Common Types of Ocular Infections

Keratitis is the inflammation (swelling) of the cornea, the clear outer covering of your eye.¹

Infectious keratitis can be caused by bacteria, viruses, fungi or parasites invading the cornea.^1,2 Non-infectious keratitis is less common² and is usually caused by an eye injury or by a foreign body in your eye.¹
The symptoms of keratitis include:¹

• Eye pain
• Redness
• Watering eyes
• Blurred vision
• Sensitivity to light

Infectious keratitis can be treated with antibiotic, antiviral or antifungal eye drops, depending on the cause.¹

Shingles is a condition caused by the same virus that causes chickenpox.³ If you’ve had chickenpox at any point in your life, this virus lives in your body³ and it might ‘wake up’ later in your life, causing unpleasant symptoms.³

Common symptoms of shingles include fatigue, headaches and painful rashes.³ A shingles rash might start off with itching, burning or tingling sensations and then develop into blisters.³

Shingles can infect specific parts of your body, including your eyes.^3,4 It can cause inflammation in your cornea, seriously damaging your eyes, so it’s important to see an ophthalmologist right away.^3,4

A lot of people carry the herpes simplex virus in their system.⁵ Usually it doesn’t cause problems, but sometimes it can flare up and cause issues like cold sores or eye infections.⁵

A herpes simplex eye infection usually affects the top layer of the cornea, causing redness and swelling.⁵ It can also cause light sensitivity, watery eyes and blurry vision.⁵ If the infection becomes more serious and spreads deeper into the middle and inner layers of your cornea, it can damage your eyesight.⁵

There is no cure for ocular herpes, but taking antiviral medication can keep it under control.⁵

Blepharitis is a condition that affects your eyelids.⁶ It can be caused by bacteria or by a skin condition like dandruff.⁶

Common symptoms of blepharitis include:⁶

• Red, swollen eyelids
• Itching, irritation and burning
• Teary (watery) eyes
• Crusty eyelids
• Dandruff-like flakes on the eyelashes

More severe symptoms include blurry vision, missing eyelashes and swelling in other parts of the eye like the cornea.⁶

There are two types of blepharitis:⁶

• Anterior blepharitis affects the outside front edge of your eyelids (the place where your eyelashes are attached).⁶ It’s usually caused by a build-up of bacteria found on the face and eyelids.⁶ It can also be caused by allergies or a mite infestation in your eyelashes.⁶
• Posterior blepharitis affects the inner edge of your eyelid (the part that touches your eyeball).⁶ It usually happens when the glands of your eyelids produce too much oil, causing bacteria to grow.⁶ It can also develop because of other skin conditions like dandruff.⁶

The treatment for blepharitis depends on what type you have.⁶ You might need to use a gentle eye wash or ointment to keep your eyelids clean and free of crusts.⁶ You may also need to take antibiotic medication.⁶

A stye, or hordeolum,^7,8 is a small abscess (painful red lump) that grows from the base of your eyelashes or under your eyelid.^7,8 Sometimes it can make your whole eyelid swollen and red.⁸

Styes are often painful or tender to touch⁸ and most are caused by a bacterial infection.⁸ You can also get a stye if you have blepharitis.⁸

There are two kinds of styes:⁸

• An external hordeolum is a stye that begins at the roots of your eyelashes.⁸ It usually happens because of an infection in the lash hair follicle.⁸
• An internal hordeolum is a stye inside your eyelid, usually caused by an infection in an oil gland in the lid.⁸

You can treat both types of styes using topical antibiotics.⁹ You can also use warm compresses on your eyelid to help drain the stye.⁹

A chalazion is a swollen bump that grows on your eyelid, caused by a clogged oil gland.^7,8 It might happen as an after-effect of a stye.⁷

Unlike a stye, a chalazion doesn’t involve an active bacterial infection.⁷ Chalazia are less painful than styes⁸ and they usually don’t make the whole eyelid swell.⁸

A chalazion can be treated by using warm compresses and a gentle eyelid wash that will clear away any discharge, pus and crusts.⁹

Uveitis is a group of diseases that affect the uvea, the layer and structures underneath the white part of your eye.^10,11 Uveitis can also affect other areas of your eye.¹⁰

Uveitis can be caused by an infection, an eye injury or an inflammatory disease.¹² It can affect one or both eyes and symptoms include:^10,12

• Blurry vision
• Eye pain
• Redness
• Floaters (dark floating spots) in your vision
• Sensitivity to light

There are four different types of uveitis, which affect different parts of the uvea:^10,13

• Anterior uveitis affects the front of your eye, causing inflammation in the iris.^10,13 It is the most common type of uveitis.¹⁰
• Intermediate uveitis affects the ciliary body.¹³
• Posterior uveitis affects the back of your eye (the retina and choroid).^10,13 
• Panuveitis affects all layers of the uvea.¹³

Any type of uveitis can potentially lead to blindness and must be treated by an ophthalmologist.¹² The treatment will depend on the type of uveitis you have, what caused it and how severe it is.¹²

Conjunctivitis affects the conjunctiva, the thin lining that covers the whites of your eyes and the insides of your eyelids.¹⁴ The condition is often called ‘pink eye’.¹⁵

Conjunctivitis can be caused by bacteria, viruses, allergies or irritations in the eye.^14,15 Symptoms include:¹⁵

• Redness
• Itching or burning
• Eye pain
• A gritty sensation in the eyes
• Watery eyes
• Puffy eyelids
• Blurry vision
• Sensitivity to light
• Mucous, pus or discharge that makes your eyelashes stick together

There are three main types of pink eye.¹⁵

• Viral conjunctivitis is the most common type of pink eye, caused by the same virus that causes common cold symptoms.¹⁵ It’s very contagious, meaning it can spread to other people easily.¹⁵
• Bacterial conjunctivitis is caused by a bacterial infection.¹⁵ It can also be very contagious.¹⁵
• Allergic conjunctivitis is caused by an allergic reaction to a substance like pollen, smoke or swimming pool chemicals.¹⁵ It is not contagious.¹⁵

Treatment may include eye drops, depending on what type of pink eye you have and how serious it is.¹⁵

View this summary as a quick guide to these common ocular infections.