What is macular edema?
A macular edema occurs when fluid builds up in the macula. The macula is situated in the centre of the retina. The macula’s role in the retina is to enable sharp and consistent vision straight ahead of you. When fluid builds up in the macula, it becomes thicker and swells leading to blurry and distorted vision.
What causes macular edema?
When the blood vessels near the retina become damaged, it causes fluid to accumulate in the macula. There are a variety of things that can cause macular edema:
Eye surgery
Any activity that disrupts blood vessels and causes inflammation can lead to macular edema. These include surgeries for other conditions such as cataracts, glaucoma and retinal disease. Macular edema after surgery is generally very mild and easily treated with eye drops that can help reduce inflammation.
Inflammation in the retina
Uveitis describes a range of inflammatory diseases that can lead to swelling in the eye and the destruction of eye tissues. It can affect the cornea, lens, iris, retina, optic nerve, vitreous, and the sclera (white of the eye).
Blocked blood vessels
Retinal vein occlusion describes the blockage of veins attached to the retina. If the fluids in these veins cannot drain properly or leak into the macula, this causes macular edema. High-blood pressure, glaucoma and inflammation from other conditions that can cause blocked blood vessels.
Age-related macular degeneration
Age-related macular degeneration (AMD) breaks down the macular which is vital for ensuring that you can see clearly ahead of you. AMD has two main forms; wet and dry AMD. In ‘wet AMD’ (also known as ‘neovascular AMD’), blood vessels below the retina, also known as the choroid, leak fluid into the macula. Dry age-related macular degeneration on the other hand, is a slow deterioration of the cells of the macula, as the retinal cells die off and are not renewed often over many years.
What are the symptoms of macular edema?
Macular edema affects the central field of vision. One of the first symptoms of the condition will be a blurry or distorted image. The changes in your vision may start with mild blurriness, before eventually becoming impossible to ignore. If macular edema has only affected one eye, changes in eyesight may not be noticeable until the condition has advanced, or until both eyes are heavily affected.
How is macular edema diagnosed?
There are three different ways in which a macular edema can be diagnosed:
Optical coherence tomography (OCT)
This is a popular choice as it is non-invasive. This involves a specialised tube that uses light to produce a high definition cross-sectional image of eye tissue, including the retina. This is one of the most effective ways to identify a cystoid macular edema.
Fluorescein angiography
This method uses a micro camera system to locate leakages in blood vessels that occur during macular edema. A special dye is injected into a vein in your arm. This quickly travels to your eye where it makes blood vessels show up on digital photos.
Dilated retinal exam
In this method, the doctor uses a special lens to see the macula and identify the cysts.
What is diabetic macular edema?
Diabetic macular edema (DME) is the result of fluid build-up in the macula part of the retina, due to diabetic retinopathy. In order to develop DME, you must first have diabetic retinopathy.
Common symptoms of diabetic macular edema are floaters, blurry vision and in some cases, blindness if the problem is not diagnosed and treated fast enough.
There are two main forms of diabetic macular edema:
Focal DME
This occurs due to abnormalities in the blood vessels in the eye. A focal laser treatment is used to treat this type of diabetic macular edema.
Diffuse DME
This occurs because of widening/swelling retinal capillaries (very thin blood vessels). A grid laser treatment is used to diffuse this type of diabetic macular edema.
