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MANAGEMENT OF DIABETIC RETINOPATHY ( for pharm-d students )
1. INTRODUCTION
Diabetic retinopathy (die-uh-BET-ik ret-ih-NOP-uh-thee) is a complication of diabetes
that affects the eyes caused by damage to the blood vessels of the light-sensitive tissue at
the back of the eye (retina).At first, diabetic retinopathy may cause no symptoms or only mild
vision problems. Eventually, however, diabetic retinopathy can result in blindness. Diabetic
retinopathy can develop in anyone who has type 1 diabetes or type 2 diabetes. The longer you
have diabetes, and the less controlled your blood sugar is, the more likely you are to develop
diabetic retinopathy. To protect your vision, take prevention seriously. Start by carefully
controlling your blood sugar level and scheduling yearly eye exams.
Too much sugar in your blood can damage the tiny blood vessels that nourish the retina. It may
even block them completely. As more and more blood vessels become blocked, the blood
supply to more of the retina is cut-off. This can result in vision loss. In response to the lack of
blood supply, the eye attempts to grow new blood vessels. But, these new blood vessels don't
develop properly and can leak easily. Leaking blood vessels can cause a loss of vision. Scar
tissue may also form, which can pull on the retina. Sometimes, this can cause the retina to
detach. Elevated blood sugar levels can also affect the eyes' lenses. With high levels of sugar
over long periods of time, the lenses can swell, providing another cause of blurred vision.
Diabetic retinopathy usually affects both eyes. People who have diabetic retinopathy often
don't notice changes in their vision in the disease's early stages. But as it progresses, diabetic
retinopathy usually causes vision loss that in many cases cannot be reversed.
As the disease progresses, diabetic retinopathy symptoms may include: Spots, dots or
cobweb-like dark strings floating in your vision (called floaters),Blurred vision, Vision that
changes periodically from blurry to clear, Blank or dark areas in your field of vision, Poor night
vision Colours appear washed out or different, Vision loss. Diabetic retinopathy symptoms
usually affect both eyes. Careful management of your diabetes is the best way to prevent vision
loss. If you have diabetes, see your eye doctor for a yearly diabetic retinopathy screening with
a dilated eye exam even if your vision seems fine because it's important to detect diabetic
retinopathy in the early stages. If you become pregnant, your eye doctor may recommend
additional eye exams throughout your pregnancy, because pregnancy can sometimes worsen
diabetic retinopathy
The need to estimate the demand for DR services is a critical step in the development of clinical
guidelines. Worldwide, the global burden of diabetes is estimated at 346 million people. This
is projected to increase to 438 million by the year 2030.Retinopathy remains a challenging
complication of diabetes that can adversely affect a patientâs quality of life. Although
ophthalmologists can often stabilize the condition or reduce vision loss, prevention and early
detection remain the most effective ways to preserve good vision in patients with diabetes.
Ensuring tight glucose and blood pressure control and referring patients for ophthalmologic
examination are important ways in which internists and other clinicians can help to maximize
their patientsâ vision and therefore their quality of life. New treatments may offer greater hope
for sustained visual improvement in patients with diabetic retinopathy
2. SIGNS AND SYMPTOMS
It's possible to have diabetic retinopathy and not know it. In fact, it's uncommon to have symptoms in
the early stages of diabetic retinopathy.
As the condition progresses, diabetic retinopathy symptoms may include:
ï· Spots or dark strings floating in your vision (floaters)
ï· Blurred vision
ï· Fluctuating vision
ï· Dark or empty areas in your vision
ï· Vision loss
ï· Difficulty with colour perception
Diabetic retinopathy usually affects both eyes. Diabetic retinopathy may be classified as early or
advanced, depending on your signs and symptoms.
A. Early diabetic retinopathy.
This type of diabetic retinopathy is called nonproliferative diabetic retinopathy (NPDR). It's
called that because at this point, new blood vessels aren't growing (proliferating). NPDR can
be described as mild, moderate or severe. When you have NPDR, the walls of the blood
vessels in your retina weaken. Tiny bulges (called micro aneurysms) protrude from the vessel
walls, sometimes leaking or oozing fluid and blood into the retina. As the condition
progresses, the smaller vessels may close and the larger retinal vessels may begin to dilate
and become irregular in diameter. Nerve fibres in the retina may begin to swell. Sometimes
the central part of the retina (macula) begins to swell, too. This is known as macular edema.
B. Advanced diabetic retinopathy.
Proliferative diabetic retinopathy (PDR) is the most severe type of diabetic retinopathy. It's
called proliferative because at this stage, new blood vessels begin to grow in the retina. These
new blood vessels are abnormal. They may grow or leak into the clear, jelly-like substance
that fills the center of your eye (vitreous). Eventually, scar tissue stimulated by the growth of
new blood vessels may cause the retina to detach from the back of your eye. If the new blood
vessels interfere with the normal flow of fluid out of the eye, pressure may build up in the
eyeball, causing glaucoma. This can damage the nerve that carries images from your eye to
your brain (optic nerve).
3. DIAGNOSIS OF DIABETIC RETINOPATHY
The only way to detect diabetic retinopathy and to monitor its progression is through a
comprehensive eye exam. There are several parts to the exam:
Visual Acuity Test
This uses an eye chart to measure how well you can distinguish object details and shape at
various distances. Perfect visual acuity is 20/20 or better. Legal blindness is defined as worse
than or equal to 20/200 in both eyes.
Slit-lamp Exam
A type of microscope is used to examine the front part of the eye, including the eyelids,
conjunctiva, sclera, cornea, iris, anterior chamber, lens, and also parts of the retina and optic
nerve.
Dilated Exam
Drops are placed in your eyes to widen, or dilate, the pupil, enabling your Eye M.D. to examine
more thoroughly the retina and optic nerve for signs of damage.
Ultrasound
If your ophthalmologist cannot see the retina because of vitreous haemorrhage, an ultrasound
test may be done in the office. The ultrasound can "see" through the blood to determine if your
retina has detached. If there is detachment near the macula, this often calls for prompt surgery.
When your diabetic retinopathy screening is complete, your ophthalmologist will decide when
you need to be treated or re-examined. If you have diabetes, you should see your
ophthalmologist right away if you have any visual changes that affect only one eye, last more
than a few days, and are not associated with a change in blood sugar
Fluorescein angiography
Your doctor may order fluorescein angiography to further evaluate your retina or to guide laser
treatment if it is necessary. This is a diagnostic procedure that uses a special camera to take a
series of photographs of the retina after a small amount of yellow dye (fluorescein) is injected
into a vein in your arm. The photographs of fluorescein dye traveling throughout the retinal
vessels show which blood vessels are leaking fluid, how much fluid is leaking, how many blood
vessels are closed, whether neovascularization is beginning.
Optical coherence tomography (OCT)
OCT is a non-invasive scanning laser that provides high-resolution images of the retina,
helping your Eye M.D. evaluate its thickness. OCT can provide information about the presence
and severity of macular edema (swelling).
4. MANAGEMENT OF DIABETIC RETINOPATHY
Treatment depends largely on the type of diabetic retinopathy you have. Your treatment will
also be affected by how severe your retinopathy is, and how it has responded to previous
treatments.
A. EARLY DIABETIC RETINOPATHY
If you have nonproliferative diabetic retinopathy, you may not need treatment right away.
However, your eye doctor will closely monitor your eyes to determine if you need treatment.
It may also be helpful to work with your diabetes doctor (endocrinologist) to find out if there
are any additional steps you can take to improve your diabetes management. The good news
is that when diabetic retinopathy is in the mild or moderate stage, good blood sugar control
can usually slow the progression of diabetic retinopathy.
B. ADVANCED DIABETIC RETINOPATHY
If you have proliferative diabetic retinopathy, you'll need prompt surgical treatment.
Sometimes surgery is also recommended for severe nonproliferative diabetic retinopathy.
Depending on the specific problems with your retina, options may include:
I. LASER SURGERY
The laser is a very bright, finely focused light. It passes through the clear cornea, lens
and vitreous without affecting them in any way. Laser surgery shrinks abnormal new
vessels and reduces macular swelling. Treatment is often recommended for people with
macular edema, proliferative diabetic retinopathy (PDR) and neovascular glaucoma.
Laser surgery is usually performed in an office setting. For comfort during the
procedure, an anaesthetics eye drop is often all that is necessary, although an anaesthetic
injection is sometimes given next to the eye. The patient sits at an instrument called a
slit-lamp microscope. A contact lens is temporarily placed on the eye in order to focus
the laser light on the retina with pinpoint accuracy.
With laser surgery for macular edema, tiny laser burns are applied near the macula to
reduce fluid leakage. The main goal of treatment is to prevent further loss of vision by
reducing the swelling of the macula. This treatment causes abnormal new vessels to
shrink and often prevents them from growing in the future. It also decreases the chance
that vitreous bleeding or retinal distortion will occur. Panretinal laser has proven to be
very effective for preventing severe vision loss from vitreous haemorrhage and traction
retinal detachment. Multiple laser treatments over time may be necessary. Laser
surgery does not cure diabetic retinopathy and does not always prevent further loss of
vision.
5. 1) Focal laser treatment.
This laser treatment, also known as photocoagulation, can stop or slow the leakage of
blood and fluid in the eye. It's done in your doctor's office or eye clinic. During the
procedure, leaks from abnormal blood vessels are treated with laser burns. Focal laser
treatment is usually done in a single session. Your vision will be blurry for about a day
after the procedure. Sometimes you will be aware of small spots in your visual field
that are related to the laser treatment. These usually disappear within weeks. If you had
blurred vision from swelling of the central macula before surgery, however, you may
not recover completely normal vision. But, in some cases, vision does improve.
2) Scatter laser treatment
This laser treatment, also known as panretinal photocoagulation, can shrink the
abnormal blood vessels. It's also done in your doctor's office or eye clinic. During the
procedure, the areas of the retina away from the macula are treated with scattered laser
burns. The burns cause the abnormal new blood vessels to shrink and scar. Scatter laser
treatment is usually done in two or more sessions. Your vision will be blurry for about
a day after the procedure. Some loss of peripheral vision or night vision after the
procedure is possible.
II. ANTI-VEGF THERAPY (Avastin, Lucentis, Eylea)
Anti-VEGF therapy involves the injection of the medication into the back of your eye. The
medication is an antibody designed to bind to and remove the excess VEGF (vascular
endothelial growth factor) present in the eye that is causing the disease state. The FDA has
approved Lucentis for macular edema and additional treatment options include Avastin and
Eylea.
III. INTRAOCULAR STEROID INJECTION
Intraocular steroid injection is a treatment for diabetic macular edema. This therapy
helps reduce the amount of fluid leaking into your retina, resulting in visual
improvement. Due to the chronic nature of diabetic eye disease, this treatment may need
to be repeated or combined with laser therapy to obtain maximum or lasting effect.
IV. VITRECTOMY SURGERY
Vitrectomy is a surgical procedure performed in a hospital or ambulatory surgery centre
operating room. It is often performed on an outpatient basis or with a short hospital stay.
Either a local or general anaesthetic may be used. During vitrectomy surgery, an operating
microscope and small surgical instruments are used to remove blood and scar tissue that
accompany abnormal vessels in the eye. Removing the vitreous haemorrhage allows light
rays to focus on the retina again. Vitrectomy often prevents further vitreous haemorrhage
by removing the abnormal vessels that caused the bleeding. Removal of the scar tissue
helps the retina return to its normal location. Laser surgery may be performed during
vitrectomy surgery. . You may be told to keep your head in certain positions while the
bubble helps to heal the retina. It is important to follow your ophthalmologist's instructions
so your eye will heal properly.
6. V. MEDICATION INJECTION
In some cases, medication may be used to help treat diabetic retinopathy. Sometimes a
steroid medication is used. In other cases, you may be given an anti-VEGF medication.
This medication works by blocking a substance known as vascular endothelial growth
factor, or VEGF. This substance contributes to abnormal blood vessel growth in the eye
which can affect your vision. An anti-VEGF drug can help reduce the growth of these
abnormal blood vessels. After your pupil is dilated and your eye is numbed with
anaesthesia, the medication is injected into the vitreous, or jelly-like substance in the back
chamber of the eye. The medication reduces the swelling, leakage, and growth of unwanted
blood vessel growth in the retina, and may improve how well you see. Medication
treatments may be given once or as a series of injections at regular intervals, usually around
every four to six weeks or as determined by your doctor.
ALTERNATIVE TREATMENTS
You may hear or read about natural cures or home remedies, but currently there are no proven
alternative or complementary therapies than can cure diabetes or diabetic retinopathy. It's
important not to delay standard treatments to try unproven therapies. Early treatment is the best
way to prevent vision loss. Several alternative therapies have shown some benefits for people
with diabetic retinopathy, but more research is needed to understand whether or not these
treatments are effective and safe. Potential alternative therapies include:
ï· Bilberry
ï· Butcher's broom
ï· Ginkgo
ï· Grape seed extract
ï· Pycnogenol (Pine bark)
Be sure to let your doctor know if you are taking any herbs or supplements. They have the
potential to interact with other medications, or cause complications in surgery, such as
excessive bleeding. The thought that you might lose your sight can be frightening, and you
may benefit from talking to a therapist. Your doctor can provide a referral. Or, you may find
the camaraderie and encouragement that a support group can offer is helpful to you. Ask your
doctor about support groups for people with diabetic retinopathy in your area. If you've already
lost some vision, ask your doctor about low vision products and services that can help make
daily living easier. For example, special lenses, magnifiers and video magnifiers are available.
7. PREVENTION
If you have diabetes, reduce your risk of getting diabetic retinopathy by doing the following:
ï· Make a commitment to managing your diabetes.
Make healthy eating and physical activity part of your daily routine. Try to get at least
150 minutes of moderate aerobic activity, such as walking, each week. Take oral
diabetes medications or insulin as directed.
ï· Monitor your blood sugar level.
You may need to check and record your blood sugar level several times a day â more-
frequent measurements may be required if you're ill or under stress. Careful monitoring
is the only way to make sure that your blood sugar level remains within your target
range. Ask your doctor how often you need to test your blood sugar.
ï· Ask your doctor about a glycosylated haemoglobin test.
The glycosylated haemoglobin test, or haemoglobin A1C test, reflects your average
blood sugar level for the two- to three-month period before the test. For most people,
the A1C goal is to be under 7 percent. If you've been meeting your blood sugar goals,
your doctor will likely perform this test twice a year. But, if your A1C is higher than
your goal, more frequent testing is recommended. Remember, keeping your blood sugar
level as close to normal as possible slows the progression of diabetic retinopathy and
reduces the need for surgery.
ï· Keep your blood pressure and cholesterol under control.
High blood pressure and high cholesterol increase the risk of vision loss. Eating healthy
foods, exercising regularly and losing excess weight can help. Sometimes medication
is needed, too.
ï· Lifestyle Modification
If you smoke or use other types of tobacco, ask your doctor to help you quit. Smoking
increases your risk of various diabetes complications, including diabetic retinopathy.
Talk to your doctor about ways to stop smoking or to stop using other types of tobacco.
ï· Pay attention to vision changes.
Yearly dilated eye exams are an important part of your diabetes treatment plan. Contact
your eye doctor right away if you experience sudden vision changes or your vision
becomes blurry, spotty or hazy.
Remember, diabetes doesn't necessarily lead to poor vision. Taking an active role in diabetes
management can go a long way toward preventing complications.
8. CONCLUSION
Diabetic retinopathy (DR) is a microvascular complication of diabetes. Research has clearly
demonstrated that blindness from diabetes is almost entirely preventable with early diagnosis,
optimization of risk factors and timely photocoagulation where appropriate.
Presently, 70% of
diabetes occurs in lower and middle-income countries, where systematic screening for
retinopathy is rare. Careful management of your diabetes is the best way to prevent vision loss.
If you have diabetes, see your eye doctor for a yearly diabetic retinopathy screening with a
dilated eye exam even if your vision seems fine because it's important to detect diabetic
retinopathy in the early stages New treatments may offer greater hope for sustained visual
improvement in patients with diabetic retinopathy
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1. American Diabetes Association. Standards for medical care: Screening
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2. Izzo JL Jr, LevyD, Black HR. Clinical advisory statement: Eye care :, Treatment of
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3. Vasan RS, Larson MG, Leip EP, et al. Impact of Lase Surgery in Modern Treatments.
N Engl J Med 2001;345:1291â1297
4. Chobanian AV, Hill M.: Acritical reviewof current scientific evidence. Eye Care DR
2000;35:858â863.
5. Staessen JA, Thijs L, Fagard R, Diagnoses Of Diabetic Retinopathy :. Lab Report Data
in Europe Eye Health Plus 1999;282:539â546.
6. Buchbinder A, Miodovnik M, McElvy S, et al. Is insulin lispro associated with the
development or progression of diabetic retinopathy during pregnancy? Am J Obstet
Gynecol 2000;183:1162â1165.