What Causes Fluid Behind the Retina?

The retina at the back of the eye is the tissue you rely on for sight. The eyes themselves are fed by numerous blood vessels and filled with fluid. Sometimes, though, there can be problems. Fluid can build up behind the retina due to different conditions, including macular edema and central serous retinopathy.

Here's what to know to recognize what may be causing fluid underneath the retina and the steps you need to take for appropriate diagnosis and treatment.

Causes of Fluid Behind the Retina 

More than one thing can cause fluid to build up behind the retina. So it's important to take a closer look to determine the reason in your case.

Macular Edema

With macular edema, fluid builds up in an area of the retina known as the macula. This is the area that you rely on for sharp central vision. If fluid builds up underneath, it can get distorted as the tissue swells.

Fluid leakage can come from damaged blood vessels nearby in the retina. This can be the result of a number of different conditions. Macular edema can be caused by any disease that damages blood vessels and can even result from eye surgery.

Central Serous Retinopathy

With central serous retinopathy, fluid can build up under the retina. The retinal pigment epithelium (RPE), which is between the choroid and the retina, stops functioning as it should. Without this working right, fluid begins to build up under the retina.

This can cause visual distortion and even a slight retinal detachment in some cases. Those most at risk for this condition are men ranging in age from their 30s to their 50s, people with type A personalities, those taking steroids, and people with autoimmune disorders.

Diabetic Retinopathy

Cases of diabetic retinopathy result from the elevated blood sugar that occurs in those who have diabetes. Over time, high amounts of sugar in the blood can damage the retina by affecting the blood vessels. The blood vessels swell, and the tight junctions in them break down, leading to bleeding or leaking fluid.

Also, glycosylated red blood cells (which have sugar bound to the hemoglobin) do not bring enough oxygenated blood. This triggers the formation of new blood vessels. These, however, are fragile and easily leak and bleed further. This leads to more fluid behind the retina and ultimately may end up in a detachment.

Choroidal Effusion

The choroid is a layer of spongy blood vessels between the retina and the white part of your eyes, known as the sclera. The role of the choroid is to deliver nutrition and oxygen to the outside portion of the retina.

If fluid or blood (choroidal effusion) gets between the choroid and sclera, it can lead to a detachment, known as serous choroidal detachments. These are generally related to low intraocular pressure, usually following recent glaucoma surgery.

This decrease in pressure allows the fluid to accumulate in the space around the cells while the capillaries become more permeable due to inflammation.

Diagnosis of Fluid Behind the Retina

To determine if you may have fluid beneath the retina, your eye doctor will thoroughly examine your eyes. Some of the tests they will likely use may include:

Amsler Grid Test

An Amsler grid test is an easy way to determine if your all-important central vision has changed. With this test, you simply look at the grid-like squares and tell the doctor whether any of the lines look wavy or if there are any missing areas. This can help to detect even minor vision changes.

Optical Coherence Tomography (OCT)

Optical coherence tomography takes cross-sectional pictures of your retina with a special camera. It can measure retinal thickness and detect fluid beneath the retina and swelling. With this information, your doctor can determine whether you need treatment for any fluid trapped under the retina.

Fundus Autofluorescence (FAF)

With autofluorescence imaging, the idea is to make use of the retina's naturally occurring fluorescence. Even without injecting any dye, when a blue light is used to illuminate the retina, certain structures glow.

These glowing structures can be captured in a black and white image. Characteristic patterns may then indicate that diseases like age-related macular degeneration or central serious retinopathy are progressing and can help indicate appropriate treatment.

Fluorescein Angiography

Fluorescein angiography can be used to diagnose swelling in the retina. With this, a yellow fluorescein dye is injected into your arm. When it reaches your eyes a few seconds later, it will cause them to shine brightly. A special camera can then be used to take pictures of the area. These can alert your doctor about what type of treatment is needed and where.

Indocyanine Green Angiography

With indocyanine green angiography, the dye works similarly to fluorescein but only can be viewed in infrared light. Also, it circulates deeper into the retinal layers where they can be photographed with an infrared-sensitive camera. This is often used for choroidal angiography to complement fluorescein angiography of the retina.

Ocular Ultrasound

With this test, also known as a b-scan ultrasound, sound waves are used to create a picture of structures within the eye. This technique can be used to detect complications such as retinal detachment, diabetic retinopathy, and eye cancers.

Treatment of Fluid Behind the Retina

Deciding on the best treatment for any particular case of fluid behind the retina will be based on the cause here. Some possible treatment approaches include the following:

• Medications such as corticosteroids or anti-inflammatory drugs aim to quell inflammation. These can come in the form of drops, pills, or even dispersed via extended-release devices in some cases.
• Sometimes, it may be necessary to use a surgical approach such as a vitrectomy in which the jelly-like substance that normally fills the eye is removed.
• In some cases, such as in diabetic retinopathy, laser treatment may stop blood vessels from leaking and reduce retinal swelling.
• If you have macular edema, you may be treated with what's known as anti-VEGF injections. Vascular endothelial growth factor (VEGF) is a protein that leads to the production of new blood vessels. With macular edema, these blood vessels may leak. The use of anti-VEGF can slow the production of these new blood vessels.
• Making lifestyle changes, such as controlling blood sugar levels in the case of diabetic retinopathy, should also be kept in mind when considering how to help alleviate fluid behind the retina.

Summary

Fluid beneath the retina can occur due to inflammation or leaking blood vessels in conditions such as diabetic retinopathy, macular edema, central serous retinopathy, and choroidal effusion. An eye doctor will perform an eye exam and may use various imaging methods to assess the problem.

Treatment depends on the condition causing the fluid buildup. Anti-inflammatory medications, surgery, laser treatment, anti-VEGF injections, or lifestyle changes may be used.

A Word From Verywell

Fluid beneath the retina can come from a variety of sources. The good news is once practitioners figure out what may be at the root in your particular case, there are many different treatments that may alleviate this and help to preserve your vision.