Age Related Macular Degeneration (AMD)

There are two types of AMD: the dry form and the wet form.

In the dry form of AMD, a progressive atrophy of the macular region occurs and there is not treatment to stop this progression. Some studies show a protective effect of antioxidant pills and vitamins to avoid progression of the disease. In the dry form the loss of vision is slower than in the wet form, but some patients start their condition as a dry form and may evolve to the wet form.

In the wet form of AMD some abnormal blood vessels (neovascularisation) originate and grow underneath the retina and they let blood and fluids leak, which causes the retina to stop functioning properly, causing distorted vision (seeing objects deformed) and blurred vision (as a spot appears in the middle of the vision).

Wet AMD vision loss can progress very fast and severely with no treatment. 50% of patients suffering from this form of AMD will develop the disease in their other eye.

There are other causes of central vision loss due to the growth of new blood vessels underneath the retina, such as high myopia, uveitis, angioid streaks, chronic central serous chorioretinopathy, trauma, etc. In some cases, the cause is unknown (idiopathic). Without treatment visual loss can be fast and severe.

Ranibizumab (Lucentis®) was developed to treat wet AMD (intravitreous delivery). Lucentis blocks a substance called vascular endotelial growth factor (VEGF). This process inhibits the growth of blood vessels, essential for the development of new abnormal blood vessels.

Ophthalmologists are using Lucentis to treat patients with wet AMD and similar conditions, as research studies prove that VEGF is one of the causes of blood vessels growth in this disease.

Clinical trials performed in animals and humans showed that in most patients treated with ranibizumab the subretinal fluid is re-absorbed and the macula may recover its normal appearance, improving in some cases visual accuity without causing retinal toxicity. (N Engl J Med.2006 Oct;355:1419-31, N Engl J Med.2006 Oct; 355:1432-44, Ophthalmol Clin North Am. 2006 Sep; 19(3):361-72, J Fr Opthtalmol. 2006 Sep;29(7):731-737, Invest Ophthalmol Vis Sci. 2006 Jan;47(1):357-63,Klin Monatsbl Augenheilkd 2005 Jun;222(6):480-484,Arch Ophthalmol. 2005 Apr;123(4):509-516, Invest Ophthalmol Vis Sci.2005 Feb;46(2):726-733.13:363-372).

Ranibizumab can also be used to treat macular edema secondary to vascular diseases (diabetic maculopathy, macular edema after venous occlusion,…).

The aim of the treatment is to reduce further visual loss. Even though some patients gain some vision, visual recovery is not always observed with medication, and sometimes medication cannot stop the progression of the disease.

The drug is delivered into the vitreous cavity with an injection after dillating the pupil, and applying topical anaesthesia.

Antibiotic eye drops are prescribed for 1 week. The patient will have to attend the office on the first and seventh day alter the injection, to assess possible complications. The most serious complications of this type of procedure are severe posterior uveitis (1.4%) and endophthalmitis (1%).

Reinjecting Lucentis may be required in regular intervals, depending on how the disease responds.

The treatment usually consists of three intravitreous Lucentis injections. A monthly ranibizumab injection is applied for three months.

Depending on the results it may be necessary to give more injections, either in relapses or in those cases with limited response after the three inicial injections.

In more aggressive forms with minimal response to this drug, the combination of several treatments may be necessary.

It is important to know that there is no healing treatment for this disease. Current treatments there are palliative (they stop the progression of the disease avoiding further visual loss) and sometimes the disease re-activates again and more treatments are required.

 POSSIBLE COMPLICATIONS

Systematic complications:

Increase of the blood pressure has been reported (more frequently in those cases involving hypertensive patients). 16% of hypertensive patients suffered from an increase in blood pressure.For this reason, the pressure is checked in the operating theatre, before and after the injection. The patient is requested to check it again during the first few days after the procedure.

Haemorrage (5%) and thrombosis (1%) have been observed, in patients treated with intravitreous ranibizumab during clinical trials.

Any drug may cause allergic reactions in a small group of patients. E.g. facial rash, itch, breathing difficulties, and anaphylactic shock. These reactions are generally more frequent in patients with known allergies.

Intravitreous injection complications

Side effects are not very severe: ocular pain, subconjunctival haemorrhage, vision with floaters, eye inflammation and other visual discomfort.

Serious possible complications of intravitreous injection are: retinal detachments, cataract, glaucoma, hypotony, haemorrhage and infection (endophthalmitis). These complications are rare and need to be treated as they can affect vision.

In order to reduce the risks of some side effects of intravitreous injection, especially infections (endophthalmitis), we perform the injection in the operating theatre.

OTHER TREATMENT OPTIONS

LUntreated wet AMD can cause severe central vision loss. Sometimes it is necessary to combine several treatments to stop the process and avoid progressive visual loss.

There are currently four available therapeutic options for AMD:

-    Photodynamic therapy, with a drug named Visudyne

-    Intravitreous treatment, with a drug named Macugen

-    Intravitreous treatment, with a drug named Trigon Depott

-    Intravitreous treatment, with a drug named Avastin

All these treatments have proved to reduce visual loss.