Diabetes: Danger to Eyes and Health

World Diabetes Day 14 November 2017

Since April 2016, the Ministry of Health has declared a war on diabetes”, as Singapore has over 400,000 people with this disease, with one in 3 Singaporeans having a lifetime risk of getting it.

Diabetes is also a global problem. Here are some figures from International Diabetes Federation’s (IDF) Diabetes Atlas (7th Edition).

  • About 415 million people worldwide have diabetes (1 in 11 people)
  • By 2040, about 642 million adults will have diabetes (1 in 10 people)
  • 46.5% of adults have diabetes that is undiagnosed
  • Over half a million children have Type 1 diabetes
  • Every 6 seconds a person dies from diabetes-related causes
  • 1 in 7 births is affected by gestational diabetes

Diabetes is not only life-threatening, it is also sight-threatening.

Diabetes has been associated with:

  • Cataracts
  • Bleeding in the retina
  • Glaucoma
  • Double vision
  • Dry eyes
  • Refractive changes (changes in the power of the eye)
Diabetic cataract
Diabetic retinopathy

Types of diabetes:

Type 1 – Also known as juvenile diabetes, it typically affects children and young adults. The body is unable to produce insulin, a hormone that is needed to regulate the amount of glucose in the blood and cells.

Type 2 – This is the more common type of diabetes, where the body cannot use insulin properly.  This is known as insulin resistance. Initially, the body is able to compensate by producing more insulin, however, over time it becomes insufficient to regulate blood glucose, so medication becomes necessary.

Both types of diabetes can affect eyes and vision.

How does diabetes cause eye problems?

Fundamentally, diabetes is a disease of the blood vessels.  The eye relies on the blood vessels for oxygen and nutrients, as well as to carry away waste products from its metabolic activities.  When the peripheral blood circulation is impaired, tissues degenerate in the eye structures and its associated nerves.  This gives rise to:

  • Bleeding vessels on the retina (the light receptors of the eye), subsequently causing irreversible scarring and disruption of retinal tissues.
  • Swelling of the macula (the part of the retina that is responsible for central vision) and blurry or distorted vision (and colours).
  • Paralysis of the nerves that control the muscles of the eye. This affects the alignment and movement of the eyes, causing double vision. Double vision, in turn, may cause blurriness, headaches, disorientation, and nausea.
Double vision may be mistaken for blurry vision and affects orientation and mobility.

How do I know if I have diabetes?

The most reliable way to diagnose diabetes is to have a check with your doctor or GP.

A number of tests will be done:

  • Fasting plasma glucose blood test
  • Glucose tolerance test
  • Random plasma glucose test
  • HbA1c glycated haemoglobin

Some of these tests may be repeated over time for your doctor to assess if there is diabetes or pre-diabetes. These tests are also done on known diabetics to check if their diabetes management is effective.

From the American Diabetes Association

How does an eye check reveal diabetes?

Some undiagnosed diabetics have signs of diabetes-related damage that shows up in an eye exam.  Typical findings are: cataracts, bleeding in the retina, abnormal vessels in the retina and other parts of the eye, and a recent- onset eye misalignment (squint).

Some of these signs and symptoms of vision disturbances may be temporary or may need urgent medical attention. Therefore it is important to have a comprehensive eye exam for those who are at risk of diabetes.

Who are at risk of diabetes?

The following are risk factors for diabetes.

  • High Body/Mass Index (BMI) >25 kg/mm2
  • High blood pressure
  • Diagnosis of gestational diabetes during pregnancy (for females)
  • Diagnosis of Type 2 diabetes in your immediate family

For a quick self-assessment of your risk factors, check out Healthhub Sg.

How can optometrists help diabetics?

Optometrists not only check vision, but also eye health. The optometrist uses various equipment such as the slit lamp and fundus photography to examine the structures of the eye such as the crystalline lens and retina.  Eye pressure can also be measured to check for risk of glaucoma. The eye is a unique organ that allows fine blood vessels to be examined non-invasively.  Such detailed examination of the eye provides clues to one’s health, such as any indication of diabetes, high blood pressure and cholesterol, nerve impairment, brain injury etc. Your optometrist will advise you to seek medical attention if necessary.

Optometrists are also able to treat some vision disturbances that are caused by eye diseases. For example, those who have recent onset double vision due to nerve paralysis may need special prismatic glasses to have normal vision while their diabetes is being managed.

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