Degenerative Myopia

Degenerative myopia also known as malignant or pathological myopia, is a condition, which starts in early childhood. Degenerative myopia is when someone has high myopia and their eyeball elongates quickly causing degenerative changes to the eyes. With high myopia your eyeball is more elongated, causing the retina (light sensitive layer at the back of the eyes) to stretch & thin. The stretching and thinning can cause changes to the retina and affect your vision.

Early and regular eye examinations are crucial to detect, treat and monitor degenerative myopia especially in young children.

• Poor vision

• Frequent changes in your myopia or increases in your prescription

• Light sensitivity

• If your central vision is affected – difficulty in seeing fine detail, colour or grey or blank areas

Pathological myopia may cause the following eye conditions

• Staphylomas is when the retina & sclera stretch and thin; the back of the eyeball begins to bulge. This can lead to loss of vision and sometimes blindness.

• Myopic foveoschisis (myopic traction maculopathy) is caused by Staphylomas. Where the bulging at the back of the causes the layers of the central vision (macula) to split away from each other. This will eventually cause distortion to your central vision and can lead to a macula hole or retinal detachment.

• Myopic Macular Degeneration, as the eyeball stretches the layers under the macula (central vision) become stressed and damaged. Abnormal blood vessels can grow in the damaged areas under the macula, which can then leak fluid & cause scarring. You would experience a loss of your central vision.

• Fuch’s spots are the abnormal network of blood vessels in the macula region, which cause damage to the central vision

• Lacquer cracks are fine lines seen on the retina, they are caused by breaks in Bruch’s membrane (Bruch’s membrane is between the retina and choroid, at the back of the eyes), they are usually just monitored and are a warning sign that further complications could occur in the future.

• Retinal atrophy is the stretching & thinning of the retina; this occurs as you become more short sighted and your eyeball becomes longer. The areas of thinned retina may not function properly or at all. These areas of your vision would appear patchy or blank. If retinal atrophy occurs at the macula (central vision) it may affect your ability to see detail and colour, this is known as dry myopic macular degeneration.

• Dry myopic macular degeneration may affect your ability to see detail, cause straight edges to appear wavy, cause difficulty in reading.

• Thinning of the retina can also cause retinal holes and lattice degeneration (a type of thinning retina). Patients with degenerative myopia that have lattice degeneration or retinal holes are at more risk of having a retina detachment. An ophthalmologist may recommend treatment to avoid a future detachment. If the break occurs in the retina, fluid can leak behind the retina, this pushes the retina forward and eventually causes the retina to detach. A retinal detachment would appear as a shadow or curtain in your vision. If you experience this you must get to your local hospital eye service immediately. Patients with degenerative myopia should undergo a dilated fundus (retina, nerve and macula) check yearly.

• Glaucoma; the drainage angle of eye can be affected with degenerative myopia. This causes a build up of fluid, as the drainage angle is impaired, the eye pressure begins to rise and causes damage to the optic nerves. Patients with degenerative myopia should undergo intensive visual fields yearly. Untreated Glaucoma causes a patient to lose their peripheral vision over time.

• Choroidal Neovascularisation (CNV), are new blood vessels that have grown from the Choroid (layer under the retina) and passed between any breaks or tears in the retina. As the new blood vessels are very weak they can leak easily. The leakage of fluid can cause damage and swelling (oedema), neovascularisation can occur anywhere on the retina including your central vision, the macula (this is called wet myopic macular degeneration).

• Wet Myopic macular degeneration occurs suddenly and will affect your colour vision, ability to see detail, cause straight edges to appear very wavy, cause difficulty in recognising faces and reading. Patients may also experience grey or blank spots in their central vision. If you notice any of this you must see your optician or an ophthalmologist at your local eye hospital immediately.

• Foster Fuchs spot is when the new blood vessels and leakage in the central vision has dissipated. A circular spot of scarring is left behind on the macula. The scarring causes the patient to experience a permanent blank spot in their central vision.

• Fast progressing myopia (short sightedness)

• Genetic link

• Associated with other conditions such as Down’s syndrome, Ocular Albinism, Infantile Glaucoma, Marfan’s Syndrome, Ehlers-Danlos Syndrome, Retinopathy of Prematurity, low birth weight, and maternal alcoholism.  Patients with these diseases should be carefully monitored for pathological myopia.

• Retinal atrophy, lattice degeneration and lacquer cracks are not usually treated. They are monitored to ensure further retinal complications do not occur. If a retinal tear is present they can use laser (retinopexy) or freezing (cryotherapy or cryopexy) to seal the tear and stop a retinal detachment from occurring.

• Myopic choroidal neovascularisation (growth of new blood vessels) is treated with anti-VEGF injections, the anti-VEGF injection reduces or stops the growth of new blood vessels. This helps reduce leaking of the blood vessel and oedema (fluid build up which causes swelling to the retina). You will need a series of injections over the coming months and will be monitored by your ophthalmologist closely.

• New blood vessels can also be treated with a laser treatment called photodynamic therapy (PDT); you are injected with a drug called Verteporfin (into your arm), the drug travels to the blood vessels in the eye, this helps the ophthalmologist locate the new blood vessels in the eyes, the laser then stunts their growth by activating the drug and stops any further leakage.

• Retinal detachments if they are to occur can be treated with: scleral buckling, a sponge of piece of silicone is attached to the sclera (white of your eye) this causes the sclera to indent and meet the detached area of the retina. Vitrectomy (removal of jelly vitreous) and a gas bubble or silicone oil, which pushes retina back in place. Pneumatic retinopexy, a gas bubble is inserted into the vitreous jelly to push the retina back into place.

Other things you can do

• If you are light sensitive due to your pathological myopia, good quality polarizing sunglasses with 100% UV protection, will help

• You may be referred to a low vision clinic if your sight is significantly affected, a low vision clinic will give you practical advice and magnifying aids to help you see better

• Check with your ophthalmologist if you can be registered as sight impaired or severely sight impaired. Registration can help with financial concessions and expert practical help

• Patients with -10.00DS prescription or more are entitled to a basic free NHS eye test and a complex voucher towards their glasses or contact lenses.

• We advise that you have extra tests outside of the basic NHS test to ensure that every aspect of the health of your eyes is reviewed in detail. Tests outside a basic NHS test would include, intensive visual field tests, wide field OCT scans of the retina & macula, Gonioscopy (review of the drainage angle for suspect glaucoma) and Dilated 3D bio headset or indirect ophthalmoscopy viewing of the retina. All these tests are included in our gold test, NHS patients can upgrade to Gold test too.

• Atropine eye drops in younger patients may help slow the progression of myopia

• Orthokeratology or Multifocal contact lenses in younger patients may help reduce the rate of progression in myopia; further research is still being conducted into this.

• If you already have significant myopia, regular eye checks are recommended annually. If you are concerned you can have your eye tests more often.

• Some hospital eye services have an ECLO (Eye Clinic Liaison Officer) who can provide further support

• Contacting the RNIB or macular society for further support, visual aids and practical advice

• Inform the DVLA of your eye conditions if you drive