Certified Ophthalmic Medical Technologist (COMT) Practice Exam

What type of defect would NOT typically be found in a patient with optic nerve head disease?

1. Nasal step defect

2. Arcuate bundle defect

3. Horizontal meridian alignment defect

4. Temporal wedge defect

The correct answer is: Horizontal meridian alignment defect

In the context of optic nerve head disease, it is important to understand the types of visual field defects that are commonly associated with this condition. The correct answer suggests that a horizontal meridian alignment defect is not typically seen in such patients. Optic nerve head disease primarily impacts the nerve fibers that carry visual information from the retina to the brain. The defects associated with this condition often reflect damage to specific ganglion cell layers, leading to characteristic patterns in the visual field. Nasal step defects, arcuate bundle defects, and temporal wedge defects are all consistent with the pathways affected by optic nerve head disease. Nasal step defects often occur due to loss of temporal visual field sensitivity, while arcuate defects represent damage along the path of the nerve fiber bundles in a characteristic arc. Temporal wedge defects can arise from localized loss due to optic nerve issues, affecting peripheral visual fields. In contrast, a horizontal meridian alignment defect is less characteristic in optic nerve head disease and typically denotes issues that aren’t confined to the pathways directly related to the optic nerve itself. This type of defect may arise from other conditions affecting broader visual processing or structural alterations elsewhere in the visual pathway, rather than localized damage to the optic nerve head. Therefore, this type of defect is not