Why You Should Be Looking for Diabetic Retinopathy

Over 20% of patients have retinopathy when they are first diagnosed with type 2 diabetes

Emily Chew PhD of the National Eye Institute

Diabetes blindness

Over 34 million people or more than 10% of people in the US have diabetes. In 2018 alone, an estimated 1.5 million new cases of diabetes were diagnosed in the in American adults aged 18 or older. Among the many potential complications and risks posed by diabetes is diabetic retinopathy. 

High blood sugar levels can damage blood vessels throughout the body including the eyes. Damage to the eyes begins when excess sugar in the blood blocks blood vessel passage to the patient's retina, causing swelling and leakage. Alternately, the vessels close altogether, and do not let blood pass through. In some instances, the patient's eye will attempt to create new blood vessels to compensate for the blocked ones.  The problem is that these new blood vessels are abnormal; they don’t work very well and tend to leak or bleed easily. Any and all of these things can cause visual impairment. 

Over 20% of patients with type 2 diabetes have retinopathy at the time when they are first diagnosed, and most develop symptoms over time. In fact, diabetic retinopathy is the most common cause of blindness in adults aged 20-74 years old. Almost half of all Americans diagnosed with diabetes have some degree of retinopathy, but half of them are unaware that they have it and are at risk of losing their vision.

Identifying diabetic retinopathy at every stage

There are four stages of diabetic retinopathy; mild, moderate, severe non-proliferative, and proliferative. 

Symptoms of diabetic retinopathy include:

  • Loss of central vision i.e. when driving or reading
  • Color blindness
  • Blurred vision
  • Black spots and ‘holes’ in the patient's vision
  • Small spots in the patient's vision caused by bleeding known as ‘floaters.’

Other risk factors for diabetic retinopathy to screen for in patients with diabetes:

  • High blood pressure
  • High cholesterol
  • Tobacco use
  • Being Black, Latinx, or Indigenous
  • Pregnancy. A woman who develops gestational diabetes is at higher risk of developing type 2 diabetes over time.
  • Family history. Have any of your patient's relatives experienced visual impairment?

Early treatment can slow or stop damage from diabetic retinopathy and prevent blindness

If you don't have the capacity to treat eye complications in your practice, refer the patient to an ophthalmologist or eye clinic so they can still get treatment right away. Treatment options for diabetic retinopathy include:

Focal Laser Treatment, also known as photocoagulation. In this treatment, leaks from abnormal blood vessels are treated with direct laser burns. It is usually done in an ophthalmologist's office or clinic and can be completed in a single session.

For patient's suffering from blurred vision caused by macular edema (aka the buildup of fluids within the center of the retina) the procedure might not return their vision to normal. It can reduce the likelihood of the macular edema progressing further. 

Scatter Laser Treatment, also known as pan-retinal photocoagulation. This procedure targets areas away from the central macular with scattered laser burns.  The burns are used to scar and even shrink abnormal blood vessels in the eye. Like focal laser treatment, this treatment is also typically done in an ophthalmologist's office or eye clinic. Scatter laser treatment usually takes two or more sessions and leaves the patient with blurred vision for a day or so following the procedure. There is a risk of peripheral or night vision loss following the procedure.

Vitrectomy. A tiny incision is made in the eye and blood and any scar tissue tugging on the retina are removed. This procedure has to be performed in a hospital or surgical center using general anesthesia. 

Eye injections. Medicines can be injected directly into the eye after anesthetic has been administered, which can slow down or even reverse the effects of retinopathy.  These treatments come in two general categories.

  1. Corticosteroids. These medications can reduce macular swelling thus resulting in clearer vision.  Due to the chronic nature of diabetic retinopathy, the treatment is often administered monthly and/or combined with laser therapy to achieve lasting, maximum results. The steroids can be absorbed via injections, eye drops, or in some cases an implant can be installed in the eye to dispense regular doses of medication over time. Patients with implants can sometimes forego monthly injections. But corticosteroids can also increase a patient’s risk for cataracts or glaucoma. 
  2. Anti-VEGF Drugs. These drugs are administered directly into the eye to prevent the formation of new blood vessels. Anti-VEGF drugs stabilize or even improve eye function in a majority of patients, but 40% of patients are not helped by them, and the medication is not without long term risks.

    This is why a new study out of Scripps Research has caused so much interest. Scientists at Scripps found a drug regimen VEGF (vascular endothelial growth factor) that seems to offer promise. Dr. Emily Chew of the National Eye Institute called the findings "very exciting," and noted "it would be remarkable to add another potential therapy for patients.”

 

In the meantime, Dr. Chew advises that diabetics get yearly eye exams with specialists to test for retinopathy in addition to preliminary screenings at medical appointments with their endocrinologists and PCPs.

Remember, many early stage cases of retinopathy do not present symptoms, and the patient is often completely unaware of the condition. Dr. Chew also recommends yearly dilation testing. She says that the best way to reduce the risk of diabetic eye disease is proper management of diabetes including control of glucose levels, blood pressure, and blood cholesterol.

Though final treatment of diabetic retinopathy may occur in an opthamologist's office, eye clinic or surgical center, early screening and treatment by PCPs and endocrinologists can prevent the patient from ever having to undergo invasive procedures if their diabetic retinopathy is caught early.

Continue Reading:
Early Detection of Diabetes Comes Through the Eyes
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