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Diabetic retinopathy Macular Degeneration Testing

What is a Fluorescein Angiogram?

Fluorescein Angiogram is a diagnostic test used by retina specialists.A fluorescein angiogram is a diagnostic test used to evaluate the health and blood flow of the retina.  It can be a diagnostic tool and is used primarily by retinal specialists.

Inject Dye into the Arm

A small amount (3-5 cc) of fluorescein dye is injected into your arm.  The dye will travel to  your retina in about 12-15 seconds (depending upon your heart).  A series of pictures are then taken as the dye travels through the retina.

Usually there are no side effects.  Itching and nausea can occur, but passes quickly.  As with peanuts or bee stings, severe allergy to the dye can occur.

The test may last for as long as 15 minutes depending on what we are studying.

The dye is cleared by the kidneys…your skin will have a yellowish tint and your urine will be colored for the next day!

Fluorescein is unique to ophthalmology, it is not related to other contrast dyes used in other fields such as urology, cardiology or radiology.

Macular Degeneration

The test is great for evaluating macular degeneration.  The retina is a laminated tissue (it has 3 layers)  and abnormalities of all 3 layers can be detected.  Macular degeneration is a disease of the middle layer of the retina called the retinal pigment epithelium (the RPE).

It’s a perfect way to diagnose cases of wet macular degeneration and to monitor patients receiving anti-VEGF treatments.

I use this test to differentiate patients with “normal” drusen from patients with drusen who have macular degeneration.

Diabetic Retinopathy

Diabetic retinopathy has characteristic changes of the normal vessels causing macular edema.  Abnormal vessels can grow in various parts of the eye in patients with proliferative diabetic retinopathy.

The different manifestations of diabetic retinopathy can all be diagnosed with a fluorescein angiogram.

 Other Eye Diseases

There are many other diseases, principally of the retina, where a fluorescein angiogram is helpful including; central serous retinopathy, macular edema, macular dystrophy (e.g. Stargardt’s disease), retinitis pigmentosa to name a few.

What Does This Mean?

Performing an angiogram is a team effort.  While it is my practice to personally inject the dye into your arm, many other practices have taught their staff to perform the actual injections.

The most important person in this process is the photographer.  There is a true art to taking ophthalmic pictures and, in fact, there is a certification available.

In most offices, only a few people have enough experience to run the camera and larger practices may even have a dedicated ophthalmic photographer!

Ophthalmic photography is a little known, but truly valuable, profession.

 

 

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Macular Degeneration Testing

Eye Examination for ARMD: Macular Degeneration

When You Need Eye Exam for Macular Degeneration. Randall Wong, M.D., Retina specialist, Fairfax, Virginia.Routine eye examinations for macular degeneration in patients without symptoms are probably not necessary.

Unlike conditions such as diabetic retinopathy, where the disease is likely to occur  yet still be asymptomatic, macular degeneration is not “silent” and does have associated symptoms.

Once diagnosed with macular degeneration; however,  routine examinations are important.

Family History Does Not Matter

While it is true that patients of northern European descent have a greater chance of developing the eye degeneration, brothers and sisters and children of patients with the disease are not necessarily at any higher risk.

For example, if I contract the disease, my twin brother is not necessarily going to get the disease.

Vision Must “Degenerate”

The most common symptoms of macular degeneration are decreased vision (e.g. blurry vision) and/or the development of distortion.  Both signify a change in vision.

Without a change in vision, that is, if your vision remains 20/20 it is unlikely you have ARMD.

Signs vs. Symptoms of ARMD

Signs of a disease are those things we, as doctors, see or find during an examination. If you have no  signs of macular degeneration, you do not have it.

For instance, drusen and pigment changes in the retina are common signs, or findings, of dry macular degeneration.  Fluid, edema and blood are common findings of wet ARMD.

Pigment changes, fluid and blood may cause blurry and distorted vision….symptoms (subjective, what the patient experiences) of macular degeneration.

Often, patients are diagnosed with drusen.  Drusen alone, especially without loss of vision, do not make the diagnosis of macular degeneration.

Advancing Age and Macular Degeneration

The National Eye Institute has a nice review of macular degeneration.  The incidence of developing macular degeneration does increase with age.  This means the chance of getting the disease does increase with age, but not without signs and symptoms.

What Does This Mean?

In short, unlike diabetic retinopathy, a disease that may develop without symptoms,  you can safely monitor yourself for any symptoms of the ARMD, regardless of ethnicity, age or family history.

If you develop symptoms of decreased vision or if you develop decreased vision you should get an eye exam.  Often, patients are directed to test themselves with an Amsler Grid.  This is a simple way to monitor changes in your vision.

If you have signs of the disease, for example, drusen and changes in the retina, you might ask your doctor about getting examinations on a routine basis.  This will be more important in the future if/when we discover changes in our diet or behavior (i.e. quitting smoking) alter the course of developing the disease.

If you have neither symptoms nor findings, you most likely require exams periodically as directed by your doc.

 

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Diabetic retinopathy Testing

When to Get Eye Examinations for Diabetic Retinopathy

Regular eye examinations prevent vision loss in diabetic retinopathy. Randall V. Wong, M.D., Retina Specialist, Fairfax, Virginia.All patients with diabetes should get checked for diabetic retinopathy at least annually.  This recommendation is supported by the American Academy of Ophthalmology and the American Optometric Association.

Diabetic Retinopathy Occurs in Everyone

It is likely almost every patient with diabetes will develop some diabetic retinopathy….even if the sugar is well controlled and the A1C is low!  For reasons we do not understand, the duration of having the disease is the largest risk factor to your developing the disease, with dietary factors a close second.

Perfect Vision Does Not Ensure No Disease

You can have perfect (20/20) vision and still have diabetic retinopathy.  The eye disease can be present without any signs or symptoms!   The most common symptoms of diabetic retinopathy include blurry vision.  It’s impossible for you to tell if this is due to diabetic retinopathy, change in sugar level or other eye disease.

Routine Eye Examinations Can Prevent Loss of Vision

Severe vision loss is unlikely to occur in your lifetime if the disease is identified early by dilated eye examination.  The goal of treatment is to prevent vision loss and/or preserve your excellent vision.

As you can not tell if you have the disease, you can not tell if you need treatment.

The Exam is Easy

The best test is a dilated eye exam.  Again, this needs to be done by your eye professional at least yearly.

We are only looking for two signs of diabetic eye disease;  presence of macular edema and evidence of proliferative diabetic retinopathy.  Macular edema is usually easily seen with my naked eye (and a special lens).  PDR is defined as neovascularization (abnormal blood vessel growth) on the iris, optic nerve or retina.

Testing for Diabetic Retinopathy

The single best test is probably a fluorescein angiogram.  This test can show macular edema, active PDR and abnormalities in blood flow.  This test can show subtle changes in the retina as pictures of the eye are taken as the fluorescein dye is injected into your arm.

Optical coherence tomography is also helpful in characterizing any possible macular edema.  It can NOT diagnose the disease.  This is a non-invasive test.

Your retina specialist might choose to either of these tests, but neither is a routine component of a diabetic eye exam.

What Does This Mean?  Regular examinations are worthwhile and integral to maintaining excellent vision for your lifetime.  Unlke other eye diseases where routine screening is less fruitful, the goal of routine examination is to treat you before you even think you need treatment!

 

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Macular Degeneration Testing

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).

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