Tag: Macular degeneration

What is Geographic Atrophy?

Geographic atrophy is an advanced form of macular degeneration. Vision loss is irreversible.

Geographic atrophy (GA) is a progressive and irreversible form of advanced age-related macular degeneration (AMD) that affects the central portion of the retina, known as the macula. It is a leading cause of severe vision loss and visual impairment among older adults.

The macula is responsible for providing sharp, detailed, and central vision, which is essential for tasks such as reading, driving, and recognizing faces. In GA, the cells in the macula begin to degenerate and die, leading to the loss of these critical visual functions.

The term “geographic atrophy” refers to the characteristic appearance of the damaged areas in the macula. As the disease progresses, patches of atrophy develop, giving the appearance of irregularly shaped, well-demarcated lesions. These lesions can vary in size, shape, and location, and they can gradually expand and merge together over time.

The exact cause of GA is not fully understood, but it is believed to involve a combination of genetic, environmental, and lifestyle factors. The risk of developing GA increases with age, and individuals with a family history of AMD are also at higher risk.

Currently, there is no cure for GA, and treatment options are limited. However, researchers are actively investigating potential therapies to slow down the progression of the disease and preserve vision. Some experimental treatments include anti-inflammatory drugs, antioxidants, and cellular therapies.

Early detection and regular eye examinations are crucial for managing GA. High-resolution imaging techniques, such as optical coherence tomography (OCT), can help identify the presence and progression of GA. Additionally, lifestyle modifications, such as eating a healthy diet rich in fruits and vegetables, not smoking, and maintaining regular exercise, may help reduce the risk or slow down the progression of GA.

Living with GA can be challenging, as it can significantly impact an individual’s quality of life and independence. Therefore, it is important for individuals with GA to seek support from low vision specialists, who can provide assistance in adapting to vision loss and recommend visual aids and devices to enhance remaining vision.

In conclusion, geographic atrophy is a severe and irreversible form of AMD that leads to progressive vision loss. While there is no cure, ongoing research offers hope for potential treatments. Early detection, regular eye examinations, and lifestyle modifications are essential for managing GA and minimizing its impact on daily life.

If you would like to schedule an appointment, please call us (877) 245.2020.

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

What Causes a Macular Hole?

Retinal surgery sometimes uses injection of gas into the eye, especially when you have a macular hole.

Causes of a macular hole are discussed in this article and explained in the embedded video.

A macular hole is a hole at the very center of the retina. The retina is the layer of tissue that lines the inside of the eye and it contains millions of light-sensitive cells that receive and send visual information to the brain.

The macula portion of the retina contains the highest concentration of light-sensitive cells and is responsible for high-resolution, detailed central vision and most of our color vision.

Holes in the macula can be caused by injury, but most macular holes occur in people over the age of 60 and are caused by the vitreous gel in the eye pulling on the macula. These are called idiopathic macular holes and are, for reasons unknown, more common in women than men.

The Role of the Vitreous in Macular Holes

The vitreous contains millions of microscopic fibers that attach to the retina. As people age the vitreous slowly shrinks and pulls away from the retina’s surface and natural fluid fills in the area where the vitreous contracted. This is normal and usually causes no problems beyond possibly seeing “floaters” in your visual field from time to time.

However, in some cases the vitreous is so firmly attached to the retina that when it pulls away it can tear the retina slightly and cause a hole to form. Small holes sometimes heal on their own, but they can also gradually increase in size causing vision loss.

Other Causes of Macular Hole

The following additional conditions can cause a macular hole to develop:

  • Blunt trauma to the eye
  • Diabetic eye disease 
  • High degree of myopia (nearsightedness)
  • Macular pucker—caused by scar tissue on the macula

Symptoms of a Macular Hole

In the early stages there may be a slight distortion or blurriness in central vision. As the hole increases in size, straight lines and objects look bent or wavy, vision becomes increasingly blurrier and a dark spot may appear in the center of your vision.

Treatment of Macular Holes

A surgery to remove the vitreous gel (vitrectomy) and prevent it from continuing to pull on the retina is currently the best way to repair a macular hole. After the removal of the vitreous gel, a bubble containing a mixture of air and gas is put into the eye to prevent subretinal fluid from seeping behind your retina and destabilizing the healing process.

The gas bubble will slowly dissipate and be replaced with aqueous humor produced by your eye. You may be asked to keep your head in a face-down position for several days to keep the bubble in place. CAUTION: As long as any of the gas bubble remains in your eye you must not fly in an airplane because the bubble can expand in the reduced pressure of the cabin causing severe pain and possible loss of sight.

Another potential treatment for some patients with macular holes is the injection of an antiplasmin inhibitor that inactivates plasmin, an enzyme that breaks down the fibrin in blood clots.

Success Rate

The vitrectomy success rate is over 90% with patients regaining most of their lost vision. The gas bubble starts to shrink 7 to 10 days after the vitrectomy, but it takes about 6 to 8 weeks for the gas bubble to be totally absorbed. Vision will continue to improve during that 6 to 8 week time.

Complications

In less than 10% of cases the vitrectomy may cause cataract formation, retinal detachment, infection, glaucoma, bleeding or a re-opening of the macular hole. 

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

If you would like to schedule an appointment, please call us (877) 245.2020.

Drug Delivery for Eye Disease

Eye drops are great for only certain eye diseases. There are other routes used to treat your retina.

There are different routes of drug delivery to treat your eye disease.

Not all parts of the eye can be reached by the same route. Eye drops and ointments applied by patients directly to the eye is the route to get to the cornea, conjunctiva, and sclera, but getting to the retina in the back of the eye requires a different route—an injection.

Intravitreal Injections

Only an intravitreal injection will reach the retina because the retina is part of the brain and is protected by the blood-brain barrier.

Intravitreal means that the injection is into the vitreous of the eye. The vitreous is a clear, colorless, jelly-like substance that fills the space between the lens and the retina. Intravitreal injections of anti-VEGF are placed in the vitreous near the retina to treat wet macular degeneration and diabetic retinopathy.

The injections are done in a doctor’s office and the eye is numbed before the injection. They are a safe and effective way to prevent further vision loss.

Eye Drops

Eye drops are the preferred route of drug delivery to treat eye diseases in the front part of the eye. They are commonly used to treat eye infections, allergies, inflammation, glaucoma, and to provide lubrication for dry eyes.

Eye drops come in solutions and suspensions. In a solution the particle sizes are very small and they completely dissolve in the solvent mixture making a solution clear. Suspensions consist of larger particles that are suspended in a solvent. The larger particles will settle to the bottom so suspensions must be shaken before use to re-suspend the therapeutic particles.

If you are applying more than one drop to an eye, allow the first drop to absorb completely before applying a second drop so the medication doesn’t end up running down your cheek.

Medicated Contact Lenses

For some corneal infections a special type of contact lens or a collagen shield is soaked in antibiotics and placed on the eye.

Ointments

Although ointments are greasy and somewhat difficult to apply they are the preferred eye medication for use on infants and very small children because they stay in the eye longer than eye drops. Ointments are also used for nighttime applications of eye medication so the ointment can cover the eye while you sleep.

Sustained Release Drug Systems

These are biodegradable, implanted devices that supply a slow, steady release of a drug over an extended time to maintain the therapeutic level of the drug to the target area. It is new technology and is available for the treatment of glaucoma, vascular occlusions and diabetic retinopathy.

If you would like to schedule an appointment, please call us (877) 245.2020.

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

Why Injections Not Drops

Here’s why eye drops don’t work for treating diseases of the retina.

The blood brain barrier blocks most medications from reaching the retina. You may wonder why there isn’t a pill, or an eye drop that treats these retinal diseases and why the only effective treatment is a shot in the eye, an intraocular injection.

Intraocular injections are common and effective ways to treat wet macular degeneration, diabetic retinopathy and retinal vascular occlusions.

Pills, eye drops, and even IV solutions cannot penetrate to the retina because it is protected by the blood-brain barrier. Direct injection circumvents this barrier.

The eye is the only part of the brain that can be viewed directly. And that is done when an eye doctor uses an ophthalmoscope and shines a bright light into your eye and can view the innermost layers of the eye—the retina, and the optic nerve.

Blood Brain Barrier

The blood-brain barrier (BBB) is a protective layer of endothelial cells that protects the brain from any pathogens or toxins that may be circulating in the blood supply, but it also restricts entry of large-molecule medications and 98% of all small-molecule drugs. So, the only way to get therapeutics to the brain or to the deep structures of the eye is to go through or behind the BBB.

The BBB allows water, some gasses, and fat-soluble molecules to dissolve in the cell membranes and cross its boundary. Alcohol, caffeine, and nicotine easily cross the BBB because they are lipophilic (attracted to fat) and mix easily with the fat in the BBB to gain entry. Oxygen and anesthesia are gasses that can pass through the BBB.

As part of the brain, the BBB prevents therapeutics that have been ingested and are circulating in the blood to gain entry to the eyes. The medication will travel through the body, but almost none of it will reach the eyes.

Leaky Blood Vessels

Wet macular degeneration is caused when blood vessels behind the retina grow abnormally and leak blood and fluid that distorts vision. If left untreated the leaking blood vessels will cause irreversible damage to the photoreceptors that create central vision.

A Shot in the Eye

The only way to get enough medication directly to the retina to stop the growth of the leaky blood vessels is to use an intravitreal injection. An intravitreal injection means that the medication is injected into the vitreous (jelly-like fluid) of the eye where it will diffuse to the retina.

In addition, injecting anti-vascular endothelial growth factor (anti-VEGF) directly into the eye where the leaky vessels are growing, prevents the anti-VEGF from circulating in your blood supply and possibly adversely affecting systemic blood vessels as it moves along to the eye.

The intravitreal injections are painless because the eye is numbed, and the injections can be done in your doctor’s office. They are a safe, and effective way to prevent leaky blood vessel damage to your retina.

Coming Advances in Treatment

An implanted reservoir that delivers sustained-release anti-VEGF directly to the retina is in the experimental phase. And the field of nanotechnology is in the preliminary research stages of developing nanoparticles as a potential way to transfer medication in eye drops across the BBB.

If you would like to schedule an appointment, please call us (877) 245.2020.

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

What is Legal Blindness?

Legal blindness can be caused by a variety of diseases. Here’s how it is defined and links to resources.

Legal blindness is a legal definition that is used to refer to patients with vision loss who qualify for government assistance. This is not total blindness.

Legal blindness is defined as a patient’s best visual acuity (aka best corrected) in either eye is 20/200 or less or the size of the visual field (peripheral vision) is less than 20 degrees. In other words, if both eyes do not see well, the vision is no better than 20/200 in better seeing eye.

“Best corrected” refers to the use of the best corrective lens/contact lens for the patient.

A central visual acuity of 20/200 or worse means that a legally blind person must be 20 feet away from an object to see what a “normal” person can see from 200 feet away.

Loss of peripheral vision can also qualify as legal blindness. Most patients normal peripheral vision can see at least 140 degrees without turning the head. Legally blind peripheral vision is less than 20 degrees.

Causes of Legal Blindness

  • Age-related macular degeneration (ARMD) is one of the leading causes of legal blindness in Americans aged 60 and older. ARMD affects the macula (functional center of the retina) and therefore decreases central vision.
  • Cataracts will affect almost everyone by the age of 80. Cataracts blur both central and peripheral vision (though reversible with cataract surgery).
  • Diabetic retinopathy is another leading cause of blindness and affects the blood vessels in the back of the retina. Diabetic retinopathy causes either blurring of the central vision (most common), but can affect peripheral vision, too.
  • Glaucoma is a progressive disease that damages the optic nerve. Glaucoma primarily causes visual field loss and, only in the late stages, affects central vision.

NOTE: All of the disease described above have available treatments which, in most cases, can preserve vision or slow down progression if diagnosed timely.

Low Vision Aids

May low-vision aids and devices are available to assist individuals who are legally blind. Both near and distance vision can be improved with low-vision aids.

For example, desktop, stand-alone and hand-held magnifiers are available. These may be helpful for close range work such as reading or computer use. Prices vary up to several hundred dollars.

Wearable devices that magnify are also available. Mounted binoculars, wearable HD autofocus cameras with TV viewing and electronic headsets with built-in cameras can help patients with central and peripheral vision loss. Prices vary up to several thousand dollars.

Resources

There are many governmental and non-governmental resources for those who are legally blind.

For example, the American Foundation for the Blind (AFB) can assist those with low-vision. Founded in 1921, the AFB ensures that patients who are blind, legally blind or otherwise visually impaired have access to educational materails, technology and legal information.

Here are additional resources that help blind, legal blindness and visually impaired.

Low Vision Evaluation

If you feel you suffer from legal blindness or need more information, a low-vision examination is the first place to start. Eye doctors specializing in low vision can advise and educate you about the best low-vision aids for your specific visual needs.

If you would like to schedule an appointment, please call us (877) 245.2020.

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

Warnings Issued About Beovu

Beovu is FDA approved for the treatment of wet ARMD. An unusual complication may be associated with the drug…

Beovu was recently cleared by the FDA for the treatment of wet macular degeneration. Warnings about its use were recently issued by the American Society of Retina Specialists (ASRS).

Beovu is yet another anti-VEGF medication and, like the others, is delivered directly into the eye by injection. The drugs usually need to be repeated every 4-6 weeks and for an undetermined period.

At the recent meeting of the American Society of Retina Specialists (ASRS), a warning letter was issued to its retina specialist members that a very unusual side effect has been reported.

14 patients with retinal vasculitis have been reported. 11 of the 14 cases were reported to have occlusive retinal vasculitis resulting in severe vision loss. Retinal vasculitis is an unusual complication of any of the anti-VEGF medications.

Anti-VEGF Medications

Other medications used for the treatment of wet macular degeneration include:

  • Macugen (pegaptanib)
  • Avastin (bevacizumab)
  • Lucentis (ranibizumab)
  • Eylea (aflibercept)

Anti-VEGF medications temporarily halt the abnormal growth of neovascularization (abnormal blood vessels) within the layers of the retina. Because the vessels tend to grow back, injections need to be repeated.

Until Beovu was FDA approved, most anti-VEGF injections are repeated every 4-6 weeks. Beovu is unique in that it was approved for a possible 3 month dosing schedule (i.e. an interval of 3 months vs. 4-6 week).

Visual results were comparable to the visual results obtained by Eylea. The drug was not tested against the other anti-VEGF injections in the data submitted for FDA approval.

Novartis Response

Novartis Pharmaceuticals is the manufacturer of Beovu and in two public statements stands by the safety and efficacy of the drug as reported to the FDA.

The company states that the 14 cases of vasculitis fall well within the reported incidence of severe vision loss although it is not clear that vasculitis, specifically, was ever reported as a side effect.

The company is moving forward with its own investigation of these “post-marketing” events and is engaging the help of an external Safety Review Committee (SRC).

If you would like to schedule an appointment, please call us (877) 245.2020.

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

Jon Doe