April 12, 2019 Conference
Functional deficits in glaucoma can be assessed by visual field testing using either automated static perimetry, or less commonly kinetic Goldmann perimetry performed by a skilled perimetrist, or highly specialized electrophysiological techniques, such as the recording of retinal ganglion cell (RGC) response with the pattern reversal electroretinogram (PERG) and the photopic negative response (PhNR). Clinicians most commonly employ automated static perimetry to look for characteristic functional defects and then repeat these tests to assess for progression. However, visual field defects in glaucoma may not show up on automated field tests until 25% to 35% of the RGCs have been lost. Electrophysiological methods provide objective measures of retinal ganglion cell function that are more sensitive to glaucomatous damage making them ideal for earlier diagnosis and monitoring. However, these highly specialized clinical tests are less readily available and saturate early in the disease, making them less useful for monitoring advanced glaucoma.