The front clear portion of the eye is called the cornea and allows a clear view for our vision. The protective, white covering on the outer wall of the eye is called the sclera. The iris is the colored ring on the front of the eye that controls the amount of light that enters the eye. The round opening in the center of the iris is the pupil. The iris is consisted of muscles that will dilate (widen) the pupil in dim light and constrict (narrow) the pupil in bright light. Located just behind the iris is the crystalline lens, which focuses light on the back wall of the eye. The center of the eye is filled with a jelly-like substance called vitreous. When light enters the eye, it passes through the clear cornea, pupil and lens and through the clear vitreous in the center of the eye. The light is then focused on the thin layer of light-sensing cells lining the back wall of the eye called the retina. The retina converts the light into signals, which are sent through the optic nerve to the brain where they are recognized as images. The retina has two main parts: the peripheral retina and the macula. The macula is the area in the center of the retina that is responsible for seeing fine detail. The peripheral retina gives us vision to the side, this is what we call peripheral vision.
The above diagram shows the back wall of the eye, called the retina. The white spot is the optic nerve and the darker area in the middle of the diagram is the macula, the area responsible for central vision.
Age Related Macular Degeneration (AMD) is the leading cause of blindness in the world. There are two forms of AMD, dry and wet. With the dry form of AMD, patients have yellow deposits within the retina called drusen. Atrophy may develop from drusen that have been present for a long time causing the macula to thin and lead to slow progressive vision loss. Wet AMD is less prevalent but causes more severe vision loss if not diagnosed and treated. In wet AMD, new blood vessels grow under the retina. These new vessels are weak and may leak fluid and blood, causing swelling which usually decreases a person’s vision.
Nonproliferative diabetic retinopathy (NPDR) is the most common type of diabetic retinopathy. It can be described as mild, moderate or severe. When you have NPDR, the walls of the blood vessels in your retina are damaged. Small bulges extend from the vessel walls, sometimes leaking or oozing fluid and blood into the retina. These bulges are called microaneurysms. As the condition progresses, the smaller vessels may close entirely and the larger retinal veins may begin to swell.
PDR (proliferative diabetic retinopathy) is an advanced disease state in which new abnormal blood vessels begin to grow along the retina. The new blood vessels are weak and increase a patient’s risk of developing bleeding in the eye (vitreous hemorrhage). The usual treatment for patient’s who have developed PDR is pan retinal photocoagulation. This is a laser, which is applied to the periphery of the retina in an effort to reduce the risk of bleeding.
Macular edema is the term used for swelling in the small central part of the retina used for sharp straight-ahead vision. The retina is a thin layer of tissue that lines the back of your eye. It is nourished by blood vessels that become affected by diabetes. These blood vessels weaken and some of them develop balloon-like swellings called microaneurysms. The walls of the blood vessels and the microaneurysms become leaky. Excess fluid and lipids (fatty materials) leak from the blood into the retina causing it to become thickened or swollen. This swelling of the central part of the retina leads to decreased vision.
The macula is the small area in the center of the retina that allows you to see fine details clearly. As a person ages, the vitreous in the center of the eye shrinks and pulls away from the retina . As the vitreous pulls away, the retina initiates a healing response that may cause scar tissue to develop on the macula. The scar tissue can warp and contract and cause wrinkling, creasing, or bulging on the macula. Symptoms of a macular pucker can range from mild to severe and may include blurred vision, distorted or wavy vision, difficulty reading, gray and/or cloudy area in the central vision, and a central blind spot. Peripheral or “side” vision is not affected by macular puckers. Macular puckers are associated with eye conditions such as vitreous detachment, torn or detached retina, inflammation inside the eye, severe trauma to the eye, and/or disorders of the blood vessels in the retina.
The macula is the central area of the retina that is responsible for seeing fine details. Attached firmly to the retina is the vitreous gel that fills the center of the eye. As a person ages, the vitreous shrinks and contracts which causes tractional forces on the macula. In most cases the vitreous gel separates with no adverse side effects, but, in some cases the vitreous is firmly attached to the macula. The tractional forces can cause a small hole in the macula, which is known as a macular hole. Symptoms of a macular hole include: loss of central vision and distortion.
Repair of a macular hole involves vitrectomy surgery. This operation is done to remove the vitreous jelly of the eye that is causing traction to the macula. During the surgery, the surgeon may also remove additional tissue causing traction and preventing the hole from closing. Also, during the surgery, the eye will be filled with a gas bubble that will stay in the eye and dissolve over time; the duration can vary depending on the type of gas used to fill the eye. After surgery, the patient will have to be in a face down position for four to seven days. Following the positioning requirements is important to maximize the chance of success of the surgery. When in a face down position, the bubble will press against the macular hole aiding it in closure. There is rental equipment available to assist with face down positioning.
It is very important to see your ophthalmologist at the first signs of vision change, since the macular hole surgery has the best results when the procedure is done within 6 months to one year after the formation of the hole.
The macula is the dark area in the center of the photo. Within the center of this area is the macular hole.
As seen in this red free image, the macular hole is located in the center of the retina.
This is a normal scan of the retina.
In this scan, you can see a full thickness hole in the macula.
This scan shows an epi-retinal membrane with vitreo-macular traction.
This OCT displays macular edema associated with a retinal vein occlusion.
This image shows cystoid macular edema following cataract extraction.
The next four images are all taken of the same eye. These images depict age-related macular degeneration with a pigment epithelial detachment, subretinal fluid and edema.
This scan shows a pigment epithelial detachment with subretinal fluid and edema associated with age-related macular degeneration.
The following image is taken from a Fluorescein Angiography corresponding to the previous OCT scan which shows age-related macular degeneration.
The next OCT scan was performed one week after an intravitreal injection of avastin for the treatment of the macular degeneration.
This scan was performed one week after an Avastin injection. When compared to the previous scan, there is much less swelling and a smaller pigment epithelial detachment.
This scan was performed six weeks after treatment with Avastin. Notice the absence of the edema, subretinal fluid and the pigment epithelial detachment.
The retina is the light sensitive tissue that lines the inside of the eye and sends signals to the brain. When the retina detaches, it is pulled away from the choroid layer, which is a thin layer of blood vessels that nourishes the retina and supplies it with oxygen. The longer a retina is detachment from the underlying layer, the longer it is deprived of oxygen which in turn can lead to permanent vision loss. Symptoms of a retinal detachment are: the sudden onset of many floaters or spots floating in the vision, flashing lights, a shadow or curtain covering a portion of the vision, sudden blur in the vision.
A retinal detachment is more likely to occur in people who are nearsighted or have relatives who have had a retinal detachment, have lattice degeneration, or have had an intraocular surgery such as cataract surgery. A detachment can occur as a result of the vitreous, the jelly-like fluid in the eye, shrinking and causing a tear in the retina. The primary cause of a retinal detachment is a posterior vitreous detachment. A posterior detachment occurs when the vitreous within the eye shrinks and contracts and pulls away from the retina. As the vitreous pulls away, portions of the vitreous will not fully detach from the retina where it can cause a tear in the retina. When a tear occurs it creates a hole in the retina where vitreous fluid can leak beneath the retina and cause an accumulation of fluid. Usually, retinal detachments will start in the periphery of the retina and as fluid accumulates under the detached retina, the detachment will progress toward the area of central vision. Retina detachments can also occur as a result of trauma, advanced diabetes, or inflammatory disorders.
The above diagram shows a cross-section of a retinal detachment.
The only effective treatment of retinal detachments is by surgery. If a retinal tear has not progressed to a detachment or is small and localized, then it can be treated by an in-office laser surgery treatment. Laser surgery can usually prevent a retinal detachment and preserve almost all vision. Depending on the severity of the retinal detachment, the vision might not return fully following a surgical repair of the retina. If untreated, a retinal detachment can result in total vision loss, thus it is important be checked by your doctor at the first signs of a retinal detachment.
The above diagram depicts how the vitreous is removed from the eye during vitrectomy surgery.
A vein occlusion occurs when a blood vessel in the retina is blocked. A blockage leads to hemorrhaging and leakage of fluid in the areas of the blocked blood vessels. The two types of occlusions are central and branch retinal vein occlusions. A central vein occlusion occurs when the central vein, located by the optic nerve becomes blocked. When one of the smaller branches of the vessels become blocked it is called a branch retinal vein occlusion. There are certain illnesses that increase the risk of developing a retinal vein occlusion such as diabetes, glaucoma, high blood pressure, age-related vascular disease, and blood disorders. When a vein occlusion occurs, there is a 10 percent chance that a vein occlusion may occur in the other eye in the future.
As a result of a retinal vein occlusion, macular edema can develop from the leakage of blood and fluid into the retina from the blood vessels. Macular edema causes swelling of the macula, which is the central portion of the retina that is responsible for seeing fine detail. Macular edema can cause blurred vision and decreased vision. A retinal vein occlusion can also cause the growth of abnormal vessels in the retina also called neovascularization. These abnormal vessels are very fragile and can cause leakage of blood and fluid into the vitreous, which can cause spots or cloudiness in the field of vision called floaters. In advanced cases of retinal vein occlusions, neovasularization can cause glaucoma and retinal detachments.
There is currently no known cure for a retinal vein occlusion. The treatment and prognosis of a vein occlusion depends on the severity and location of the blockage. In some cases laser surgery is used to prevent further hemorrhaging in the vitreous or to treat the abnormal blood vessel growth. Also, intraocular injections can be used to treat the growth of abnormal blood vessels. In other cases surgery may be necessary. You may be able to prevent a retinal vein occlusion from occurring again by properly managing health conditions that lead to this condition.
This image shows leakage of blood due to a central retinal vein occlusion.
Central serous retinopathy causes a slight accumulation of fluid beneath the central area of the retina called the macula. The fluid accumulation causes a central scotoma (area of decreased or loss of vision) and will usually spontaneously resolve with in a few months. There is a chance that there will be a reoccurrence after the first episode.
Below is a series of images from a fluorescein angiography test of a patient with classic characteristics of central serous retinopathy. Fluorescein angiography is a test where the blood vessels of the eye are photographed as a fluorescent dye is injected into the bloodstream by way of a vein in the arm or hand.
Left: The fluroescein dye reacts to the illumination of the camera as it passes through the blood vessels of the eye. Right: the first sign of leakage of fluid is apparent as a small cloud near the center of the retina.
Left: As more dye leaks, it begins to form the classic “Smokestack”. Right: At the end of the test, you can definitively see the “Smokestack”
Diabetic macular edema (DME) occurs due to an accumulation of fluid in the central retina. This causes the vision to become blurred. For many years the treatment for DME was focal and grid laser treatments. Many clinical trials have recently demonstrated the benefits of anti-VEGF medications for DME. This treatment has now become the standard of care for most cases of DME.
There are three types of anti-VEGF medication: Avastin, Lucentis and Eylea. These medications are injected into the vitreous cavity of the eye and can be very effective at restoring and maintaining vision. Better visual results are obtained than with laser treatments, although in some cases laser added after injections can be beneficial. Intravitreal steroid injections or implants are also very effective and may lead to long lasting reduction in macular thickening and improved vision.
The doctors and staff at Carolina Retina Center can discuss which treatments are best for you.
Small gauge vitrectomy surgery using 25 gauge and 23 gauge instruments has revolutionized the way doctors at Carolina Retina Center perform surgery. The incisions are so small that that they seal without the need for sutures. This leads to quicker recovery and greater comfort in the post-operative period. These instruments, which are smaller than the needles used to draw blood, allow a very comfortable surgical experience and because sutures are not usually required the vision recovers faster. This technology is used to treat diabetic retinopathy, retinal detachment, macular hole, macular pucker and vitreous hemorrhage. The doctors and staff at Carolina Retina Center can discuss which treatment is best for you.
Dr. Gross was the lead author on the Diabetic Retinopathy Clinical Research Network (DRCR.net) clinical trial Protocol S published in the Journal of the American Medical Association (JAMA) in October 2015. This landmark paper compared panretinal photocoagulation (PRP) with intravitreal Lucentis (an anti-VEGF agent) for the treatment of proliferative diabetic retinopathy (PDR). The two year study showed that both treatments were effective during the study period. Lucentis treatments were more effective at preventing macular edema, preserving peripheral vision, and reducing the need for surgery for vitreous hemorrhage and retinal detachment. Lucentis was more effective for improved vision over the course of the study period.
Currently the treatment for diabetic macular edema (DME) is anti-VEGF injections. Therefore in patients with both PDR and DME the use of anti-VEGF injections can treat both diseases simultaneously. Even in patients without DME the injections have benefits over PRP laser. The injections usually are given monthly for 6 months and then can often be spread out. However, for the best results, it is very important that the patient keep every scheduled appointment.
Laser treatment is still a very effective treatment and may be better for those patients that are unable to maintain frequent visits. The treatment can be done in one or two visits and the results can be long lasting. Nonetheless, every patient with diabetic retinopathy requires frequent monitoring.
Lucentis is usually only covered by most insurance companies for DME. Avastin is covered for PDR and may be a reasonable alternative medication. The doctors and staff at Carolina Retina Center can discuss which treatment is best for you.
Although is might be scary to have an injection of medication into your eye it actually sounds worse than it really is. The doctors at Carolina Retina Center first make sure the eye is numbed with topical anesthetic drops, then antiseptic betadine is applied to the eye to sterilize the surface and finally a thicker anesthetic is applied to the eye. This provides a near painless procedure and many patients only feel a little pressure from the tiny needle. A lid speculum is placed to keep the lids open and the lashes away. There is no down time after the injection although patients are advised to not swim or go in a sauna for two days after the procedure. The eye may feel a little irritated for up to 24 hours after the procedure. If so, simply close your eyes for a rest or use artificial tears. You may notice a small red spot at the injections site. That is normal and will absorb within a few days. Call the office if you notice the eye to be very red and inflamed, significant pain, loss of vision or any discharge.