Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which visual field defect is specifically described as an arcuate bundle defect?

1. A loss of vision in the nasal field

2. A loss of vision in the very center of the visual field

3. A loss of vision in the peripheral field

4. A loss of vision in the temporal field

The correct answer is: A loss of vision in the nasal field

The correct choice refers to a visual field defect known as an arcuate bundle defect, which is characterized by specific patterns of vision loss that typically follow an arcuate or curving trajectory. This defect often represents damage along the optic nerve or the visual pathways, particularly impacting the retinal nerve fiber layer that corresponds to the arcuate fibers in the temporal retina. This type of defect commonly occurs in conditions affecting the optic nerve, such as glaucoma or damage caused by visual pathway lesions. The arcuate scotoma generally manifests as a loss in the visual field that is not uniform but instead creates a distinctive arching pattern, predominantly affecting the nasal field of vision. People experiencing this condition may notice that objects in their nasal visual field become less visible or are completely obscured, while other areas remain intact. In contrast, other options describe different types of visual field defects that do not align with the characteristics of an arcuate bundle defect. For instance, loss of vision in the very center of the visual field is more indicative of macular degeneration, while peripheral field loss may be associated with a variety of conditions including retinitis pigmentosa. Temporal field loss can occur due to issues with the optic nerve or chiasm but is not specifically labeled as an arcuate bundle