German
Ελληνικά
In very young children, who are not cooperative, the presence of strabismus can be identified by using the lens-pen and by observing the reflections of light on the cornea of the child’s eyes.
In very young children, who are not cooperative, the presence of strabismus can be identified by using the lens-pen and by observing the reflections of light on the cornea of the child’s eyes.
If both eyes are looking straight ahead, the corneal reflections of a lens that illuminates near the root of the child’s nose are at the center of each pupil.
If one eye squints, the reflection of light on the pupil will appear displaced.
More specifically, if the eye is squinting inwardly, the reflection will be located outwardly of the pupil, while if the is eye squinting outwardly the reflection will be located nasally.
This test is called Hirschberg test, named after the ophthalmologist who first applied it.
The measurement’s distance of the reflection of light to the center of the pupil gives us a measure of the angle of strabismus. Every millimeter deviation corresponds to an angle of strabismus approximately equal to 7 degrees.
Thus, if the reflection is at the pupil’s labrum (2mm from the center of a pupil of 4mm), the deviation is about 15 degrees.