Methods: OPs were recorded from a comeal lens, after Ganzfeld stimulation. The analog recording bandwidth was set to IO@1Khz. OPs were acquired following three difrerent protocols: 1) immediately after an abmot change in background illumination, 2) followina various time of preahaptation and 3) duhng the adaptation period. Purpose: The Visual Evoked Potential (VEP) crossed asymmetry revealed in...

Purpose. To describe the characteristics of rod and cone functions in rat models for congenital stationary night blindness (CSNB) and retinal cone dysfunction (RCD). Methods. Rod and cone function were isolated by recording the rod-/cone-driven flicker and blue light flicker electroretinograms (ERGs). Results. During dark adaptation, the amplitudes of flicker ERGs in CSNB rats were lower than t...

The highly specialized metabotropic glutamate receptor type 6 (mGluR6) is postsynaptically localized and expressed only in the dendrites of ON bipolar cells. Upon activation of mGluR6 by glutamate released from photoreceptors, a nonselective cation channel is inhibited, causing these cells to hyperpolarize. Mutations in this gene have been implicated in the development of congenital stationary ...

An appreciation of the relation between laboratory measures of visual deficit and everyday perceptual experience is fundamental to understanding the impact of a visual condition on patients and so to a fuller characterization of the disorder. This study aims to understand better the interpretative processes by which modified sensory information is perceived by a patient with congenital stationa...

Using adaptive optics imaging tools to image the living retina, numerous investigators have reported temporal fluctuation in the reflectivity of individual cone photoreceptors. In addition, there is cone-to-cone (spatial) variation in reflectivity. As it has only recently become possible to image the complete rod photoreceptor mosaic in the living human retina, we sought to characterize the ref...

PURPOSE To study the slow and fast rod signals of the scotopic 15-Hz flicker ERG in patients carrying mutations in the NYX gene, which has been recently identified as the cause of the complete form of congenital stationary night blindness, CSNB1. METHODS Twenty eyes of 11 patients with CSNB1 who had nondetectable standard ERG rod b-waves were involved in the study. Scotopic ERG response ampli...

The aim of this study was to identify mutations in the TRPM1, GRM6, NYX and CACNA1F genes in patients with congenital stationary night blindness (CSNB). Twenty-four unrelated patients with CSNB were ascertained. Sanger sequencing was used to analyze the coding exons and adjacent intronic regions of TRPM1, GRM6, NYX and CACNA1F. Six mutations were ...

Retinal bipolar cells are essential to the transmission of light information. Although bipolar cell dysfunction can result in blindness, little is known about the factors required for bipolar cell development and functional maturation. The basic helix-loop-helix (bHLH) transcription factor Bhlhb4 was found to be expressed in rod bipolar cells (RB). Electroretinograms (ERGs) in the adult Bhlhb4 ...

Sir,?In your August number, I have just read Dr. J. M. Richardson's letter regarding night-blindness and its speedy cure under treatment with liver. Obviously, there are cases of functional night-blindness in which there are no ophthalmic changes and which are the result merely of defective nutrition, anaemia, ill-health, etc. The rapid improvement under liver treatment is not, therefore, surpr...

and Nyctalopia as different clinical entities. Under ' Hemeraiopia ' (night blindness) he says ' The patients state that they see normally well during the day but during the evening must be led along in less well illuminated streets, etc.'. Under ' Nyctalopia' he _ says ' The symptom opposed to that of hemeraiopia is nyctalopia, i.e. that condition in which during the evening (in reduced illumi...