Uncommon Wet Macular Degeneration Conditions
The underlying problem in wet AMD is the growth of abnormal blood vessels underneath the macula which cause swelling, bruising, bleeding and scarrring of the macula. The collection of blood vessels is given the term ‘choroidal neovascular membrane’ or CNVM for short.
When CNVM is identified in a patient complaining of reduced eyesight or distorted vision, if the patient is aged over 55 years then this is usually called wet AMD. However CNVM can occur in people under the age of 55 – in this case we often call this wet macular degeneration or wet MD for short.
There are a range of other conditions that predispose the eye to developing CNVM disturbances as follows :
- Short sighted people -(Myopia).
This is one of the commonest risk factors for developing CNVM. This type of wet macular degeneration is often not ‘age-related’ as people can develop this condition in their twenties or thirties. In such cases the diagnosis is termed myopic wet macular degeneration. Treatment is as for wet AMD – often with anti-VEGF injections. At Bettersight our experience is that quite often people with this type of wet MD tend to require less frequent injections but achieve good vision stabilisation.
- Inflammation related CNVM.
Inflammatory CNVM can occur in a wide range of rare inflammatory eye disorders. At Bettersight we have treated people with punctate inner choroidopathy CNVM, Serpiginous CNVM, Multifocal Choroiditis CNVM amongst others. Once again treatment is as for wet AMD with anti-VEGF injections being the first line treatment though in some cases argon laser treatment has also proven to be useful. Our experience is again a trend towards less frequent injections being required as compared to wet AMD treatments.
- Angiod Streak related CNVM.
This is a rare eye disorder that leads to cracks forming in the layer of tissue behind the retina – called bruchs membrane. These fault lines become areas of weakness that seem to allow the development of CNVM lesions sometimes at a very young age. Unfortunately CNVM related to angiod streaks tends to take on a more aggressive stance than typical wet AMD. First line treatment is with anti-VEGF injections – perhaps augmented with other modes of treatment such as Photodynamic therapy where indicated.
Angiod streaks can sometimes be linked to other medical conditions that can affect the skin and joints of a patient – such as pseudoxanthoma elasiticum and Ehlers Danlos syndrome amongst others.
- Idiopathic CNVM.
Here a patient under the age of 55 presents with wet macular degeneration symptoms and is found to have CNVM changes on a angiogram test but a detailed evaluation does not provide us with any clues as to the underlying reason for the condition arising. Idiopathic CNVM can occur at any age – even in childhood – and treatment is generally as for wet AMD – with anti-VEGF injections as first line options. Unfortunately idiopathic CNVM can often behave in a more aggressive manner than wet AMD.