Short-term inter-visit variability of erg amplitudes in normal subjects and patients with retinitis pigmentosa.

Purpose: To evaluate the short-term test/retest variability in visually normal subjects and patients with retinitis pigmentosa (RP), and to assess the effect of stimulus intensity and baseline amplitude on electroretinogram (ERG) variability.

Methods: Eighteen patients with RP and nine visually normal subjects had a series of three unilateral ERGs, with an inter-visit interval of no less than 2 days and no more than 2 weeks. Responses to dark-adapted and both light-adapted single flash and 32 Hz flicker stimuli were recorded from a dilated eye over a range of stimulus intensities.

Night blindness and abnormal cone electroretinogram ON responses in patients with mutations in the GRM6 gene encoding mGluR6.

We report three unrelated patients with mutations in the GRM6 gene that normally encodes the glutamate receptor mGluR6. This neurotransmitter receptor has been shown previously to be present only in the synapses of the ON bipolar cell dendrites, and it mediates synaptic transmission from rod and cone photoreceptors to this type of second-order neuron. Despite the synaptic defect, best visual acuities were normal or only moderately reduced (20/15 to 20/40).

Dark adaptation of rod photoreceptors in normal subjects, and in patients with Stargardt disease and an ABCA4 mutation.

Purpose: Psychophysical and electroretinographic (ERG) studies indicate that patients with Stargardt disease exhibit abnormally slow rod dark adaptation after illumination that bleaches a substantial fraction of rhodopsin. However, relatively little information is available concerning rod recovery in this disease after weaker adapting (i.e.

Novel mutations in the cellular retinaldehyde-binding protein gene (RLBP1) associated with retinitis punctata albescens: evidence of interfamilial genetic heterogeneity and fundus changes in heterozygotes.

Objective: To evaluate the molecular genetic defects associated with retinitis punctata albescens (RPA) in 5 patients from 3 families with this disease.

Methods: We examined 3 probands and 2 clinically affected relatives with RPA. Clinical examinations included best-corrected visual acuity, visual field testing, electroretinography, dilated fundus examination, and fundus photography.

ABCA4 gene sequence variations in patients with autosomal recessive cone-rod dystrophy.

Objective: To identify sequence variations in the ABCA4 gene in a cohort of patients with autosomal recessive cone-rod dystrophy.

Methods: The coding sequences of the ABCA4 gene were analyzed in 30 unrelated probands. In those patients with plausible disease-causing variations, correlations were made between genotype and fundus phenotype as well as with electrophysiological and visual field findings.