The EOG measures the electrical difference that exists between the cornea and the retina; this is the resting or standard potential of the eye. ISCEV standards for electro-oculography recommend that EOG's be recorded with pupil dilation, under light-adapted and dark-adapted states. The Arden ratio in young children (2-3 years) is comparable to that recorded in adults.
EOGs are most appropriate when diseases that affect the retinal pigment epithelium may be present. The only disease that is consistently associated with abnormal EOGs, however, is Best (vitelliform) macular dystrophy. Best disease is an autosomal-dominant macular degeneration that may be congenital or may have an onset of up to 7 years of age.