Diabetes Mellitus and Diabetic Retinopathy

What is Diabetes Mellitus?

Retrieved from the National Eye Institute

How is Diabetes Mellitus diagnosed?

Diabetes may have symptoms in some people, and no symptoms in others. Generally, Type 1 diabetes mellitus presents with increased thirst (polydipsia), frequent urination (polyuria), and increased hunger (polyphagia). Symptoms may develop rapidly, over weeks to months.  Untreated, this condition may cause a person to lose consciousness and become very ill (diabetic ketoacidosis).  Prolonged high blood glucose can cause glucose absorption in the lens of the eye, leading to temporary  changes in lens shape and vision changes. Blurred vision is a common complaint leading to a diagnosis of diabetes.

Type 2 diabetes and gestational diabetes may have minimal symptoms and may be diagnosed only when blood glucose levels  are measured with a simple blood test. A single, elevated measurement may be all that is needed to make the diagnosis. In some circumstances, it may require multiple measurements of blood glucose to determine the degree of impairment of glucose metabolism. . Some people develop diabetes that resolves if they lose weight. Your doctor is the person to help you determine if you might have diabetes.

How is Diabetes Mellitus treated?

Diabetes mellitus is a chronic disease for which there is treatment but no known cure.  Treatment is aimed at keeping blood glucose levels as close to normal as possible.  This is achieved with a combination of diet, exercise and insulin or oral medication.  Type 1 diabetics often need to be hospitalized for a period of time acutely after they are diagnosed to get their glucose levels down to an acceptable range.

How important is it to control blood sugar levels?

Studies suggest that good control of blood sugar levels decreases the risk of complications from diabetes. In addition to measuring blood glucose levels, glycated hemoglobin (also referred to as Hb A1C, or hemoglobin A1C) can be measured with a simple blood test.  This gives the doctor a more accurate picture of  the overall blood sugar levels over the preceding 3 months.  The recommended Hb A1C level is 6.5%.

What are complications of Diabetes Mellitus?

All forms of diabetes mellitus carry the risk of long term complications.  These typically develop 10-20 years after diagnosis, and are related to damage to blood vessels.  Diabetes increases the risk of cardiovascular disease, stroke, and peripheral vascular disease.  Small blood vessel (capillary) damage can affect the eyes, kidneys and nervous system.

How can Diabetes Mellitus affect the eyes?

1. Acutely if a person’s blood glucose is very high, the glucose can enter the lens within the eye and temporarily cause blurred vision.  Therefore blurred vision can be an initial sign of diabetes in a person with very high glucose levels.  This type of blurred vision will resolve after the blood glucose level is normalized.
2.Retinopathy – diabetes may cause blood vessels in the retina (the light sensitive lining of the eye) to become damaged (leaky or blocked) or grow abnormally [See figure 1]. Retinopathy is rare before the age of 10 and the risk increases with the length of time a person has diabetes. Treatments such as laser, intraocular injections, or other surgery may be helpful to prevent visual loss or restore sight. The longer a patient has diabetes, the greater chance of developing an eye problem.  All patients with diabetes are at risk for developing retinopathy.  Early retinopathy may have no symptoms, but early treatment is essential to prevent any loss of vision. Therefore, dilated eye examinations by an ophthalmologist are recommended yearly.
3.Cataract – may occur at a younger age in diabetic patients
4.Glaucoma- is more likely to develop in diabetics than in the general population..

How often should I have my eyes examined if I have Diabetes Mellitus?

A dilated eye examination  is recommended at the time of diagnosis. Depending on what is found, your doctor will recommend follow-up visits based on your condition. Most patients require yearly dilated eye examinations.