The red reflex is elicited in the Brückner test, a pediatric screening tool often used by primary care doctors and pediatricians to detect abnormalities of the eyes and ocular diseases. Originally described as a “transillumination” test, Brückner found that the red reflex was useful in detecting strabismus and amblyopia in young children. The red reflex from the retina is a quick and non-invasive test used to identify opacities in the visual axis, such as a corneal abnormality or cataract, as well as abnormalities in the posterior segment of the eye, such as retinoblastoma.
A red reflex should appear red, orange, or yellow and be symmetric across both pupils. Eliciting a normal red reflex requires transmission through a transparent optical media, including the tear film, cornea, aqueous humor, lens, and vitreous body. An abnormal or absent red reflex can indicate sight and life-threatening pathology, including congenital cataracts, retinal abnormalities, retinoblastoma, strabismus, or refractive errors. Abnormal red reflex requires urgent referral to an ophthalmologist. Currently, the American Academy of Pediatrics policy recommends eye examinations for neonates and children from birth to 2 years of age at specific intervals during the newborn examination and well-child visits.
The red reflex test uses an ophthalmoscope or retinoscope, with the examiner standing approximately 1 to 2 feet away from the patient. The direct ophthalmoscope should be set at “0,” and the examiner directs the light onto both eyes simultaneously. The pupils will become illuminated as light reflects off the back of the retina and through the aperture of the scope. The examiner should then move closer also to assess each eye individually. For the pupils to be large enough for light to enter, the examination should be performed in a dark or dimly lit room.