Contributor: Gordon K. Klintworth Retinitis pigmentosa
(pigmentary retinopathy) is a clinically and genetically
heterogeneous group of retinal degenerations that primarily
affect the rod photoreceptors. Initial symptoms include
nyctalopia during adolescence. A ring scotoma develops and
extends peripherally until only a small visual field remains
(tunnel vision, visual field constriction), which too is
eventually lost. Fundoscopic exam reveals extremely attenuated
retinal blood vessels. Eventually the electroretinogram shows no
activity. The optic disc develops a waxy yellowish pallor due to
glial proliferation. The retinal pigment epithelium atrophies
and becomes mottled gray with hyperpigmented and hypopigmented
areas. The intraretinal pigment has been likened to bone
spicules or the appearance of bone corpuscles. The
choriocapillaris eventually atrophies, exposing large vessels
and a whitish yellow choroid. Retinitis pigmentosa has many
causes and numerous types are recognized. Based on the mode of
inherita