Inflammatory & Infectious Eye Conditions

What are inflammatory & infectious eye conditions?

Red, sore or irritated eyes are common, but the cause is not always the same. Some conditions affect the surface of the eye, while others cause inflammation deeper inside the eye or infection of the cornea. Symptoms can overlap, which is why persistent, painful or vision-changing symptoms should be assessed rather than self-diagnosed.

At personalEYES, our ophthalmologists assess and manage a broad range of inflammatory and infectious eye conditions. Treatment depends on the part of the eye involved, the cause of the problem and how severe the condition is.

When should a red or painful eye be assessed urgently?

Seek urgent eye care if you develop sudden or significant vision loss, severe eye pain, marked light sensitivity, a rapidly worsening red eye, a white spot on the cornea, significant swelling around the eye, or new symptoms while wearing contact lenses. These features can occur with conditions that may threaten sight if treatment is delayed.

Uveitis

Uveitis is a group of conditions that cause inflammation inside the eye, usually affecting the uvea — the middle layer of the eye. Depending on where the inflammation is located, uveitis may be described as anterior, intermediate, posterior or panuveitis. It can affect one or both eyes and may develop suddenly or gradually.

Common symptoms

• Red eye
• Eye pain
• Sensitivity to light (photophobia)
• Blurred or reduced vision
• Floaters or dark spots in the vision
• Occasionally flashes of light

What can cause it?

In many people, no single cause is identified. Uveitis can be associated with autoimmune or inflammatory conditions, infections, eye injury, and occasionally medicines. Because eye inflammation may be linked to a condition elsewhere in the body, your ophthalmologist may ask about joint, skin, bowel or general health symptoms.

How is it diagnosed?

An ophthalmologist examines the eye with a slit lamp and may dilate the pupils to assess the back of the eye. Depending on the pattern and severity, additional testing may include retinal imaging, eye scans, blood tests or other investigations.

How is it treated?

Treatment is tailored to the type and cause of uveitis. Anti-inflammatory treatment may include corticosteroid eye drops, tablets, injections or other medicines that control the immune system. If an infection is responsible, specific antibiotic, antiviral or other anti-infective treatment may be required. Dilating drops may also be prescribed in some forms of anterior uveitis to reduce discomfort and prevent complications.

Important: Sudden eye pain, significant light sensitivity or a new reduction in vision should be assessed promptly.

Iritis (Anterior Uveitis)

Iritis is inflammation of the iris, the coloured part of the eye. It is commonly used to describe anterior uveitis, the most frequent form of uveitis. The inflammation occurs at the front of the eye and can cause a painful, light-sensitive red eye.

Common symptoms

• Aching or painful eye
• Redness, often more noticeable around the coloured part of the eye
• Sensitivity to light
• Blurred vision
• A small or irregular-looking pupil in some cases

What can cause it?

Iritis may occur without an obvious cause. It can also be linked to autoimmune and inflammatory conditions, infections or previous eye trauma. Some people experience recurrent episodes.

How is it diagnosed?

The diagnosis is made during an eye examination using a slit lamp, which allows the ophthalmologist to see inflammatory cells inside the front of the eye. Eye pressure is also checked because inflammation and its treatment can sometimes affect pressure.

How is it treated?

Treatment commonly involves prescription anti-inflammatory eye drops. Dilating or cycloplegic drops may be used to relax the iris, reduce pain and lower the risk of the iris sticking to the lens. Treatment usually needs to be tapered under medical supervision rather than stopped suddenly.

Important: Do not use leftover steroid eye drops for a new red eye unless an eye specialist has advised you to do so, because some infections can worsen with inappropriate steroid use.

Scleritis

Scleritis is inflammation of the sclera, the tough white outer coat of the eye. It is less common than episcleritis but is more serious and can threaten vision. The pain is often deep and intense and may feel worse with eye movement or at night.

Common symptoms

• Deep, severe or boring eye pain
• Marked redness, sometimes with a purple or bluish-red appearance
• Eye tenderness
• Watering
• Sensitivity to light
• Blurred or reduced vision in more severe cases

What can cause it?

Scleritis can occur on its own, but it may be associated with systemic inflammatory or autoimmune disease. Less commonly, it can be caused by infection. This is why an ophthalmologist may recommend medical investigations, particularly when scleritis is severe, recurrent or affects the back of the eye.

How is it diagnosed?

A detailed slit-lamp examination helps distinguish scleritis from more superficial causes of redness. Imaging, such as ultrasound or other scans, may be needed if posterior scleritis is suspected. Blood tests or referral to another specialist may also be recommended to look for an underlying condition.

How is it treated?

Treatment depends on severity and cause. It often requires oral anti-inflammatory medicines, corticosteroids or medications that suppress inflammation in the immune system. Infectious scleritis requires treatment directed at the infection. Care may be coordinated with a rheumatologist or other physician when systemic disease is involved.

Important: Severe eye pain, pain that wakes you at night, or redness associated with reduced vision requires prompt ophthalmic assessment.

Episcleritis

Episcleritis is inflammation of the episclera, a thin layer of tissue between the conjunctiva and the white sclera. It often appears as a bright red patch on one part of the eye and is usually much less painful than scleritis.

Common symptoms

• Localised or sector-shaped redness
• Mild aching, soreness or tenderness
• Gritty or irritated feeling
• Watering
• Usually little or no effect on vision

What can cause it?

Most cases do not have an identifiable cause. Episcleritis can recur, and in a small number of people recurrent or severe episodes may be associated with an inflammatory condition elsewhere in the body.

How is it diagnosed?

An eye examination is important when the diagnosis is uncertain because scleritis, keratitis and uveitis can also cause a red eye. The ophthalmologist examines the layers of the eye and checks that the cornea and deeper eye structures are not involved.

How is it treated?

Episcleritis often settles without treatment over several weeks. Lubricating eye drops can improve comfort. If symptoms are persistent or troublesome, an eye specialist may recommend anti-inflammatory treatment.

Important: Blurred vision, severe pain or significant light sensitivity are not typical of simple episcleritis and should be assessed promptly.

Conjunctivitis (Pink Eye)

Conjunctivitis is inflammation of the conjunctiva, the thin transparent membrane covering the white of the eye and the inside of the eyelids. It is a common cause of red eye and may be infectious, allergic or caused by irritation.

Common symptoms

• Pink or red eye
• Watering
• Itching or burning
• Gritty sensation
• Sticky or crusted eyelids
• Clear, white, yellow or green discharge depending on the cause
• Mild eyelid swelling

What can cause it?

Viral conjunctivitis is common and can spread easily between people. Bacterial conjunctivitis may cause thicker sticky discharge. Allergic conjunctivitis commonly affects both eyes and is often very itchy. Dust, chemicals and other irritants can also inflame the conjunctiva.

How is it diagnosed?

Many cases can be recognised from the symptoms and examination. If symptoms are severe, unusual or persistent, the eye may need closer examination and occasionally a swab to identify an infectious cause.

How is it treated?

Treatment depends on the cause. Viral conjunctivitis often improves with time and supportive care. Bacterial infections may sometimes require antibiotic drops or ointment. Allergic conjunctivitis may improve with allergen avoidance and anti-allergy treatment. Good hand hygiene and avoiding shared towels, cosmetics or eye products can reduce spread when infection is suspected.

Important: Eye pain, significant light sensitivity, reduced vision or a very red eye are not typical of uncomplicated conjunctivitis and may indicate a more serious condition.

Keratitis

Keratitis means inflammation of the cornea, the clear window at the front of the eye. Keratitis can be infectious or non-infectious. Because the cornea is essential for clear vision, some forms of keratitis need urgent treatment.

Common symptoms

• Painful red eye
• Sensitivity to light
• Blurred or reduced vision
• Watering or discharge
• Foreign-body or gritty sensation
• A white or cloudy spot on the cornea in some infections

What can cause it?

Causes include bacteria, viruses such as herpes simplex, fungi and Acanthamoeba, as well as non-infectious inflammation. Contact lens wear is an important risk factor for microbial keratitis, particularly when lenses are worn overnight, exposed to water, or not cleaned and stored correctly. Corneal injury and some pre-existing eye surface conditions can also increase risk.

How is it diagnosed?

The ophthalmologist examines the cornea with a slit lamp and special dye. If an infection or corneal ulcer is suspected, a sample from the cornea may be taken to identify the organism and guide treatment.

How is it treated?

Infectious keratitis is treated with medication targeted to the cause, such as intensive antibiotic, antiviral or antifungal treatment. Drops may initially be required very frequently. Non-infectious keratitis is managed according to the underlying problem. Contact lenses should not be worn while an active corneal infection is being treated unless specifically instructed by your eye specialist.

Important: Contact lens wearers with a painful red eye, reduced vision or light sensitivity should seek urgent eye assessment.

Ocular Herpes (Herpes Simplex Eye Disease)

Ocular herpes is an eye infection caused most often by herpes simplex virus type 1, the same virus that commonly causes cold sores. The virus can remain inactive in the body and later reactivate in or around the eye. When the cornea is involved, it is often called herpes simplex keratitis.

Common symptoms

• Usually affects one eye
• Redness
• Eye pain or discomfort
• Watering
• Sensitivity to light
• Blurred vision
• Swollen eyelid
• Occasionally blisters or a rash around the eyelid

What can cause it?

After a person has acquired herpes simplex virus, the virus remains in nerve tissue and can reactivate. Episodes may occur without a clear trigger, although illness, stress, eye injury, bright sunlight or reduced immunity may sometimes be associated with recurrence.

How is it diagnosed?

An ophthalmologist examines the eye carefully, often using fluorescein dye to look for characteristic corneal changes. In some cases a sample may be taken. It is important to distinguish ocular herpes from other causes of red eye because treatment is specific.

How is it treated?

Antiviral eye medication or antiviral tablets may be prescribed. Some forms of herpes eye disease also require steroid eye drops, but these should only be used under ophthalmologist supervision and usually alongside antiviral treatment. Recurrent disease may occasionally require longer-term antiviral medication.

Important: A painful red eye with light sensitivity or blurred vision, particularly with a history of cold sores or previous ocular herpes, should be assessed promptly.

Eye Infections

Eye infection is a broad term covering infections that can affect the eyelids, conjunctiva, cornea or deeper tissues of the eye. Some are mild and self-limiting, while others can progress quickly and affect sight.

Common symptoms

• Redness
• Pain or soreness
• Watering
• Sticky or pus-like discharge
• Swelling
• Blurred vision
• Sensitivity to light
• A feeling that something is in the eye

What can cause it?

Eye infections may be caused by viruses, bacteria, fungi or other microorganisms. Infection can spread through direct contact, contaminated hands or objects, and poor contact lens hygiene. Eye injury or recent eye surgery can also increase the risk of certain infections.

How is it diagnosed?

The assessment depends on which part of the eye is affected. Your ophthalmologist may examine the eye with a slit lamp, check the cornea with dye, measure vision and eye pressure, and take a swab or corneal sample if needed.

How is it treated?

Treatment is based on the cause and location of the infection. Antibiotics are used for bacterial infections, antivirals for certain viral infections, and antifungal or other specialised medicines when indicated. Not every red eye needs antibiotics, so accurate diagnosis is important. Avoid sharing towels or eye make-up, wash hands regularly, and avoid contact lenses during an active infection unless your eye-care professional says otherwise.

Important: Any infection associated with reduced vision, significant pain, marked light sensitivity, increasing swelling or rapid deterioration should be treated as urgent.

How are these conditions different?

Many eye conditions cause redness, but the pattern of symptoms can offer clues. The list below is a general guide only — an eye examination is needed for diagnosis.

• Conjunctivitis — itchy, gritty or burning; vision usually mild (marked photophobia is atypical); routine unless pain or vision change.
• Episcleritis — mild ache or tenderness; vision usually unaffected; usually non-urgent.
• Uveitis / iritis — aching or painful; photophobia and blurred vision can occur; prompt assessment.
• Scleritis — deep, severe pain; can affect vision; prompt / urgent assessment.
• Keratitis — painful, gritty or foreign-body sensation; photophobia and blurred vision common; urgent if infectious or contact lens-related.
• Ocular herpes — pain or irritation; photophobia / blurred vision may occur; prompt assessment.