Macular degeneration affects cells in the macula, which is the part of the retina responsible for central vision.  Central vision is essential for most basic tasks like reading, driving, recognizing people, etc.  Thus, although macular degeneration leaves peripheral vision un-impaired, it can be quite debilitating in its advanced state.

The disease exists in two forms, dry and wet.

Dry macular degeneration is by far the most common (roughly 90% of all cases).  However, it is the milder of the two forms, develops gradually, and usually leads to only minor vision loss.  Dry macular degeneration tends to occur when yellow fatty particles called drusen accumulate in the retina underneath the macula.  This build-up results in thinning and drying-out of the macular cells.

Wet macular degeneration is less common, but the vast majority of severe vision loss cases result from this form.  First, abnormal blood vessels form underneath the surface of the retina.  Leakage of blood and other fluids from these blood vessels permanently damage the outside cells (which detect incoming light).  As these cells are damaged, vision is lost.

The primary cause of macular degeneration remains unknown.  Macular degeneration typically occurs more frequently in the aging population with patients over 60.  Research has shown there are many other factors such as family history, smoking, hypertension, obesity, and/or a high cholesterol, high fat diet that may contribute towards the development of macular degeneration.

Macular degeneration symptoms may include:

• Shadows, blurriness, or holes in the center of vision.
• Straight lines appear wavy.
• Trouble seeing details both up close and at a distance.
• Difficulty telling colors apart, especially ones close in hue.
• Vision can be slow to come back after bright light exposure.

Avastin Injection for Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in people over 50 years of age.  It is caused by the breakdown of the central portion of the retina (the highly sensitive part of your eye that works like the film in a camera to pick up the picture) called the macula.  The macula is responsible for the fine central vision in the eye that is needed for driving a car, reading fine print, recognizing faces, etc. There are two types of macular degeneration: dry and wet.  In the “wet” form of AMD, abnormal blood vessels grow in the back of the eye.  Sometimes these vessels leak blood or fluid that causes blurred or distorted vision.  Without treatment, vision loss may be quick and severe.

There are other eye conditions that cause loss of vision due to abnormal growth of blood vessels in the back of the eye.  These can occur even in young patients, and include, but are not limited to, conditions such as high myopia (nearsightedness), histoplasmosis, angioid streaks, and eye injury.  Sometimes there is no known reason for the abnormal blood vessels.  Without treatment, vision loss may be quick and severe.

Macular edema, or swelling around the macula,, is edema that affects vision but does not respond adequately to the usual treatment methods.  It can occur with conditions such as central retinal vein occlusion and diabetic retinopathy.  Without effective treatment, vision loss could progress and become permanent.

Avastin was not initially developed to treat your eye condition.  Based upon the results of clinical trials that demonstrated its safety and effectiveness, Avastin^TM was approved by the Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancer.  As a condition of approval, the manufacturer produced a “label” explaining the indications, risks, and benefits.  The label explains that Avastin^TM works by blocking a substance known as vascular endothelial growth factor or VEGF.  Blocking or inhibiting VEGF helps prevent further growth of the blood vessels that the cancer needs to continue growing.  
  
Once a device or medication is approved by the FDA, physicians may use it “off-label” for other purposes if they are well-informed about the product, base its use on firm scientific method and sound medical evidence, and maintain records of its use and effects.  Ophthalmologists are using Avastin^TM “off-label” to treat AMD and similar conditions since research indicates that VEGF is one of the causes for the growth of the abnormal vessels that cause these conditions.  Some patients treated with Avastin^TM had less fluid and more normal-appearing maculas, and their vision improved.  Avastin^TM is also used, therefore, to treat macular edema, or swelling of the macula.

Off-Label Drugs Here are some examples of common drugs being used "off-label": 1)  Eye antibiotics 2)  Botox 3)  Zoloft & Paxil 4)  Methotrexate

The goal of treatment is to prevent further loss of vision.  Although some patients have regained vision, the medication may not restore vision that has already been lost, and may not ultimately prevent further loss of vision caused by the disease.  After the pupil is dilated and the eye is numbed with anesthesia, the medication is injected into the vitreous, or jelly-like substance in the back chamber of the eye. Avastin^TM is administered by an injection into your eye as needed at regular intervals (about every four to six weeks); your ophthalmologist will tell you how often you will receive the injection, and for how long. 

You do not have to receive treatment for your condition, although without treatment, these diseases can lead to further vision loss and blindness, sometimes very quickly. Other forms of treatment are available.  At present, there are three FDA-approved treatments for neovascular age-related macular degeneration:  photodynamic therapy with a drug called Visudyne™ and injection into the eye of two other VEGF inhibitors drugs called Macugen™ and Lucentis™. Although both of these treatments have been proven to slow down the rate of visual loss, most people do not get back better vision.  Dr. Takle Jr., and Dr. Cribbs will discuss with you the benefits and risks associated with these other choices of treatment.  In addition to the FDA-approved medications, some ophthalmologists use intravitreal Kenalog^TM—a long-acting cortisone-like drug—“off-label” to treat eye conditions like yours.

Complications when AvastinTM is given to patients with cancer

When Avastin^TM is given to patients with metastatic colorectal cancer, some patients experienced serious and sometimes life-threatening complications, such as gastrointestinal perforations or wound healing complications, hemorrhage, arterial thromboembolic events (such as stroke or heart attack), hypertension, proteinuria, and congestive heart failure. 

Patients who experienced these complications not only had metastatic colon cancer, but were also given 400 times the dose you will be given, at more frequent intervals, and in a way (through an intravenous infusion) that spread the drug throughout their bodies. 

Risk when Avastin^TM is given to treat patients with eye conditions

Ophthalmologists believe that the risk of these complications for patients with eye conditions is low.  Patients receiving Avastin^TM for eye conditions are healthier than the cancer patients, and receive a significantly smaller dose, delivered only to the cavity of their eye.  While there are no FDA-approved studies about the use of Avastin^TM in the eye that prove it is safe and effective, there are ongoing clinical trials of a similar drug as well as studies of patients receiving Avastin^TM “off-label.”   One study of patients who received Avastin^TM through an intravenous infusion reported only a mild elevation in blood pressure.  Another study of patients treated like you will be with intravitreal Avastin^TM (that is, Avastin^TM injected into the eye) did not have these elevations or the other serious problems seen in the patients with cancer. 

However, the benefits and risks of intravitreal Avastin^TM for eye conditions are not yet fully known.  In addition, whenever a medication is used in a large number of patients, a small number of coincidental life-threatening problems may occur that have no relationship to the treatment.  For example, patients with diabetes are already at increased risk for heart attacks and strokes.  If one of these patients being treated with Avastin^TM suffers a heart attack or stroke, it may be caused by the diabetes and not the Avastin^TM treatment.  This possible relationship is the subject of ongoing clinical investigations.

Known risks of intravitreal eye injections

Your condition may not get better or may become worse.  Any or all of these complications may cause decreased vision and/or have a possibility of causing legal blindness.  Additional procedures may be needed to treat these complications.  During the follow up visits or phone calls, you will be checked for possible side effects and the results will be discussed with you.

Any medication has the potential to cause allergic reactions in a small number of people.  Symptoms of an allergic reaction can include a rash, hives, itching, shortness of breath, and rarely death.  In general, allergic reactions to medicines are more likely to occur in people who have allergies to other drugs, foods, or things in the environment, such as dust or grass.  If you have allergies to other medicines, foods, or other things in the environment, or if you have asthma, you should let Dr. Takle or Dr. Cribbs know.

Possible complications and side effects of the procedure and administration of Avastin^TM include but are not limited to retinal detachment, cataract formation (clouding of the lens of the eye), glaucoma (increased pressure in the eye), hypotony (reduced pressure in the eye), damage to the retina or cornea (structures of the eye), and bleeding.  There is also the possibility of an eye infection (endophthalmitis).  You may receive eye drops with instructions on when to use them to reduce the possibility of this occurring.  Any of these rare complications may lead to severe, permanent loss of vision.

Patients receiving an injection of Avastin^TM may experience less severe side effects related to the pre-injection preparation procedure (eyelid speculum, anesthetic drops, dilating drops, antibiotic drops, povidone-iodine drops and the injection of the anesthetic).  These side effects may include eye pain, subconjunctival hemorrhage (bloodshot eye), vitreous floaters, irregularity or swelling of the cornea, inflammation of the eye, and visual disturbances.

If you are experiencing any symptoms of macular degeneration, we encourage you to contact us today to schedule a consultation.