Dilated pupil examinations allow physicians to use special eye drops that give them a clearer view of the health of their patients’ eyes. These drops enlarge the pupil, the black, circular part of the eye that allows light into the eye. Such tests are crucial for people with diabetes, who are at high risk of developing several eye disorders.

High glucose (blood sugar) levels, high blood pressure, unhealthy levels of cholesterol and other factors associated with diabetes can weaken the walls of the retinal capillaries (tiny blood vessels) of the retina. Nerve fibers also may become damaged because of lack of blood flow.

Many eye disorders occur without manifesting any symptoms in the early stages. Dilated pupil examinations can help physicians uncover subtle changes in the retina, optic nerve or other eye structures that may indicate the beginnings of a more serious problem.

Eye disorders associated with diabetes include:

• Diabetic retinopathy. Damage to the blood vessels that bring oxygen and nutrients to the retina, the light-sensitive tissue at the back of the eye. It is the leading cause of blindness in working–age American adults.

  

• Glaucoma. Damage to the optic nerve, usually caused by an increase in fluid pressure inside the eye. It leads to loss of peripheral (side) vision and can eventually cause blindness. Glaucoma also occurs in nondiabetics, but the risk of getting the disease is much higher in people with diabetes.
  
  
• Cataracts. Clouding of the lens of the eye. It tends to occur in older people and also affects nondiabetics. However, diabetes increases the risk of developing cataracts at a younger age.
  
  
• Age-related macular degeneration (AMD). A disease that blurs central vision. It is a leading cause of vision loss in elders. The National Eye Institute reports a link between obesity (a common feature of type 2 diabetes) and the progression of AMD. Maternally inherited diabetes and deafness (MIDD), a rare form of type 2 diabetes, can cause damage similar to that of AMD.

In addition, Wolfram syndrome, a rare genetic disorder, involves insulin-dependent diabetes, damage to the optic nerves, deafness and diabetes insipidus. 

Other endocrine disorders that may impair vision include Graves’ disease, which can cause the eyes to bulge and can cause severe double vision, scar the corneas and damage the optic nerves.

Individuals with diabetes should have a dilated pupil examination at least annually. This will help physicians to better diagnose and treat eye disorders in the early stages of their development. Women with diabetes who become pregnant should promptly schedule a dilated pupil examination.

Sometimes this test helps uncover diabetes in a person who was previously undiagnosed. Blurry vision or other visual difficulties can be a symptom of diabetes. Follow-up testing with glucose tests can yield a diagnosis of prediabetes or diabetes and lead to treatment that will limit complications.

Patients may want to schedule the eye examination with an ophthalmologist (a physician who specializes in eye diseases). An ophthalmologist is the only specialist who can detect, diagnose and treat diabetic retinopathy. Some optometrists can perform the dilated pupil examination, but they are not medical doctors and cannot perform surgery to treat diabetic eye disease.