What Causes a Macular Hole?
If you have had the macular hole for less than 6 months, there is a 90% chance your operation will be successful and that you will regain some or all of your lost vision. The success rate drops to 60% if the macular hole has been present for longer than a year.
What is a Macular Hole?
A macular hole is a gap in the retina at the back of the eye. Macular holes are relatively rare and occur in about 8 out of every 100,000 people. It is twice as common in women.
The macula is an oval-shaped area near the center of the retina. It contains the photoreceptor cells that create a high-resolution, detailed central vision and most of our color vision.
A macular hole can develop when a stretch hole develops in the center of the macula, creating a break in the macula. The vitreous is usually very adherent to the macula and may exert some influence in the stretching. The exact mechanism of macular hole formation is not known.
What is the Vitreous Humor?
The vitreous humor is the transparent, clear, gel-like fluid that fills the space in the eye between the lens and the retina.
As we age the vitreous begins to liquefy and shrink. The collagen and proteins in it can also become stringy. When these microscopic fibers float around in the rest of the vitreous they can cause specks or strings or other dark floating shapes that you can see. These are called “floaters” and they are common and harmless.
However, in a small number of cases when the vitreous shrinks those tiny, intertwined fibers in it can exert a pull on the macula and cause a tear.
Symptoms of a Macular Hole
The most common symptoms of a macular hole are blurring and distortion of your central vision. Straight lines appear wavy or bent and you may develop a blind spot in the center of your vision.
Are Macular Holes the Same as Macular Degeneration?
No. They are separate conditions and not related to each other. Their symptoms are similar because they both affect the macula—the portion of the retina that creates central vision.
A vitrectomy is the most common treatment for macular holes. The vitreous humor is removed to stop the pull or traction on the macula. A gas bubble (containing a mixture of air and gas) is placed in the eye to protect the macula from subretinal fluids while it heals. Keeping your head in a face-down position helps the gas bubble remain in the proper place.
The gas bubble will slowly dissipate, but the length of time for that dissipation depends on which gas was used. While the bubble is in place your vision will be very poor and clouded. As the bubble shrinks you will see a horizontal line across your vision. This is where the bubble meets the fluid that is gradually replacing your vitreous humor.
Another treatment for some patients with macular holes is an injection of an antiplasmin inhibitor that inactivates plasmin, an enzyme that breaks down the fibrin in blood clots and can help relieve the traction caused by the intertwined stringy protein and collagen fibers in the vitreous humor.
Who is at Risk for Developing a Macular Hole?
The following conditions can increase the risk of developing a macular hole:
- Diabetic eye disease
- A high degree of myopia (nearsightedness)
- Macular pucker—caused by scar tissue on the macula
- Blunt trauma to the eye
Harmful effects from a macular hole repair are unlikely, but you should be aware of the possible complications.
- A hole that fails to close. The surgery can be repeated in this case.
- Development of a cataract.
- Retinal Detachment (This is uncommon and occurs in 1 to 2 out of every 100 patients.)
- Infection (This is rare and occurs in 1 in 1,000 patients.