Chiasmal Herniation (PowerPoint)

This woman was 61 years old when she underwent initial neuro-ophthalmologic evaluation. Twenty-three years earlier, she had undergone removal of a pituitary adenoma followed by radiation therapy. At that time, she had noted a preoperative visual field defect that improved somewhat after the surgery. Twenty-two years before neuro-ophthalmologic evaluation, she was found to have a mild bilateral superotemporal defect on tangent fields. Thirteen years before diagnosis, she was noted to have chronic open-angle glaucoma OU. One year before neuro-ophthalmologic evaluation, progressive visual field loss OD was noted. Upon initial neuro-ophthalmologic assessment, her best corrected acuities were 20/30 OD and 20/25 OS. Ishihara color plates were 100% correct OU. There was no relative afferent pupillary defect. Motility and corneal sensation were normal. Intraocular pressures were 16 mm Hg OD and 14 mm Hg OS. The visual fields are shown in this image. The right optic disc showed a cup:disc ratio of 0.5, with pallor at 7 o'clock. The rest of the rim was pink. The left disc had a cup:disc ratio of 0.6, breaking to the rim with a notch at 4 o'clock, with pallor temporally>superiorly. The assessment was that, although some visual field loss was due to her pituitary tumor and some to her glaucoma, another part was probably vasculopathic, a result of the chiasm descending into the sella. She has exhibited stable visual function over the ensuing 7 years.