Electrophysiological evaluation of retinal ganglion cells in glaucoma

    Glaucoma is characterized by an apoptotic retinal ganglion cell (RGC) death, whereas bipolar cells and photoreceptors remain nearly normal. The death of RGC during the progression of glaucoma results in visual field defects.

    Visual field testing is commonly used to evaluate visual function in patients with glaucoma. However, visual field test is subjective test, thus its result is not always correct. In addition, visual field test is not sufficient to detect nerve dysfunction in early stage glaucoma.

    Electroretinogram (ERG) can measures the electrical responses of various cell types in the retina, including the ganglion cells objectively.

    Multifocal ERGs (mfERGs) can be recorded from many focal retinal areas during a single recording session. There have been several studies that examined the relationship between the mfERGs and different morphological parameters. However, the relationships between the mfERGs and the visual fields and retinal nerve fiber layer thicknesses have not been determined.

    Recently we reported about the correlation between N2 amplitude of mfERGs and visual field and RNFL thickness in glaucoma patients. Our results demonstrated that the N2 amplitudes of the mfERGs within a radius of 20°from the fovea were significantly correlated with both the retinal sensitivity and RNFL thickness.