Early Detection & Diagnosis

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Blue-Yellow Visual Field Testing
Without prompt treatment, glaucoma can cause loss of vision due to damage to the optic nerve. One way to measure the amount of damage to the nerve is to measure the amount of peripheral or side vision that has been lost. Glaucoma does not affect your central reading vision until the late stages of the disease. At this late stage, a glaucoma victim may already be partially blind. Therefore, it is important to measure the peripheral vision in the early stages of the disease, so that proper treatment can be given to prevent blindness. This is accomplished with visual field testing (• See Photos), which is an examination that measures the amount of vision lost.

Research has shown us that before damage shows up on standard types of visual field tests, which use white lights of varying intensities, a person may have already lost 50% of nerve tissue inside the eye. Ideally, damage to the nerve should be detected as early as possible, so that maximum visual function is preserved.

Blue-yellow visual field testing is a recent development that allows us to detect damage to the visual field up to five years earlier than possible with standard white visual field testing. Blue-yellow visual field testing is also called short-wavelength testing, SWAP, or color visual field testing. This type of testing is most helpful in two situations. The first situation when blue-yellow testing is helpful is when the diagnosis of glaucoma is suspected, but not yet proven. Since this test shows damage earlier than other types of visual field testing, it may help make an early diagnosis of glaucoma, so that treatment can be initiated to prevent further loss of vision. The second situation when blue-yellow testing is helpful is when a person has early glaucoma with only minor loss of peripheral vision. Blue-yellow testing may help determine if visual loss is stable or progressive. This will help the doctor decide if more aggressive treatment is necessary.

The examples below show how blue-yellow testing detected more damage to a person’s vision than standard white visual field testing (• See Photo).

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