OPTIC DISC DRUSEN DEFINED BY BETA-SCAN ULTRASONOGRAPHY

This study was undertaken to investigate the frequency of optic nerve drusen, as determined by ultrasonic criteria, in a nonselected general ophthalmology practice. The salient features of optic nerve drusen th at was defined in this manner were also determined in this consecutive , retrospective case series in a general ophthalmology practice that w as equipped with an ultrasound laboratory. One hundred fifty-three pat ients with optic nerve drusen were diagnosed from a total of 2,397 pat ients, with a mean follow up of 5.4 years. Ultrasound investigations w ere performed by an experienced ultrasonographically trained ophthalmo logist who was seeking minor variations from normal other than cupping in the appearance of one or both optic nerve heads. Optic nerve druse n were identified by the maintenance of a typical acoustic signal at l ow gain levels in the prelaminar optic nerve. An estimated optic nerve drusen prevalence rate of 3.7% was made in white general practice pat ients. The optic nerve drusen were bilateral in 63% and buried within the nerve head in 62%. In most patients, optic nerve drusen appeared t o enlarge slowly if at all over time. Although adults were almost alwa ys asymptomatic, transient symptoms developed in many children. Ultras onically defined optic nerve drusen were much more common in this popu lation than anticipated. The drusen commonly remain buried, even at an advanced age. Transient visual observations and migraine may be assoc iated with the condition in children.