Perret Opticians
We have been opticians for three generations in our family, and our activity is targeted on three areas, optometry, contact lenses and optical instruments.












The Red Eye


Contents of this Page


Introduction: The Red Eye

There are numerous conditions which can cause eye redness, and nearly any condition causing symptoms of discomfort will also lead to eye redness. Redness usually specifically refers to the "white of the eye." Redness here can be due to engorged blood vessels on the surface of the eye, or due to hemorrhage on the surface. The location and pattern of redness may be important to making a diagnosis, as may be any associated symptoms and findings.

This page discusses a few causes of eye redness which are not discussed elsewhere. There are also links to other Symptom and Diagnosis pages based on other symptoms in addition to the redness.


For eye anatomy explanations, go to ANATOMY


Conjunctivitis, or "pink eye", is an infection of the lining over the sclera (the "white of the eye"). This lining is the conjunctiva, and it also lines the inside of the eyelids. The infection is typically either caused by a virus, or by bacteria.

Viral conjunctivitis is common in adults, and is extremely contagious (even with indirect contact). Sometimes it may occur with the common cold. The eyes become injected and itch. There may be a watery or mucoid discharge, and the lids may swell. Both eyes are usually affected. Treatment is to reduce symptoms, since antivirals are not available. It usually runs its course in about 2 weeks. Care must be taken to wash the hands after touching the eyes.

Bacterial conjunctivits is more common in children. While also contagious, it requires more direct contact for spread than a viral infection. Eye redness, lid swelling, and a heavy pus-like discharge are common. Treatment with antibiotic eyedrops, ointments, and sometimes even pills by mouth are necessary for treatment. Cultures may be taken to determine the bacteria involved and appropriate antibiotics.


Subconjunctival hemorrhage

A subconjunctival hemorrhage usually appears as a sudden, spontaneous, bright red patch on the surface of the eye. This occurs when a small blood vessel breaks in the lining over the eye (the conjunctiva). It is usually otherwise painless, and the vision is not affected. The redness can be quite dramatic. This can occur spontaneously, or after direct trauma, sneezing or coughing, or straining. High blood pressure is another possible cause. The redness usually disappears over a one week period.

Subconjunctival Hemorrhage



Episcleritis is an inflammation of the episclera, which is a fibrous layer between the white wall of the eye (the sclera) and the lining of the eye (the conjunctiva). With this condition, there is a patch of injected blood vessels on the surface of the eye (only a part of the eye is red). It may be associated with mild irritation, or sometimes iritis. The condition may resolve without treatment, but it also can recur, and may affect both eyes. It sometimes is associated with gout.

Medication (eyedrop) toxicity

Many prescription and non-prescription eyedrops can create ocular irritation or allergy, especially if used for a long period of time. Over-the-counter eyedrops such as artificial tears, allergy eyedrops, and contact lens solutions all contain preservatives unless the bottle specifically states "preservative free". These preservatives can commonly cause eye irritation and redness, if the user is sensitive to that preservative.

Prescription antibiotic eyedrops can be effective at treating infection, but they can also be quite irritating to the eye and may cause prolonged irritation and redness. This may lead to confusion as to whether or not the infection has really been treated. Steroid eyedrops usually are not particularly irritating. A few prescription allergy eyedrops are known to cause some eye redness and burning on installation.

Vasoconstricting or decongestant eyedrops ("get the red out" drops) simply blanch out blood vessels on the eye surface, concealing redness. If these eyedrops are used frequently to mask redness, there may be a rebound redness when the drops are discontinued. This may lead to more usage of the eyedrop to conceal the worsening redness.



A pinguecula is an extremely common lesion which consists of a yellow-white deposit on the bulbar conjunctiva adjacent to the nasal or temporal aspect of the limbus Histological examination shows degeneration of the Collagen fibres of the conjunctival stroma, thinning of the overlying epithelium and occasionally calcification. Some pingueculae may enlarge very slowly but surgical excision is seldom required.




A pterygium is a non-cancerous growth of the conjunctiva onto the cornea. It may start as a "pingueculum", which is a small lump of tissue located on either side of the cornea on the sclera. A pterygium has a "head", which may progressively cover the cornea, and a "body" which extends toward the corner of the eye (usually the inside corner). Often the "body" of a pterygium may appear red, with noticeable blood vessels.

A pterygium which progressively moves toward the pupil may need to be surgically removed in order to prevent the vision from being affected. Redness and irritation from a pterygium can be managed with artificial tears, and with other prescription eyedrops.

Pterygia seem to occur more frequently in people who spent much time outside, and is especially common in the southern lattitudes. If they need to be removed, there is a possibility of recurrence.


Other Conditions causing redness found on other pages:

Allergic problems - usually with itching and irritation.
Blepharitis - itching, burning, eyelid irritation.
Cellulitis (infection) of eyelid skin - eyelid swelling, tenderness.
Contact lens related problems - may have pain, scratchy sensation.
Corneal abrasion - pain, tearing, sensation that something is in eye.
Dry eye - irritation, scratchy sensation, sometimes tearing.
Ectropion (out-turning) of eyelid - scratchy sensation, pain, tearing.
Entropion (in-turning) of eyelid - scratchy sensation, pain, tearing and discharge.
Glaucoma (acute) - pain, blurred vision.
Iritis - pain, sensitivity to light, blurred vision.
Phlyctenulosis - sensation that something is in eye, burning, itching.
Scleritis - pain, blurred vision.
Thyroid related eye disease - scratchy sensation, double or blurred vision, protruding eyes.
Trichiasis (in-turning of eyelashes) - scratchy sensation, pain, tearing.



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