Adult vitelliform macular (or foveomacular) dystrophy (AVD) is a condition affecting the centre of the macula – the most sensitive, central part of the retina.
It can be easily mistaken for age-related macular degeneration (AMD) but is very different in its prognosis and its long-term effect on vision.
This condition involves the build-up of waste material under the fovea and can cause similar symptoms to those of AMD, such as central visual distortion and patchy loss of vision, which is often more noticeable when reading. As it is a genetic eye condition, adult vitelliform dystrophy is often inherited from a parent, although cases can occur where there is no history of the condition in the family. It is also common for people to have signs of AVD but no problems with their vision whatsoever, as the diagnosis is often made with high quality colour photography, auto-fluorescence imaging or optical coherence tomography (OCT). Whilst there is no treatment available for this condition, the good news is that progression tends to be very slow and is unlikely to cause the severe loss of vision that can result from AMD.
Distinguishing Adult Vitelliform Dystrophy from AMD
Telling the difference between adult vitelliform dystrophy and AMD can be very difficult and often needs a combination of examination and tests such as OCT, colour photography, auto-fluorescence and fluorescein angiography. More recently, OCT angiography is proving to be very useful; AVD does not usually involve the development of abnormal blood vessels, whilst wet age-related macular degeneration (AMD) does. Until now, it has been very difficult to interpret other tests and close follow-up, repeating tests and even trying treatments has been the main way of making a definite diagnosis.
It is important to keep in mind that even patients with adult vitelliform dystrophy can develop abnormal blood vessels behind the macula that need to be treated. As a result, it is vital to seek urgent retinal attention if any new distortion or loss of central vision is noticed.