General information:
The age-related macular degeneration is a disease of the retina that preferentially affects the elderly in which progressively and irreversibly damages the macula, which is dedicated to vision statement of the visual details far and near, the color vision, and contrast sensitivity.
Macular degeneration is one of the most debilitating eye diseases in industrialized countries after the 55 anni, affecting about 8% of the population, and reaching 30% after 75 anni.years
This disease is so widespread in the elderly population and is expected to increase with the lengthening of the average age and life expectancy.
Macular degeneration is generally classified into a dry form or character in chronic atrophic, slow and progressive and in a damp or wet form, faster and more aggressive, highly disabling and characterized, so distinctive, by the presence of choroidal neovascularization (CNV).
The diagnosis of the disease is mainly carried out with fluorescein angiography with or without indocyanine green angiography with, tests that allow most of the time to identify the subretinal neovascularization, establish its headquarters, assess the size and type.
Today CNV secondary to AMD is classified as:
- Predominantly classic, that is well defined on fluorescein angiography
- Minimally classic or
- cculta, when it is not visible on fluorescein angiography
- The Retinal angiomatous proliferation (HBP) in which the new vessels grow from the retina and the choroid
- The Idiopathic polypoid choroid vasculopathy (IPCV)
What treatments are now available to us:
- Fotocoagulazione laser : The main limitation of this therapy is due both to the partial effect that the small percentage of patients who applied, about 20%. In fact, laser therapy can not be carried out in central subfoveal CNV.
- Photodynamic Therapy (PDT): It consists of the injection into a vein in the arm of a photosensitizing substance, verteporfin, which binds to choroidal neovascularization. After about 10 minutes from injection to the NVC is irradiated with laser light that activates the verteporfin in order to close the new vessels. It is a treatment that should be repeated on average 3 times a year. The aim of PDT is to shut the NVC and prevent that there is a further loss of vision. From the statistical point of view has been shown that people who undergo PDT lose sight less than people who do not make no treatment. The important thing to understand is that the PDT is not improved significantly in the view. The PDT is not equally effective in all cases and types of CNV, so there is a need for some alternative treatment options, as the possibility of combination treatments that can enhance the effectiveness.
- Intravitreal injection of Kenacort (triamcinolone acetonide): The triamcinolone acetonide is a steroid that once injected into the eyeball exerts anti-inflammatory, anti-edema and antioangiogenetica. To date, the best way is to use it in combination with photodynamic therapy. The intraocular injection is performed in the operating room under sterile conditions, after instillation of anesthetic eye drops and does not require hospitalization. The injection of Kenacort is a specific process that is used off-label outside of the indications for which it was authorized and this is apparent by reading the descriptive leaflet inside the packaging that contains the only indication to use intra-articular.
- Angiogenesis and antiangiogenic therapy: Some clinical trials have demonstrated the clinical benefit of anti-angiogenic drug therapy that, through inhibition of the human VEGF (stands for Vascular Endothelial Growth Factor) growth factor or endothelial cell, blocks the genesis of vascular disease. Currently there is a new experimental drug treatment that uses the bevacizumab (AVASTIN®) which is a humanized monoclonal antibody anti-VEGF, produced by recombinant DNA technology, who has demonstrated strong anti-angiogenic activity / anti-edema and arrest the genesis vascular disease. L’AVASTIN® (bevacizumab): Avastin ® is a new drug that is used in cancer therapy to stop the growth of the neovascular network in anarchist forms of cancer metastatic colorectal cancer.
The treatment in macular degeneration involves the injection of intraocular substance, spreading into the vitreous and retinal thickness, comes into contact with the CNV where he practices primarily characterized by a series of effects:
- Inhibition of growth and extension of the neovascular process.
- Regression of neovascularization.
- Stabilization of the membrane and decrease the degree of endothelial permeability in the microcirculation of the CNV.
- Reduction in the intensity of diffusion of protein molecules and lipid extravascular spaces, reduction of edema and normalization of central retinal thickness macular.
The realization of these effects can produce results of clinical relevance because the drug has the potential to control the severity of the disease and slow its progression over time.
An 'Another effect of VEGF inhibition by bevacizumab is the ability to create a land microvascular more like the normal one in which the low permeability of new vessels, the decrease in retinal edema, and better oxygenation of the potential for neovascularization would increase the bioavailability of O2 in the CNV and to increase the sensitivity to PDT.
Possible applications dell'avastin outside the field of oncology regarding the treatment of neovascular macular degeneration type, and vascular diseases of the retina characterized by a marked exudative and edematous component as diabetic retinopathy and central retinal vein occlusion.
Procedure for the intravitreal injection of bevacizumab. The procedure is performed in hospital outpatient surgery. Informed consent was read and discussed with the patient.
The intravitreal injection is then performed under sterile conditions, in the operating room, after topical anesthesia with colliri. After injection, the patient is kept under observation for a few hours and checked the next few days.