Red eyes: Causes, symptoms and treatment

April 1, 2026

Red eyes are a very common reason for seeking ophthalmological care, and although in many cases they don't represent a medical emergency, they can also be a visible symptom of more serious eye diseases. Identifying the cause of the redness is key to applying the appropriate treatment and preventing complications.

At Clínica Nivaria , we expertly and personally evaluate each case of eye redness, distinguishing between mild, moderate or severe situations, and offering effective treatments based on clinical evidence.

What does it mean to have red eyes?

Having red eyes involves the dilation of blood vessels in the conjunctiva , the membrane that covers the white of the eye (sclera). This causes a reddish or bloodshot appearance, which may be localized to one area or affect the entire surface of the eye.

Redness may occur with or without other associated symptoms such as itching, burning, discharge, pain, photophobia (sensitivity to light), or blurred vision. The diagnosis is guided by these accompanying symptoms.

What are the most common causes of red eyes?

Red eyes can have many causes , ranging from temporary irritations to serious illnesses. The most common ones are detailed below:

1. Conjunctivitis

One of the most common causes. There are several types:

Viral conjunctivitis : highly contagious, it usually starts in one eye and spreads to the other. It causes redness, tearing, photophobia, and a foreign body sensation.
Bacterial conjunctivitis : causes thick (pus-like) discharge, discomfort, and redness. It often affects both eyes.
Allergic conjunctivitis : causes intense itching, redness, and tearing. It is usually bilateral and occurs in people with a history of allergies.

2. Dry eyes (dry eye syndrome)

Dry eye can cause chronic redness, burning, blurred vision, and a gritty feeling. It is very common in people who work with screens or in air-conditioned environments.

3. Blepharitis

Inflammation of the eyelid margins. It causes eye redness, crusting of the eyelashes, burning, and tearing. It is a common cause of persistent redness.

4. Use of contact lenses

Improper use of contact lenses (excessive hours, poor hygiene, or prolonged use) can irritate the ocular surface, causing redness, discomfort, and a risk of infection.

5. Foreign body in the eye

A particle of dust or sand can irritate the conjunctiva and cause localized redness, sharp pain, and tearing. Immediate evaluation is required if it does not resolve spontaneously.

6. Eye injuries

Blows, injuries, or surgical procedures can inflame the structures of the eye and cause redness, in addition to other significant visual symptoms.

7. Subconjunctival hemorrhage

It appears as a bright red spot in the eye, caused by a ruptured small blood vessel. Although it may look alarming, it is usually painless and benign, resolving on its own within a few days.

8. Uveitis

Inflammation of the inside of the eye (uvea), which can cause red eyes, pain, photophobia, and decreased vision. It is a serious condition that requires urgent treatment.

9. Acute glaucoma

An ophthalmological emergency . It occurs due to a sudden increase in intraocular pressure and causes painful red eye, blurred vision, nausea, and vomiting . If not treated promptly, it can lead to irreversible vision loss.

10. Keratitis

Inflammation or infection of the cornea. It can cause intense red eyes, severe pain, tearing, and sensitivity to light. It can lead to a corneal ulcer if not treated properly.

When is it necessary to see an ophthalmologist?

Although red eyes are often due to benign causes, it is important to seek medical attention if:

The redness persists for more than 2-3 days .
There is intense eye pain or pressure in the eye .
It is accompanied by blurred vision, visual loss, or flashes of light .
There is abundant discharge or a yellowish/greenish color .
The eye is very sensitive to light (photophobia) .
It occurred after a blow or trauma .
You wear contact lenses and notice pain or decreased vision.

At Clínica Nivaria , we offer specialized and priority care for acute symptoms such as red eyes.

Diagnosis of red eyes

The diagnostic process begins with a complete ophthalmological examination , which includes:

Medical record

Onset of redness and its evolution.
Presence of accompanying symptoms.
Use of contact lenses, history of allergies, eye trauma, previous surgeries, or systemic diseases.

Slit-lamp examination

It allows for detailed evaluation of the ocular surface, cornea, conjunctiva and anterior chamber, to detect signs of inflammation, ulcers, foreign bodies or secretions.

Intraocular pressure measurement

Important to rule out acute glaucoma , one of the most serious causes of red eye.

Additional tests

In some cases, the following are performed:

Fluorescein staining : to detect lesions in the cornea.
Culture of eye secretions , if a resistant bacterial infection is suspected.
Optical coherence tomography (OCT) or fundus examination , if there is suspicion of internal involvement of the eyeball.

Treatment for red eyes depending on the cause

Each case requires a personalized treatment plan . Below is a summary of the most common measures:

Cause	Treatment
Viral conjunctivitis	Washes with saline solution, lubricating eye drops, hygiene measures
Bacterial conjunctivitis	Topical antibiotic eye drops
Allergic conjunctivitis	Topical antihistamines, artificial tears, avoid allergens
Dry eye	Artificial tears, eyelid hygiene, treatments such as pulsed light
Blepharitis	Daily eyelid cleaning, local heat, antibiotic eye drops if there is an infection
Improper use of contact lenses	Discontinue use, anti-inflammatory treatment, and antibiotics if complications arise.
Foreign body	Safe extraction by a specialist, antibiotic eye drops
Uveitis	Topical or systemic corticosteroids, treatment of the underlying cause
Acute glaucoma	Urgent medication to reduce eye pressure, possible surgery
Keratitis	Antibiotics or antivirals, close monitoring to prevent ulcers

⚠️ Important : Do not self-medicate or use eye drops on your own , especially eye drops with corticosteroids, as they can worsen infections or mask serious symptoms.

Red eye prevention

Many cases of eye redness can be prevented with a few basic precautions:

Avoid touching your eyes with dirty hands .
Wash your hands frequently , especially if there are viral infections nearby (conjunctivitis, colds).
Do not share eye hygiene products, towels, or cosmetics .
Wear protective goggles if you work in environments with dust, smoke, or chemicals.
Hydrate your eyes if you spend many hours in front of screens.
Wear certified sunglasses to protect yourself from ultraviolet radiation.
Do not wear contact lenses beyond the recommended time and maintain proper hygiene.
Go for regular eye exams , especially if you have chronic conditions such as allergies, diabetes, or glaucoma.

What do we do at Clínica Nivaria for red eyes?

At Clínica Nivaria , we treat red eyes with a holistic approach, taking into account:

The urgency of the case .
The specific cause of the redness .
The patient's general eye health status .
Advanced diagnostic technology to detect even causes not visible to the naked eye.
A team of ophthalmologists with experience in ocular surface, retina, glaucoma, uveitis and surgery .

Furthermore, in cases of persistent or recurring redness, we provide personalized follow-up , adjusting the treatment according to the patient's progress.

When is it an emergency?

Remember: red eyes can be a warning sign of conditions that require immediate attention. Don't wait for the symptom to resolve on its own if it's accompanied by: