Corneal Light Reflex Test (Hirschberg Test)

What is the corneal light reflex test?

The corneal light reflex test lets healthcare providers check your eye alignment using light reflecting on your corneas. All it takes is a dim room and a penlight or similar tool. It’s also known as the Hirschberg test, after its creator, German ophthalmologist Julius Hirschberg. This test is simple, painless and takes just a moment or two.

The corneal light reflex test is extremely common in a few different settings:

• Eye exams. Eye care specialists like optometrists or ophthalmologists use it during eye exams.
• Childhood development checks. Pediatricians commonly use this test on infants and children during wellness visits and checkups. It’s a key screening for conditions like strabismus (eye misalignment) or amblyopia (lazy eye).
• Annual checkups for adults. It’s common for providers to do this test during physical exams and neurological exams. These exams are a core part of routine checkups.

How does the corneal light reflex test work?

A healthcare provider doing the Hirschberg test looks for a small point of reflecting light on the surface of your eyes. If your eyes align properly, the reflection will appear in the same spot on both corneas.

What should I expect during the test?

Before a provider or eye specialist does the corneal light reflex test, they’ll dim the lights in the room. That makes it easier for them to see the reflection on your corneas. Once the lights are dim, your provider will sit in front of and facing you with a small light in their hand. They’ll have you look at the light. While you do, they’ll look closely at your eyes to see the positioning of the reflection.

What should I expect after the test?

After the test, your provider will do one of two things, depending on what they find:

• If your eyes align properly, your provider will move on to other parts of the exam.
• If your eyes don’t appear to align properly, your provider will try to confirm the misalignment and measure it using other simple tests.

What do the results of the test mean?

Your healthcare provider can tell you whether or not they see a misalignment during or right after the test. They can also talk you through related tests and measurements that they use to confirm if you have a misalignment and measure the size of it.

If your eyes have normal alignment, your provider will record that using either “symmetry” or “ortho” on your record. “Symmetry” means the reflection positions match on both eyes. “Ortho” comes from the ancient Greek word meaning “straight.”

One reason providers confirm misalignments is a condition called pseudostrabismus. That’s when something makes you look like you have a misalignment even though you don’t. It’s possible when you have certain facial features like epicanthal folds (monolid eyes). It can also happen with certain differences in your facial structure or when the distance between the center of your pupil and nose (pupillary distance) isn’t the same on both sides.

If your provider confirms your eyes don’t align properly, they’ll record what kind of misalignment it is. Examples include:

• Esotropia
• Exotropia
• Hypertropia
• Hypotropia

If my provider confirms the misalignment, what are the next steps?

If a pediatrician or primary care provider finds that you have (or a child you care for has) an eye misalignment, they’ll refer you to an ophthalmologist. Ophthalmologists can determine what’s causing your misalignment and recommend treatment options.

If the misalignment is brain-related, what are the next steps?

Providers like neurologists can use the corneal light reflex to check for brain-related issues. Examples include strokes or concussions. The next steps and treatment for these depend strongly on the underlying cause and other factors. In those situations, your provider can tell you what to expect next in your specific case.

When should I call my healthcare provider?

Gradual misalignments may be hard to see at first. If you think you see an eye misalignment in a child you care for, call their pediatrician and ask for an appointment. Conditions like amblyopia (lazy eye) are treatable in early childhood. But past a certain age, they cause permanent vision loss, so it’s best not to delay diagnosis and treatment. In adults, gradual misalignments mean you should schedule an appointment with an eye care specialist.

When a noticeable eye misalignment happens suddenly (over a span of minutes or hours), it’s a medical emergency and needs immediate care. That’s especially true after a head injury or with any warning signs of a stroke. In these cases, call 911 (or your local emergency services number) immediately.