Macula Surgery
MACULAR HOLE & EPIRETINAL MEMBRANE
The inner lining covering the back of the eye is known as the retina and functions similar to the film in the back of a camera absorbing light to form an image of the outside world. The macula is one of the most important components of the retina. It is the part designed for detailed vision such as depth and colour perception that we use for activities like reading and looking at faces. A macular hole, as the name suggests, is a hole that forms at the macula. This will usually produce symptoms of blurred or distorted vision and can progress if left untreated to a permanent blind spot in the central vision. Peripheral or side vision is unaffected and there is no pain associated with the formation of the hole.
Most macular holes occur in the elderly. The vitreous (gel substance which fills the posterior segment of the eye) begins to pull on the delicate macular tissue resulting in the formation of a tear. The torn area gradually enlarges to form a round hole. There are other less common causes of macular holes such as injuries to the eye and long term swelling of the macula. Macular holes are not associated with, or caused by any specific medical condition.
The most common initial symptoms of a macular hole are blurred and distorted vision. If the hole remains untreated it can enlarge in size and visually you will notice a blind spot develop in your central vision. Peripheral or side vision is generally unaffected by a macular hole and it is also relatively uncommon for a macular hole to occur in both eyes.
Your Ophthalmologist will perform a comprehensive examination of the back of your eyes which requires dilating drops. Following this assessment, an Optical Coherence Tomography (OCT) scan may be required. An OCT is a non-contact, non-invasive imaging technique used to obtain high resolution, cross-sectional images of the macula. It may also be necessary that you undertake a photographic test called a retinal angiogram to further assess the hole. This test involves a dye being injected into your blood stream and photos being taken of the retina as the dye travels through highlighting the blood vessels.
The only treatment available to repair and possibly improve vision distorted by a macular hole is a Vitrectomy. Unfortunately, neither medication nor laser surgery are alternatives. A Vitrectomy is a surgical procedure involving the use of delicate instruments inserted into the eye to remove the vitreous gel which is pulling on the macula. The eye is then filled with a gas bubble which will slowly dissolve. After surgery, the patient must maintain a constant face down position for up to 72 hours so that the gas bubble remains in contact with the macula. A successful visual result often depends on how well this position is maintained, although success also depends on how long the hole was present prior to surgery. The macular hole usually closes and the eye slowly regains part of the lost sight.
Risks of vitrectomy surgery include:
- Infection
- Bleeding
- Some loss of side vision
- Detachment of the retina
- Increased rate of cataract formation
- Eye pain due to high pressure following surgery
Details regarding risks and complications will be provided by your treating Ophthalmologist when discussing surgery and proceeding with consent. At this time, your Brisbane Eye Clinic Ophthalmologist will be pleased to answer any queries you may have.
Is it really important to maintain a face down posture following surgery?
Yes. During a vitrectomy a gas bubble is positioned inside the back segment of the eye in order to allow the macular hole to close. The bubble is crucial in stopping fluid from entering the hole as any fluid that deposits into the hole will result in it remaining open. In order for the bubble to remain over the macula it has to remain at the back of the eye. This is why you must maintain a face down posture for up to 72 hours, as the gas bubble will float to the back of the eye and ensure there is no fluid present at the macula.
It is extremely important that you do not fly in an airplane or travel up to high altitudes until the gas bubble in your eye has dissolved as this can cause a dangerous rise in eye pressure. This may take up to 8 weeks to dissolve – please discuss with your Ophthalmologist before flying.
EPIRETINAL MEMBRANE
The retina is a light-sensitive tissue lining the inner surface of the eye. It is sensitive to light and acts like a film in a camera, capturing images before sending them via the optic nerve to the brain where they are interpreted. The macula is a small area at the centre of the retina in the back of your eye that allows you to see fine details clearly and perform activities such as reading and driving.
An epiretinal membrane is a thin sheet of fibrous tissue that can develop on the surface of the macula resulting in blurred or distorted vision. An epiretinal membrane may also be referred to as a macular pucker, premacular fibrosis, surface wrinkling retinopathy or cellophane maculopathy.
An epiretinal membrane develops as a result of cellular changes that occur in the back of the eye between the vitreous (a gel-like substance that fills the posterior portion of the eye) and the macula. Normal biological cells that are derived from the retina and other tissues within the eye become detached and are released into the vitreous, eventually settling on the surface of the macula. If enough cells accumulate on the surface, they can begin to form a membrane. In the majority of cases, the membrane will develop within an eye that has no history of previous problems. There are occasions, however, that an epiretinal membrane will develop as a result of retinal detachment, trauma, inflammatory disease, blood vessel abnormalities or other pathological conditions.
In many instances an epiretinal membrane can remain mild and consequently does not have a significant impact on the macula or your vision. In other cases, however, the membrane may become more prominent and create a disturbance in the retina which leads to blurred vision or distortion of images. It typically only affects the centre area of vision and does not cause blurred or distorted peripheral (side) vision.
Your ophthalmologist can detect an epiretinal membrane during a comprehensive eye examination that includes the following:
- Viewing the macula with an ophthalmoscope.
- Retinal Angiography – a special camera is used to take photographs of the macula.
- OCT (Optical Coherence Tomography) – a non-contact, non-invasive imaging technique used to obtain high resolution cross-sectional images of the macula.
An epiretinal membrane can be treated with vitrectomy surgery. It is important to note, however, that not all epiretinal membranes require treatment, especially if the membrane is mild. There is no non-surgical treatment for an epiretinal membrane.
A Vitrectomy is a surgical procedure involving the use of delicate instruments inserted into the eye to remove the vitreous gel which is pulling on the macula. The epiretinal membrane is then gently peeled and the scar tissue removed from the surface of the retina, relieving the traction and reducing the distortion to the retinal surface. The eye is partly filled with an air bubble which will slowly dissolve. After surgery, some patients may be asked to maintain face down position overnight until the removal of the dressing, so that the air bubble remains in contact with the macula. A successful visual result often depends on how well this position is maintained. The majority of patients will have a significant improvement in their vision after surgery, however, this may occur gradually over the span of several months. The amount of improvement in vision after surgery is dependant upon the severity and chronicity of the epiretinal membrane, the amount of vision the patient had preoperatively and the presence of any other ocular pathology.
Risks of vitrectomy surgery include:
- Infection
- Bleeding
- Some loss of side vision
- Detachment of the retina
- Increased rate of cataract formation
- Eye pain due to high pressure following surgery
Details regarding risks and complications will be provided by your treating Ophthalmologist when discussing surgery and proceeding with consent. At this time, your Brisbane Eye Clinic Ophthalmologist will be pleased to answer any queries you may have.
Your ophthalmologist will determine this on a case by case basis. In some cases, you may be advised that you need to maintain a constant face down position overnight until the removal of the dressing.
Retinal tears can sometimes be the cause of epiretinal membranes developing in an eye. During the course of your vitrectomy surgery, the ophthalmologist may discover these retinal tears. These tears will be operated on using the technique of cryotherapy or laser photocoagulation during the vitrectomy surgery.
Instances of regrowth are very uncommon, however, in a small number of cases the epiretinal membrane can reoccur.
Any surgical or invasive procedure carries risks. Before proceeding, you should seek an opinion from an appropriately qualified health practitioner.
