corneal light reflex test
A screening test using penlight reflection off the corneas to detect manifest strabismus and estimate deviation magnitude.
Full Definition
The corneal light reflex test, also known as the Hirschberg test, involves shining a penlight at the patient's eyes from approximately 33 cm distance and observing the position of the light reflexes on each cornea. In orthotropic eyes, the reflexes appear symmetric and centered over the pupils. Asymmetric reflexes indicate manifest strabismus, with the direction and magnitude estimated based on reflex displacement. Each millimeter of reflex displacement corresponds to approximately 15 prism diopters of deviation (angle kappa). Modifications include the Krimsky test using prisms to center the reflexes. This test is particularly valuable for screening young children and documenting large-angle strabismus when cover testing is not feasible.
Usage
Usage note: Document reflex positions precisely and estimate deviations. Note any angle kappa or facial asymmetry that might affect interpretation.
In Context
- "The corneal light reflex test revealed temporal displacement of the left eye reflex, indicating esotropia." — Strabismus screening documentation
- "Hirschberg testing estimated a 30 prism diopter exotropia based on nasal reflex displacement." — Quantitative strabismus assessment