Have you got AMD?

[22/08/2014]

Have you got AMD?

Dear Readers,

Do you know what AMD is? It stands for Age Related Macular Degeneration and this 'mouthful' describes an eye disease which has become the leading cause of blindness in developed countries for people over the age of 50 years.

As its name suggests, it is more common in older people (over 50 years) and it is a degenerative disease of the macula.

What is the Macula?

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If the human eye is likened to a camera, then the retina is like the film of the camera (I know, film cameras are getting obsolete now!). The macula is the most sensitive part of the retina and is what we use 90% of the time in our day to day activities i.e. driving, reading, writing, etc.....

In AMD, there is an accumulation of "waste material" at the macula which eventually leads to a loss of central vision.

AMD_simulation

In end stage disease, the central vision is completely lost and consequently, functional vision is lost! (see above) Affected individuals will not be able to read or drive or even recognise faces but they will still be able to navigate and walk without bumping into things because their side vision is intact.



Types of AMD

There are 2 broad categories of AMD - dry and wet. Dry AMD is more common (~80%) and slowly progressive whereas wet AMD is less common but potentially visually devastating! (see below)

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In wet AMD (see below), there is bleeding at the macula and this can result is sudden loss of vision. Dry AMD can also convert to wet AMD in some cases.

Wet AMD



Treatment of AMD

There has been a revolutionary change in the way AMD is treated in the last decade and this is largely due to the development of a group of drugs called anti-VEGF.

LucentisAvastineylea
Before this, ophthalmologists could do little to improve vision and it is not uncommon for us to "sit idly by" as we see our patients go blind from this disease.

These drugs however, are not without problems. Avastin is actually used 'off-label' for the treatment of wet AMD but is most frequently used because it is significantly cheaper. It is a drug used to treat metastatic bowel cancer and is now used at a significantly lower dose to treat wet AMD.

Lucentis and Eylea are designed specifically to treat wet AMD but are extremely expensive. These drugs are administered via an intravitreal injection into the eye and need to be done very frequently (monthly or bi-monthly) and there is no apparent end point as we do see recurrences in patients who have been stable for several years. This would lead to very frequent visits to the ophthalmologist for the patient, an "injection frenzy" for the ophthalmologist not to mention the very high costs to the patient!

Nevertheless, this is the best option available for now and until research throws up another better option, we are going to be injecting for the foreseeable future.

How about dry AMD?

What was described earlier was treatment for wet AMD. If you remember, dry AMD is by far the common form of the disease and sad to say - there is NO TREATMENT available at the moment. There are supplements which are recommended for the reduction of risk of conversion to wet AMD but the effects are modest at best. There is a lot of research going into this area but nothing which is currently available for the ophthalmologist to combat dry AMD!

I leave you with a short video which tells the viewer a little bit about the problem of AMD - in particular for viewers in Malaysia (where I am now!)

In the meantime, look after yourselves and YOUR EYES!!



In February this year, a paper was published in the New England Journal of Medicine which reported the results of a study conducted in USA whereby 3 anti-VEGF agents were used in a large cohort of patients to treat Diabetic Macular Oedema. These 3 agents (Avastin, Lucentis and Eylea) were compared head-to-head in the treatment of patients over a 1 year period. The results reported has significant impact on the way ophthalmologists will treat their patients. This study, known as Protocol T, has created ripples in the ophthalmology community as the results have far-reaching impact on how patients with Diabetic Macular Oedema. In summary:-

1) Patients with visual acuity 6/12 or better, can be treated with any of the 3 anti-VEGF agents with no significant difference in visual outcomes.

2) Patients with visual acuity worse than 6/12 will benefit more with treatment with Eylea compared to the other 2 agents.

3) The average number of injections required over the first one year period is 8 and this is regardless of whichever agent is used.

What are the immediate implications of this study on the patients?

1) Patients should expect very frequent visits to the eye clinic for injections and follow-up over the first year period

2) There is significant financial burden associated with treatment as per injection, Eylea and Lucentis costs approximately US$2000 whereas Avastin is a fraction of the cost (~ US$100).

3) With this treatment, we are able to prevent significant visual impairment due to diabetic macular oedema when before we only had laser which was nowhere nearly as effective!

LucentisAvastineylea

In the US now, there is a big push by the US ophthalmologists to reverse a ruling passed by the FDA (Food & Drug Administration) which will practically prevent the use of Avastin for intravitreal injections. This decision by the FDA had come about following safety issues with the preparation of Avastin for injections as this drug was never made for eye treatment but for cancer treatment instead. Consequently, small amounts of Avastin have to be drawn out from the sterile bottle and issues with the correct dosage and mainly with sterility had been highlighted. There was a spate of severe eye infections from Avastin injections reported a while ago which was very 'bad publicity' for the drug!

Nevertheless, I believe each anti-VEGF agent still has its role. In my current practice in Malaysia, my patients are very price sensitive and it is only ethical that all my patients are aware of what available treatment options there are and the risks and benefits associated with each one.

So remember to always have a thorough discussion with your ophthalmologist to better understand what is required to treat your eye condition and never be afraid to seek a second (or third) opinion. I have often sent my patients away to get another opinion and they are always grateful that they are not under pressure to take my word as the 'gospel truth'! Ultimately, as physicians, we owe it to our patients to be updated with the latest treatment modalities and provide the best care we can.