Towards objective assessment of the inner retinal functions

Retinal anatomic structure and physiology function are very complex.Electroretinogram (ERG) is currently the only objective assessment for retinal function.There are groups of devastating diseases characterized by affecting the inner retinal functions.However, compared with its advantages in evaluating the outer retina function, ERG is less sensitive in judging the inner retinal function.The decrease of sensitivity is mainly associated with the crosstalk between the rod and cone systems in the longer visual signal pathways.In the past twenty years, new recording techniques in ERG analysis including oscillatory potentials, ON-OFF responses, photopic negative responses and scotopic threshold response have been developed.These ERG components are generated from the bipolar cells, amacrine cells or retinal ganglion cells and are becoming novel tools to assess the function of the inner retina.Ophthalmologists should fully understand the clinical significance of these ERG components in assessing inner retinal function to better guide the diagnosis and treatment of retinal diseases.