Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which of the following conditions can lead to a nasal step in visual field testing?

1. Compressive optic neuropathy

2. Retinal detachment

3. Diabetic retinopathy

4. Cataract formation

The correct answer is: Compressive optic neuropathy

A nasal step in visual field testing is typically associated with compressive optic neuropathy. This condition arises when there is pressure on the optic nerve, which can lead to specific patterns of visual field loss. A nasal step refers to a situation where the border of the visual field is not smooth; instead, there is a distinct step-like change in sensitivity found in the nasal (inner) part of the visual field. Compressive optic neuropathy can occur as a result of various factors, such as tumors or swelling in the area surrounding the optic nerve, which alters the projection of visual stimuli from the retina to the brain. This disruption typically manifests as a loss of peripheral vision that can be observed in visual field testing, creating the characteristic nasal step. In contrast, conditions like retinal detachment, diabetic retinopathy, and cataract formation typically do not produce a nasal step. Retinal detachment generally presents with a more widespread loss of vision or the formation of scotomas depending on the area affected. Diabetic retinopathy may show diffuse field loss or areas of decreased sensitivity but does not create a specific nasal step. Cataracts primarily cause blurred vision and reduced overall visual acuity without directly affecting the visual field in the manner that leads to