Certified Ophthalmic Technician (COT) Test 2025 – 400 Free Practice Questions to Pass the Exam

Homonymous congruous visual field defects with macular sparing are typically associated with lesions in the occipital cortex, where the primary visual processing occurs. When a stroke or a lesion affects this area, it can lead to a loss of visual field in the same area for both eyes (homonymous), and the congruous nature indicates that the visual field loss is symmetrical on both sides.

Macular sparing is particularly interesting because it suggests that the central vision area is still intact despite the damage in the occipital region. This sparing occurs because of the dual blood supply to the macular region—one from the branches of the internal carotid artery and the other from the posterior cerebral artery. Therefore, an injury to the occipital cortex can cause substantial visual field loss, yet the area corresponding to the macula remains unaffected.

In contrast, the other options do not typically lead to this pattern of visual field defects. Lesions in the retina usually cause localized defects or scotomas that do not exhibit the same congruency, while damage to the optic nerve usually results in a field loss that is more unilateral or affects different areas for each eye. The frontal lobe primarily influences higher cognitive functions and does not have a direct