What causes a macular hole?
Most of the eye’s interior is filled with vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape. The vitreous contains millions of fine fibers that are attached to the surface of the retina. As we age, the vitreous slowly shrinks and pulls away from the retinal surface. Natural fluids fill the area where the vitreous has contracted. This is normal. In most cases, there are no adverse effects. Some patients may experience a small increase in floaters, which are little “cobwebs” or specks that seem to float about in your field of vision
However, if the vitreous is firmly attached to the retina when it pulls away, it can tear the retina and create a macular hole. Also, once the vitreous has pulled away from the surface of the retina, some of the fibers can remain on the retinal surface and can contract. This increases tension on the retina and can lead to a macular hole. In either case, the fluid that has replaced the shrunken vitreous can then seep through the hole onto the macula, blurring and distorting central vision.
Macular holes can also occur in other eye disorders, such as high myopia (nearsightedness), injury to the eye, retinal detachment, and, rarely, macular pucker.
What are the symptoms of Macular Hole?
The symptoms of macular hole include:
• A decrease in the ability to see fine details when a person is looking directly at an object, no matter how close or far away it is.
• A change in vision that makes a person feel like he or she is looking through a dense fog or thick, wavy glass.
• The appearance of a dark spot across the middle of the field of view.
When these symptoms are caused by a macular hole, they will occur in only the eye with the macular hole. It is very rare for someone to have macular holes in both eyes.
If any of these symptoms occur, it is important to schedule an appointment with your doctor as soon as possible. The doctor will use a special instrument to look inside the eye and see whether the macula has a hole in it.
To diagnose a macular hole, your doctor will perform special imaging tests called optical coherence tomography that gives them a cross sectional view of your retina. This tests helps diagnose a macular hole and can differentiate it from other diagnosis that may appear similar.
How is macular hole diagnosed?
During an eye exam, your ophthalmologist will dilate your pupils and examine your retina. You may have a test called fluorescein angiography that uses dye to illuminate areas of the retina.
Another test called optical coherence tomography (OCT) is most helpful in making an accurate macular hole diagnosis. With OCT, a special diagnostic laser camera is used to photograph your retina. It measures the thickness of the retina and is also very sensitive at detecting swelling and fluid. OCT can also diagnose small macular holes that are too small to be seen in an examination or with angiography.
How is a macular hole treated?
Although some macular holes can seal themselves and require no treatment, surgery is necessary in many cases to help improve vision. In this surgical procedure–called a vitrectomy–the vitreous gel is removed to prevent it from pulling on the retina and replaced with a bubble containing a mixture of air and gas. The bubble acts as an internal, temporary bandage that holds the edge of the macular hole in place as it heals. Surgery is performed under local anesthesia and often on an out-patient basis
Following surgery, patients must remain in a face-down position, normally for a day or two but sometimes for as long as two-to-three weeks. This position allows the bubble to press against the macula and be gradually reabsorbed by the eye, sealing the hole. As the bubble is reabsorbed, the vitreous cavity refills with natural eye fluids.
Maintaining a face-down position is crucial to the success of the surgery. Because this position can be difficult for many people, it is important to discuss this with your doctor before surgery.