Certified Ophthalmic Medical Technologist (COMT) Practice Exam

What is a frequent presenting complaint of patients with large pituitary adenomas?

1. Optic neuritis

2. Visual field loss

3. Color vision defects

4. Glaucoma

The correct answer is: Visual field loss

Patients with large pituitary adenomas often present with visual field loss due to the tumor's location and its effect on surrounding structures. The pituitary gland is situated at the base of the skull and is closely positioned to the optic chiasm, where the optic nerves partially cross. As a adenoma grows, it can compress the optic chiasm, leading to characteristic visual field defects such as bitemporal hemianopsia, where patients lose peripheral vision on both sides. The impact on the optic chiasm is especially pronounced in larger adenomas, which can substantially affect a patient’s visual field and cause these specific vision losses. This is why visual field loss is commonly reported as a presenting complaint in patients with significant pituitary tumors. Other options, while they can be related to various eye conditions or neurological disorders, are less directly linked to the physiological consequences of a large pituitary adenoma. For instance, optic neuritis is primarily associated with inflammation of the optic nerve, while color vision defects and glaucoma typically arise from different causes unrelated to the structural effects of a pituitary adenoma.