What difference will I see during a field exam if I have loss due to saggy eyelids verses glaucoma?
If you have visual field loss due to low eyelids, the field loss will be limited to the upper hamisphere of your visual fields.
Visual field exam for droopy eyelids vs. glaucoma
When testing visual fields for eyelid surgery, the lids are tested in their natural position, then taped or held up where they will rest after surgery. You should notice that the lights or white dots presented are seen higher up once the eyelid is elevated. In glaucoma, the eyelids don't affect the visual field, per se, and the defects which appear in advance glaucoma look very different than those in patients with droopy eyelids.