 My name is Cole Swiston, a fourth year medical student at the University of Wisconsin School of Medicine and Public Health, and this is a brief video on evaluation of the red reflex in adult and pediatric patients. The objectives for this video are to understand the basic physics and physiology which result in the red reflex, to learn the purpose of red reflex testing in both pediatric and adult patients, to learn how to perform red reflex testing with the direct ophthalmoscope, to see our other video on the use of the direct ophthalmoscope for more details. Finally, become familiar with basic etiologies of an abnormal red reflex in both pediatric and adult patients. The red reflex is a reflective phenomenon seen when light passes through the pupil and is reflected back off of the retina to a viewing aperture, creating a reddish-orange glow. You may notice this commonly in pictures with flash. Red reflex testing is a valuable tool for detection of abnormalities in the normally transparent visual axis or in the retina. Loss of transparency in any of these structures can alter the red reflex, including from front to back, the tear film, cornea, aqueous humor, lens, vitreous gel, and retina. In pediatric patients, abnormalities in the red reflex can be the first clue to sight-threatening conditions that cause amblyopia or life-threatening pathologies such as retinoblastoma. Similarly, the red reflex can assist in the diagnosis of conditions causing visual loss in adults. When examining the red reflex, look first for its presence or absence, the color of the reflex, brightness, and, importantly, symmetry between eyes. In order to perform red reflex testing, position your patient so your eyes are level with theirs and dim the room lights for better visualization of the reflex. In this case, we'll leave the lights on so you can see the technique. So now we're going to position the patient so his eyes are level with mine. Take your direct ophthalmoscope, switch the on switch to the on position, and set the diopter setting to zero or to match your refractive error. Position the direct ophthalmoscope close to your dominant eye and then 12 to 18 inches away from the patient's eye. Direct the light source towards their eye and have them look towards the light. In a pediatric patient, it might be helpful to use hand motions or toys. Position yourself 12 to 18 inches away from the patient's eye and direct them to look into your light. Shine the light on each eye individually and then both eyes simultaneously to check for symmetry of the reflex. This image illustrates a normal red reflex with a reddish-orange glow. There is no dulling or whitening of the reflex, which indicates a transparent and healthy visual axis and retina. Also note the symmetry between each eye. The American Academy of Pediatrics recommends red reflex testing in all patients during the neonatal period and during all subsequent well child and routine health appointments. Any abnormalities discovered, especially leukocorea, require urgent referral to an ophthalmologist. Leukocorea is a term for whitening of the red reflex. The most common conditions causing this whitening are retinoblastoma, a serious tumor in the back of the eye, cataracts, persistent fetal vasculature, or Coates disease. Coates disease is characterized by abnormal blood vessel development in the retina and can threaten vision if left untreated. Another important aspect of red reflex testing is the evaluation for symmetry between eyes. Asymmetry would be considered an abnormal result and is generally evaluated with the Breckner test, where both eyes are visualized simultaneously with the dracked ophthalmoscope. In the trabismus or misalignment of the two eyes, the deviated eye will generally have a lighter and brighter red reflex. If the refractive error is different between the two eyes, termed anisomatropia, one reflection also may be brighter than the other. It is especially important to evaluate for these conditions as they both may lead to amblyopia, which is abnormal development of the normal visual pathways. Similar to a pediatric patient, dulling, dimming, or asymmetry in an adult patient often indicates opacity of structures in the visual axis. The most common cause of this dulling in adult patient is a cataract, but may also clue you into other pathologies in the cornea, vitreous, or retina. We hope this video helps you become more familiar with the basics of red reflex testing. Thank you very much and be sure to browse the many other videos on the Moran Core website for additional information on core ophthalmologics, knowledge, and skills.