Certified Ophthalmic Medical Technologist (COMT) Practice Exam

Which condition is indicative of a central scotoma as assessed during the Amsler grid test?

1. Inability to see all four sides of the grid

2. Presence of straight lines

3. Center spot not visible

4. Normal vision in all grid areas

The correct answer is: Center spot not visible

A central scotoma refers to a blind spot or a significant loss of vision in the center of the visual field. During the Amsler grid test, which is specifically designed to assess macular function, the presence of a central scotoma is indicated by the absence of visualization at the center of the grid. If the center spot is not visible, it suggests that the macula, which is responsible for detailed central vision, has a defect or dysfunction. When the center spot is missing, it signifies that the central region of the retina is affected, which can occur in various conditions such as age-related macular degeneration or other retinal diseases. The other options do not specifically indicate the presence of a central scotoma. For instance, inability to see all four sides of the grid can suggest peripheral vision issues but does not specifically point to a central defect. The presence of straight lines might indicate preserved integrity in retinal function, and normal vision in all grid areas suggests no scotoma at all. Each of these does not capture the essence of a central scotoma as clearly as the absence of the central spot does.