The eyeball is a hollow organ connected to the brain by the optic nerve. On entering the eye, the optic nerve spreads out in a thin layer of nervous tissue-the retina-and covers the inside of the eye like wallpaper.
For those with wet macular degeneration, the Food and Drug Administration has approved Visudyne®, a drug therapy for this form of the disease (also known as photodynamic therapy, PDT) and as recent as 2005, a treatment called Macugen. Macugen (pegaptanib sodium injection), is the first effective treatment that helps preserve vision for all subtypes of neovascular AMD. The neovascular “wet” form of macular degeneration is characterized by the invasion of new, poorly formed blood vessels beneath the retina. These new blood vessels are poorly formed and leak their contents into the retina and subretinal space, casuing injury to the retina and scarring. Scientists are currently studying laser treatments for dry macular degeneration as well.
Deterioration of the macula results in blurry vision when a person looks directly at an object; peripheral or side vision is unaffected. Macular degeneration developing in one eye usually indicates that the other eye is also in danger of developing the disease. Regular examinations at home with the Amsler Grid are important to detect early changes in persons prone to macular degeneration. An Amsler Grid and instructions on proper use are listed below. Patients who have macular degeneration may find performing visual tasks such as reading, writing, typing, sewing, etc., still possible with the use of magnification and strong, focused lighting.
Instructions on using the Amsler Grid:
Wear your reading or bifocal glasses.
Cover the opposite eye. Test each eye separately.
Look at the center dot.
Keep your vision on it at all times.
While looking directly at the center and only the center, be sure that all of the lines are straight and all the small squares are the same size. If any area on the grid becomes distorted, blurred, discolored or otherwise abnormal, see your ophthalmologist immediately.
What is the Macula?
Before you can get a solid understanding of macular edema it is important to get an idea of what the macula is all about. The macula is the part of the retina that provides you with your sharpest central vision. A normal, healthy macula allows you to see objects clearly. The interior of the back part of the eye is lined with a wall paper like structure known as the retina. This layer of tissue acts a lot like film in a camera but also transmits images to the optic nerve.(which then sends to brain) – The macula is a very small area at the center of the retina. This is a thin layer of light-sensitive tissue that lines the back of the eye.
What is Macular Edema?
Macular edema is swelling or thickening of the eye’s macula, the part of your eye responsible for detailed, central vision.
What is Diabetic Macular Edema?
When long-standing diabetes damages the delicate blood vessels within the retina, they leak fluid into the surrounding tissues. Sometimes, this happens in the center of the retina and the macula itself becomes swollen. When this occurs, we call the swelling diabetic macular edema.
Diagnosing Macular Edema
During routine dilated eye exams our eye doctors may detect central swelling. Depending on the amount of fluid that has leaked these spots may be easy or hard to detect. A fluorescein angiography procedure is conducted where sodium fluorescien dye is injected into an arm or hand and then retina photographs are taken. If there are any abnormalities on the retina, the dye will usually reveal them by leaking, staining or by its inability to get through blocked blood vessels.
Macular Edema Treatment
The treatment of cystoid macular edema may include one or more of the following:
Ocular steroid eye drops to decrease swelling
Injection of ocular steroids around the eye to reduce swelling
Oral anti-inflammatory medicines
Surgery to remove excess fluid from the center of the eye (vitrectomy)
What causes macular edema?
There are various ways that cystoid macular edema develop. Patients with diabetic retinopathy are at risk for developing CME as well as those with uveitis and retinal vascular disease. There are also reported cases of CME is patients who have had recent eye surgeries like cataract surgery. When a patient develops this after cataract surgery post operative inflammation may cause the vessels in the center of the retina to leak. Swelling and distorted vision with result when the leaking of the blood vessels begins.