Reflexes of the Eye

What are the reflexes of the eye?

The reflexes of the eye are a series of automatic changes in your eyes that help you see and protect your eyeballs from damage. They’re involuntary movements — which means you can’t control them and don’t have to think about them.

Your eyes are organs that allow you to see. Many parts of your eye work together to bring objects into focus and send visual information to your brain.

Eye reflexes protect your eyeballs and adjust your eyes to different lighting conditions. They ensure there are no gaps in your vision, even if you move your eyes quickly or light changes suddenly.

Some reflexes of the eye make your eyes move or change as reactions to things going on around you.

Your eye has reflexes that involve most of the parts of your eye, including your:

• Pupil.
• Cornea.
• Tear system.
• Ocular nerve.

Other eye reflexes happen in response to changes in other parts of your body, including your:

• Muscles.
• Nerves.
• Nervous system.

An eye care specialist will test the reflexes of your eyes during an eye exam. They’ll check specific reflexes if you’re experiencing symptoms or have issues with a specific part of your eyes or vision.

How do the reflexes of the eye work?

The reflexes of the eye respond to electrical signals traveling through a loop of special nerve cells to your brain and back. These paths are made of:

• Receptors.
• Afferent neurons.
• Efferent neurons.
• Effectors.

How these paths work is similar to typing on a keyboard. You press a key, then an electrical signal travels from that key though a wire to your computer which turns that signal into a letter on your screen. But instead of typing one letter at a time, your eye reflexes constantly adjust and protect your eyes without you even needing to think about them.

What are the types of eye reflexes?

The reflexes of the eye include your:

• Pupillary reflexes.
• Corneal reflexes.
• Vestibulo-ocular reflex.
• Oculocephalic reflex (doll’s eye reflex).
• Palpebral oculogyric reflex (Bell’s reflex).

Pupillary reflexes

The pupil is the black center of your eye. Your pupils change in size to control how much light enters your eye. Muscles in your iris (the colored part of your eye) control the size of your pupil. Pupillary reflexes make your pupil change size automatically in different amounts of light. You might see this called pupillary accommodation. They maintain your vision in different conditions by changing how much light enters your eyes and hits your retinas. Pupillary reflexes include:

• The pupillary light reflex: The pupillary light reflex makes your pupils shrink (contract) in bright light. Muscles in your irises squeeze tighter and make your pupils smaller when bright light hits your eyes.
• The pupillary dark reflex: The pupillary dark reflex makes your pupils get bigger (dilate) when you enter a dark space. Your irises relax and open to let more light into your eyes.
• The ciliospinal reflex: The ciliospinal reflex makes your pupils dilate if something hits your face or neck.

Corneal reflexes

The cornea is the clear window on the front of your eye. It’s made of tough, transparent tissue. Together with the sclera (white of your eye), the cornea helps protect your eye. There are two corneal reflexes:

• The blink reflex: The blink reflex is exactly what it sounds like — an automatic response that makes you blink when something touches your cornea.
• The tear reflex (lacrimatory reflex): The tear reflex is also triggered by something touching your eye. It makes your tear system flood your eye with fresh tears to wash away anything that’s stuck in your eye.

You experience the two corneal reflexes every time a loose eyelash falls into your eye. You blink without thinking about it, then your eye is suddenly watery with new tears to wash it clear. Other situations can trigger your blink or tear reflexes, including:

• Bright light.
• Feeling upset or sad.
• Coughing.
• Vomiting.
• Wind or cold air.

Vestibulo-ocular reflex

Six muscles control your eyes’ movements. They let you intentionally look left, right, up and down. They also move your eyes during the vestibulo-ocular reflex. Your brain and oculomotor nerve automatically make tiny adjustments to your eye muscles when your head moves. Even when you’re not thinking about it, your head moves all the time, especially when you’re walking, running or doing any other physical activity. The vestibulo-ocular reflex keeps your eyes level when your head moves. If you didn’t have a vestibulo-ocular reflex, your vision would constantly be blurry or feel like you were on a boat in choppy waves.

Oculocephalic reflex (doll’s eye reflex)

The oculocephalic reflex is one way for an eye care specialist to test how well your cranial nerves are working. You might see it referred to as the doll’s eye reflex. It’s a form of accommodation eye test — motions or movements that help eye care specialists see how your eyes adjust to changes. If your eye care specialist is checking your doll’s eye reflex, they’ll hold your eyelids open and quickly move your head back and forth from left to right. Your eyes should reflexively adjust to stay looking straight ahead, even if your head is moving. If your vision gets significantly worse during the test — or if your eyes move too much — something might be interfering with either the nerves or muscles that keep your eyes stable. Your eye care specialist will probably need other tests to diagnose what’s affecting your eyes.

Palpebral oculogyric reflex (Bell’s reflex)

The palpebral oculogyric reflex makes you unconsciously move your eyes up if someone tries to touch or force them closed. It’s also known as the Bell’s reflex. You’ve experienced it if your eyes move up when you put contact lenses or eye drops in your eye. Some people’s eyes perform a Bell’s reflex when they’re putting makeup on. Unlike other reflexes of the eye, the Bell’s reflex doesn’t actively help your vision or protect your eyes. Experts think it’s a built-in defense mechanism. People with Bell’s palsy and other forms of facial paralysis won’t have a Bell’s reflex. Not having a Bell’s reflex isn’t a sign that something’s wrong with your eyes. In fact, around 10% of people naturally don’t have Bell’s reflex.

What are the common conditions and disorders that affect the reflexes of the eye?

Anything that damages your eyes, muscles, nerves or brain can affect the reflexes of your eyes. Some issues that can interfere with your eye reflexes include:

• Eye injuries.
• Neuropathy.
• Strokes.
• Paralysis.
• Brown syndrome.
• Horner’s syndrome.
• Strabismus (crossed eyes).
• Nystagmus.

A note from Cleveland Clinic

Your eyes are an important part of how you interact with the world around you. Even if you’re not thinking about them, your eye is protected and controlled by reflexes. They automatically keep your vision stable and protect the tissues in your eyes from damage and foreign objects.

Even if you don’t intentionally control them, if something’s wrong with one of the reflexes of your eye, it can make your eyes feel “off” or not quite right. Visit an eye care specialist if you notice any changes in your eyes or vision.