Diabetic retinopathy

Diabetic retinopathy (DR) is an eye condition where the retina is damaged from long standing diabetes mellitus (DM) which if left untreated, may lead to extensive vision loss or even blindness.

Below are statistics from the United States which clearly mirrors the rates of Diabetic Retinopathy in Ireland.

The National Institute of Health (NIH) points to it as the leading cause of blindness for America's working-age population. The U.S. Centers for Disease Control and Prevention (CDC) added that there are 5 million citizens age 40 onward afflicted with DR as a result of diabetes, type 1 or 2. By 2050, the number could reach 16 million.

-In 2010, about 9% of the U.S. population (26 million) had diabetes while 79 million more are at risk.

-Up to 24,000 new diabetic retinopathy-related vision loss cases are from the U.S.

-According to the United Health Foundation (UHF), America's number of diabetes and obesity (a major cause of diabetes) cases continues to rise. The increase in 2011 was up by 4.8% from 2010, a total of 42.6% increase from 2001.

- UHF further said that 2011 data has about 27.5% of obese adult Americans, up by 2.2% from 2010, a total of 37.5% from 2001.

With the help of insulin, a hormone produced by the pancreas, blood sugar (glucose) is converted into energy for proper bodily functions. Diabetes mellitus (DM) is a disorder that sends blood sugar levels abnormally high (hyperglycemia) causing damage to small blood vessels. This can obstruct blood flow into organs, the eyes included.

Two Types of Diabetes

Type 1

This is an insulin-dependent type of condition because the body is unable to produce adequate supplies of insulin. A regular injection of insulin-supplying medications to regulate levels of blood sugar is necessary.

Type 2

Enough insulin is produced by the body, but it is unable to properly use it hence the abnormality in blood sugar levels.

Both types increase the risks of diabetic retinopathy due to high blood sugar levels that cause damage to vessels inside the eye at the level of the retina. The retina can be likened to the film at the back of a camera and is where the photoreceptors (light sensitive cells for good vision) are located.

Symptoms and Detection

Normally, diabetic retinopathy only develops with long-term diabetes (at least 10 years) but taking care of eye health should be prompt when there is a history of diabetes in the family. If diagnosed with diabetes, see an optometrist or an ophthalmologist once yearly for a dilated eye examination. Occasionally if the blood sugar level is high DR can occur at an earlier stage in the disease, i.e. before 10 years. So have your eyes evaluated by an ophthalmologist (eye doctor) shortly after your diagnosis is made.

Symptoms of diabetic retinopathy and other diabetes-related eye problems include:

-Sudden myopia (short sightedeness)

-Cataracts

-Eye pain

-Double, fluctuating, blurry or distorted vision

-Eye floaters and/or blind spots (in the late stages of diabetic retinopathy)

-Corneal defects or corneal wounds that are slow to heal

-Scotoma (shadow in the eyes view field)

-Presbyopia-unrelated near vision issues

Other signs may appear during an eye exam including swelling of the retina, traces of blood deposits or fluid leakages from blood vessels. Flourescein angiography (a special test)may be conducted to get a conclusive diagnosis. An illuminated dye is injected through the veins in the arm to allow flow into the retina and then photographed showing the illuminated dye. An ophthalmologist will be able to see the extent of the disease using this method.

Neuropathy (nerve damage) is an often-neglected diabetic eye disease symptom affecting the muscles of eye movement where nystagmus (uncontrolled eye movements) and double vision is experienced.

Diabetic Eye Diseases

Early stages of diabetic retinopathy create swelling in the retina caused by leaked fluid or blood. In later stages, blood leaks into the eye's vitreous (the clear, jelly-like substance in the centre of the eye) can lead to vision problems and subsequent blindness.

Clinically Significant Macular Edema (CSME) common in Type 2 diabetes patients can cause reduced or distorted vision due to the swelling of the macula, which is the central part of the retina that enables you to see detail. Laser photocoagulation (laser heat) is often carried out to destroy abnormal, leaky blood vessels in the retina.

Diabetic macular edema (DME) is classified into focal (described as leaky blood vessels caused by microaneurysms or other vascular defects) and diffuse (where tiny blood vessels in the retina are either dilated or swollen).

Macular edema can occur independently or along with NPDR or PDR - see below.

Non-proliferative Diabetic Retinopathy (NPDR) is an early occurrence small haemorrhages and retinal deposits which are typically the first signs of DR. Often, on closer eye examination, microaneurysms (tiny vessel abnormalities) are exposed in the retina.

Proliferative Diabetic Retinopathy (PDR) this poses a greater risk for blindness. An increased presence of neovascularisation (new abnormal blood vessels) on or near the optic nerve and extending into vitreous is observed. Pre-retinal bleeding can also occur in the vitreous humor or on the retina. Partially blocked blood flow in the small arteries can cause ischemia (inadequate blood supply) resulting in lack of oxygen to the retina.

Besides central blindness, other permanent complications like tractional retinal detachment and neovascular glaucoma may result from neovascularization. Laser treatments for diabetes-related eye diseases may only be required in advanced conditions so make sure to have a regular check-up.

Who Are at Risk?

Diabetics unable to control blood sugar levels and hypertension are likely to develop diabetes-related eye problems including diabetic retinopathy accompanied by blindness.DR risk is higher in pregnant diabetic women.

AAO and American Diabetes Association noted that minority groups are also at risk. An average diabetic's chance of going blind is 25 times more likely than  normal but it is twice as much for African-Americans after DR was observed in this minority group in their 20s.

Hispanics are also at a higher risk of developing DR after Los Angeles Latino Eye Study observed 42% of them battling DR after 15-years of diabetes. The National Eye Institute-funded study concluded that Hispanics, compared with non-Hispanic Caucasians, are more prone to DR.

Director at Ocular Epidimiology Center at the Doheny Eye Institute, Dr. Rohit Varma stressed the importance of regular dilated eye examinations for diabetic Latinos. The doctor added that Latinos with a disease-damaged eye need closer monitoring to avoid damage to both eyes.

Also in the list are Native Americans. For instance, Pima Indians risk is 35% higher compared with the 9% chances of the common populace.

Is DR a Disability?

Under the Americans with Disabilities Act (ADA), disabled persons may avail of some workplace and public place accommodation due to their limited range of functioning. For diabetics, sufficient evidence regarding diabetes and diabetic retinopathy still has to be accumulated to allow any entitlements.

In the 2008 an amended American Diabetes Association (ADA) guideline, further lawful protection was extended to diabetics such as extra breaks from work (for insulin injections, etc). Also, Management can't dismiss or refuse employment to those who are still able to perform basic functions.

According to the American Diabetes Association, a mild diabetic patient whose sight may function properly during the day may find night vision a challenge and special illumination may have to be in place as a special accommodation.

Diabetics in Ireland who have poor vision may be able to register with the National Council for the Blind in Ireland (NCBI) which permits them to avail of certain services and statutory benefits.

Diabetic Retinopathy Prevention

With regular check-ups and proper treatment, DR is a condition that can be prevented or curtailed. To control it and its progress ensure that:

• Blood sugar is regularly monitored and kept under control within normal limits.
• A healthy diet is maintained, smoking and alcohol are avoided, and regular exercise program is practiced.
• Doctor's advice is followed and this includes a regular eye check-up.