Patterns of visual loss associated with pituitary macroadenomas

Abstract

To describe the patterns of visual loss associated with pituitary macroadenomas compressing the anterior visual pathway. A prospective survey of 29 patients with pituitary macroadenomas who presented to the neurosurgical unit at St Vincent's Hospital, Melbourne. Selected patients had histologically verified pituitary macroadenomas, and visual defects (acuity, colour and/or field loss) consistent with anterior visual pathway compression. All patients had visual field defects detected on perimetry, and the majority were asymmetrical. Bitemporal defects were most common but field defects ranged from monocular defects to generalised constriction. Four patients (13.8%) did not report visual symptoms, and of those who had symptoms, blurred vision was the most common complaint. Ninety-six per cent of eyes had field loss, 56% had decreased colour vision, 46% had decreased acuity, 31% had optic disc pallor, and 2% had an ophthalmoplegia. Patients with visual pathway compression by pituitary macroadenomas may be asymptomatic despite having field defects. Perimetry is the most sensitive method of identifying compression, followed by colour vision, visual acuity, then the presence of optic atrophy. Automated static threshold perimetry appears to show early field defects better than manual kinetic perimetry. All patients with pituitary macroadenomas should have thorough ophthalmological examinations, including perimetry to document visual deficits secondary to compression.