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"Low Vision" Is Not "No Vision:" Part 1

I am happy and honored to introduce Dr.  Chris Renner as a contributor to RetinaEyeDoctor.com!  He and I practice closely together in Northern Virginia.  I asked him to write about Low Vision.“Randy”

What is Low Vision?

The great advances in treatment of eye disease have prevented many cases of blindness, however, many patients suffer partial visual loss and are left with reduced visual function.  This limited level of vision, whether lack of visual clarity or loss of peripheral vision is called “low vision.”  Common causes of low vision are macular degeneration, diabetic eye disease and stroke.

Low vision describes a decreased level of visual function and inability to perform the normal tasks of life even when you are wearing your best glasses.  Maybe you have difficulty reading the newspaper or computer screen, or writing a check or reading your mail.  A low vision evaluation can help you find the right tools to allow you to perform your normal daily activities.

A low vision evaluation and treatment will not improve your eye health or restore your sight.  The goal is to restore function, the ability to perform the tasks in day-to-day life. I ask each low vision patient to list three activities that they are struggling with and we focus on improving their ability to complete those tasks. This might require special eyeglasses, magnifiers, aids or computer programs.  Most patients have several different low vision “tools,” just like you might have several different screwdrivers in a toolbox. Most low vision devices help you by providing significant magnification.

The most powerful (and simplest) tool for allowing the patient with low vision to read is called a reading microscope.  It is a special high-power pair of eyeglasses, possibly with prism, which allows you to see items approximately five times larger than usual.  A reading microscope has the advantage of being relatively inexpensive, small and portable, and allows you to keep your hands free to hold whatever you are reading.  The disadvantage is that you must hold your reading material approximately four inches from your nose and can read only a few words at a time. Reading microscopes are the most popular form of low vision device.

Other low vision devices include hand magnifiers, spotting telescopes, closed circuit television cameras, visual field expanders and computer software to magnify or read text on the computer.  Each of these items can be extremely helpful in the right circumstances for the right patient.  In Part 2 I will discuss hand magnifiers and telescopes.

Chris Renner, O.D.

Optometrist, Low-Vision Specialist
Baileys Crossroads, Virginia

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Signs Vs. Symptoms of Macular Degeneration

Signs of a disease are actually “findings upon an examination.”  Signs are what a doctor sees.  Symptoms are what ails the patient.  Both signs and symptoms should match up to make a diagnosis.  Sometimes there is a disconnect, that is, signs are present, but no symptoms, etc.

Signs of macular degeneration include drusen, pigment changes, serous fluid and blood;

  • Drusen – either “hard” or “soft”
    • Hard Drusen – fine well defined white spots in the retina
    • Soft Drusen – larger, lacier edged white spots
  • Pigment Changes – either increased or decreased pigment
  • Fluid – actual clear accumulation of fluid in the retina
  • Blood – er, blood

Symptoms of Macular Degeneration include;  blurry vision, distortion and scotomas (dark/blind spots in the vision).

What Does This Mean? If you have symptoms of macular degeneration, and the symptoms are persistent, then I’d recommend your eye doctor examine you.  If your doctor examines you and see “signs” of macular degeneration, then a fluorescein angiogram might be ordered to help confirm the diagnosis.  Not everyone will insist on a fluorescein angiogram.

A fluorescein angiogram will demonstrate areas of degeneration (defects in the RPE layer of the retina) and can also confirm suspicious area of neovascularization; leading to the diagnosis of “wet” macular degeneration.

Sometimes, patients have no complaints, but a doctor notices drusen in the retina.  Not all drusen are associated with macular degeneration.  Some drusen are normal for patients.  Taking into account the patient’s age, vision and lack of symptoms, it is likely that these “drusen” are normal and not associated with disease.  The fluorescein should be normal.

“Randy”

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax, Virginia

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Avastin: An Adjunctive Therapy for Proliferative Diabetic Retinopathy

Avastin® is useful for a variety of eye conditions;  it is principally used to treat wet macular degeneration and is becoming a popular option to treat diabetic macular edema.  On occasion, Avastin has also been useful, in my practice, to treat patients with proliferative diabetic retinopathy.

VEGF (Vascular Endothelial Growth Factor) also causes abnormal blood vessels to grow in cases of “wet” macular degeneration and … proliferative diabetic retinopathy.

Proliferative Diabetic Retinopathy (PDR) is defined by the presence of abnormal “neovascularization.”  These are abnormal proliferations of blood vessels that grow inside the eye.  In patients with diabetic retinopathy, the VEGF is produced in response retinal ischemia; retinal demand for oxygen exceeds the supply due to poor blood supply.  VEGF then causes neovascularization to develop.  This neovascularization can cause blindness by causing retinal detachments or neovascular glaucoma.

The  traditional treatment for proliferative diabetic retinopathy has been laser photocoagulation.  The laser treatment, called pan-retinal photocoagulation (PRP), has been the treatment of choice for years.  The PRP destroys enough tissue so that the available blood supply is adequate to meet the oxygen requirements of the tissue.  When this occurs the “ischemia” is cured, VEGF is no longer produced and the proliferative retinopathy becomes stable.

Occasionally, I have  patients that do not respond well, or completely, to pan-retinal photocoagulation.  Lately, on select cases, I have used Avastin as an alternative to pan-retinal photocoagulation for the treatment of proliferative diabetic retinopathy.

So far the treatment works well.  The neovascular tissue regresses quickly and I recheck patients every 4-6 weeks.  The injections do need to be repeated.

What Does This Mean? Pan-retinal Photocoagulation has been the gold-standard for the treatment of proliferative diabetic retinopathy.  The PRP can decrease light to dark adapatation, that is, it takes awhile to get used to light when coming out of a movie theater.  It is a difficult procedure to perform, but has been very effective over the years.  I consider it a good “fix.”

An alternative therapy is welcomed for two reasons.  Avastin injections are certainly easier to perform and seem not too affect the vision.  Avastin also treats the disease by a different mechanism and may increase the chances of achieving stability.  On the other hand, Avastin does NOT change the relative ischemia in the retina, that is, the oxygen demand is still greater than oxygen supply.  It may be less of a permanent “fix.”

“Randy”

Randall V. Wong, M.D.
Retina Specialist, Ophthalmologist
Fairfax, Virginia

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A1C Now Used to Diagnose Diabetes

The American Diabetes Association now recommends basing the diagnosis of diabetes upon the hemoglobin A1C levels and not on fasting glucose tests.  In addition, an A1C of less than 7.0% should be the target for glucose control.  How with this impact the treatment of diabetic retinopathy?

The change in recommendations stems from the fact that the A1C blood test is an easier, and faster, test to run than measuring a fasting plasma glucose and an oral glucose tolerance test.  Both tests require overnight fasting for accuracy; that is, it relies on patient compliance.  The A1C does NOT require overnight fasting.

A1C measures the average blood glucose levels for the period of up to 3 months and was previously used just to measure sugar control over time, but now, it is recommended to be used for diagnosis;

  • A1C  of 5%  – no disease
  • A1C of 5.7 to 6.4% – likely prediabetes
  • A1C > 6.5% – likely diabetes

The ability to diagnose the test using A1C guidelines now means that the diagnosis of diabetes can be made earlier.  Earlier detection (diagnosis) may mean a greater chance of  “curing” type II diabetes by making lifestyle changes earlier.

What Does This Mean? The ability to diagnose and treat this disease now has some firm, “black and white,” guidelines.  More patients will be detected and at an earlier age.  Therapy and education may be instituted earlier.  For instance, patient education regarding diabetic retinopathy may be instituted sooner.  In this respect, more patients will be “saved” over the long run.  In theory, patients will be directed for eye exams before the retinopathy begins.

It is also likely, that with tighter sugar control (i.e. good A1C levels), diabetic eye disease will progress slower.  We’ll see.

“Randy”

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax Virginia

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Blood in the Retina: You Make the Call

A patient of mine returned this morning with complaints of decreased vision in the right eye.  She is 84 years old, has a history of smoking and noted some “blurriness” in the right eye for the past few months.  With both eyes open, however, she sees pretty well.

Retinal Blood, Right Eye
Blood, Right Eye

The first thing we did was examine her.  This is a retinal photograph of the right eye.  What do you see?  There is blood distributed underneath the retina.  The white areas are signs of chronic leakage and are called exudates.  The left eye, pictured below is normal.  What do we need to do next?

"Normal" Left Eye

The next step is to perform a fluorescein angiogram.  The retinal hemorrhage is characteristic of bleeding due to “wet” macular degeneration.  The fluorescein angiogram should show evidence of neovascularization and provide evidence of the correct wet macular degeneration diagnosis.

Fluorescein Angiogram

What Does This Mean? The first picture is typical (although exaggerated) of patients with wet macular degeneration.  While most do not bleed, the blood doesn’t cause any further permanent damage.  The fluorescein angiogram is the best test to confirm “neovascularization” in the retina, the source of bleeding.  Years ago (say around 2000) there would be nothing to do.  Laser photocoagulation would not be helpful as there is too much blood.  Now, the best choice is to consider intravitreal injections of Avastin (anti-VEGF).

I’d recommend an initial course of three injections of Avastin.  We’ll be starting within the next week.

“Randy”

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax, Virginia

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"Cross My Heart, Hope to Die, Stick a Needle in My…"

I give intravitreal eye injections everyday!

It is one of the most rewarding things I do!

And they come back for more!  My patients love it because anti-VEGF injections usually work really well, especially if the wet form of macular degeneration is caught early.

Suspicion Confirmed When I examine a patient and suspect that a patient has wet macular degeneration, I’ll usually confirm the diagnosis by performing a fluorescein angiogram.  Once confirmed, I’ll usually recommend intraocular treatment with Avastin.  I have not used Macugen in about 3 years and only occasionally use Lucentis.

First Injection I usually discuss the whole procedure of delivering an intraocular injection and reassure everyone that it is a painless event.  Prior to the actual injection, as I described in a previous post, antibiotic drops are to be used and a second prescription is given for the Avastin.  The Avastin is prepared for us by an adjacent compounding pharmacy (a specialty pharmacy that breaks up the Avastin into smaller doses for ophthalmic use).

Series of Injections My usual practice is to commit to 3 treatments given every 6 weeks.  After this short series, we reassess and determine if more injections are necessary.  Some docs may give injections as frequently as every 4 weeks “come he** or high water.”

More……….please? Aissa and Dick, my teammates, can tell as soon as a patient walks through the door if the injections are working.  They are ecstatic.  They smile, they bounce, they can’t wait for the next injection!  In general, the better the vision, the more aggressive I am at recommending additional injections.  If we aren’t getting the visual results we had hoped, then maybe I’ll be less emphatic.  So, after the first 3 shots, I’ll recommend more if there continues to be improvement.  The additional shots decrease the chance of recurrence…..we think.

No More Needles! This can be good news or bad.  I’ll recommend stopping the injections if I don’t expect any more improvement, or, we never improved at all.  In this latter case, we are giving up and throwing in the towel.  Sometimes the disease wins!

Shot Holiday After we stop injections, I warn that we are looking for signs of recurrence.  Initially, I’ll usually see patients every 6 weeks and then less frequently if there are signs of stability.  Any time I suspect that there is recurrence, or if there is a decreased vision or distortion, I’ll obtain a fluorescein angiogram to confirm recurrence.  The fluorescein angiogram is the best test for this.

An OCT (Optical Coherence Tomography) is another test that is commonly used by retina specialists.  In this scenario, it is usually used to detect swelling, or leakage, presumably from the neovascularization.  It can not, however, actually confirm active neovascularization.  It is used to monitor progress of the treatment.

What Does This Mean? This is how I “roll.”  There are lots of variations to this regimen, but most retina specialists practice pretty similarly.  Basically, we treat to seek improvement, then monitor for signs of improvement.  This is truly one of the most rewarding things I do!  Before injections (including PDT – see section on macular degeneration), we offered little hope of improvement from this blinding disease.  The ability to change the natural course of this disease is miraculous!

“Randy”

Randall V. Wong, M.D.

Retina Eye Doctor
Ophthalmologist
Fairfax Virginia

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Macugen: First anti-VEGF Eye Injection….so, Where's Waldo?

Like the image game “Waldo,” Macugen® seems to be lost in a sea of literature about other anti-VEGF intraocular injections.  Macugen was; however, the first intraocular injection for the treatment of wet macular degeneration.  It became FDA approved for the treatment of wet ARMD in 2004.  Where is it now?

The First anti-VEGF Intraocular Injection. Quite simply, this was a significant change for the treatment of retinal disease; specifically diabetic retinopathy and macular degeneration.  Macugen was significant for several reasons; it was the first actual drug designed to treat wet macular degeneration, it was the first ophthalmic anti-VEGF drug designed to treat a disease at the molecular level and it was the first therapeutic drug delivered by intraocular injection.

Prior to Macugen, intraocular injections were not routine, or “state of the art,” treatment for any eye disease.  The immediate success of Macugen, however, changed the way we treated retinal disease.  Direct, intraocular injections are now routine, e.g. Lucentis® and Avastin®.  Ozurdex® (Allergan), a sustained release system, and other similar systems, will also be delivered by………..intraocular injection.

What Does Anti-VEGF Mean? Vascular Endothelial Growth Factor (VEGF) was reviewed yesterday.  It is has several properties that are implicated in the disease process occurring in both diabetic retinopathy and macular degeneration.  VEGF is a protein that is produced by the retina.  VEGF must bind, or “plug in,” to a receptor for it to work.

Anti-VEGF drugs, like Macugen, Lucentis and Avastin, act to prevent VEGF from binding, or “plugging in” to its receptor.  The process is very similar to an antigen and an antibody.  Macugen is actually an “aptamer” against VEGF.  This anti-VEGF aptamer is injected directly into the eye.  It will find, and bind to, any VEGF floating around in the vitreous and retina.  The VEGF is no longer able to link to its receptor………voila, no more damage.

Different Types of VEGF are present throughout the body.  There are actually six different “isoforms” of VEGF.  Macugen was designed only against VEGF 165.  It was well known to cause vascular permeability (vascular leakage) at the time of its design.

So Where is Waldo? (i.e. What Does This Mean?)  I do not use Macugen much anymore.  There are several reasons.  The out of pocket costs to my patients are too high.  Insurance only covers so much of the drug and the rest is out of pocket expenses.  This is the same issue I have with Lucentis.  It costs my patients too much (Medicare only pays 80%).

Most importantly, the results I had with Macugen were not as impressive as Lucentis or Avastin..  One difference may be that Macugen is targeted against only one isoform of VEGF whereas the other drugs target more than VEGF 165.

“Randy”

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax Virginia

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VEGF Causes Blindness in Diabetes and Macular Degeneration

Vascular Endothelial Growth Factor is implicated in both diabetic retinopathy and wet macular degeneration.  Anti-VEGF medications, such as Macugen®, Lucentis® and Avastin® have changed the way we handle both diseases.

This week we’ll review VEGF and the three key anti-VEGF medications.

What is VEGF? Vascular Endothelial Growth Factor (VEGF) is a substance that is produced in the eye.  There are several forms of VEGF.  VEGF has three significant properties;

  1. Causes Inflammation
  2. Causes angiogenesis (creates new blood vessels)
  3. Causes vascular permeability (blood vessels leak)

VEGF in Diabetic Retinopathy causes diabetic macular edema and proliferative diabetic retinopathy (see illustration).  Proliferative diabetic retinopathy, by definition, is the proliferation of abnormal blood vessels on the surface of the retina and other internal structures of the eye, such as the iris. It can cause a vitreous hemorrhage.

Proliferative Diabetic Retinopathy
VEGF Causes Retinal Neovascularization

VEGF in Macular Degeneration causes the “wet” form of macular degeneration.  The “wet” form derives from the presence of “choroidal” neovascularization, or, abnormal blood vessels growing within the layers of the retina.

Wet Macular Degeneration
VEGF Causes Choroidal Neovascularization

VEGF Binds to Receptors to cause its effects on the blood vessels in the eye.  At the molecular level, the VEGF protein binds to a receptor the same way an electrical cord plugs into the wall.  You could say that the VEGF protein “plugs in” to the receptor.  Once activated, the receptor is then causes inflammation, angiogenesis and vascular leakage.

Blocking VEGF is possible using anti-VEGF agents such as Macugen, Lucentis and Avastin.  Once blocked, the receptor can no longer be activated and the effects on the blood vessels are reversed.  More specifically, once the VEGF pathway becomes blocked, macular edema may reverse, neovascularization of the retina may stop and, in macular degeneration, the choroidal/abnormal blood vessels may shrink, too.

Later this week, we’ll review each of the current anti-VEGF medications.

“Randy”

Randall V. Wong, M.D.

Ophthalmologist, Retina Specialist
Fairfax Virginia

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New Review Section: Diabetic Retinopathy, Signs, Symptoms and Treatment Options

I just completed the new section on diabetic retinopathy.  As with the other sections, it is a comprehensive review of diabetic retinopathy.

The link is located on the left panel under “SECTIONS” or click here.

My next goal will be to complete the various sections (I haven’t decided if I even need extra topics) and then continue posting as usual.  I still need a better way to organize the content of the web site.

Other than the obvious “one stop” reading, the section on diabetic retinopathy and macular degeneration will be a nice and easy way to keep up to date with big news about these subjects.

I believe this is a pretty simple way to develop some more structure to this site.  I would appreciate hearing your thoughts about;

What additional topics, if any, are needed?

Suggestions on easy ways to navigate/find information on the site.

I’d appreciate any “comments.”

Thanks again.

“Randy”

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax, Virginia

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New Section on Macular Degeneration: Signs, Symptoms and Treatment

I have created a new section entitled “Macular Degeneration:  Signs, Symptoms and Treatment” on the site.  This should serve as an “anchor” page to give a nice overview of the various aspects of macular degeneration.  It should be used as a reference area for the web site.

It is always easy to find……..on the left panel of the blog.

Counter-intuitive – I am not sure why I could not have designed this page, and others, such as diabetic retinopathy and retinal detachment earlier, but I couldn’t figure out how I wanted the page to work.  My wife, Amy, just mentioned this the other week, and suddenly, the plans for the navigational architecture for the site just opened up for me.

I would have thought that having a nice anchor or “all-about macular degeneration”  page would have been the first thing I started with, but oh well.  (I used to do the same thing when writing term papers; I’d write the conclusion first and then gather the arguments and write the opening paragraph last.)

Intuitive Navigation – I plan to have a similar page for diabetic retinopathy and perhaps a few other sections.  The sections are technically “pages” and will always be just one click away as they are listed separately, and differently from the usual, more frequent, posts.

In this way, I am hoping that new visitors will gain some core knowledge about the particular disease and then develop a deeper understanding, or appreciation of the frequent articles.

Directions – I have also (many of you may have seen the email mentioning this over the weekend) created a small welcome page that should remain in full view on the “Home” page.  It will guide new visitors to the different areas of the page.  I have always felt it was somewhat confusing.

Hope this will make reading and learning a bit easier.

Comments are welcome.

“Randy”

Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax, Virginia

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offices

Currently, I see patients with retinal diseases; macular degeneration, retinal detachment, macular holes, macular pucker within several different practices.....it's a different arrangement, but it allows more continuous care with many eye specialists. In addition, I am very accessible via the web. To schedule your own appointment, call any of the numbers below.

Capital Eye Consultants
Randall V. Wong, M.D.
Contact: Brigitte O’Brien

A: 3025 Hamaker Court, Suite 101 • Fairfax, Virginia 22031
Ph: 703.876.9630
F: 703.876.0163
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Dressler Ophthalmology Associates, PLC
Randall V. Wong, M.D.
Contact: Andrea Armstrong (Surgery/Web)
Chrissy Megargee (Web)

A: 3930 Pender Drive, Suite 10 • Fairfax, Virginia 22030
Ph: 703.273.2398
F: 703.273.0239
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