diabetic neuropathy. We present the baseline findings of the 'Longitudinal Assessment of Neuropathy in type 1 Diabetes using novel ophthalmic Markers'(LANDMark) study. METHODS The LANDMark study is a 4-year,(More)
Impaired central vision has been shown to predict diabetic peripheral neuropathy (DPN). Several studies have demonstrated diffuse retinal neurodegenerative changes in diabetic patients prior to retinopathy development, raising the prospect that non-central vision may also be compromised by primary neural damage. We hypothesise that type 2 diabetic patients(More)
PURPOSE To explore the effects of glaucoma and aging on low-spatial-frequency contrast sensitivity by using tests designed to assess performance of either the magnocellular (M) or parvocellular (P) visual pathways. METHODS Contrast sensitivity was measured for spatial frequencies of 0.25 to 2 cyc/deg by using a published steady- and pulsed-pedestal(More)
PURPOSE To analyze the repeatability of measuring nerve fiber length (NFL) from images of the human corneal subbasal nerve plexus using semiautomated software. METHODS Images were captured from the corneas of 50 subjects with type 2 diabetes mellitus who showed varying severity of neuropathy, using the Heidelberg Retina Tomograph 3 with Rostock Corneal(More)
PURPOSE Arbitrary numbers of corneal confocal microscopy images have been used for analysis of corneal subbasal nerve parameters under the implicit assumption that these are a representative sample of the central corneal nerve plexus. The purpose of this study is to present a technique for quantifying the number of random central corneal images required to(More)
PURPOSE To introduce techniques for deriving a map that relates visual field locations to optic nerve head (ONH) sectors and to use the techniques to derive a map relating Medmont perimetric data to data from the Heidelberg Retinal Tomograph. METHODS Spearman correlation coefficients were calculated relating each visual field location (Medmont M700) to(More)
Some people who experience migraine demonstrate reduced visual contrast sensitivity that is measurable between migraines. Contrast sensitivity loss to low spatial frequency gratings has been previously attributed to possible impairment of magnocellular pathway function. This study measured contrast sensitivity using low spatial frequency targets (0.25-4(More)