This month a patient asked: “How can diabetes affect the eye?”
Dr. Patel answered:
Compared to non-diabetics, individuals with diabetes are more likely to develop cataracts at a younger age and are twice as likely to develop glaucoma. The leading cause of blindness and low vision in adults aged 20-65 is a condition caused by diabetic retinopathy.
What is Retinopathy?
Retinopathy is a term used to describe damage to the retina, a thin, light-sensitive tissue that lines the inside surface of the eye. When light enters the eye, nerve cells in the retina convert the light into electrical impulses. These electrical impulses are carried by the optic nerve to the brain, which interprets them as visual images.
When describing the process of retinopathy, two terms are commonly used. Proliferative is a general term that means to grow or increase at a rapid rate by producing new tissue or cells. Non-proliferative indicates that this process is not yet occurring. Diabetic retinopathy occurs when there is damage to the small blood vessels in the retina.
According to the National Eye Institute, diabetic retinopathy has four stages:
- Mild non-proliferative retinopathy: At this early stage, small areas of balloon-like swelling occur in the retina’s tiny blood vessels.
- Moderate non-proliferative retinopathy: As the disease progresses, some blood vessels that nourish the retina become blocked.
- Severe non-proliferative retinopathy: Many more blood vessels become blocked, which disrupts the blood supply that nourishes the retina.
- Proliferative retinopathy: At this advanced stage, signals sent by the retina trigger the development of new blood vessels that grow (or proliferate) in the retina and the vitreous, which is a transparent gel that fills the interior of the eye. Because these new blood vessels are abnormal, they can rupture and bleed, causing hemorrhages in the retina or vitreous. Scar tissue can develop and can tug at the retina, causing further damage or even retinal detachment.
Symptoms of Diabetic Retinopathy
The early stages of diabetic retinopathy usually have no symptoms. The disease often progresses unnoticed until it affects vision. A comprehensive eye exam allows the doctor to check the retina for:
- Changes to blood vessels
- Leaking blood vessels or warning signs of leaky blood vessels, such as fatty deposits
- Swelling of the macula
- Changes in the lens
- Damage to nerve tissue
Treatment for Diabetic Retinopathy
Treatment for diabetic retinopathy is often delayed until it starts to progress to proliferative retinopathy, or after fluid builds-up in a region of the retina called the macula.
Comprehensive eye exams are needed more frequently as diabetic retinopathy becomes more severe. People with severe nonproliferative diabetic retinopathy are at a high risk and may need a comprehensive dilated eye exam as often as every 2 to 4 months. The American Academy of Ophthalmology recommends that all diabetic patients undergo a dilated retinal examination annually.
