C-wave and ERG records have been taken from patients with juvenile macular degeneration, cone dysfunction syndrome, non exudative macular degeneration and from patients who have taken hydroxychloroquine for more than a year. The study of these recordings showed that in juvenile macular degeneration the involved area might be larger than ophthalmoscopically visible. In cone dysfunction syndrome the prolonged latence implicit time can serve as a further diagnostic sign of the disease. In non exudative macular degeneration there is more extensive R.P.E. involvement than usually believed and finally in hydroxychloroquine retinopathy, the C-wave is a better criterion to monitor the disease than ERG.