Macula of retina Archives - Retina Specialist | Fairfax, Virginia

Diabetic Macular Edema: Have No Fear

Diabetic Macular Edema,

Diabetic macular edema (DME) is swelling in the retina caused by diabetic retinopathy. More specifically, the swelling is located in the macula, the functional center of the retina.

Diabetic Macular Edema Occurs In Almost Everyone

DME is the most common “side effect” or complication of diabetic retinopathy. It should not be feared, but rather, it should be expected. Almost every diabetic patient will develop some degree of macular swelling in their lifetime.

Diabetes can be considered a disease of blood vessels, caused in some way by high sugar levels. For reasons that are not completely known, the blood vessels in the retina start to leak, both blood and the fluid component of blood.

As the leakage nears the macula, we get concerned as swelling in the macula leads to loss of vision. The idea of treatment is to prevent the fluid from ever reaching the macula. If fluid has already developed, treatment may prevent further leakage (and thus preserve vision) or possibly decrease the swelling (and maybe improve vision).

Laser Treatment is Only Approved Treatment

The only FDA approved treatment for diabetic macular edema, aka clinically significant macular edema (CSME), is laser treatment. The laser is used to burn those areas around the macula that are leaking. Often, the laser results in stablizing the retina and preventing further leakage.

Laser is Painless

The laser does not hurt. There are no nerve endings underneath this portion of the retina. The treatment may last just a few minutes and is accomplished while you are sitting at the laser. In fact, the visit should mimic a routine dilated exam.

After treatment, no “healing” is really needed. I personally do not recommend any drops, patches or time off from work. Your doctor’s recommendations may vary.

Laser treatment for diabetic macular edema takes several months to start working. After 4-6 months, I can usually tell if more treatment will be needed.

What Does This Mean?

Laser treatment for diabetic macular edema is the gold standard. While DME is quite common, the treatment works best if instituted early in the disease process, preferably while the vision is 20/20.

Not all patients can be treated with laser. Other treatments for DME include intraocular injections of Avastin or Kenalog. Using any of these tools, almost everyone with diabetic retinopathy may be treated.

Regardless, fear not, the treatment for the disease is quite successful in preventing further vision loss. It is painless, safe and effective.

How to Diagnose Macular Degeneration

Unlike the diagnosis of diabetic retinopathy, a patient with macular degeneration must have symptoms of the disease for the diagnosis to be made. In most cases, the retina should have characteristic “damage,” and, most importantly, the patient must be having symptoms, i.e. decreased vision and/or distortion.

In Whom We Make the Diagnosis

Patients afflicted with macular degeneration are almost always greater than 55 years old, show signs of the disease, often of northern European ancestry and have decreased vision and/or distortion.

The disease is progressive and, in most cases, affects both eyes.

Symptoms of Macular Degeneration

As I wrote last week, a patient with diabetic retinopathy may not have anything wrong with their vision, that is, they may not have symptoms.

A patient with macular degeneration must have visual symptoms.

What are Drusen?

Some of the hallmarks of macular degeneration include the presence or absence of pigmentary changes, fluid, blood and drusen.

Drusen are creamy white spots within the layers of the retina. There are two types, hard and soft, but both can be associated with macular degeneration. They are not diagnostic of the disease, but many non-retina physicians know this.

Drusen may be present in the retina without other evidence of degeneration. Drusen may be normal.

Fluorescein Angiography is Diagnostic

As with any retinal disease, a good dilated pupil exam is necessary to look at the retina. If there are no signs of the disease, the vision is good, no further testing is needed.

If there are signs of the disease, then a fluorescein angiogram should be performed. This test involves injection of a dye into your arm. The dye travels to the retina and pictures are taken. A fluorescein angiogram is a great test for showing just how healthy, or unhealthy, the retina can be.

A fluorescein angiogram can diagnose macular degeneration.

What Does This Mean? In contrast to diabetes, where patients must be examined routinely due to the potential of a lack of symptoms, macular degeneration patients don’t benefit from routine examination if they have no symptoms. (I am not saying don’t get an eye exam as many people are unaware of having vision loss!)

By definition, macular degeneration damages the macula. Therefore, if present, there should be changes in the vision.

In cases of suspected macular degeneration, diagnostic tests are available. At times, patients can look like they have ARMD, yet have normal vision. As this is a progressive disease, those that are suspected of developing the disease should be followed regularly in years to come.

A normal fluorescein angiogram can also determine if drusen are normal, or associated with the disease.

As always, see your eye doctor if you develop any persistent decreased vision or distortion (symptoms continuously present for more than one day).

Retinal Detachments Can Blind

The natural history of a retinal detachment is blindness. “Natural history” of a disease is the same as the usual outcome. So, the usual outcome of a retinal detachment is complete blindness if eye surgery is not performed.

Retinal Detachments Only Become Larger

Retinal tears and holes cause a retinal detachment. A small amount of fluid goes through the tear and gets underneath the retina causing the detachment. With time the amount of fluid increases underneath the retina, and so, too, the size of the retinal detachment enlarges.

Always Lose Side Vision First

Because all tears and holes occur in the peripheral retina (the portion of the retina giving us peripheral, or side, vision), you always lose your side, or peripheral vision, first. As the detachment grows, the macula becomes detached and central vision will eventually be lost. The initial goal of retinal detachment surgery is to fix the detachment before the central eyesight is affected. By doing so, you minimize the risk of permanent loss of your central.

We usually try to operate within days.

When the macula (central portion of the retina responsible for reading, etc.) detaches, there can be permanent loss of eyesight despite successful surgery.

Rods and Cones

The retina is a laminated tissue. It has several layers. The rods and cones are underneath the top layer. Loss of vision from a detachment is due to the physical separation of the rods and cones (aka photoreceptors) from the layer beneath them.

Retinal Detachment Surgery Prevents Blindness

There are several ways to fix a retinal detachment. These are outlined in the overview of retinal detachments. The goal of any retinal detachment surgery is to prevent blindness by reattaching the retina and, if possible, fix the eye before central vision is affected.

Longstanding Retinal Detachments

Chronic, or longstanding, retinal detachments are those unfortunate eyes that were never diagnosed or operated upon. In general, eye surgery doesn’t always work to restore sight in these cases. Permanent damage to the rods and cones occurs with time, and, despite success in reattaching the retina, vision does not return.

By chronic, I’d say conditions lasting months to years.

Losing the Eye Can Happen

In extreme cases of retinal detachments that never get repaired, the eye can start to die and shrink. This condition, phthisis bulbi, occurs when the retina has not been attached for years (generally). While it doesn’t always occur, it can be extremely disfiguring and can be a psychological nightmare.

What Does This Mean? Because the outcome of a retinal detachment is so grim, surgery is almost always recommended. If the natural history is blindness, that is, the chance of going blind is 100%. Though there are risks of eye surgery (blindness), the chances are small. Thus, there really isn’t much to lose by operating.

Are You At Risk For Developing Macular Degeneration?

A family member is diagnosed with macular degeneration and you wonder if you will develop the same eye disease. In most cases, macular degeneration is not inherited, but the risk factors probably are.

“My Father Was Diagnosed, What About Me?”

This is a common question and fear. The natural assumption is that this is a disease that “runs in the family.” Far from true. While there are a few macular dystrophies that are inherited, macular degeneration per se, is not.

We don’t really know the exact genetics of this retinal disease. A few genes have been identified to be associated with the disease. A few families have been studied. Overall, what we know as “macular degeneration” is probably a collection of diseases that develops given the right set of circumstances (i.e. given certain risk factors that are inherited, macular degeneration may be more likely to develop).

Patients at Risk

Patients at highest risk for the disease are usually of northern European ancestry and have blue eyes. There are weaker associations with female gender, poor nutrition and sun exposure. There is a very strong association with smoking and the development of the wet form of the disease.

The age of onset is also critical. The diagnosis of macular degeneration is usually not made until after age 55. Patients younger than 55 probably have another type of macular problem. Remember the macula is a specific place in the retina, hence, when used as an adjective, there are many “macular diseases.”

What Can You Do?

If you are worried that you may develop macular degeneration, get a dilated eye exam. Have your eye doctor examine you. If there is any question about the disease, see a retina specialist.

If you develop persistent changes in your vision, especially distortion, see your eye doctor.

What Your Doctor Can Do

Many times, if I have doubts about a disease, I’ll recommend a fluorescein angiogram. A fluorescein angiogram is a diagnostic test that involves injection of a dye into your arm. As the dye travels to your retina, pictures of the retina are obtained.

This is probably the best, and most sensitive, test for macular degeneration. It is basic tool of a retinal specialist.

What Does This Mean? If a family member contracts macular degeneration, it does NOT mean that you will get it, too. You probably share the same risk factors for developing the disease and, therefore, have a slightly higher risk of developing the disease.

Be proactive. Don’t wait for you develop symptoms. Get a thorough eye exam. The disease does not develop overnight and your eye doctor should be able to determine if you are risk for developing the disease.

Optometry Student's First Retinal Surgery

Optometry students frequently rotate through our office. One of our visiting students had the chance to watch me in the operating room. I asked her to write about the experience…

Hello,

My name is Maggie, and I’m a fourth year student at the SUNY College of Optometry in NYC. I had the opportunity to observe retinal surgeries with Dr Wong in the OR, and it was an amazing experience!

The first surgery was scheduled at 7:30am (I know, I wasn’t too excited) for a vitrectomy to repair a retinal detachment. The patient had developed a retinal detachment secondary to a retinal hole. Sub-retinal fluid can accumulate under the hole and cause the retina to detach, which then needs to be treated. The urgency of treatment depends on the location of the detachment and the condition of the macula (the central part of vision). If the macula is still attached, ie “macula-on retinal detachment”, the patient needs to be treated as soon as possible, which was the case in patient# 1.

The patient was already prepped for surgery (with pre-operative antibiotics, anesthesia etc). Retinal surgeries usually do not require general anesthesia; the patient was given retrobulbar anesthesia, which is local “blocking” of an area supplied by a specific nerve. I was very excited to be in the OR; I have observed a few surgeries before but this was my first ocular surgery! I got to sit right behind Dr Wong and see the entire thing. Dr Wong had warned me about the graphic nature of ocular surgery, but it wasn’t bad at all! There wasn’t any blood or fluid gushing out, as one would imagine. It was a relatively clean, blood-less surgery! The incision was made 5mm lateral to the limbus (where the color part of your eye meets the white part). This was like “port of entry” to get into the retina. Before performing the laser, Dr Wong performed a “vitrectomy”. Vitreous is the jelly part of the eye, between the lens and the retina. It sort of keeps the eye intact, keeps the retina attached to the choroid. However, it can also block the surgeon’s view and interfere with laser treatment, which is why it is necessary to remove it.

After the vitrectomy, Dr Wong sealed up the retinal hole with the laser and repaired the retinal detachment. The surgery went well, and the patient was discharged after being given post-op anti-biotics/anti-inflammatory.

The second patient was scheduled for a membranectomy secondary to epi-retinal membrane (ERM). An ERM is a membrane that forms over the macula. ERM can distort vision and cause traction on the macula, which is when treatment is indicated. The pre-op process is similar to the one described above; vitrectomy is also necessary in this case. After the vitrectomy, Dr Wong physically peeled off the membrane with forceps! This is a very delicate procedure since the membrane is over the macula; and a little slip up can affect the central vision! You could actually see the membrane coming off-of the macula! Again, the patient was discharged after the appropriate post-op treatment.

Both the patients are scheduled to see Dr Wong for follow up visits.

Being in the OR was an awesome experience, and I can’t wait to go back!

Vision Saved by Web Site

Vision saved by reading a web site? Yes, my patient saved his own vision after reading about retinal detachments on this blog. Learning from a credible health information source (this blog) about his condition initiated a cascade of events leading to saving his vision.

A retinal tear or retinal hole can cause a retinal detachment. Flashes and floaters sometimes precede the formation of a retinal tear, or, there may not be any symptoms at all. Retinal holes are usually associated with a condition called lattice degeneration, a natural thinning of the retina.

Web Site Saves Vision

Last week a patient came to the office with decreased vision in the right eye. He lost most of his vision in the right eye. I diagnosed a retinal detachment and scheduled him for surgery. His visual prognosis, despite successful surgery, is not great as the retinal detachment is of unknown duration and the macula is also detached.

I suggested he read this blog specifically about retinal detachment and “PVD and Floaters.”

Several days later, floaters developed in the left eye (the “good” eye). Now educated about retinal detachments, he emailed, concerned about a possible retinal detachment developing in the remaining eye.

I was able to successfully laser the tear and thereby prevent a retinal detachment!

What Does This Mean?

I will be operating on his “bad” in the next week or so. Due to the length of time of the detachment, there is an urgency, but no real emergency. Still, he has learned the significance of a long standing retinal detachment.

Using this web site as a tool for patient education, he was able to learn much more about retinal detachments, especially warning signs of a retinal tear!

Another advantage of learning through a web site is you can go at your own pace. You can re-read and research. This is a huge advantage over a doctor visit or reading a printed flyer.

“Unlearning” something takes more time and energy than initial “learning.” Clearly, since the original cause of vision loss was “missed,” it took additional time for my patient to “unlearn” and then “relearn.”

A web site affords time to “unlearn.”

Lastly, armed with new information, specifically warning signs of a retinal detachment, my patient emailed me about his new “learned” concerns.

Email is easier than a phone call. No answering machines, recordings and leaving messages. Email is a form of communication that is convenient and less intimidating than a phone call.

Regardless, this new “system” worked well and in favor of my patient last weekend.

The Internet can work for improving health care!

You Look All Bent Out of Shape

Distortion, also known as metamorphopsia, is a symptom of many macular diseases. Anything that affects the macula can cause distortion; epiretinal membranes, macular holes, macular edema, diabetic retinopathy and macular degeneration. The macula is a place in the retina, the functional center. Thus, the term “macular” becomes an adjective when describing retinal disease located in the center of the retina.

OCT scan of a retina at 800nm with an axial re... — Image via Wikipedia

The macula is a small area of the retina measuring about 1.5 x 1.5 mm. It is very sensitive and allows us our best color vision and the ability to see 20/20. A normal macula (fovea) is smooth and slightly concave (see OCT). Light falls on the normal macula giving us vision. This is very similar to a projector focusing images onto a movie screen. If there is a physical change to the macula or disease, central vision is usually affected.

Macular Pucker or Epiretinal Membranes

Epiretinal membranes are, as the name implies, membranes that develop on the surface of the retina and cause the underlying retina to wrinkle, or “pucker.” This physical wrinkling of the macula causes decreased vision and distortion.

Surgically removing the membrane usually improves the distortion and can improve the vision, too.

Macular Holes

If you were to poke a pin through a piece of ballon and then stretch out the rubber, you’d create a nice round hole. A macular hole is actually a stretch hole in the center of the macula. Images that fall within this hole are not seen as there literally is no retina in the center of the macula.

Symptoms include decreased vision, distortion and sometimes, scotomas, which are the fancy name for blindspots.

Macular Edema

Swelling of the macula can occur from a variety of causes. The two most common causes germaine to this web site are diabetic retinopathy (more specificially, diabetic macular edema) and swelling secondary to choroidal neovascularization in cases of wet macular degeneration.

Other causes, however, include central serous retinopathy, central and branch vein occlusions, cystoid macular edema from cataract surgery (uncommon these days) and from cases of intraocular inflammation (aka uveitis).

Macular Degeneration Causes Distortion 3 Different Ways

As above, choroidal neovascularization can physically distort the retina and cause distortion. These abnormal blood vessels can develop in between the layers of the retina causing physical disruption of the retina. The analogy here is exactly like the “Princess and the Pea.”

Wet macular degeneration can also cause macular edema as we discussed above.

Dry macular degeneration can also cause symptoms of distortion. One of the layers of the retina, called the RPE, becomes diseased and degenerates. This loss of one of the principle layers of the retina can cause distortion.

What Does This Mean? Distortion, or metamorphopsia, can be a symptom of a variety of retinal or macular disorders, not just macular degeneration. The key for saving your sight is early detection and diagnosis. Usually this may require consultation with a retina specialist to discuss the various treatments.

A fluorescein angiogram and/or an OCT (Optical Coherence Tomography) may be very helpful to your doctor, but this can vary.

Other causes of metamorphopsia, not related to the retina, could include large amounts of astigmatism or a decentered lens.

While most causes are indeed retina related, it is also important to note that most have a treatment with the exception of dry macular degeneration. There is some rumbling; however, that there may be some promising treatments for dry macular degeneration in the near future.

Drusen Not Associated with Macular Degeneration

Drusen are associated with macular degeneration but are not diagnostic of the disease. Too many feel that these “spots” are indicative of ARMD, but they can, and often are, normal.

What Are These White Lesions?

Drusen are white spots, or lesions, seen within the layers of the retina. There are two types; hard and soft. The differences between the two are somewhat subtle.

Hard drusen are small and well defined with sharp borders. A poppy or sesame seed is an example of an object with sharp margins. “Hard” can be associated with macular degeneration, usually dry.

Soft drusen are larger and have fluffier borders. A cotton ball has fluffy margins. “Soft” can be normal, but are usually seen more often with exudative, or wet, ARMD.

Familial Drusen

Drusen, by definition, can be found anywhere in the retina. When they are located outside the macula, they are usually of no consequence and not related to any disease, especially macular degeneration. I am usually concerned when they are located within the macula.

But most non-retina people (i.e. doctors) are afraid to mention this – drusen away from the macula are of little consequence and can just be a family trait – if anything.

Other “Findings” of Macular Degeneration

“Findings” are the signs or physical characteristics of disease. These are things we look for as signs of disease.

Symptoms of ARMD are ways you describe changes in your vision.

Other signs of ARMD include, atrophy of pigment, increased pigmentation, fluid and blood. There may be fibrosis – a sign of old choroidal neovascularization.

Many doctors will term anything abnormal in the macula as “scars.”

Making the Diagnosis of Macular Degeneration

Patients have to have 3 criteria;

Patients have to be over 50-55 years old
Patients have to “look” like they have the disease (that is, they have signs)
Patients have to have “symptoms” of the disease (that is, they have decreased vision)

Having just drusen, for example, but no change in vision or other signs of the disease, probably do NOT signify macular degeneration. It may be a sign of early disease and careful monitoring may be prudent.

Many times macular degeneration is diagnosed based solely upon the physical findings, but unless there is any evidence of decreased vision, I’d hold off on making the diagnosis.

Best Test for Diagnosis

If there is any doubt about the diagnosis of macular degeneration, the single best test, in my opinion, is a fluorescein angiogram. This test can show any damage to the macula that can not be seen by the usual methods. More subtle damage can be detected in this manner.

Drusen, unassociated ARMD, will not show any macular damage.

What Does This Mean? This means there are far fewer patients that actually have the disease than are diagnosed. In other words, there are instances where ARMD shouldn’t really be diagnosed. Many docs feel that it is safer to give the diagnosis for liability reasons.

I don’t understand this.

If there is any question about the presence, or absence, of macular degeneration, have your doctor order a fluorescein angiogram.

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