The retina is a very thin layer of tissue that lines the inner part of the eye. It is responsible for capturing the light rays that enter the eye. These light impulses are then sent to the brain for processing, via the optic nerve. The retina contains rods and cones which are photoreceptor cells that are sensitive to light. Rods function mainly in dim light, while cones are responsible for daytime vision and perception of color.
The macula is a small and highly sensitive part of the retina responsible for detailed central vision. The macula allows us to appreciate detail and perform tasks that require central vision such as reading and driving.
The vitreous is a thick, clear gel that fills the center of the eye. It is composed mainly of water and comprises about 2/3 of the eye's volume, giving it form and shape.
- Age-related Macular Degeneration (AMD)
- Diabetic Retinopathy
- Detached and Torn Retina
- Epiretinal Membranes(ERM)
- Macular Holes
- Flashes and Floaters
AMD is one of the most common causes of poor vision after age 60. It accounts for more than 90% of new cases of legal blindness in the United States. It is an eye disease involving the macula, a small area in the center of the retina in the back of the eye. The deterioration of this area results in gradual decrease of sharp, central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading, driving, and recognizing faces.
In some people, AMD advances so slowly that it will have little effect on their vision as they age. But in others, the disease progresses faster and may lead to a loss of vision in one or both eyes.
How does AMD damage vision?
The retina is a paper-thin tissue that lines the back of the eye and sends visual signals to the brain. In the middle of the retina is a tiny area called the macula. The macula is made up of millions of light-sensing cells that help to produce central vision.
AMD occurs in two forms:
• Dry AMD: Everybody with AMD has this type at onset. Scientists think that that AMD is caused by many factors and that family history, smoking, uncontrolled blood pressure play a role. However, we still have a lot to learn. Nine out of 10 people have “dry” AMD which leads to the slow break-down or thinning of the light-sensing cells in the macula and a gradual loss of central vision.
• Wet AMD: Sometime after the onset of dry AMD, patients can develop a more serious form of the disease known as “wet” AMD in which serious and rapid damage to the macula can typically lead to a more dramatic decrease in vision. This affects about 1 out of 10 all people with AMD. In wet AMD, new fragile blood vessels may begin to grow and can cause bleeding and fluid under the macula. In the last several years, there have been promising treatments for this type of AMD which include off label Avastin, Lucentis, and Eylea. Top
Who is most likely to get AMD?
The greatest risk factor is age. Although AMD may occur during middle age, studies show that people over age 60 are clearly at greater risk than other age groups. For instance, a large study found that people in middle age have about a two percent risk of getting AMD, but this risk increased to nearly 30 percent in those over age 75. A recent study of 150 people age 100 found them all to have some form of AMD. If we live long enough, we all stand to develop some form of the disease.
Other Age-related Macular Degeneration risk factors include:
• Gender: Women tend to be at greater risk for AMD than men.
• Race / Blue Eyes: Whites are much more likely to lose vision from AMD than Latinos and Asians, and those of African descent rarely develop AMD.
• Family History: Those with immediate family members who have AMD are at a higher risk of developing the disease.
• Smoking: Smoking may increase the risk of AMD.
What are the symptoms?
Neither dry nor wet AMD cause any pain. The most common early sign of dry AMD is blurred vision. As loss of nerve cells progresses, people experience gradual loss of central vision. Often this blurred vision will go away in brighter light. Eventually, there will be a small, but growing blind spot in the middle of the field of vision.
The classic early symptom of wet AMD is that straight lines appear crooked. This is similar to the effect of looking through a fun-house mirror. This is caused by leaking blood from the damaged vessels lifting the macula. There may also be a small blind spot in wet AMD cases, causing central vision loss.
If you believe you have symptoms of age-related macular degeneration, contact us for an evaluation. Early diagnosis and treatment is crucial in preserving vision.
How is it detected?
You are at risk to develop AMD if you are over age 60 and have had recent changes in your central vision. To look for signs of the disease, eye drops are used to dilate, or enlarge, your pupils. Dilating the pupils allows us a better view of the back of the eye. You may also be asked to view an Amsler grid, a pattern that looks like a chess board. Early changes in your central vision will cause the grid to appear distorted, a sign of AMD.
Diabetes can affect blood vessels and organs throughout the body. It can particularly affect the eye causing a condition known as diabetic retinopathy. Diabetic retinopathy is a disease in which the retina is starved of oxygen and ultimately damaged. The condition develops when many years of high blood sugars, often aggravated by high blood pressure and cholesterol, causes severe injury to the blood vessels that supply oxygen to the retina. The vessels often begin to function poorly and can even leak fluid into the center of the retina, called the macula. Other complications include macular swelling, called macular edema, which can also lead to impaired vision. When treated properly, diabetic retinopathy and its effects are reversible; when ignored, it can lead to permanent vision loss and other health problems.
Who is most at risk for diabetic retinopathy?
Anyone with Type I (juvenile onset) or Type II (adult onset) diabetes is at risk.
What are the symptoms?
Diabetic retinopathy often has no early warning signs. At some point, though, you may develop macular edema, which blurs vision, making it hard to do things like read and drive. In some cases, your vision will get better or worse during the day. As new blood vessels form at the back of the eye, they can bleed (hemorrhage) and blur vision. The first time this happens it may not be very severe. In most cases, it will leave just a few specks of blood, or spots, floating in your vision. They often go away after a few hours. These spots are often followed within a few days or weeks by a much greater leakage of blood. The blood, too, will blur your vision. In an extreme case, one will only be able to tell light from dark in that eye. It may take the blood anywhere from a few days to months or even years to clear from the inside of the eye. In some cases, the blood will not clear. Also, you should be aware that large hemorrhages tend to happen more than once, often during sleep. Also, patients with diabetes tend to develop cataracts earlier. Top
How is it detected?
It is very important that patients with Diabetes get a dilated exam at least once a year to screen for any retinal changes associated with this condition as early detection is the best protection against loss of vision. Pregnant women with diabetes should schedule an appointment in their first trimester, because retinopathy can progress quickly during pregnancy. In our practice, patients typically have seen their optometrist or ophthalmologist (Eye M.D.) prior to being referred to us for a more specialized evaluation. More frequent medical eye examinations may be necessary after a diagnosis of diabetic retinopathy. Diabetic retinopathy is detected during an eye examination that includes:
• Visual acuity test: Eye chart test measures how well you see at various distances.
• Pupil dilation: Drops are placed into the eye to enlarge the pupil. This allows us to see more of the retina and look for signs of diabetic retinopathy. After the examination, close-up vision may remain blurred for several hours.
• Ophthalmoscopy: This is an examination of the retina in which the eye is examined by looking through a device with a special magnifying lens or using a bright light to look through a special magnifying glass to look at the retina.
• Optical Coherence Tomography (OCT): This device helps us better assess macular edema in high resolution and provides an objective way to monitor response to treatment.
• Fluorescein Angiography: Should we suspect that you need treatment for macular edema, we may ask you to have a test called fluorescein angiography, during which a special dye is injected into the arm and photographed as it passes through the blood vessels in the retina. This test allows us to find the leaking blood vessels and to target them during laser surgery.
• Based on our findings, we will categorize your disease as non-proliferative or proliferative diabetic retinopathy.
What is Non-proliferative Diabetic Retinopathy?
Nonproliferative diabetic retinopathy (NPDR), commonly known as background retinopathy, is an early stage of diabetic retinopathy. In this stage, tiny blood vessels within the retina leak blood or fluid. The leaking fluid causes the retina to swell or to form deposits called exudates.
Many people with diabetes have mild NPDR, which usually does not affect their vision. When vision is affected, it is the result of macular edema or macular ischemia, or both.
What is Macular Edema and Ischemia?
Macular edema is swelling or thickening of the macula, a small area in the center of the retina that allows us to see fine details clearly. The swelling is caused by fluid leaking from retinal blood vessels. It is the most common cause of visual loss in diabetes. Vision loss may be mild to severe, but even in the worst cases, peripheral (side) vision continues to function. Laser treatment can be used to help control vision loss from macular edema. Some patients benefit from use of intraocular steroid injection. Newer treatments are being investigated such as use of anti-VEGF treatment in this condition.
Macular ischemia occurs when small blood vessels (capillaries) close. Vision blurs because the macula no longer receives sufficient blood supply to work properly. Unfortunately, there are no effective treatments for macular ischemia.
What is Proliferative Diabetic Retinopathy?
Proliferative diabetic retinopathy (PDR) is a complication of diabetes caused by changes in the blood vessels of the eye. If you have diabetes, your body does not use and store sugar properly. High blood sugar levels create changes in the veins, arteries, and capillaries that carry blood throughout the body. This includes the tiny blood vessels in the retina, the light-sensitive nerve layer that lines the back of the eye.
In PDR, the retinal blood vessels are so damaged they close off. In response, the retina grows new, fragile blood vessels. Unfortunately, these new blood vessels are abnormal and grow on the surface of the retina, so they do not resupply the retina with blood.
Occasionally, these new blood vessels bleed and cause a vitreous hemorrhage. Blood in the vitreous, the clear gel-like substance that fills the inside of the eye, blocks light rays from reaching the retina. A small amount of blood will cause dark floaters, while a large hemorrhage might block all vision, leaving only light and dark perception.
The new blood vessels can also cause scar tissue to grow. The scar tissue shrinks, wrinkling and pulling on the retina and distorting vision. If the pulling is severe, the macula may detach from its normal position and cause vision loss.
Laser surgery may be used to shrink the abnormal blood vessels and reduce the risk of bleeding. The body will usually absorb blood from a vitreous hemorrhage, but that can take days, months, or even years. If the vitreous hemorrhage does not clear within a reasonable time, or if a retinal detachment is detected, an operation called a vitrectomy can be performed. During a vitrectomy, the eye surgeon removes the hemorrhage and any scar tissue that has developed, and performs laser treatment to prevent new abnormal vessel growth.
People with PDR sometimes have no symptoms until it is too late to treat them. The retina may be badly injured before there is any change in vision. There is considerable evidence to suggest that rigorous control of blood sugar decreases the chance of developing serious proliferative diabetic retinopathy.
A retinal detachment is a very serious problem that usually causes blindness unless treated. The appearance of flashing lights, floating objects, or a gray curtain moving across the field of vision are all indications of a retinal detachment. If any of these occur, see your eye doctor right away.
As one gets older, the vitreous (the clear, gel-like substance that fills the inside of the eye) tends to shrink slightly and take on a more watery consistency. Sometimes as the vitreous shrinks, it exerts enough force on the retina to make it tear.
Retinal tears can lead to a retinal detachment. Fluid vitreous, passing through the tear, lifts the retina off the back of the eye like wallpaper peeling off a wall. Laser surgery or cryotherapy (freezing) are often used to seal retinal tears and prevent detachment.
The retina is a layer of light-sensing cells lining the back of your eye. As light rays enter your eye, the retina converts the rays into signals that are sent through the optic nerve to your brain, where they are recognized as images.
The macula is the small area at the center of your retina that allows you to see fine details. The macula normally lies flat against the back of the eye, like film lining the back of a camera. As you age, the clear, gel-like substance that fills the middle of your eye begins to shrink and pull away from the retina. In some cases, a thin “scar tissue” or membrane can grow on the surface of the macula. When wrinkles, creases, or bulges form on the macula due to this scar tissue, this is known as an epiretinal membrane or macular pucker. Damage to your macula causes blurred central vision, making it difficult to perform tasks such as reading small print or threading a needle. Peripheral (side) vision is not affected.
Symptoms, which can be mild or severe and affect one or both eyes, may include:
• blurred detail vision;
• distorted or wavy vision;
• gray or cloudy area in central vision; and
• blind spot in central vision.
RVC Team will examine your eye to evaluate for an epiretinal membrane by examination and special photographic techniques. If your symptoms are mild, no treatment may be necessary. Updating your eyeglass prescription or wearing bifocals may improve your vision sufficiently. If you have more severe symptoms that interfere with your daily routine, we may recommend vitrectomy surgery to peel and remove the abnormal scar tissue. During this outpatient procedure, RVC Team uses tiny instruments to remove the wrinkled tissue. Vision often improves as does distortion.
Be sure to discuss your options with RVC Team doctors. If surgery is recommended, you should be aware that as with any surgical procedure, rare complications can occur, including infection.
The macula is the part of the retina responsible for acute central vision, the vision you use for reading, watching television, and recognizing faces. A macular hole is a small, round opening in the macula. The hole causes a blind spot or blurred area directly in the center of your vision.
Most macular holes occur in the elderly. When the vitreous (the gel-like substance inside the eye) ages and shrinks, it can pull on the thin tissue of the macula, causing a tear that can eventually form a small hole. Sometimes injury or long-term swelling can cause a macular hole. No specific medical problem is known to cause macular holes.
Small specks or clouds moving in your field of vision as you look at a blank wall or a clear blue sky are known as floaters. Most people have some floaters normally but do not notice them until they become numerous or more prominent.
In most cases, floaters are part of the natural aging process. Floaters look like cobwebs, squiggly lines, or floating bugs. They appear to be in front of the eye but are actually floating inside. As we get older, the vitreous (the clear, gel-like substance that fills the inside of the eye) tends to shrink slightly and detach from the retina, forming clumps within the eye. What you see are the shadows these clumps cast on the retina, the light-sensitive nerve layer lining the back of the eye.
The appearance of flashing lights comes from the traction of the vitreous gel on the retina at the time of vitreous separation. Flashes look like twinkles or lightning streaks. You may have experienced the same sensation if you were ever hit in the eye and “saw stars.”
Floaters can get in the way of clear vision, often when reading. Try looking up and then down to move the floaters out of the way. While some floaters may remain, many of them will fade over time.
Floaters and flashes are sometimes associated with retinal tears. When the vitreous shrinks, it can pull on the retina and cause a tear. A torn retina is a serious problem. It can lead to a retinal detachment and blindness. If new floaters appear suddenly or you see sudden flashes of light, contact your eye doctor immediately.