Diabetic Retinopathy Archives - Nader Moinfar, MD, MPH, FACS, FASRS

Floaters from Vitreous Hemorrhage

Vitreous hemorrhage from various causes can cause floaters.

Vitreous hemorrhage can cause floaters in the eye. Bleeding inside the eye is called vitreous hemorrhage. Symptoms of this type of bleeding range from a showere of floaters to incomplete darkness (lots of blood).

Floaters due to blood can not be distinguished by other types of floaters based upon appearance. Often floaters from hemorrhage have appeared suddenly and don’t necessarily last as long as chronic (long-lasting) floaters, but they can.

Causes of Vitreous Hemorrhage

Any bleeding into the vitreous is called vitreous hemorrhage. Hence, there are a variety of causes of bleeding into the vitreous;

Retinal tears
Retinal Detachments
Trauma
Diseases of the retina (eg. proliferative diabetic retinopathy)
Complications of retinal vascular disorders
Posterior Vitreous Detachment

Treatments

For all intents and purposes, blood in the vitreous does not cause long-lasting damage. It is most important to establish the underlying cause of the bleeding and treat that disorder whenever possible.

For dense vitreous hemorrhages, it may indeed be prudent to consider a vitrectomy to remove the blood to restore vision, but more importantly, and to allow the retina specialist to perform a thorough examination of the eye with the blood removed.

Retinal Tears and Bleeding

As an example, a retinal tear can cause a vitreous hemorrhage if the tear rips across a retinal blood vessel and causes bleeding. There may be too much blood to actually visualize a retinal tear. Keep in mind, retinal tears can lead to retinal detachments.

Retinal detachments can be potentially blinding and, in cases of all retinal tears, we would like to treat the tear before a retinal detachment develops.

Vitreous Hemorrhage Can Resolve

Blood in the vitreous usually absorbs and can clear on with a vitrectomy. There is no specific timing of this and it can take weeks or even months. Sometimes, blood does not clear on its own and vitrectomy may be necessary.

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

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