What is the Fovea?
The fovea or fovea centralis is a small depression at the center of the retina that's responsible for central vision. It's the point at which visual acuity is at its highest.
Visual acuity is the ability to identify the details of objects when you look at them.
The fovea contains many cones (the cells that receive visual information). This is why the fovea is responsible for clear vision.1
The central fovea appears as a small flat spot at the retina's center. It's about 1.5 mm in diameter and contains about 199,000 cones/mm squared.2
A unique feature of this central pit is the displacement of other retinal components to create space for cones. This can be seen through a standard optical coherence tomography (OCT) that indicates foveal thickness.3
The fovea has no rods. Rods enable scotopic vision or vision at low light levels. They are more abundant in the surrounding retina.
Although the fovea is in the retina, it receives its blood supply from the choroid rather than the central retinal artery that supplies the retina.
The choroid is a vascular eye layer found between the retina and sclera. It also supplies blood to other parts of the retina.
The fovea enables sharp central vision (foveal vision).
This type of vision enables you to perform activities that require visual detail like reading, writing, or driving.
To see well, you must focus the image on the fovea centralis. This is the reason why you unconsciously move your head or eyes when reading this sentence — to center the words on the fovea.
Fovea Problems & Diseases
Left untreated, a variety of eye diseases may impair the fovea, resulting in vision loss.
The following are examples of fovea-related issues:
Branch Retinal Vein Occlusion (BRVO)
One major artery and one main vein go through the retina of the eye. Branch retinal vein occlusion occurs when the branches of the retinal vein get blocked.4
Blood and fluid may leak out onto the retina when a vein is blocked, causing macular swelling. This may compromise your central vision.
Choroidal Neovascular Membranes
Choroidal neovascular membranes (CNVM) are new, abnormal blood vessels that form underneath the retina and cause damage.
These blood vessels develop in the choroid. They are able to get past the choroid-retina barrier. This may cause visual loss when they leak or bleed in the retina. This condition is typically related to advanced wet macular degeneration.
This is a serious infection of the retina caused by cytomegalovirus. It can lead to foveal damage.
Cytomegalovirus retinitis most often affects people with weak immune systems.
Symptoms include a slow onset of floaters. This can progress to central vision loss.
This is a common disease among people with diabetes. The high sugar levels in their blood cause damage to blood vessels in the eye, causing them to leak.
The vessels can also become blocked, causing blood flow to stop. Abnormal new vessels may develop.
All the scenarios above affect the ability to see.
Histoplasmosis is an infection of the lung caused by inhaling airborne spores from the fungus type called Histoplasma capsulatum.
Doctors believe that, even if it’s mild, the infection might spread to the eye through the bloodstream.
It may cause a dangerous disease known as presumed ocular histoplasmosis syndrome (POHS) if it progresses into the eye.5
Macular degeneration is a common eye infection. It's the leading cause of vision loss among people aged 50 years or older.
When you have macular degeneration, you lose your central vision. This means that you can’t see the fine detail of objects regardless of your distance from them.
However, your peripheral (side vision) won’t be affected.
This is a break in the tissue of the macula.
Things in your center vision become blurry, wavy, or distorted as the hole forms. As the hole expands, a dark or blind area appears in your central vision.
This condition does not affect peripheral vision.
Retinoblastoma is an eye cancer. The cancer begins in the retina and can spread to other parts of the eye. It occurs when the retina's nerve cells become abnormal, increasing in size and quantity.
The cells ultimately join together to create a tumor. Usually, the cells distribute in and around the eye but can spread to other parts of the body. Retinoblastoma typically affects children and can spread aggressively, requiring immediate medical attention.
Also known as fundus flavimaculatus, this is a kind of macular degeneration in which the macula's photoreceptor cells die.
Unlike age-related macular degeneration, Stargardt's disease can affect young adults and children.
The disease results in central vision loss at an early age.
When to See a Doctor
Several eye problems can affect the fovea. Consult your eye doctor if you have any persistent issues with your eyes.
Seek emergency treatment if an eye issue is causing flashes or vision loss.
Foveal diseases are treated depending on the cause of damage.
Common treatments include:
- Laser surgery. Also known as focal laser treatment, laser surgery stops blood vessels from leaking into the retina if you have diabetic retinopathy.
- Medications. An ophthalmologist may administer medications such as eye injections. This is common in the treatment of branch retinal vein occlusion (BRVO). Anti-VEGF drugs treat abnormal blood vessels.6
- Vitrectomy. This is a surgery used to treat macular holes. It involves replacing the vitreous fluid with a gas bubble to help flatten the hole.
- Supplements. Your eye doctor may prescribe supplements rich in lutein, zeaxanthin, vitamin C, vitamin E, and zinc to protect against progression of macular degeneration.
Why Routine Eye Exams are Important
Routine treatment is important because it helps your eye doctor detect any issues before they become serious.
During a routine eye exam, your opthamologist will check for all common eye issues such as cataracts, macular degeneration, tears, or detachments.
They'll also give you advice on best care practices to keep your eyes healthy.
Other Parts of the Eye
Other important parts of the eye include:
- The cornea. The clear bulging surface of the eye.
- Sclera. The white part of the eye.
- Conjunctiva. Covers the sclera.
- Iris. The color part that surrounds the pupil.
- The lens of the eye. The clear part of the eye that helps with focus.
- Pupil. An opening through which light passes into the eye.
- Vitreous Humor. The fluid-filled space between the lens and the retina.
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