Visual field defects in 23 acromegalic patients

Pituitary tumors are the third most common primary intracranial neoplasm. Pathologic proliferation of the somatotrophs results as overproduction of growth hormone presenting as acromegaly. In pituitary adenomas typical visual field (VF) defect is bitemporal hemianopsia but tumor size and optic chiasmal position may cause variable VF defects and VF examination may remain normal. We retrospectively reviewed the medical records of 23 acromegalic patients with pituitary adenomas who received VF tests in the Department of Ophthalmology and Endocrinology, Ondokuz Mayis University Hospital, between 2000 and 2012. Pituitary tumor volume was calculated after performing measurements of tumor diameter in three orthogonal planes using Cavalieri’s principle. VF test was performed with a Humphrey field analyzer 750 using a 4-mm² Goldmann size III stimulus. The mean age of the 23 patients (11 male/12 female) was 50.4 ± 11.9 years. 15 patients (65.2 %) had normal VF, two patients (9 %) had quadrantanopsia, three patients (13 %) had hemianopsia and three patients (13 %) had three quadrantanopsia. Among the patients with normal VF, four patients had a suprasellar mass that was elevating the chiasm and spreading along the optic tracts. We also observed VF defects typical of a chiasmal compression even though no suprasellar extension was detected in a few cases. Tumor volume of the patients with VF defects was significantly larger than tumor volume of patients with normal VF ( p = 0.02). Tumor volume is an important parameter in VF defects. Advanced neuroimaging assesments should always be complemented in patients even with normal VF.