Lawrence E. Leguire

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Utilizing a high intensity photographic flash unit, electroretinograms were recorded from normal adults under fully light adapted conditions over a 5 log unit range of stimulus luminance (-1.35 to 3.34 log cd-s/m2). At lower luminance levels b-wave amplitude increased with increased luminance until it reached a maximum (Vmax of the Naka-Ruston equation) in(More)
The negative afterimage from grating can be considered equivalent to a renal grating, the contrast of which decreases over time. The interval between the onset of the afterimage and the time at which the effective contrast of the afterimage falls below threshold defines afterimage duration. In a series of experiments with several predictions based on this(More)
Normative dark-adapted electroretinograms were recorded simultaneously with a skin electrode and corneal electrode for varying stimulus intensities. The electroretinogram b-wave amplitudes for each electrode were fitted by the Naka-Rushton equation, and the parameters Vmax, K and n were evaluated. A comparison of parameters between the two electrodes showed(More)
When acuity was used to evaluate amblyopia in children, the amblyopic eye had decreased acuity and the nonamblyopic eye had normal acuity. However when Contrast Sensitivity Functions (CSFs) were used to evaluate amblyopia, losses in the CSF were discovered in both the amblyopic and the nonamblyopic eyes. During the course of occlusion therapy, the amblyopic(More)
PURPOSE To evaluate the efficacy and tolerance of two low doses of levodopa/carbidopa (25/6.25 mg, 50/12.5 mg) and placebo (Tums) in 20 children with amblyopia between the ages of 4 and 14 years. METHODS A double-masked placebo-controlled randomized 8-hour study was performed during which subjects received one of two doses of levodopa/carbidopa or(More)
PURPOSE This study investigates interocular differences in the level and extent of cortical activation in amblyopic and normal subjects. SUBJECTS AND METHODS Blood oxygenation level dependent functional magnetic resonance imaging (FMRI) was performed at 1.5 T. A total of 5 subjects with amblyopia and 6 control subjectswere recruited. Visual stimuli(More)
To determine the threshold characteristics of optokinetic nystagmus (OKN), contrast thresholds for involuntary OKN were measured for gratings of different spatial frequency to yield an OKN-contrast sensitivity function (OKN-CSF). The OKN-CSF resembled an inverted U-shaped function with temporal-to-nasal and nasal-to-temporal movement yielding similar(More)
PURPOSE To identify the neural circuitry of idiopathic infantile nystagmus syndrome (INS), characterized by an early onset alternating series of slow and rapid eye movements that can manifest in different waveforms and genetic lines. The neural circuitry of INS is currently unknown. METHODS A novel functional magnetic resonance imaging (fMRI) method,(More)
Pattern visual-evoked response binocular summation (VERBS) was recorded in normal infants, between the ages of 1-58 months, and in similar-aged esotropic infants before and at various times after corrective surgery. The normal subjects had no significant VERBS at 1.5 months of age, developed a rapid acceleration of VERBS between 1.5-3 months, and then(More)