Diabetes-related eye complications
Diabetes raises the risk of the following conditions that affect the eyes:
- Diabetic retinopathy is damage to the posterior wall of the eye also known as the retina.
- Dry eye or reduced tear production
- Cataract or clouding of the lens
- Vitreous hemorrhage which is bleeding into the gel at the back of the eye
- Macula edema, swelling at the back of the eye
Diabetic retinopathy
Diabetes damages the small blood vessels of the retina which is a layer at the back of the eye that captures images and transmits them to the brain for processing. When these blood vessels get damaged, they bleed easily and leak fluid. Over time scars are formed which then contract and pull on the retina causing retinal detachment.
The scars and retinal detachment cause loss of vision. This damage to the retina is known as Diabetic Retinopathy and occurs over a period of time. It is painless and usually progressive. If detected early measures are taken to prevent progression and prevent loss of vision. This requires one to have a regular examination of the eye by an eye doctor in what we call screening.
Screening for retinopathy
Screening is a regular examination of the eye to check for signs of diabetic retinopathy. All diabetic patients need to screen for eye disease at least once a year. The objective of screening is to pick out early diabetic retinopathy signs and institute treatment when necessary to prevent loss of vision.
During the screening, the eye doctor takes a thorough history of your illness and finds out if there are any eye symptoms. The quality of your vision or how clearly you can see, (also known as visual acuity test), is checked. This involves reading letters or numbers on a visual acuity chart.
The eye doctor then examines the anterior/ front part of your eyes. Thereafter a drop is instilled in your eyes to dilate the pupils and allow the eye doctor to carry out a thorough examination of the back of your eye.
In some centers, a picture of the back of your eye/retina also known as a fundus photograph is taken by a technician and the picture checked for signs of diabetic retinopathy. If there are any suspicious signs the patient is then referred to an eye doctor for further examination and treatment.
Patients with Type 1 diabetes are screened at the age of 12 years. Then annually thereafter or as advised by the eye doctor. ALL patients with Type 2 diabetes should be screened immediately after the diagnosis of Type 2 Diabetes is made. Thereafter an annual examination is done or more frequently as advised by an eye doctor.
ALL pregnant mothers with diabetes should have their eyes examined at least once every trimester and soon after delivery. If significant damage is seen during screening, treatment is initiated. Treatment may be the laser of the retina or injection of medication into the eye or a combination of both or eye surgery by an eye doctor.
Strict control of blood sugar is also recommended. If a patient with diabetes notices any abnormality with the eyes he /she should visit an eye doctor immediately.
Dry eye
The amount of tears produced to keep the eye moist is reduced if one has diabetes. This will cause a sensation of sand underneath the eyelids, redness, tearing, and occasional blurring of vision. Treatment: Once diagnosed by an eye doctor one is given artificial tears or gels or both to keep the eye well moisturized.
Cataract
A cataract is an opacity/ clouding of the clear lens which is inside the eye. This causes poor vision. When a diagnosis of cataract is made by an eye doctor, surgery to remove the opacified lens and replace it with a clear artificial lens is recommended. A decision on whether or not to operate is made by both the patient and the eye doctor.
Vitreous hemorrhage
This is bleeding into the gel that is found at the back of the eye. When this occurs vision becomes poor or hazy. This requires an urgent assessment by an eye doctor who then checks the quality of the patient’s vision. An ultrasound of the eye is also done to check if there is associated injury at the back of the eye (detachment of the back layer of the eye also known as the retina).
If the vitreous hemorrhage is not associated with any injury at the back of the eye the eye is given time to clear the blood over a period of several weeks to months. If there is an associated injury at the back of the eye, then surgery to remove the blood and repair the retina is recommended.
Macular edema
The macula is a spot on the retina at the back of the eye that is responsible for the sharpest/clearest vision in the eye. Macula edema is an accumulation of fluid and swelling at this spot. This fluid comes from the leaking blood vessels damaged by high blood sugar. As a result, vision becomes blurred and images distorted.
Treatment involves injections in the eye that help clear the fluid. Laser around the macula may also be done. If a patient notices blurred vision they should visit an eye doctor for a thorough examination and timely treatment.