Diabetic Retinopathy is a potentially blinding complication of diabetes that damages the eye's retina. The retina is a thin membrane located in the inside of the eye, adhered to the wall of the eye like "wallpaper" and that acts like the film of a camera, capturing the image that will be transmitted to the brain through the optic nerve. The macula is the central area of the retina. We use the macula to see details, colours, read small print and discriminate faces, between others. Diabetic Retinopathy can affect half of all patients diagnosed with diabetes.
Diabetic Retinopathy occurs when Diabetes Mellitus damages the blood vessels in the retina impairing its oxygenation and nutrition.
Some patients with Diabetic Retinopathy develop a condition called Macular Oedema, which occurs when the damaged blood vessels leak fluid onto the macula. The leaked fluid makes the macula swell and this in turn blurs the central vision.
As the Diabetic Retinopathy progresses, it enters its advanced or proliferative stage where new and abnormal blood vessels grow along the retina and use the gel-like vitreous that fills the inside of the eye as scaffolding.
There are two different types of Diabetic Retinopathy:
Non-proliferative Diabetic Retinopathy (NPDR)
Non-proliferative diabetic retinopathy is the early stage of diabetic retinopathy. In this stage, tiny blood vessels in the retina outside the macula leak blood and fluid.
People with non-proliferative diabetic retinopathy may experience no visual symptoms. However, those who do experience problems are those who develop macular oedema or macular ischaemia.
Macular ischaemia occurs when small blood vessels that nourish the macula close off leading to cell death with irreversible blur or loss of central vision.
Proliferative Diabetic Retinopathy (PDR)
 Proliferative diabetic retinopathy is the more severe stage of the disease when abnormal blood vessels grow along the retina or optic nerve head. In PDR much of the circulation of the retina closes down and abnormal blood vessels grow into the retina in an attempt to compensate for the reduced blood flow. These abnormal vessels unfortunately do not adequately compensate the reduced blood flow, are often fragile and may bleed. Scar tissue usually develops along these new vessels. When the scar tissue contracts it can cause the retina to pull away from the wall of the eye – causing Retinal Detachment or Vitreous Haemorrhage (bleeding into the jelly of the eye).
As abnormal blood vessels can grow in any part of the retina, both central and peripheral vision can be affected by Proliferative Retinopathy.
Mr Stanga photocoagulates using the new OptiMedica PASCAL® Pattern Scan Laser Photocoagulator system. The PASCAL® laser uses a semi-automated pattern generation method. As many as 25 spots can be delivered in 0.5 sec. This new system significantly reducing both treatment time and patient discomfort. The PASCAL® laser may allow for more rapid, precise, and safe treatment. One thousand burns can be carried out within an average time of four minutes and generally more confortably for the patient than when using standard single spot argon lasers. Laser photocoagulation remains the most widely used primary treatment for PDR and macular oedema for the time being.
Some ophthalmologists have now started treating both PDR and macular oedema with drugs, as single therapy or in combination with Vitrectomy, that act against VEGF by blocking it. Mr Stanga will discuss with you the best option for you.
Mr Stanga is currently indicating either Lucentis® or Avastin® as anti-VEGF drugs.
It is possible that the pre-operative intraocular injection of anti-VEGF drugs can reduce the risk of intraoperative bleeding during surgery while attempting to severe abnormal new vessels or scar tissue, any intraocular bleed in the immediate post-operative period as well as reducing any pre-existing macular oedema.
If, after extensive discussion with Mr Stanga, it is decided that preoperative anti-VEGF is the best way forward for you then Mr Stanga will inject intraocularly an anti-VEGF drug (either Lucentis® or Avastin®) 1 week prior to the surgery to the eye where a vitrectomy has been. See AMD section for more details on anti-VEGF drugs.
If you are having anti-VEGF treatment, please inform Mr Stanga if you are pregnant as we don’t yet know whether these drugs are safe for an unborn baby. If necessary, we can draw a blood specimen from your arm vein to determine if you are pregnant.
It is sometimes necessary to carry out investigations both initially and at regular intervals. The most commonly requested tests are fundus fluorescein angiography (FFA) and Optical Coherence Tomography (OCT).
During FFA a dye injected into a vein in the patient's arm and flash photographs are obtained through dilated pupils. FFA provides a detailed view of the macular blood vessels.
OCT is a non-contact test that is analogous to ultrasound but uses near-infrared light instead of sound to images the macula by means of cross-sectional images similar to a histopathological microscope section. OCT can be very useful to determine the presence or absence of fluid, objectively determine the retinal thickness and response to treatment.
Lucentis® has been used in approximately 3000 patients for the treatment of age-related macular degeneration. Studies in approximately 1300 patients have so far shown that Lucentis® is effective and well tolerated.
Intravitreal injection of Avastin® has been shown to induce regression of diabetic retinal as well as iris neovascularisation (NV). A retrospective review conducted in the United States of America of consecutive patients receiving intravitreal Avastin® for PDR at two clinical practices (26 patients) showed no significant ocular or systemic side effects. All patients demonstrated reduction or absence of angiographic leakage of NV following injection, sometimes within 1 day. The NV also appeared to involute in most patients with a dramatic reduction in the calibre of perfused blood vessels. In some patients, a subtle reduction in leakage of iris or retinal NV was observed in the fellow or uninjected eye. This short-term study demonstrated proof of principle that intravitreal Avastin® can cause at least short term regression of retinal and iris NV secondary to PDR.
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