Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which visual field defect can commonly present as an arcuate scotoma?

1. Retinal detachment

2. Macular degeneration

3. Optic nerve head disease

4. Cataracts

The correct answer is: Optic nerve head disease

An arcuate scotoma is a specific pattern of vision loss that appears as an arc or wedge-shaped area of decreased sensitivity within the visual field. This type of visual field defect is often associated with conditions affecting the optic nerve or its pathways. Optic nerve head disease, which includes conditions like glaucoma and optic neuritis, can lead to arcuate scotomas due to damage or pressure on the nerve fibers in the optic disc area. In glaucoma, for instance, the loss of ganglion cells can create characteristic patterns of vision loss, including arcuate defects that follow the contour of the peripheral visual field, corresponding to the areas of nerve fiber damage. Similarly, other optic nerve pathologies can disrupt the normal conduction of visual signals, leading to scotomas that reflect the underlying disease process. The other conditions listed do not typically result in arcuate scotomas. Retinal detachment may cause more diffuse or irregular visual deficits depending on the area of the retina affected. Macular degeneration primarily impacts central vision, leading to a central scotoma rather than an arcuate one. Cataracts affect the clarity of vision uniformly rather than creating specific visual field defects. Thus, the relationship between optic nerve head disease and arcuate scotomas makes