Enlargement of the optic disk in childhood optic nerve tumors.

Two children, a 9-year-old girl and an 8-month-old girl, were first examined because of unilateral proptosis. Both children were found to have unilateral optic nerve glioma, accompanied in the second case by neurofibromatosis. Two years after Patient 1 was first examined, the initial findings of thin vertical retinal striae and a gray opacification of the peripapillary retina had resolved. The enlarged left optic disk had an average diameter of 2 mm while that of the normal right optic disk was 1.6 mm. The disk-arteriolar ratio was R.E.:16:1 and L.E.: 20:1. Four years later, the patient's visual acuity was still 20/20 in both eyes and the only visual field abnormality was an enlarged blind spot corresponding to the enlarged left optic nerve head. Fundus photographs, orbital echography, and computed tomography showed no change in the size or location of the optic nerve glioma during the six-year follow-up period. In Case 2, the initial intraocular pressure was higher in the proptotic right eye than in the left eye (25 vs 19 mm Hg), but subsequent intraocular pressures were within normal limits and approximately equal in the two eyes. The disk-arteriolar ratio was R.E.:21:1 and L.E.: 18:1 and the cup-disk ratio was R.E.: 0.7 and L.E.: 0.3. Computed tomography disclosed an enlarged right retrobulbar optic nerve, a superior orbital fissure that was much larger on the right than on the left, and a larger cavernous sinus on the right. The right sphenoid bone was partially absent. Despite mild developmental delay, the patient's visual acuity apparently remained normal and the ophthalmologic findings did not change significantly during the 18-month follow-up period.