THE OPTOMETRIC TECHNICIAN – JANUARY 2017

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How to manage patients with diabetic retinopathy, from asking the right questions to administering the diagnostic tests and more.

As an optometric technician, we play an important role in the success of the optometric practice. We need to know the ramification of different diseases in the eye. One disease that might present in the office is diabetic retinopathy. It is imperative to know the symptoms and when a diabetic would be at risk.

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Taking OCT and OCTA images, such as with the AngioVue From Optovue, Inc., can provide views of the retina so the optometrist can determine ocular health.

WHAT IS DIABETES?
To understand diabetic retinopathy you need to first understand diabetes. Diabetes is the condition in which the body does not properly process food for use as energy. Most of the food a person consumes is turned into glucose, or sugar, for the body to use as a form of energy. The pancreas, an organ that lies near the stomach, produces the hormone insulin to help glucose get into the cells of bodies. When someone has diabetes, their body either doesn’t make enough insulin or can’t use its own insulin as well as it should. This causes sugars to build up in blood. Diabetes can cause serious health complications including heart disease,  kidney failure, lower-extremity amputations and blindness. High blood sugar level (diabetes) can cause the following symptoms:
“¢ frequent urination, especially at night
“¢ blurred vision
“¢ fatigue or low energy
“¢ increased thirst
“¢ increased hunger
“¢ dry skin
“¢ slow healing wounds

WHAT ARE THE CAUSES OF DIABETIC RETINOPATHY?
Beyond the presence of diabetes, how well a patient’s blood sugar is controlled is a major factor in determining how likely they are to develop diabetic retinopathy with accompanying vision loss.

Diabetic retinopathy is caused by changes in the blood vessels of the retina, which is the thin, light-sensitive inner lining in the back of the eye. Diabetic retinopathy happens when high blood sugar damages the tiny blood vessels of the retina. When the nerve cells are damaged, vision is impaired. These changes can result in blurred vision, hemorrhage in the eye, or, if untreated, retinal detachment. The longer a person has diabetes, the higher the risk of developing diabetic retinopathy.

THE STAGES OF RETINOPATHY
Diabetic retinopathy is broadly classified as non-proliferative diabetic retinopathy and proliferative retinopathy.

Non-proliferative diabetic retinopathy is generally not sight-threatening itself unless macular edema is present. Proliferative retinopathy is a more dangerous state of diabetic eye disease. This could block the passage of light to the retina causing loss of vision and even blindness to occur. Another risk is that the fragile blood vessels hemorrhage, which causes scar tissue, and may pull on the retina and cause a retinal detachment.

The Right Questions
As an optometric technician, we are the first to have interaction with the patient. It is important to ask the right questions so we can provide the doctor with information in understanding the patient’s current condition. To do so, we need to:
“¢ identify any recent episodes involving vision or overall health
“¢ understand and properly administer appropriate tests
“¢ identify patient’s signs and symptoms of diabetic retinopathy
“¢ educate the patient about the importance of annual eye exams

For patients with diabetes, always ask:
“¢ case history questions
“¢ do they know their last A1c?
“¢ do they know if their cholesterol is within normal levels?
“¢ when was the last time their blood sugar was tested?
“¢ how are they managing their diabetes (pills, insulin, etc.)?
“¢ is their glucose under control?
“¢ has their vision been stable since their last visit?
“¢ how are they feeling today?
“¢ are they eating right and exercising?
“¢ are they taking their medications?
“¢ are they new or established with your practice?

Always be sure to check blood pressure and document, document, document.

DIAGNOSTIC TESTS
Many times diabetic retinopathy is detected during a comprehensive dilated eye exam that includes:
1. Visual acuity testing: This eye chart test measures a person’s ability to see at various distances.

2. Tonometry: This test measures pressure inside the eye.

3. Pupil dilation: Drops placed on the eye’s surface dilate (widen) the pupil, allowing an optometrist to examine the retina and optic nerve.

4. Optical coherence tomography (OCT): This is similar to ultrasound but uses light waves instead of sound waves to capture images of tissues inside the body. The OCT provides detailed images of tissues that can be penetrated by light, such as the eye. This test is usually performed by a technician, while the optometrist interprets the information and determines the diagnosis.

During the examination the optometrist will be looking for changes of the blood vessels that might be leaking or swelling in the macula (DME). If DME or severe diabetic retinopathy is suspected, the optometrist would refer the patient to a specialist to perform a fluorescein angiogram. This is used to look for damaged or leaky blood vessels. In this test, a fluorescent dye is injected into the bloodstream, often into an arm vein. Pictures of the retinal blood vessels are taken as the dye reaches the eye.

TREATMENT
Treatment of diabetic macular edema has evolved a great deal in the last five to ten years and is based on the severity of the edema. At present, there are three options: laser treatment, injection or steroids.

Laser Treatment
A retinal surgeon uses a beam of high-intensity light, which is directed into the eye to seal off leaking blood vessels and prevent additional blood and fluid from leaking into the vitreous.

Injections
The most effective treatments to date for blood vessel damage are the anti-angiogenic drugs Avastin, Lucentis and Eylea. They are administered by injection directly into the eye.  The abnormal vessels will disappear within 24 to 48 hours; however, the effects of the drug will wear off. Treating edema requires frequent injections.

Steroids
Intravitreal steroids are used to treat swelling caused by diabetic macular edema. While steroids can reduce retinal edema dramatically, they have side effects, including the development of glaucoma and cataracts in some patients. The steroid medications currently available are Kenalog, Ozurdex and Iluvien.

In addition, many diabetics develop a tractional retinal detachment. This occurs when fibrous tissue pulls the retina away from the underlying tissue layers. The technique to repair is called vitrectomy, which is the removal of the vitreous from the eye, and replacing it with a clear salt solution. This allows the physician to have clear media to look through in order to perform the laser treatment.

Roberta Beers, CPOT, is an optometric assistant in Erie, PA.

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