Occurrence:
(1) usually sporadic, occasionally familial
(2) more common in females and in Whites
Clinical features:
(1) There is a conical excavation of the posterior fundus and optic disc which is usually unilateral. Occasionally the nerve head is elevated.
(2) The excavation is filled with glial tissue.
(3) There is usually a reduction in visual acuity.
(4) Retinal blood vessels are increased in number and size, and they tend to run a straight course.
(5) The anomaly may be associated with a transphenoidal encephalocele (see below).
(6) The retina around the optic disc may show dysplasia and pigment clumping.
(7) Complications include rhegmatogenous retinal detachment and subretinal neovascularization.
Features of a patient with a transphenoidal encephalocele:
(1) hypopituitarism, including dwarfism
(2) broad head with hypertelorism
(3) flattened nasal bridge
(4) nasal obstruction, in which case it may be misdiagnosed as a nasal polyp (a nasal polypectomy may be catastrophic for the patient)
(5) cleft palate or lip
