Schematic<unk>  waves of healthy people.<unk>  measures the electrical responses of various cell types in the retina, including the photoreceptors (rods and cones), inner retinal cells (bipolar and amacrine cells), and the ganglion cells. Electrodes are placed on the surface of the cornea (DTL silver/nylon fiber string or<unk>  Jet) or on the skin beneath the eye (Sensor Strips) to measure retinal responses. Retinal pigment epithelium (RPE) responses are measured with an EOG test with skin-contact electrodes placed near the canthi. During a recording, the patient's eyes are exposed to standardized stimuli and the resulting signal is displayed showing the time course of the signal's amplitude (voltage). Signals are very small, and typically are measured in microvolts or nanovolts. The<unk>  is composed of electrical potentials contributed by different cell types within the retina, and the stimulus conditions (flash or pattern stimulus, whether a background light is present, and the colors of the stimulus and background) can elicit stronger response from certain components. If a dim flash<unk>  is performed on a dark-adapted eye, the response is primarily from the rod system. Flash<unk> s performed on a light adapted eye will reflect the activity of the cone system. Sufficiently bright flashes will elicit<unk> s containing an a-wave (initial negative deflection) followed by a b-wave (positive deflection). The leading edge of the a-wave is produced by the photoreceptors, while the remainder of the wave is produced by a mixture of cells including photoreceptors, bipolar, amacrine, and Müller cells or Müller glia. The pattern<unk>  (PERG), evoked by an alternating checkerboard stimulus, primarily reflects activity of retinal ganglion cells.
Electroretinography
Microperimetry
Retinal birefringence scanning
Scanning laser ophthalmoscopy
Retinal vessel analysis
Ocular tonometry
Fundus photography
Pelvimetry