Visual field defects in patients with pituitary adenomas

Area of Science:

• Neurosurgery
• Ophthalmology
• Radiology

Background:

• Pituitary adenomas commonly cause visual impairments, notably bitemporal hemianopsia due to suprasellar extension.
• Optic chiasm compression is the primary mechanism for visual field defects in these cases.

Purpose of the Study:

• To investigate the relationship between visual field defects and optic chiasm compression in patients with pituitary adenomas.
• To evaluate the correlation between imaging-measured chiasm compression and visual field impairment.

Main Methods:

• Retrospective review of 70 pituitary adenoma patients' medical records and radiological films (1994-1996).
• Comparison of visual field scores with chiasm compression levels measured via computed tomography (CT) and magnetic resonance (MR) imaging (sagittal and coronal).
• Evaluation of correlations between visual field defects and pathological diagnosis or prior surgical history.

Main Results:

• Significant linear correlation found between visual field defect severity and chiasm compression, regardless of imaging modality (CT: r=0.764, sagittal MR: r=0.688, coronal MR: r=0.717).
• Visual field defects predominantly occurred when chiasm compression surpassed a specific threshold.
• Non-functional pituitary adenomas and a history of prior surgery were associated with more severe visual field defects.

Conclusions:

• A direct linear relationship exists between visual field defects and optic chiasm compression, measurable by CT and MR imaging.
• Visual field impairment typically manifests when chiasm compression exceeds a critical level.
• Patients with non-functional pituitary adenomas or previous operations experience more pronounced visual field deficits.