What Is A Macular Hole?
The Macula, which is a specialized area of the retina, is responsible for clear, detailed vision. A macular hole is an abnormal opening which, forms in the center of the macula over weeks to months.
Clinical photo and cross section of a macular hole
The central portion of the eye is filled with a jelly-like substance known as the vitreous. With age, the vitreous shrinks and pulls away from the surface of the retina. In most cases, this pulling away or vitreous separation occurs without any negative effect. In some individuals, however, there may be an area where the vitreous is firmly attached to the surface of the retina.
As the shrinkage and forward movement of the vitreous progresses, traction or pulling can be exerted on the retina, and eventually a small hole may form in the central portion of the retina (the macula), known as a macular hole. The fluid which has replaced the vitreous jell in many areas may then seep through the hole, causing a localized separation of the retina centrally. This process results in a defect or dark spot in the central vision with distortion and central vision loss resulting.
Symptoms of a macular hole are common to most conditions affecting the central part of the retina. They include:
- Blurred central vision.
- Distorted, “wavy” vision.
- Difficulty reading or performing tasks that require seeing detail.
- Gray area in central vision.
- Central blind spot.
The diagnosis of a macular hole is made when your eye care provider performs a dilated retinal examination of the back of the eye. A fluorescein angiogram (injection of a dye into the vein with photographs taken of the back of the eye) is sometimes necessary to determine if macular hole is due to the vitreous traction as described above, and not secondary to other problems. Until recently, very little could be done to correct the visual deficit resulting from macular holes. As a result of the introduction of microsurgical techniques, it is now possible to offer a surgical procedure with the potential for some visual improvement. This procedure is known as a vitrectomy, and involves the microscopic removal of the vitreous jell within the center of the eye. Particular attention is paid to removing any of the vitreous attachments to the macula, thus releasing the traction or pulling on the retina which caused the macular hole initially. In order to completely close the macular hole, however, additional pressure must be exerted to allow for complete healing. To assist in this process, a large air bubble is placed within the eye, which, when it comes into contact with the retina, presses it against the wall of the eye, sealing the macular hole. This process acts much like a hand holding wall paper against the wall permitting it to stick and remain in position as the “wallpaper glue” dries. In order to have its maximal effect, the air bubble must apply upward pressure forcing the macula against the retina. Because the macula is located in the back part of the eye, a patient’s head must remain in a “face-down” orientation allowing the air bubble to exert upward pressure. Patients must maintain this face-down position for approximately 2-3 weeks after surgery in order to achieve successful closure of the macular hole and maximize the chances for vision improvement. This face-down positioning is the single most critical portion of the procedure for closing macular holes. As a result, emphasis must be placed on the patient’s ability to cooperate with strict face-down positioning at all times for a period of approximately two to three weeks after surgery. Position of air bubble when standing. Position of bubble when face down.
At the end of the 2-3 week period of strict face-down positioning, the patient is then permitted to resume a more normal upright posture. The air bubble itself, however, may take anywhere from 6-8 weeks following surgery to completely disappear. The air bubble is gradually reabsorbed by the body, and the vitreous cavity is then fills itself with a liquid that is naturally produced inside the eye. The surgical procedure itself is performed typically under local anesthesia, and sometimes requires an overnight hospital stay. A postoperative examination within 24 hours of the surgery is required in all cases. Regular follow-up examinations are performed during the first three weeks of recovery, to monitor for successful closure of the hole and check for potential complications. Patients typically utilize several eye drops applied to the operated eye over the course of several weeks following the surgical procedure. Approximately 6-8 weeks after surgery, when the bubble has completely reabsorbed, the patient is measured for glasses. Full visual recovery may take as long as three months following the surgical procedure.
Frequently asked questions
No, macular holes and macular degeneration are two separate and distinct conditions. As described elsewhere on this website, macular degeneration is a condition affecting the tissues lying under the retina, while a macular hole involves damage from within the eye, at the junction between the vitreous and the retina itself. There is no relationship between the two diseases.
There is no known inheritance pattern for macular holes, and there is no evidence that macular holes are carried from one generation to another.
Depending upon the degree of attachment or traction between the vitreous and the retina, there may be risk of developing a macular hole in the other eye. Your eye care provider can determine the status of the vitreous jell and its degree of traction on the retinal surface in the uninvolved eye. In those cases where the vitreous has already become separated from the retinal surface, there is very little chance of developing a macular hole in the other eye. On the other hand, when the vitreous remains adherent and pulling on the macular region in both eyes, then there may be a greater risk of developing a hole in the second eye.
In very rare instances, trauma or other conditions lead to the development of a macular hole. In the vast majority of cases, however, macular holes develop spontaneously. As a result, there is no known way to prevent their development through any nutritional or chemical means, nor is there any way to know who is at risk for developing a hole prior to its appearance in one or both eyes.
There is evidence in the scientific literature that macular holes present for less than six months have a better chance of repair and visual recovery than those present for more than six months. Studies have shown, however, that some vision improvement can take place in patients with more long-standing macular holes, but rapid evaluation and treatment is preferable in patients with this condition. If a macular hole exists in one eye, it is therefore very important to monitor for any vision changes in the second eye, and report these vision changes to your eye care provider immediately.
Typically, for macular holes less than six months in duration, a vision improvement of approximately three lines on the eye chart (or 50% improvement) can be achieved. Obviously, this is an “average” visual improvement. Vision recovery varies on a patient-by-patient basis, and each patient must be evaluated on an individual basis and discuss with their eye care provider the expectations for visual recovery. Some patients achieve only a small amount of vision recovery, while others achieve a more significant improvement.
Face-down positioning is crucial to the success of the operation. If a patient is not able to maintain face-down positioning, it is unlikely that the operation will succeed. Therefore, before macular hole surgery is considered, a patient should experiment at home with maintaining a face-down position for a period of time to ensure that they are able to comply with the restricted activities necessary in the postoperative period. Some patients, because of medical conditions or physical limitations, may be unable to comply with the positioning and would not likely be good candidates for this procedure.
During the postoperative period, the air bubble in the eye will be pressing on the macula to ensure closure of the hole. While the air bubble is present in the eye, the eye is unable to focus light properly, and therefore vision is significantly disrupted. Often patients are only able to see shapes, shadows or hand movements in front of their eyes while the bubble is large. As the bubble begins to shrink, usually between the third and fourth week, vision begins to return. Final vision recovery is often not achieved for 6-12 weeks following the operation after the bubble completely resolves, the macular hole heals, and a final prescription for glasses is given. For those patients who have not had cataract surgery, the vision may begin to exhibit gradual deterioration approximately 6-12 months after the operation as a cataract develops. Once cataract surgery is performed, vision would then typically return to its maximal level.
Patients are not permitted to fly when there is a large air bubble present inside the eye. When a person travels by air, there are changes in air pressure which can result in expansion of the air bubble and increased eye pressure. In order to prevent this complication, patients are restricted from any type of air travel until the bubble is nearly gone, or small enough that the patient’s eye care provider considers it safe to fly.
When surgery is performed to close a macular hole, no laser treatment is applied to the hole itself, as laser can be damaging to the delicate central tissue of the macula. In order to avoid this damage, the air bubble alone is used to help provide the seal between the retina and the wall of the eye. Experiments have been performed in recent years in an attempt to determine if chemicals applied to the surface of the macular hole at the time of surgery will increase the success rate for the operation. Studies have not yet conclusively demonstrated that application of any chemicals are necessary to have a successful result from the surgical procedure.