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RAPDx Expanded Pupil Examination

RAPDx is a computerized pupillographer that is designed to detect a relative afferent pupillary defect. This type of pupil defect is known as RAPD and can occur in several eye diseases and neurologic conditions.


The RAPDx uses visible light to stimulate pupil responses, and then calculates from these responses the magnitude of the relative afferent pupillary defect.

Are You At Risk For

  • Glaucoma
  • Retinal Disease
  • Optic Nerve Disease
  • Brain Tumor
  • Neurologic Disease

RAPDx Expanded Pupil Examination


The RAPDx test is a non-invasive, non-contact procedure.

  • Quick
    • usually takes 1-5 minutes
  • Painless
    • nothing ever touches your eye
  • Safe
    • FDA listed
  • Effective
    • more information

Relative Afferent Pupillary Defect

A relative afferent pupillary defect (RAPD) generally occurs when there is a difference in the severity of a disease process between the eyes.

  • Decreased central vision does not necessarily correlate with a relative afferent pupillary defect.
  • Decreased peripheral vision does correlate with a relative afferent papillary defect.
  • Some eye diseases will lead to a significant decrease in visual acuity with a RAPD, while other conditions present with good visual acuity.
  • A relative afferent pupillary defect can also be detected with a “swinging flashlight” test by a skilled observer.
  • If each eye has an equal amount of damage from a disease process, there will be no detectable RAPD.

Eye diseases that may lead to a RAPD

Glaucoma: Even though glaucoma usually affects both eyes, if the disease is more severe in one eye, a RAPD may be detected.

Retinal Disease: Diabetic retinopathy, arterial occlusions, sickle-cell retinopathy and retinal detachments may produce a RAPD.

Optic Nerve Disease: Disorders such as optic neuritis are a common cause of RAPD.

Brain Tumor: Lesions of the midbrain such as pineal tumors and lesions that compress the optic chiasm will often produce a RAPD.

Neurological Disease: The presence of a RAPD may help to confirm abnormalities found in other diagnostic tests, such as a visual field defect in one eye. Cerebral infarct does not usually cause a RAPD.

Reduce Your Risk

Our office now includes the RAPDx Expanded Pupil Examination when we provide comprehensive eye examinations. This state-of-the-art technology allows us to detect pupil abnormalities and prescribe a diagnostic program if eye disease or neurologic conditions are suspected.