Red eyes: what can be the causes of conjunctival hyperemia?

By Cristiano Antonino On Apr 19, 2022

So-called “red eyes”, or conjunctival hyperemia, are a very common eye disorder that is caused by dilated blood vessels due to irritation or infection

Most of the time, the pathologies that cause conjunctival hyperemia are easily diagnosed and resolve themselves in a relatively short time. In other cases, the redness of the eye may depend on injuries, trauma or foreign bodies present in the eye and, more rarely, may indicate various pathologies, even serious ones, such as: acute attacks of glaucoma, uveitis, keratitis, scleritis.

What are the pathologies that cause redness in our eyes and which tissues that form the anatomy of the eye can become irritated or inflamed?

Red eyes: how to prevent them and when to see an ophthalmologist

The varying seriousness and severity of the causes of conjunctival hyperemia necessitates a specialist diagnosis, which is necessary to distinguish between more and less serious pathologies.

As a general guideline, however, attention should be paid to periocular hygiene, which helps to avoid the most common irritations.

It is therefore inadvisable to touch one’s eyes often and to apply contact lenses without adequate training on their hygiene, the correct application methods and the right application time, while it may be useful to wash one’s hands often, to avoid the transmission of bacteria and irritants, and, in the presence of initial redness, to cleanse the periocular area with special sterile disinfectant wipes, easily available in pharmacies.

Red eyes due to scleritis or episcleritis

Scleritis is inflammation of the sclera, the whitish outer membrane of the eyes.

In the case of scleritis, the eye appears particularly red and is painful to the touch.

To resolve it, the doctor may simply prescribe a systemic therapy or combine it with a topical treatment.

In the case of episcleritis, on the other hand, the inflammation only affects the outer surface of the eye and is often due to systemic diseases, such as gout or collagenopathies.

For this reason, patients with risk factors tend to opt for a course of prevention and treat primarily the underlying disease.

When the scleritis is mild, tear substitutes with hyaluronic acid and amino acids are sufficient to resolve the redness.

More aggressive conditions, on the other hand, require topical corticosteroid therapies with low systemic absorption.

In such cases, however, it is necessary to follow medical prescriptions carefully, as corticosteroids may hinder treatment of the underlying systemic disease.

Conjunctivitis: allergic, contact or bacterial

Conjunctivitis is inflammation of the conjunctiva, the tissue covering the inside of the eyelids and the front of the eyeball.

It is a mucous membrane densely supplied with blood vessels, which can dilate due to an allergic reaction, contact with external irritants or the transmission of bacteria or viruses.

Conjunctivitis also presents ocular symptoms, such as itching, often associated with allergies, burning, in case of dryness, or predominantly catarrhal secretions, when the origin of conjunctivitis is bacterial, serous if viral.

For this reason it is advisable to book a medical consultation: the specialist will diagnose the cause of the conjunctivitis through an anamnesis of the symptoms and microscopic analysis and will set the appropriate therapy.

Conjunctivitis is usually treated with antihistamine eye drops, tear substitutes and, in the case of bacterial conjunctivitis, antibiotics.

Another condition that can affect the conjunctiva is subconjunctival haemorrhage, which occurs when one of the blood vessels supplying the conjunctiva breaks.

This tends to resolve itself within a couple of weeks, but if it recurs, the doctor may consider it necessary to request blood tests and a cardiology or internist check-up.

Pterygium and pinguecula: two disorders of the conjunctiva that cause “red eyes”

Pterygium refers to a fibrous membrane that forms on the conjunctiva and cornea, starting from the inside of the eye, and causes redness of the eye.

A similar disorder is pinguecula, which manifests itself as a thickening of the conjunctiva of the eyeball.

Both problems are treated with anti-inflammatory eye drops or corticosteroids, which are only prescribed by an ophthalmologist, while in more severe cases it may be necessary to resort to surgery to remove the membrane.

In any case, it is advisable to use sunglasses to protect the eye and artificial tears to reduce the friction caused by the sliding of the eyelid over the conjunctival surface.

Blepharitis: a pathology of bacterial origin

In the presence of conjunctivitis, the edge of the eyelid becomes inflamed and swollen: we may be dealing with blepharitis.

Blepharitis originates in the glands at the eyelashes, which are responsible for the secretion of a fluid rich in fat.

When the secretion is impaired, symptoms include redness and swelling of the eyelid, itching and the formation of scaly tissue.

The main cause of blepharitis is bacterial infections, and in the case of acute inflammation we speak of chalazion, while if only one follicle is inflamed it is a stye.

In the case of blepharitis it is essential to treat the inflamed eye with disinfected and emollient eye wipes and ophthalmic products, which often come in the form of sprays, while antibiotic eye drops and ointments, which can be combined with pain-relieving and anti-inflammatory eye drops, are needed to resolve the bacterial infection.

Ectropion and entropion: two disorders of the eyelids

Ectropion and entropion are two other disorders affecting the eyelids: in the first case the eyelid margin tips outwards, in the second inwards, causing the eye to redden.

The treatment of these two conditions involves the use of corticosteroids, anti-inflammatory eye drops or lubricants to relieve the painful symptoms.

However, when the inflammation recurs, surgery is required to resolve the problem.

Keratitis: an inflammation of the cornea

The cornea is the transparent membrane that covers the pupil and the iris at the front of the eyeball.

When the cornea is inflamed, e.g. by viruses such as herpes simplex, bacteria or fungi, but also by dry eyes or incorrect contact lens wear, keratitis occurs.

The redness, however, could also be caused by corneal abrasion, a rather severe injury that occurs when the cornea is scratched, or corneal ulcer.

It is therefore advisable to refer to your ophthalmologist to establish a diagnosis and set up the correct treatment, which may include the use of eye drops and, in certain cases, an eye patch to be maintained for a few days.

Anterior uveitis: intense pain and light intolerance

Uveitis occurs when there is inflammation of the uvea, the highly vascularised tissue surrounding the pupil.

Again, the symptoms include redness in the eye, but this is accompanied by other symptoms such as intolerance to light, pain and intense tearing.

Uveitis is a typical pathology of industrialised countries and can be inflammatory or autoimmune; infectious uveitis is rarer in our country.

In this case too, therefore, the diagnostic phase is particularly important, as it will allow the specialist to assess the most suitable treatment to control the ocular inflammation, which may involve the use of antibiotic, cortisone or cycloplegic eye drops, whose action, even combined, is useful in attenuating the painful symptoms.

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