In cases of decreased vision, 3 aspects of the patient’s history—in addition to the age of the patient—are crucial in determining the etiology:
Unilateral Versus Bilateral Involvement
Establishing the laterality of the vision loss is essential to localization of the lesion. Unilateral vision loss typically indicates a lesion anterior to the chiasm, whereas bilateral vision loss may reflect a bilateral ocular, chiasmal, or retrochiasmal lesion or a systemic process. Patients reporting vision loss should be asked whether they have checked each eye individually. A patient with a right homonymous hemianopia may mistake the temporal visual field defect as a problem with the vision of the right eye only. Binocular involvement might not be appreciated until the patient is examined.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.