There are multiple forms of macular degeneration but the most common is Age-related macular degeneration (ARMD/AMD). This form of AMD comes in 2 forms, dry and wet. The former is the early presentation, and although it can result in a significant decrease in vision this usually only occurs over a prolonged period of time unless it transforms into the wet form. With the onset of wet macular degeneration, the vision often decreases rapidly to the level of legal blindness or worse. The difference between the dry and wet form of AMD is the onset of abnormal blood vessel growth under the retina. These vessels will leak clear fluid under and into the retina, and if they rupture bleed. These result in a rapid decrease in vision and ultimate destruction of the photoreceptors, atrophy of the other layers of the macula and retina, and the formation of scar tissue.
Dry and Wet AMD
Dry AMD requires regular follow-up because occasionally the transition from dry AMD to wet AMD is not noticed by the patient. Additionally, those patients who have a high risk for wet AMD need to be placed on the nutritional supplements of AREDS2 and instructed on monitoring their vision using either the Amsler grid or the Foreseehome devise. In this way the onset of wet AMD might be detected early resulting earlier treatment and potentially better visual results. Use of the AREDS2 supplement will decrease the risk of progression of dry AMD to wet AMD by approximately 25%.
Wet AMD is currently treated with the intraocular injections to an anti-VEGF drug. This drug blocks the formation of new but abnormal vessels. There are currently 4 drugs being used, Avastin (bevacizizumab), Lucentis (ranibizumab), Eylea (aflibercept) and Beovu (brolucizumab). In administering these drugs the eye is initially prepped with a Betadine solution and topical anesthetic. This followed by a subconjunctival injection of Xylocaine or a Xylocaine ointment and a drop of betadine solution on the eye. After several minutes the anti-VEGF drug is injected into the eye. Initial treatment involves at least 3 consecutive injections approximately 4-5 weeks apart. After these injections the interval between subsequent injections would depend of the response of the wet AMD. Ideally when 2 consecutive follow-up exams show on further leakage the interval between exams is extended to 2 months. During each exam the eye is examined and a diagnostic OCT, to determine the progression/regression of the wet-AMD. Occasionally after repeated injections the eye stabilizes and no further injections are made. In other cases the eye may not dry completely but there is no progressive leakage. In such cases they are just followed and possibly receive maintenance injections as needed as determined by the eye exam. The use of Beovu has a somewhat different treatment protocol in that 3 injections are made but any subsequent injection with Beovu has to be 3 months later. Complications can occur with each injection. These could include infection, retinal detachment, adverse reaction to the medication, increased intra-ocular pressure and intra-ocular hemorrhage. Minor complications include a subconjunctival hemorrhage, corneal abrasion and accumulation of small silicone bubbles, which come from lubricant within the injection syringe. All complications can be handled successfully if treated promptly.
What Should You Do if You Are At High Risk for Macular Degeneration?
If you believe that you at an increased risk for age-related macular degeneration, it would be important to first get a complete eye exam to include a thorough retinal evaluation. This would determine if you are truly at high risk and should take appropriate steps in changing your life style and be placed on nutritional supplements with high antioxidant content. You may also be advised as to how to monitor yourself in order to detect the onset of the more sight threatening form of macular degeneration, which is more successfully treated in its early stage.
To get a thorough eye exam, call our office for an appointment at (941) 921 5335.
Dr Mel Chen
Sarasota Retina Institute