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Exploring the Causes of Subconjunctival Hemorrhage

Medically reviewed by Victor Paulino, MD, DPBO · Ophthalmology · Makati Medical Center

Written by Nikita Bhalla · Updated Aug 23, 2022

Exploring the Causes of Subconjunctival Hemorrhage

A red spot in the eye, or subconjunctival hemorrhage in medical terminology, may occur due to varied factors. Some of these factors are serious medical conditions, while others are due to reasons that do not usually require much attention. Before we start discussing the causes of a red spot on the eye, let’s talk about what it actually is. 

What is Subconjunctival Hemorrhage?

A subconjunctival hemorrhage occurs due to leakage or breaking of the narrow and fragile blood vessels below the conjunctiva, the thin and transparent membrane. This membrane is located over the sclera, the white of the eye. Blood leakage under the conjunctiva leads to a subconjunctival hemorrhage. The size of the spot can vary from a tiny speck to covering the entire sclera. 

The extent of blood leakage is determined by the severity of an injury or the size of the injured blood vessel. Not always is the injured vessel a narrow one. Large vessels may also get ruptured, causing a larger red spot that covers the entire eye. These spots, common to individuals across ages, are accompanied by pain, irritation, or other side effects. 

A red spot on the eye usually appears scary and looks like a serious cause for concern. They do not lead to vision disorders or have other side effects. It generally disappears by itself within a week or two. However, it is mostly advised that you see a doctor to eliminate the risks of a medical condition like eye infection that requires treatment. 

Now, let’s take a look at the leading causes of subconjunctival hemorrhage.

Causes of Subconjunctival Hemorrhage

Activities that increase blood pressure levels

Actions like sneezing and coughing several times in a row, vomiting, heavy-lifting, childbirth, constipation, etc. lead to a spike in blood pressure levels. This enhances the chances of a red spot on the eye. However, raised blood pressure itself does not cause such spots. These are some of the most common causes of subconjunctival hemorrhage. 

Injury to the eye

A minor eye injury caused by something that has poked the surface of your eye or you rubbing your eye a bit too hard or an insect flying into the eye. These may rupture the fragile blood vessels below the sclera, causing blood leakage. Subsequently, it might lead to a red spot on the eye. It is usually advised that you wear protective eyewear like eye shades for sports and activities that involve flying debris. Sunshades are great wear to protect your eyes when you are outside, reducing the risk of small dust particles flying into your eyes along with the wind.

Irritation from contact lens

A small dust particle caught under your contact lens may cause enough irritation for you to rub your eye hard. This might cause blood in the capillaries under the sclera to break or leak, leading to a subconjunctival hemorrhage. Make sure that you remove your lens and clean it thoroughly if it makes your eye itch. Not just that, also keep in mind not to wear your lens longer than the recommended time limit. In case you use disposable lenses, change them as per instructions on the manual. 

Blood thinners

Drugs that specialise in thinning the blood increase the chances of bleeding. Some of these medications are aspirin, heparin, enoxaparin, apixaban, enoxaparin, rivaroxaban, warfarin, and dabigatran. 


Episcleritis is a severe inflammatory disorder of the episclera, the narrow tissue between the white sclera and the conjunctiva. The episclera has a thin network of blood vessels. This condition usually gets cured by itself, although some cases may lead to inflammatory disorders in other parts of the body.

Sickle cell anemia

This blood disorder is hereditary in nature. This occurs when abnormally shaped blood cells experience obstacles in circulating blood and oxygen throughout the body. The disorder manifests itself through pain, chronic anaemia, and comma-shaped red spots on the eye or lines on the sclera. Sickling of red blood cells inside some fragile blood vessels leads to blockages, causing subconjunctival hemorrhage.

Conjunctival hemangioma

In this condition, red spot on the eye may appear due to blood vessels developing on the sclera, along with a congenital malformation of a clump. This growth is benign by nature and can be surgically removed.

Blood clotting disorders

Blood clotting disorders like von Willebrand disease and Hemophilia may raise the risk of subconjunctival hemorrhage.

Therefore, it is ideal to consult your doctor if you see a red spot on your eye, especially after experiencing these causes of subconjunctival hemorrhage.


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

Victor Paulino, MD, DPBO

Ophthalmology · Makati Medical Center

Written by Nikita Bhalla · Updated Aug 23, 2022

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