Redness of the Eye

The eye becomes “red” when blood vessels dilate and get larger or if a vessel has a bleed (Subconjunctival Haemorrhage). There are a variety of red eye causes, some of which can be serious.

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UK Statistics Relating to Red Eye

Here are some interesting statistics relating to red eye.

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Vision related outpatient appts

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Red eye presentations were Keratitis related

PMC

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Red eye presenting complaint in minor eye condition visits

~8%

Optometrist visits report ocular allergy

What is Red Eye?

Redness of the eye, also known as “bloodshot eyes,” is a common symptom that can arise from a variety of red eye causes and underlying conditions. It can be as harmless as temporary irritation or a sign of a more serious eye problem requiring immediate medical attention.

At Centre for Sight, we understand how concerning eye redness can be—especially when accompanied by discomfort, changes in vision, or discharge. Our expert consultants are here to provide timely assessment, diagnosis of and treatment to protect your vision from red eye causes and maintain overall eye health.

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What causes red eyes?

Redness occurs when the blood vessels on the surface of the eye (conjunctiva) become enlarged or inflamed. Some common red eye causes include:

Eye redness occurs when the superficial conjunctival blood vessels become dilated and more prominent, usually as a response to inflammation, irritation, infection, dry eye disease, allergy, or increased blood flow to the ocular surface.

A subconjunctival hemorrhage occurs when a small blood vessel ruptures beneath the conjunctiva, leading to a bright red patch on the white of the eye.

It is usually painless and does not affect vision, and commonly results from minor trauma, sudden increases in venous pressure such as coughing or sneezing, eye rubbing, hypertension, or the use of blood-thinning medications.

Although it can appear alarming, a subconjunctival bleed is typically harmless and resolves on its own within one to two weeks.

Inflammation and infection are common causes of eye redness, resulting from dilation of the conjunctival and episcleral blood vessels. Inflammatory conditions such as allergic conjunctivitis, dry eye disease, uveitis, and blepharitis trigger an immune response that increases blood flow to the ocular surface. Infectious causes, including viral, bacterial, or fungal conjunctivitis and keratitis, lead to redness through tissue irritation, vascular congestion, and the release of inflammatory mediators, and are often associated with discharge, discomfort, or visual symptoms.

Eyelid conditions can contribute to eye redness by disrupting the normal tear film and causing inflammation along the lid margins. Disorders such as blepharitis, meibomian gland dysfunction, styes, and chalazia lead to redness through bacterial overgrowth, gland blockage, and chronic lid inflammation, often resulting in irritation, burning, crusting, or fluctuating vision. Inflammation of the eyelids can secondarily affect the ocular surface, worsening conjunctival redness and discomfort.

The conjunctiva is a thin, transparent membrane that covers the white of the eye and lines the inner surface of the eyelids, and inflammation of this tissue—commonly referred to as pink eye or conjunctivitis—is a leading cause of eye redness. Pink eye occurs when the conjunctival blood vessels become dilated in response to infection, allergy, irritation, or environmental triggers, resulting in redness, tearing, discharge, and discomfort. Conjunctivitis may be viral, bacterial, or allergic in origin, and is one of the most frequent causes of red eye seen in both children and adults.

A corneal ulcer is an open sore on the surface of the cornea, most commonly caused by infection but also associated with trauma, contact lens overuse, dry eye disease, or immune-related conditions. It leads to eye redness through intense inflammation of the cornea and surrounding tissues and is often accompanied by pain, light sensitivity, tearing, blurred vision, and discharge. Corneal ulcers are considered an ocular emergency, as delayed diagnosis or treatment can result in corneal scarring and permanent vision loss.

Acute angle-closure glaucoma is a serious eye condition caused by a sudden rise in intraocular pressure due to blockage of aqueous humor outflow. It often presents with a red, painful eye accompanied by headache, nausea, vomiting, blurred vision, and halos around lights. Eye redness occurs as increased pressure and inflammation affect the ocular blood vessels, and this condition requires immediate medical attention, as delayed treatment can lead to permanent optic nerve damage and vision loss.

If you are unsure about your loss of vision, contact one of our Patient Coordinators who can arrange an appointment for you to see one of our surgeons. Call 0808 271 3944 or email us here.

What are the Symptoms of Eye Redness?

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If any of these symptoms accompany your red eye, it’s important to consult an eye specialist without delay.

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Depending on the cause, you may also experience:

Burning or itching

Watery or sticky discharge

Light sensitivity

Gritty or foreign body sensation

Swollen eyelids

Blurred vision or visual disturbances

Pain in or around the eye

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Eye redness in glaucoma can occur when elevated intraocular pressure causes dilation of ocular blood vessels, often accompanied by pain, blurred vision, and halos around lights.

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Dry eye can cause redness as the ocular surface becomes irritated and blood vessels dilate.

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Allergic reactions can trigger eye redness by causing inflammation and dilation of conjunctival blood vessels.

Early Detection of Red Eye

Identifying the root cause early is crucial. Some red eye causes can lead to permanent vision damage if left untreated—such as uveitis, glaucoma, or corneal ulcers.

At Centre for Sight, our team uses state-of-the-art diagnostic technology to assess the eye in detail and pinpoint the underlying issue quickly. Early detection allows us to begin appropriate treatment immediately, reducing discomfort and protecting your sight.

Whether it’s a minor irritation or a sign of a more complex condition, never ignore persistent or sudden eye redness. Our expert consultants will guide you through every step, from diagnosis of red eye causes to treatment and follow-up care.

Diagnosis & Assessment

Red eye diagnosis involves a thorough clinical assessment to identify the underlying cause whether infection, inflammation, allergy or more serious conditions so that the most appropriate and timely treatment can be provided.

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How we assess your vision

Centre for Sight provides a thorough eye assessment to identify the cause of your eye redness.

Duration: 60-90 minutes

What to Expect

Vision checks using up to 16 diagnostic tests

Consultant led care

Review of your symptoms and lifestyle

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tests and scans you may have

Your first visit is designed to be thorough yet comfortable, giving you clear answers and a personalised treatment plan for your red eyes.

Duration: 60-90 minutes

What to Expect

Comfortable non invasive tests

Clear explanation of the results

Identification of the root cause of your red eyes

Recommended next steps

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What Happens At Your First Appointment

Your first visit is designed to be thorough yet comfortable, giving you clear answers and a personalised plan for treatment.

Duration: 60-90 minutes

What to Expect

Same day insights into your eye redness

Tailored treatment plan

Our Consultants

Meet our team of expert and world-renowned Consultant Ophthalmic Surgeons

Why Choose Centre for Sight

Centre for Sight is one of the UK’s most established and pioneering eye care providers, with over 30 years of experience and multiple national firsts. We were the first clinic in the UK to perform LASIK, and among the earliest to introduce femtosecond laser technology for both laser eye surgery and cataract procedures. Our consultants have collectively performed over 35,000 cataract surgeries, delivering exceptional outcomes backed by audited results and world-class surgical expertise. You will benefit from fully consultant-led care, advanced diagnostic technology, and personalised treatment planning,  all supported by our reputation as a trusted centre where ophthalmologists from around the world come to observe and train. At Centre for Sight, innovation, safety, and excellence are built into every step of your journey.

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Our Centres

London Centre

Suite 2, 14 Queen Anne Street, London W1G 8HZ

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Centre for Sight London, located at 14 Queen Anne St, Suite 2, in the prestigious Harley Street area, offers consultations, follow-up care, and YAG laser procedures.

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Sussex Centre

Hazelden Place, Turners Hill Road, East Grinstead, West Sussex, RH19 4RH

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Arguably the most modern private eye hospital in the UK, our hospital in Sussex offers Laser Vision Correction, Corneal Transplants, Stem Cell Surgery and more.

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Surrey Centre

48 High Street, Oxshott, Surrey, KT22 0JR

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Centre for Sight London, located at 14 Queen Anne St, Suite 2, in the prestigious Harley Street area, offers consultations, follow-up care, and YAG laser procedures.

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Common questions relating to eye pain

Find quick answers to common eye redness concerns and treatments.

ye redness occurs when the tiny blood vessels on the surface of the eye become enlarged or inflamed. Common causes include conjunctivitis (pink eye), allergies, dry eyes, eye infections, blepharitis, trauma, or increased eye strain.

Seek medical attention if redness is accompanied by pain, vision changes, light sensitivity, discharge, or sudden swelling. Conditions like corneal ulcers, acute glaucoma, or severe infections can threaten vision and require prompt treatment.

Yes, allergic reactions can trigger eye redness by releasing histamines, which dilate conjunctival blood vessels. Allergic conjunctivitis often causes itching, tearing, and swelling in addition to redness.

Treatment depends on the cause. Allergic redness may respond to antihistamine or lubricating drops, bacterial infections require antibiotics, and inflammation from eyelid or corneal issues may need specific medications or procedures. Avoid rubbing the eyes and manage underlying triggers.

Some causes of red eyes, like viral or bacterial conjunctivitis (pink eye), are contagious, while others, such as allergies or dry eye, are not. Good hygiene, handwashing, and avoiding contact with infected individuals can help prevent spread.

Have Questions?

Our patient care team is here to answer any questions you may have.