Myopic Degeneration

Myopic Degeneration

Myopic Degeneration

What is Myopic Degeneration?

Myopic Degeneration is a condition found in people with severe short-sightedness or high myopia which is characterised by progressive stretching of the eyeball that damages the retina.

The causes of myopic degeneration are not clearly understood but may include biomechanical abnormalities or hereditary factors. The biomechanical theory assumes that the retina, in a myopic eye, is stretched over a larger than normal area because the eye is longer than usual.

Over time, the outer coat of the eye, known as the sclera, also stretches in response to forces like internal eye pressure. This stretching of the sclera is thought to lead to retinal degeneration. In the hereditary theory, the retinal changes are thought to be an unavoidable, inherited process.

Myopic Degeneration can result in several problems including:

• Myopic Choroidal Neovascularization: This is where there is bleeding under the retina (choroidal neovascularization), similar to Wet Macular Degeneration. This occurs often if there are cracks in the macular area (lacquer cracks) which are caused by the stretching of the eyeball.
• Myopic Macular Schisis (Myopic Foveoschisis): This is where the different layers of the retina are pulled apart by tugging of the vitreous gel on the retina, causing splitting (schisis) of the retina.
• Myopic Macular Hole: This is where a hole develops in the central area of the retina known as the macula, often from tugging of the vitreous gel on the retina.
• Retinal Tear and Detachment: People with severe short-sightedness (high myopia, pathological myopia) have an increased chance of having weak areas in the peripheral retina compared to normal people, which can result in retinal tears and detachment.

What are the symptoms?

• Decreased vision
• Sensitivity to light
• Flashes and floaters
• Distortion or crookedness of central vision
• Black or grey patches (scotomas) in the central vision
• Sudden loss of central vision if there is myopic choroidal neovascularization

How is it diagnosed?

A thorough retinal examination including specific tests such as OCT scan, retinal photography, B scan ultrasound scan, fluorescein angiography and ICG angiography may be required in order to make the diagnosis .

Myopic Degeneration B-scan

Myopic Degeneration OCT-scan

Can it be treated?

Myopic choroidal neovascularization may be treated with:
• Intravitreal Anti-VEGF injections
• Photodynamic Therapy (PDT)
• Thermal Laser

Myopic macular schisis may require treatment with vitrectomy surgery if there is progressive splitting of the retinal layers resulting in reduced vision.

Retinal tears and detachment may require repair with thermal laser surgery, cryotherapy, pneumatic retinopexy, scleral buckling or vitrectomy.

Unfortunately, many patients still have slow progressive loss of vision for which there is no current effective treatment; however there are other supportive measures which may help to slow progression.