[Long-term follow-up of deterioration of the visual field in visual acuity in retinitis pigmentosa].

The first part of this presentation is devoted to the problem of determining the precise time of onset of retinitis pigmentosa (RP). For the purpose of this discussion we will stay with the definition of the beginning of RP as that date on which the decrease in dark adaptation is first noticed, rather than visual field loss, which is subject to even greater uncertainty. The cases selected demonstrate that the period between the first sign of night-blindness and a noticeable narrowing of the visual field can vary greatly. A latent period of slow progress is followed by marked decrease in visual function. In a third period the area loss proceeds linearly. The course of the disease was observed over periods of up to 16 years using the Goldmann perimeter. Several stages of visual field deterioration are presented over periods of up to 65 years. The mode of visual field loss depends on the diameter of the test objects employed.