Flash full-field electroretinography in diseases with night blindness

Introduction
The aim of this study is to present similarities and differences of electroretinograms in early stages of retinal diseases with nyctalopia.

Material and methods
Flash full-field electroretinography was done according to ISCEV standards and also with chromatic stimulations in patients with nyctalopia, who were diagnosed as various forms of congenital stationary night blindness and various types of retinitis pigmentosa, choroideremia, gyrate atrophy and also in patients with nyctalopia, because of unknown reason. ERG results were compared with normal values and with each other.

Results
In diseases with nyctalopia the function of peripheral retina is markedly abnormal and scotopic ERG is significantly reduced or even absent. In retinitis pigmentosa a-wave is small or absent especially scotopic but photopic ERG is also abnormal. Well preserved a-wave distinguished ERG of patients with stationary night blindness from the other progressive diseases of retina or choroid.

Conclusions
In patients with nyctalopia using ERG is possible to obtain which retinal elements do not work but it is only start point to following diagostic examinations, to make proper final diagnosis.