Red reflex

The red reflex (also called the fundal reflex) refers to the reddish-orange reflection of light from the back of the eye, or fundus, observed when using an ophthalmoscope or retinoscope. The red reflex may be absent or poorly visible in people with dark eyes, and may appear yellow in Asians or green/blue in Africans.^[1]

The reflex relies on the transparency of optical media (tear film, cornea, aqueous humor, crystalline lens, vitreous humor) and reflects off the fundus back through media into the aperture of the ophthalmoscope.^[2] The red reflex is considered abnormal if there is any asymmetry between the eyes, dark spots, or white reflex (Leukocoria).

Generally, it is a physical exam done on neonates and children by healthcare providers but occasionally occurs in flash photography seen when the pupil does not have enough time to constrict and reflects the fundus known as the red-eye effect.

This is a recommended screening by the American Academy of Pediatrics and American Academy of Family Physicians for neonates and children at every office visit. The objective is to detect ocular pathology that needs early intervention and ophthalmology referral to prevent visual abnormalities and more serious, but rarely, death.

It is difficult to assess the effectiveness of the technique due to the low incidence of some of the pathology the red reflex is used to detect.^[3] For example, retinoblastoma, a neuroblastic tumor that can cause a dampened or even white reflex, occurs in 1 in every 20,000 children.^[4] Regardless of the effectiveness, it is a fast, inexpensive, and noninvasive exam that could identify ocular pathology which with early identification can alter the course of the disease.