If you have high degree myopia (short-sightedness) of over 600 degrees, you may be at risk of pathologic myopia.
Patients with short sightedness of over 600 degrees are classified as having high myopia. Myopia occurs when the eyeball is too long and light rays entering the eye are unable to focus on the light-sensitive part of the eye called the retina. (Find out more about myopia)
In high myopia, excessive elongation of the eyeball results in a risk of degeneration of the retina, in particular, to a central part of the retina called the macula. The macula has the highest concentration of cones (light sensitive cells that interpret colour images) in the retina and plays a central role in processing detailed images. (Read more on how the eye works)
Highly myopic eyes are at increased risk of pathologic myopia, a sight-threatening condition characterised by degeneration (myopic macular degeneration), stretching of the retinal layers (myopic retinoschisis) and bleeding in the macula (choroidal neovascularisation).
There may be vision loss or distortion of vision. This can occur acutely or slowly over a long period of time.
Fundus photo showing severe degeneration of the macula in a highly myopic eye. The black arrows point to areas where there is complete loss of retinal tissue and its underlying blood supply (choroid).
There is currently no treatment to prevent myopic maculopathy. However, there are several treatments being studied in the research setting to halt eye elongation and prevent formation and progression of myopic maculopathy.
For general myopia, studies have shown that a strong family history of short-sightedness and not enough time outdoors during youth are risk factors of myopia. The higher the level of myopia, the greater the likelihood of forming pathologic myopia, outpouchings (staphyloma) in the back wall of the eye, and myopic maculopathy.
Myopic maculopathy is diagnosed by careful examination by an ophthalmologist. It is supplemented by detailed imaging geared toward assessing for subtle thinning of the retina as well as the underlying blood layer (choroid) and deformability of the eye wall (sclera).
Treatment for myopic maculopathy depends on the type of problem that arises. For example, choroidal neovascularisation can be treated with intravitreal injections of anti-VEGF (vascular endothelial growth factors). For myopic foveoschisis (with foveal detachment) and macular hole, the treatment of choice is surgery including vitrectomy, membrane peel and intraocular gas.
If warranted, preparation for surgery is similar to that done prior to any vitrectomy surgery (hyperlink to section on retinal detachment).
If warranted, post-surgical care after vitrectomy surgery would be similar to that described in the retinal detachment section. Repair of myopic foveoschisis (with foveal detachment) and myopic macular holes would usually require a face-down position to allow the intraocular gas to perform its function and help the repair’s success.
Singapore has one of the highest prevalence of high myopia in the world, particularly among the younger working population. As these individuals grow older, the burden of myopia-related blindness will increase exponentially. The High Myopia Clinic at SNEC was set up to meet this emerging healthcare need. It is a specialised clinic for patients with high myopia and/or pathologic myopia.
The goal of the High Myopia Clinic is to identify patients who are at the greatest risk of permanent vision loss from pathologic myopia, and to guide research on novel treatments for the prevention of sight threatening complications.
On a typical visit to the high myopia clinic, the patient undergoes vision and eye pressure measurements similar to any other SNEC clinic. This is followed by measurements of the eye length and a series of advanced, non-invasive imaging of the optic nerve, retina and choroid to diagnose pathologic myopia-related complications like glaucoma, myopic choroidal neovascularisation, myopic retinoschisis and myopic macular degeneration.
These tests include swept source optical coherence tomography that allows high-resolution 3D imaging of the macula and the optic nerve, and optical coherence tomographic angiography for non-invasive imaging of the retinal and choroidal blood flow.
Patients may also undergo biomechanical testing to measure the stiffness of the posterior eye wall with ultrasonography to assess the risk of further eye elongation and worsening myopia. They will then be examined by one of our subspecialty experts who focuses specifically on the diseases and needs of patients with high myopia. Those with treatable conditions can be identified early and receive treatment in a timely manner to preserve or improve vision. Stable patients will be monitored on an annual basis for progression.
By caring for the large number of highly myopic patients, coupled with our sophisticated imaging techniques, we can determine which patients are at the highest risk of permanent vision loss from pathologic myopia and make advancements in the way we treat sight-threatening complications of high myopia.
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