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.
As a result of a vitreous haemorrhage vision can become markedly reduced as the retina is being blocked. Blood can generally clear up over several months. Vitreous haemorrhage is generally removed surgically if it has not cleared within 3 to 6 months. The surgery to remove a vitreous haemorrhage is called a virectomy. During this surgery, the vitreous gel, blood and scar tissue can be removed from the eye and replaced with a clear solution. Professor Stanga will carry out this surgery if necessary.
Laser photocoagulation, intravitreal anti-VEGF (Avastin®, Lucentis®, Eylea®), intravitreal steroid (Triamcinolone: Kenalog® or Triescence® or Dexamethasone: Ozurdex®) and surgery, independently from each other or in combination, are the standard treatments for Proliferative Diabetic Retinopathy and/or Macular Oedema.
Refractory Macular Oedema affects vision but does not respond adequately to the usual treatment methods. Without effective treatment, vision loss could progress and become permanent.
A molecule, called Vascular Endothelial Growth Factor (VEGF) tends to be released in eyes that have ischaemia. VEGF is thought to stimulate the growth of abnormal, leaking blood vessels that grow on the retina leading to either PDR and/or Macular Oedema.
Pan-retinal photocoagulation aims at ablating or burning thus destroying the areas of ischaemic retina which induce the formation of VEGF. Professor Stanga photocoagulates using the new OptiMedica PASCAL® Pattern Scan Laser Photocoagulator system.
The PASCAL® laser uses a semi-automated pattern generation method and as many as 25 spots can be delivered in 0.5 seconds. This new system significantly reduces both treatment time and patient discomfort. The PASCAL® laser may allow for more rapid, precise, and safer treatment. One thousand burns can be carried out within an average time of four minutes and generally more comfortably for the patient than when using standard single spot argon lasers.
For the time being laser photocoagulation remains the most widely used primary treatment for PDR and focal macular oedema.
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. Professor Stanga will discuss the best option for you.
Professor Stanga is currently indicating either Lucentis®, Avastin® or Eylea® as anti-VEGF drugs.
It is possible that the pre-operative intraocular injection of anti-VEGF drugs can reduce the risk of intra-operative 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 Professor Stanga, it is decided that preoperative anti-VEGF or steroid is the best way forward for you, then Professor Stanga will inject intraocularly an anti-VEGF drug (either Avastin®, Lucentis® or Eylea®) one week prior to the surgery to the eye that is to undergo vitrectomy surgery.
If you are having anti-VEGF treatment, please inform Professor Stanga if you are pregnant, as we do not yet know whether these drugs are safe for an unborn baby. If necessary, we can draw a blood test to determine this.
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 image 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.
You must immediately contact Professor Stanga or his team if any of the following signs of infection or other complications develop: pain, blurry or decreased vision, sensitivity to light, redness of the eye (compared to immediately after the injection) or discharge from the eye. You should not rub your eyes or swim for three days after each injection. Please keep all post-injection appointments or scheduled telephone calls so that Professor Stanga or his team can check for complications.
Although the likelihood of serious complications affecting other organs of your body is low, you should immediately contact your GP doctor or go to the Accident and Emergency Department if you experience abdominal pain associated with constipation and vomiting, abnormal bleeding, chest pain, severe headache, slurred speech, or weakness on one side of the body.
As informed by Professor Stanga and his team, symptoms of stroke include sudden changes in vision; sudden numbness or weakness of the face, arm, or leg, especially on one side of the body; sudden confusion, trouble speaking or understanding; sudden trouble walking, dizziness, loss of balance or co-ordination; sudden, severe headache with no known cause.
Please notify Professor Stanga or his team about any of these problems.
Please read the section regarding virectomy and posturing if you are undergoing this type of surgery.
Please remember that each patient is different and the information here provided is only a general guide. If you require further advice or information please contact Professor Stanga or a member of his team.
Retinal Vein Occlusion
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.
Blood is supplied to the retina through a vein and one artery which have numerous small branches that help to supply the whole of the area.
A retinal vein occlusion occurs due to a blockage of the vein or a branch of the vein that returns blood to your heart from the retina. When this happens the retina is affected and the most common symptoms are a loss of vision and sudden pain.
Your sight may be affected depending on where the blockage has happened. This blockage leads to the leakage of blood and clear fluid. If the fluid reaches the centre of your retina your vision may be affected.
The causes of a retinal vein occlusion can be due to high blood pressure, diabetes, smoking and high levels of cholesterol amongst others. Sometimes the cause is unknown.
Professor Stanga will discuss available treatment options with you.