Sclera (White of the Eye)

What is the sclera?

The sclera is the white part of your eye. It’s a protective covering that wraps over most of your eyeball. It extends from the cornea at the front of your eye to the optic nerve in the back.

The sclera is thin — only around a millimeter thick (the same as a credit card) — but it’s a strong, protective layer of tissue that gives your eye its white color. It protects and supports your eye. The plural for sclera is sclerae.

What does the sclera do?

The sclera is the supporting wall for your eyeball. It maintains your eye’s shape and protects it from injuries.

Muscles attached to the sclera help you move your eyeball.

What type of tissue is the sclera?

The sclera is made of tough collagen fibers. Collagen is a protein that’s the main ingredient in your body’s skin, muscles, bones and connective tissues.

The collagen fibers in your sclera crisscross each other in a random pattern that makes the sclera strong and flexible. That web of collagen fibers is what makes the sclera white.

Is the sclera fully white?

The random pattern of collagen fibers layered on top of each other makes your sclera white. They’re stacked crisscrossing over each other so they don’t let as much light through as other parts of your eye. For example, collagen fibers in your cornea (the clear part at the front of your eye) are neatly organized, which makes them clear enough for you to see through.

What are the parts of the sclera?

The sclera has four layers sandwiched on top of each other and connected to other parts of your eye:

• Episclera: A layer of clear, thin tissue that’s the outermost layer.
• Stroma: A layer made up of fibroblasts (cells that make collagen) and collagen fibers that blends into the episclera.
• Lamina fusca: A transitional layer between the sclera and other parts of your eye, including the iris, choroid and ciliary body (parts of your uvea — the middle layer of your eye).
• Endothelium: The basal, or innermost, layer of the sclera.

Why isn’t the sclera of my eye white?

Lots of issues and conditions can change the whites of your eyes to other colors. Everyone’s eyes are occasionally red or irritated, but you should visit an eye care specialist or healthcare provider if you notice any changes in your eyes or sclerae that last for more than a day or two.

Some eye conditions that can affect your sclera’s color include:

• Eye infections.
• Uveitis (redness usually caused by your body fighting an infection).
• Episcleritis (redness autoimmune diseases typically cause).
• Jaundice.
• Pterygium (surfer’s eye).
• Colobomas.
• Marfan syndrome.
• Anemia.
• Osteogenesis imperfecta.

Eye injuries and everyday eye irritation (like dust, allergies, smoke or sun exposure) can cause red eye (bloodshot eyes).

Visit a healthcare provider or eye care specialist if you notice changes in your eyes, including color changes or eye pain.

How can I make my sclera white again?

An eye care specialist will perform an eye exam to diagnose what’s causing the discolored sclera. They’ll suggest treatments to manage the cause, which should help the whites of your eyes return to their usual color.

You might need:

• Prescription or over-the-counter (OTC) eye drops to manage redness or irritation.
• Antibiotics to treat bacterial infections.
• Eye surgery to repair damage from some traumas or injuries.

Ask your eye care specialist how to manage any underlying health conditions you have and which treatments they recommend.

How can I protect my sclera?

The best ways to protect your sclera (and the rest of your eye) include:

• Wearing safety goggles or other eye protection for all sports, physical activity or work.
• Wearing sunglasses to protect your eyes from sun damage, wind and debris.
• Washing your hands before touching your eyes (including putting in or taking out contacts).

When should I see an eye care specialist?

Visit an eye care specialist if you notice any changes in your eyes or vision, including:

• Sclera color changes.
• Blurry vision or worsening vision.
• Discharge (pus or fluid leaking from your eye).
• Light sensitivity.
• Pain or tenderness.

A note from Cleveland Clinic

Most people see their sclerae every time they look in the mirror but never notice them unless they’re red, irritated or painful. Occasional irritation or discoloration in the whites of your eyes is common, but don’t ignore changes in your vision, eye pain or other symptoms. It’s never a bad idea to visit an eye care specialist if you’re worried about your eyes. They’ll help you understand what’s causing any symptoms you’re experiencing.