In glaucoma assessment, what does a hemifield refer to?

• A. A half of the visual field (either left or right) affected by defects
• B. A quarter of the retina
• C. The entire visual field
• D. The central 5 degrees only

Answer: (A)

A hemifield is half of the visual field. In glaucoma assessment, we describe defects that affect one half of what you can see—either the left half or the right half (and sometimes the upper or lower half, depending on how the field is divided). This reflects how glaucoma-related damage to retinal nerve fiber bundles shows up as loss in one half of the field, not the entire field or a small central area.

The other ideas don’t fit: a quarter of the retina would be a quadrant, not a hemifield; the entire visual field would be a global loss with no half-field designation; the central 5 degrees refers to a very small portion of vision, not half of the field.