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A survey of 22 cases showed the broad spectrum of lesions collectively termed "chiasmal gliomas." Three computerized tomography (CT) patterns were diagnostic: a tubular thickening of the optic nerve and chiasm, a suprasellar tumor with contiguous optic nerve expansion, and a suprasellar tumor with optic tract involvement. Globular suprasellar tumors lacking these features required a histological examination for diagnosis. Tumor growth was documented by CT in only three chiasmal gliomas; all were the globular type. Failing visual function did not reflect chiasmal tumor growth, and stable vision did not exclude it. Both patients with tubular optic nerve thickening and two of three patients with unilateral optic nerve expansion had neurofibromatosis. Five tumors became smaller after irradiation. Complications of radiation therapy included calcification of lenticular nuclei and remote infarcts. In patients who underwent biopsy, the CT appearance did not differentiate juvenile pilocytic astrocytoma from anaplastic astrocytoma. Thus, CT guides the diagnosis and neurosurgical treatment of chiasmal gliomas, establishing the need for biopsy or ventricular shunting.

In 1988, William Hoyt, MD, et al described “acute idiopathic blind spot enlargement” (AIBSE) in 7 symptomatic patients who had no apparent abnormalities of the optic disc or surrounding retina. With the use of multifocal electroretinography, they showed that the scotoma was caused by occult retinal dysfunction. In 1992, J. Donald Gass, MD, described “acute zonal occult outer retinopathy” (AZOOR) in 13 patients who had sudden loss of often large zones of visual field without fundus abnormalities. Most patients developed zonal atrophy of retinal pigment epithelium and had no improvement in vision. Gass believed that AZOOR, multiple evanescent white dot syndrome, multifocal choroiditis, and AIBSE were all variants of the same disorder. Despite over 3 decades of numerous reports, the classification of these entities, their pathogenesis, and treatment remain controversial. AIBSE and AZOOR may be mistaken for an acute optic neuropathy, so it behooves the neuro-ophthalmologist to be familiar with these disorders. This review describes the initial recognition of AIBSE and its relationship to AZOOR.

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