Chiasmal Glioma

Abstract

A 23-year-old female presented with complaints of abnormal color vision and monocular nystagmus OS since childhood. Her vision with glasses correction was 6/6 in the right eye and 3/60 in the left. She could identify 15 plates in the right eye, but only 1 plate in the left eye using the Ishihara color test. Intraocular pressures and anterior segment examinations were normal. Monocular nystagmus of the left eye was noted during ophthalmoscopic examination (Video 43.1). Left optic disc pallor was observed with sheathing changes to the retinal arteries and veins (Fig. 43.1). OCT showed severely decreased peripapillary retinal nerve fiber layer (RNFL) thickness and near total loss of the ganglion cell-inner plexiform layer (GC-IPL) in the left eye (Fig. 43.2). The peripapillary RNFL was normal in the right eye, but it is important to note that associated infero-nasal loss of the GC-IPL in the right eye could be an early sign of chiasmal involvement (Fig. 43.2). Visual field examination revealed nasal and superior defects in the left eye, with right eye sparing (Fig. 43.3). MRI showed an enlarged left optic chiasm, mainly located at the anterior portion, isointense on both T1-weighted and T2-weighted images. After gadolinium injection, there was a ring enhancement noted in the left optic chiasm (Fig. 43.4). The MRI report suggested this left optic chiasm lesion to be either optic glioma or hamartoma. The patient was followed for 4 years and her condition was stable.