Losses of hemifield contrast sensitivity in patients with pituitary adenoma and normal visual acuity and visual field.

OBJECTIVE

To detect early losses of contrast sensitivity (CS) in patients with pituitary adenomas, before the occurrence of visual acuity and visual field defects.

METHODS

CS has been evaluated in both hemifields of 28 patients with different kinds of pituitary adenoma (mainly intrasellar) and normal visual acuity and visual field, as well as in 15 age-matched controls. Two different stimuli were used: a coarse (0.3 c/deg) dynamic (10 Hz) grating and a finer (2 c/deg) static grating.

RESULTS

On average, CS and/or hemifield asymmetry were reduced in patients, whereas perimetric sensitivity was normal. CS losses were more frequent for 2 c/deg static-, as compared with 0.3 c/deg, 10 Hz stimuli. However selective losses for either stimuli were also found. CS losses did not correlate with anatomical measurements (size, chiasm involvement) of tumors as established by MRI scans.

CONCLUSIONS

CS evaluation may provide a simple and effective tool for early detection and monitoring of visual dysfunction in patients with pituitary adenoma. The lack of correlation between CS losses and chiasm involvement suggests causes different from chiasmal compression for visual dysfunction.