Macular Rotation

Macular translocation (MT) or macular rotation surgery is a new form of treatment which involves separating the retina from the back of the eye, and then turning it round so that the central retina lies in a new position. It is used to treat conditions where the central vision is being lost because a membrane has developed beneath the central part of the retina. The most common cause of this by far is age-related macular degeneration (AMD). It is easier to appreciate how the operation works if you first understand what happens with AMD.

AMD is the most common cause of visual loss in Western Europe and North America. It is essentially a wear-and-tear process at the back of the eye, beneath the central retina. The tissues beneath the central retinal become worn, and the central vision slowly deteriorates. This is known as "dry" AMD.

Some people with dry AMD develop a complication where a membrane of abnormal blood vessels grows through the worn tissues beneath the central retina. This membrane then gradually damages the retina. This is the "wet" form of the disease. Wet AMD usually damages the central vision much more quickly, and to a greater degree, than the dry form of the disease.

Back of the eye of a patient that has had the macular translocation operation.

One might the the image has been turned on its side, but in fact one is looking onto the back of the eye the right way round. The white arrow points to the "new" macula, whereas the blue arrow points to the area where the macula was before. Also the retinal blood vessels have been rotated, along with the all of the retina.

MT surgery is used to treat people who have wet AMD. Because it involves lengthy and complex surgery, the treatment is currently reserved for those who have already lost the central vision of one eye from AMD, and are starting to lose vision in the second eye from the wet form of the disease.

The surgery is lengthy and complex, and only carried out by a few specialist vitreoretinal surgeons with expertise in this field. It involves detaching the retina from the eye wall, rotating the retina by 20-450 and then reattaching the retina. The membrane that has formed can be removed at the same time. It is not sufficient just to remove the membrane, because the tissues beneath the central retina are in poor condition once a membrane has formed, and if the central retina (the macula) is left in its normal position it ceases to function properly because of the poor tissues beneath it. The rotation of the retina allows the macula to be placed onto some tissues that are in good condition, i.e. without significant wear-and-tear, so that it can function more normally.

Because the retina is rotated, the vision straight after the surgery is also rotated. This is rectified a few weeks later by a second, more minor, operation on the muscles of the eye to rotate the eyeball in the opposite direction This levels up the vision once more.

The main risk of this form of surgery is retinal detachment. If that occurs it is possible to carry out further surgery to re-attach the retina, but if the retina cannot be re-attached then the eye may lose its vision.What is the evidence that it works ?

As yet no randomised controlled trials (i.e. fully-evaluated statistically) have been published. However, a number of case series have been published in the medical literature, and the results of the operation are encouraging. Most patients have their vision stabilised or improved.

Some patients with wet AMD may be treatable using photodynamic therapy (PDT). This is sometimes called cold laser treatment. It does not involve surgery. It has been evaluated with randomised controlled trials. These show that the treatment may slow down the progression of wet AMD for some patients. However, the treatment does not improve vision.