SUMMARY
We have studied the contrast sensitivity, using the Arden grating test, in 37 eyes with visual field defects and acuity better than or equal to 20/30, of 25 patients with a diagnosis of pituitary adenoma. In 24 eyes there was active compression of the visual pathways and in the others the visual field defect was the result of previous compression (sequel). Contrast sensitivity was reduced in 87,5% of eyes with active compression and in 30,76% of the other eyes. Statistical analysis showed that the two groups were different. This test is sensitive to detect patients with active compression of the visual pathways and can help in the differentiation of these patients and those with field defects but without compression.