Retinal Conditions

Age-Related Macular Degeneration (ARMD)

ARMD is the leading cause of legal blindness in persons over the age of 55. Early symptoms include a reduction in reading speed, inability to read fine print, and skipping letters or lines when reading. Later symptoms can include distortion of straight lines or dark or missing areas in the central vision.

The macula is the central part of the retina and allows us to read fine print clearly and see colors vividly. It is this area of the retina that deteriorates in ARMD. There are 2 forms of ARMD. Everyone who has macular degeneration starts out with the dry type and 20% progress to the wet type over the course of a lifetime. Macular degeneration in its most severe forms almost never causes total blindness. Usually only central vision is lost. It is a disease that leaves older persons unable to read and drive. However, nearly all patients will still have enough vision to care for themselves.

Dry Macular Degeneration

Age Related Macular Degeneration (Dry)

As the macula ages, the retinal cells cannot remove their own waste products and begin to die. Deposits of these waste products, called drusen, build up under the retina. Drusen, when large in number and size, are the first signs of macular degeneration that an eye doctor sees on examination. Collections of drusen can crowd out other cells in the retina and can cause further damage to the retina and the pigmented cell layer underneath the retina called the retinal pigment epithelium. Eventually, clumping pigment and punched out areas of pigment loss called geographic atrophy are seen. These areas can cause blind spots in vision. These areas of atrophy progress slowly over years but can result in severe central vision loss. Currently there is no specific treatment for dry macular degeneration.

Wet Macular Degeneration

20% of patients with dry degeneration will eventually develop abnormal blood vessels under the retina that can bleed and leak fluid. Patients often have abrupt vision loss with distortion of straight lines, or a stationary, dark or blurry spot in the central vision of one eye. The vision can worsen rapidly in a few days or weeks. Treatment can include traditional laser, injection of certain pharmaceutical agents such as Lucentis™, Avastin™, or corticosteroids into the eye, and/or ocular photodynamic therapy (cold laser). Each treatment has its risks and benefits and is individualized for the patient by the retina specialist. Multiple treatments may be necessary to control the disease. The treatments usually only slow down the disease and neither cure the disease nor commonly make the vision better.

Macular Holes

Macular hole

Macular holes are part of a larger group of disorders caused by abnormal pulling or traction of the vitreous gel on the retina. The vitreous gel occupies the back two-thirds of the eye and is normally attached to the retina when you are born. As you age, the vitreous tends to separate away from the retina. Typically, between the ages of 50 and 70 in most of us, the vitreous separates completely from the retina resulting in new floaters, a process called posterior vitreous detachment. However, in some patients, particularly those between the ages of 50 and 70 years of age, when the vitreous separation is occurring, the vitreous gets hung up in the macular area and sometimes around the optic nerve and does not let go. When this happens, abnormalities develop in the macula. The most serious of these is called a macular hole. The vitreous actually pulls hard enough on the macula without letting go that it can rip the center of the macula, called the fovea (which is the thinnest part of the retina), and as this occurs, the rip expands due to a thin layer of scar tissue that forms on the surface of the retina. As the rip expands into a hole, severe vision loss occurs.

Patients who develop macular holes, may initially just experience distortion of vision and ultimately may end up with a loss of central vision with a dark blind spot in the central vision. When someone with a macular hole tries to read, letters may be missing in the center of a word. Fortunately, macular holes can be repaired with surgery. Surgery can be done as an outpatient, but will require face-down positioning for a period of eight or more days. Usually, surgery is successful in repairing 80% or more of macular holes, resulting in visual improvement. Alternatives to face down positioning are available in certain cases. Vision will improve after surgery but almost never recovers to normal levels.

Your doctor will discuss with you all of the surgical options available for the treatment of these relatively common conditions. It is important to remember that patients who have macular hole in one eye may develop and have a 5-15% chance of developing macular hole in the fellow eye.

Other forms of abnormalities between the vitreous and retina include macular pucker, which can be repaired with improvement in vision in 75% of patients who have symptoms such as distortion or decreased vision.

Ocular Histoplasmosis Syndrome

Histoplasmosis is an infectious disease caused by Histoplasma capsulatum, a yeast like fungal organism that lives in the gastrointestinal tract of birds and is spread to humans by inhalation of dried and airborne dust containing spores. Almost everyone who lives or spends time in the Ohio and Mississippi River valleys has had systemic Histoplasmosis (almost 80 million people).

Amsler grid

Most of us get exposed to histoplasmosis and develop a flu-like illness and heal from it without problems. About 10% of persons who get this flu-like illness can develop scars in the back of the eye affecting the retina and a vascular layer under the retina called the choroid (Ocular Histoplasmosis). Sometimes these scars can occur around the optic nerve or near the macula. The scars themselves do not cause any visual problems. Many years later and generally in the prime of life (ages 20 to 55) these scars can be sites for the development of new blood vessels under the retina called choroidal neovascularization. Depending on where these blood vessels grow, they may or may not cause vision loss. The closer they are to the macula the more likely they are to cause vision loss. These new vessels are most often treated with laser, which can produce a blind spot at the site of treatment but will prevent further vision loss. Even with successful laser treatment, choroidal neovascularization may come back 25% of the time in the first five years in the treated eye. In some cases the abnormal blood vessels grow directly under the very center of the macula (fovea) and cannot be treated with laser because the resulting blind spot would be in the center of vision. In these cases, medical therapy with intravitreal injection of Avastin™ and/or steroids, cold laser treatment (ocular photodynamic therapy), or simply conservative observation may be recommended. In some very severe cases, surgical removal of blood vessels may be performed.

It is very important to monitor central vision in both eyes using an Amsler grid daily if you have ocular histoplasmosis and especially if the vision has been affected in one eye. Patients who develop choroidal neovascularization in one eye have a 25% chance of developing the same in the fellow eye within 3 years if they have histo scars close to the macula.

Retinal Venous Occlusive Disease

Since the retina is an extension of the brain, just as the brain can have small strokes develop within it, the retina can also develop either strokes that occur from obstruction of the arterial or the venous circulation. If the veins and the retina become obstructed, the area that the vein drains in the retina, cannot be drained properly so as blood flows into the retina through the normal arteries, blood cannot leave the retina. As a result, fluid and blood leak in to the retina causing the retina to swell causing reduced vision.

Central Retinal Vein Occlusion

There are two kinds of vein occlusions: branch vein occlusions and central vein occlusions. Branch vein occlusions are more common in patients who are diabetic, hypertensive, or have hardening of the arteries or elevated cholesterol or triglycerides. Central vein occlusions are more common in patients who have glaucoma, high blood pressure, or diabetes. Most patients who have these conditions already have other vascular risk factors such as coronary artery disease, hypertension or history of previous stroke. Young patients who have these conditions sometimes have underlying metabolic or genetic clotting abnormalities. These vein occlusions can be severe and can cause severe vision loss and, in some cases, blindness.

Vein occlusions can be treated with the use of intraocular injections of special medications such as corticosteroids or Avastin (an antibody that inhibits a chemical called vascular endothelial growth factor). In addition, laser treatment as well as a possible surgery may be indicated in some cases. These disease processes start relatively rapidly over the course of a few weeks or months, but may persist and heal over the course of 24-48 months. When the vein occlusions become so severe that they actually start interfering with the blood flow into the eye, these vein occlusions become ischemic (loss of blood flow to the retina), resulting in severe vision loss and much greater rates of complications such as neovascular glaucoma, a kind of glaucoma that can result in blindness very rapidly. Fortunately, with modern treatment, even these very late stages of disease can be treated to prevent loss of the eye and limit the amount of vision loss. Visual prognosis for these conditions is variable and very guarded. Your doctor will discuss with you the treatment options available for the specific vein occlusion seen in your eye.