How Does Diabetes Cause Dry Eyes Diabetic Retinopathy?
Diabetes mellitus (DM) causes abnormal changes in the blood sugar (glucose) that your body ordinarily converts into energy to fuel different bodily functions.
Uncontrolled diabetes allows unusually high levels of blood sugar (hyperglycemia) to accumulate in blood vessels, causing damage that hampers or alters blood flow to your body's organs — including your eyes.
Diabetes generally is classified as two types:
  • Type 1 diabetes. Insulin is a natural hormone that helps regulate the levels of blood sugar needed to help "feed" your body. When you are diagnosed with type 1 diabetes, you are considered insulin-dependent because you will need injections or other medications to supply the insulin your body is unable to produce on its own. When you don't produce enough of your own insulin, your blood sugar is unregulated and levels are too high.
  • Type 2 diabetes. When you are diagnosed with type 2 diabetes, you generally are considered non-insulin-dependent or insulin-resistant. With this type of diabetes, you produce enough insulin but your body is unable to make proper use of it. Your body then compensates by producing even more insulin, which can cause an accompanying abnormal increase in blood sugar levels.
With both types of diabetes, abnormal spikes in blood sugar increase your risk of diabetic retinopathy.
Eye damage occurs when chronically high amounts of blood sugar begin to clog or damage blood vessels within the eye's retina, which contains light-sensitive cells (photoreceptors) necessary for good vision.
Types of Diabetic Eye Disease
Once high blood sugar damages blood vessels in the retina, they can leak fluid or bleed. This causes the retina to swell and form deposits in early stages of diabetic retinopathy.
In later stages, leakage from blood vessels into the eye's clear, jelly-like vitreous can cause serious vision problems and eventually lead to blindness.
Clinically significant macular edema (CSME). This swelling of the macula more commonly is associated with type 2 diabetes. Macular edema may cause reduced or distorted vision.
Diabetic macular edema (DME) typically is classified in two ways:
  • Focal, caused by microaneurysms or other vascular abnormalities sometimes accompanied by leaky blood vessels.
  • Diffuse, which describes dilated or swollen tiny blood vessels (capillaries) within the retina.
If you have CSME, you typically are advised to undergo laser photocoagulation.
Non-proliferative diabetic retinopathy (NPDR). This early stage of DR — identified by deposits forming in the retina — can occur at any time after the onset of diabetes.
Often no visual symptoms are present, but examination of the retina can reveal tiny dot and blot hemorrhages known as microaneurysms, which are a type of out-pouching of tiny blood vessels.
In type 1 diabetes, these early symptoms rarely are present earlier than three to four years after diagnosis. In type 2 diabetes, NPDR can be present even upon diagnosis.
Proliferative diabetic retinopathy (PDR). Of the diabetic eye diseases, proliferative diabetic retinopathy has the greatest risk of visual loss.
The condition is characterized by these signs:
  • Development of abnormal blood vessels (neovascularization) on or adjacent to the optic nerve and vitreous.
  • Pre-retinal hemorrhage, which occurs in the vitreous humor or front of the retina.
  • Ischemia from decreased or blocked blood flow, with accompanying lack of oxygen needed for a healthy retina.
These abnormal blood vessels formed from neovascularization tend to break and bleed into the vitreous humor of the eye. Besides sudden vision loss, more permanent complications can include tractional retinal detachment and neovascular glaucoma.
Macular edema may occur separately from or in addition to NPDR or PDR.
You should be monitored regularly, but you typically don't require laser treatment for diabetic eye disease until the condition is advanced.
What to expect Before,During and After Laser Treatment
Laser treatment typically requires no overnight hospital stay, so you will be treated on an outpatient basis in a clinic or in the eye doctor's office.
Make sure you have someone drive you to and from the office or clinic on the day you have the procedure. Also, you'll need to wear sunglasses afterward because your eyes will be temporarily dilated and light sensitive.
Before the procedure, you will receive a topical anesthetic or possibly an injection adjacent to the eye to numb it and prevent it from moving during the laser treatment.
Your eye doctor will make these types of adjustments to the laser beam before it is aimed into the eye:
  • The amount of energy used
  • The size of the "spot" or end of the beam that is directed into the eye
  • The pattern applied by the laser beam onto the targeted area
A laser treatment typically lasts at least several minutes, but more time may be required depending on the extent of your eye condition.
During laser treatment, you might experience some discomfort, but you should feel no pain. Right after a treatment, you should be able to resume normal activities. You might have some discomfort and blurry vision for a day or two after each laser treatment.
The number of treatments you need will depend on your eye condition and extent of damage. People with clinically significant diabetic macular edema may require three to four different laser sessions at two- to four-month intervals to stop the macular swelling.
Though the specific mechanism by which laser photocoagulation reduces diabetic macular edema is not fully understood, a landmark study called the Early Treatment Diabetic Retinopathy Study (ETDRS) showed that focal (direct/grid) photocoagulation reduces moderate vision loss caused by DME by 50 percent or more.
In December 2011, Iridex Corporation announced the results of a 10-year study of the company's MicroPulse laser therapy for treating DME. The study data showed the new micropulse technology was at least as effective as conventional laser photocoagulation in the treatment of macular edema, with less risk of thermal damage and scarring to the surrounding retinal tissue.
If you have proliferative diabetic retinopathy (PDR) — meaning that leakage of fluid has begun in the retina — the laser treatment should take from 30 to 45 minutes per session, and you may require up to three or four sessions.
Your chance of preserving your remaining vision when you have PDR improves if you receive scatter laser photocoagulation as soon as possible following diagnosis.
Early treatment of PDR particularly is effective when macular edema also is present.
Diabetic Retinopathy
Diabetic retinopathy vision-threatening damage to the retina of the eye caused by diabetes is the one cause of blindness around the world.
The good news: Diabetic retinopathy often can be prevented with early detection, proper management of your diabetes and routine eye exams performed by your optometrist or ophthalmologist

Symptoms Of Diabetic Retinopathy and other Diabetes Related Eye Problems
During an eye examination, your eye doctor will look for other signs of diabetic retinopathy and diabetic eye disease. Signs of eye damage found in the retina can include swelling, deposits and evidence of bleeding or leakage of fluids from blood vessels.
Your eye doctor will use a special camera or other imaging device to photograph the retina and look for telltale signs of diabetes-related damage. In some cases, he or she may refer you to a retinal specialist for additional testing and possible treatment.
For a definitive diagnosis, you may need to undergo a test called a fluorescein angiography. In this test, a dye is injected into your arm intravenously and gradually appears in the blood vessels of the retina, where it is illuminated to detect diabetes-related blood vessel changes and blood leakage in the retina.
One sometimes overlooked symptom of diabetic eye disease is nerve damage (neuropathy) affecting ocular muscles that control eye movements. Symptoms can include involuntary eye movement (nystagmus) and double vision.
Who gets Diabetic Retinopathy?
Beyond the presence of diabetes, how well your blood sugar is controlled is a major factor determining how likely you are to develop diabetic retinopathy with accompanying vision loss.
Uncontrolled high blood pressure (hypertension) has been associated with eye damage related to diabetes. Also, studies have shown a greater rate of progression of diabetic retinopathy in diabetic women when they become pregnant.
Of course, the longer you have diabetes the more likely you are to have vision loss.
The American Academy of Ophthalmology (AAO) notes that all diabetics who have the disease long enough eventually will develop at least some degree of diabetic retinopathy, though less advanced forms of the eye disease may not lead to vision loss.
Lasers for Diabetic Retinopathy Treatment
Laser treatment of diabetic eye disease generally targets the damaged eye tissue. Some lasers treat leaking blood vessels directly by "spot welding" and sealing the area of leakage (photocoagulation). Other lasers eliminate abnormal blood vessels that form from neovascularization.
Lasers also may be used to intentionally destroy tissue in the periphery of the retina that is not required for functional vision. This is done to improve blood supply to the more essential central portion of the retina to maintain sight.
The peripheral retina is thought to be involved in formation of VEGF responsible for abnormal blood vessel formation. When cells in the peripheral retina are destroyed through panretinal photocoagulation (see below), the amount of VEGF is reduced, along with the potential to produce abnormal retinal blood vessels.
After laser treatment of the peripheral retina, some blood flow bypasses this region and instead provides extra nourishment to the central portion of the retina. The resulting boost of nutrients and oxygen helps maintain the health of cells in the macula that are essential for detailed vision and color perception. However, some peripheral vision could be lost due to this treatment.
The two types of laser treatments commonly used to treat significant diabetic eye disease are:
  • Focal or grid laser photocoagulation. This type of laser energy is aimed directly at the affected area or applied in a contained, grid-like pattern to destroy damaged eye tissue and clear away scars that contribute to blind spots and vision loss. This method of laser treatment generally targets specific, individual blood vessels.
  • Scatter (panretinal) laser photocoagulation. With this method, about 1,200 to 1,800 tiny spots of laser energy are applied to the periphery of the retina, leaving the central area untouched.
Treatment of clinically significant DME also entails using fluorescein angiography to provide images of the eye's interior. These images accurately guide application of laser energy, which helps "dry up" the localized swelling in the macula. A fluorescein angiogram also can identify the location of blood vessel leakage caused by proliferative diabetic retinopathy.
While laser treatment for diabetic retinopathy usually does not improve vision, the therapy is designed to prevent further vision loss. Even people with 20/20 vision who meet treatment guidelines should be considered for laser therapy to prevent eventual vision loss related to diabetes.
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