Field Vision Test

The complete visual field, as seen by both eyes simultaneously, comprises the central, or foveal, vision, with which we see the sharpest detail, and the peripheral, or side, vision. Manual and computer-generated visual field tests can be performed to check for gaps in the peripheral vision that can indicate eye diseases such as macular degeneration and glaucoma, nervous system problems because of stroke, head injury, tumors, brain swelling, or any condition causing poor circulation to the brain.

Confrontation Test

• The confrontation test, given by a doctor or technician, involves slowly moving a finger or hand from the four outer areas of the peripheral field in each eye toward the center of the visual field, then back from the center to the outer edges. The patient is asked to focus on the nose of the person administering the test and signal as soon as the finger or hand appears in the line of vision.

Amsler Grid

• This test checks the macular vision to detect signs of macular degeneration. The patient is asked to focus on a black dot in the center of a grid and alert the doctor if the dot cannot be seen or if the grid lines look blurred or distorted and do not appear straight.

Perimetry Testing

• Computerized static perimetry testing and kinetic perimetry testing respectively utilize stationary and moving flashing lights that are seen while looking into a bowl-shaped instrument called a perimeter. The patient presses a button each time a light flash is seen, and a printout generated after the test indicates a loss of vision in areas where lights were not seen.

Tangent Screen Test

• In this test, which uses a screen that resembles a bulls-eye, different-size objects at the tip of a wand are moved across the screen from the outer edge to the center, with the patient signaling as soon as an object is seen. The point at which each object enters the patient's field of vision is marked on the screen, and each point is then connected to form an outline of the patient's visual field.

Frequency Doubling Analysis

• Using a shimmering grid of light to check areas of the peripheral and central visual fields, this test provides a more useful method than static perimetry testing or kinetic perimetry testing for diagnosing early glaucoma or optic nerve damage.