Definition and Terminology: Leukocoria (also spelled leukocoria or leukocoria) or “white pupil” originates from the Greek word “leukos” (white) and “kore” (pupil). It refers to the reflection of white light seen upon direct illumination of the fundus through the pupil, in contrast to the usual red glow (1).
Etiopathogenesis: Direct interference of the normal red reflex from opacities and abnormalities occurring anywhere from the crystalline lens through to the posterior pole can create the leukocoric reflex. For example the white retinal mass seen in retinoblastoma creates leukocoria (2).
Red Reflex: Light is shone (using an ophthalmoscope) directly into the pupil, if an orange/red reflection is seen the reflex is considered normal. If a white reflection is visualized the patient has leukocoria. This reflex relies on the transparency of the optical media through to the fundus (3).
Pseudoleukokoria (White Reflex): Refers to transient leukocoria due to reflection of the optic disc particularly if looking 15 degrees off axis nasally. It may also be seen in children with anisometropia, and anisometropic amblyopia (4). Findings in the latter patient reveal a darker pupil when shining light in the eye that is more focused. Although it may be a benign finding in some children a complete ophthalmic examination is required to exclude other pathologies (4).
White Reflex versus Leukocoria: An important semantic to distinguish is the fact that white reflex and leukocoria are NOT interchangeable terminologies. Leukocoria will present as a persistent white light that is reflected in a patient’s eyes despite positioning, movement or quality of light source. A white reflex on the other hand describes a transient reflection that illuminates as white in particular directions, locations or with specific lights. Both of these reflexes correlate to a number of different pathologies and are important to distinguish as individual signs.