Conjunctiva: Definition, Anatomy, and More

Get ready for a lesson in eye anatomy — in this article, we’re breaking down what the conjunctiva is, its function and structure, and the conditions and diseases that can affect it. Keep reading to learn everything you need to know about this integral part of your eye.

What Is the Conjunctiva?

The conjunctiva is the clear, thin tissue that covers the inside of your eyelid and the white of your eye. It’s a mucous membrane that keeps your eye moist, prevents foreign bodies from causing eye infections, and, with the help of your lacrimal glands, makes tears.

In the same way that your cornea covers your iris (the colored part of your eye) and pupil (the black center of your iris), the conjunctiva covers the white of your eye. You can think of it like a casing — it acts as a barrier to protect your eye from irritants, including allergens.

That said, the conjunctiva also provides lubrication and locks in moisture. Without this vital function, it would be extremely painful to open and close your eyes.

What Is the Structure of the Conjunctiva?

The conjunctiva has two main segments: the bulbar conjunctiva and the palpebral conjunctiva.

The first part, the bulbar conjunctiva, is the section of film-like tissue that covers the anterior part of the white of the eye. It extends all the way from the back of your eye to your cornea but does not cover it.

The palpebral conjunctiva is the section that covers the inner surface of your upper and lower eyelids. You might also hear it referred to as the tarsal conjunctiva. Essentially, it serves as a lining to the inner surface of the eyelids.

The place where these two sections meet is called the conjunctiva fornix.

What Is the Difference Between the Sclera and the Conjunctiva?

As you learn more about the conjunctiva, you might also come across another term — sclera. Although related, they are distinct parts of the eye.

The sclera is the white part of your eye, and the conjunctiva is the protective film that covers it. Put another way: If you think of your eye like an egg, the conjunctiva is the shell, and the sclera is the egg itself.

Are There Any Conditions That Affect the Conjunctiva?

Now that you know more about the conjunctiva and what it does, it’s time to talk about the diseases that can affect it. In this section, we’re taking a closer look at four conditions that involve the conjunctiva, ranging from common to incredibly rare.

Conjunctivitis

The most common condition that affects the conjunctiva is conjunctivitis, also known as pink eye. This infection can be caused by viruses, bacteria, allergic reactions, and irritants.

As you probably know, conjunctivitis leads to pink or red discoloration in one or both eyes. Other symptoms of pink eye include crusty discharge, swollen eyelids, blurred vision, and an itchy or burning sensation.

When contact wearers have conjunctivitis, one of the first things their doctor will tell them is to wear glasses until their symptoms subside. Luckily, that isn’t a problem when you have stylish frames from Pair!

Injected Conjunctiva

Although it may sound complicated, injected conjunctiva simply refers to bloodshot eyes. This is caused by the blood vessels in the conjunctiva starting to widen.

There are several different causes of injected conjunctiva, including trauma, dust, foreign bodies, sun exposure, allergies, and dryness. Along with bloodshot eyes, you might notice that injected conjunctiva causes them to swell and itch.

Subconjunctival Hemorrhage

Sometimes, one of the tiny blood vessels that lies over the sclera starts to bleed. This bleeding is known as a subconjunctival hemorrhage.

Since the conjunctiva acts as a kind of seal, this bleeding can create the appearance of tiny red patches in your eye. In more extreme cases, the entire white of your eye can turn red if several blood vessels start bleeding.

Like injected conjunctiva, there’s a wide range of causes of subconjunctival hemorrhages. For example, if you rub your eye too hard or strain while coughing, sneezing, or vomiting, you can trigger a subconjunctival hemorrhage. Taking blood thinners, wearing contact lenses, or sustaining an eye injury or eye infection can also cause a subconjunctival hemorrhage.

Although it may look alarming, a subconjunctival hemorrhage is usually harmless and often resolves itself in a few weeks, as the blood is reabsorbed, much like a bruise resolving.

Conjunctival Lymphoma

The final disease we’ll cover is conjunctival lymphoma. This is a rare form of lymphatic cancer that causes a pink patch in the eye. The tumor that forms as a result of this cancer can usually only be found in a routine eye exam.

Some of the symptoms of conjunctival lymphoma include blurred vision, a bump on your eye, dry eye, light sensitivity, and a slightly yellow discoloration.

Closing Thoughts on the Conjunctiva

At Pair Eyewear, we believe that eye care starts with eye knowledge. That’s why it’s important to understand your conjunctiva and why this part of your eyeball is so crucial. Remember, the conjunctiva is a thin mucous membrane that covers the white surface of the eye, keeping it well-lubricated and protected.

Several conditions can infect your conjunctiva, including pink eye, injected conjunctiva, and subconjunctival hemorrhages, which occur when small blood vessels in the white part of the eye start to bleed. That said, there are also more serious conditions to look out for, like conjunctival lymphoma.

For that reason, you should see an ophthalmologist if you notice anything in the white part of your eye. They can perform a comprehensive eye exam and make sure your eyes stay healthy. They may even provide you with a new prescription, which you can take to Pair.

Sources:

Pink eye (conjunctivitis) - Symptoms and causes | Mayo Clinic

New Clinical Grading Scales and Objective Measurement for Conjunctival Injection | IOVS

Subconjunctival Hemorrhage: Symptoms, Causes & Treatment | Cleveland Clinic

Diagnosis and Treatment of Conjunctival Lymphoma | American Academy of Ophthalmology