What is Diabetic Retinopathy ?
Diabetic Retinopathy, as the name suggests is a condition that occurs in people with diabetes.
It leads to progressive damage to the retina (the light-sensitive lining at the back of the eye).
Diabetic Retinopathy is a serious complication of diabetes that poses a threat to the sight.
Diabetes interferes by disturbing the body’s ability to use and store sugar (glucose). The disease is marked by the presence of too much sugar in the blood, which can cause damage to many body organs, including the eyes.
With time, diabetes damages the blood vessels in the retina. Diabetic Retinopathy occurs when these tiny blood vessels leak blood and other fluids.
The leakage causes the retinal tissue to swell, resulting in cloudy or blurred vision.
The condition usually affects both eyes.
The longer a person has diabetes, the higher the likelihood of the person to develop diabetic retinopathy.
Diabetic Retinopathy can cause blindness, if left untreated.
Symptoms of Diabetic Retinopathy include:
- Seeing spots or floaters
- Blurred vision
- Having a dark or empty spot in the centre of the vision
- Difficulty seeing properly at night
Fluid accumulation can occur inside the area that controls the focusing in the eye due to long periods of high blood sugar in people with diabetes.
This changes the curvature of the lens, leading to blurred vision. However, once blood sugar levels are controlled, blurred distance vision will improve.
Patients with diabetes who can better control their blood sugar levels will slow the onset and progression of diabetic retinopathy.
Often the early stages of diabetic retinopathy do not have visible symptoms.
That is why it is recommended to undergo a comprehensive dilated eye examination once a year for people with diabetes.
Early detection and treatment can help prevent significant vision loss from diabetic retinopathy.
Risk Factors:
Anyone with type 1 diabetes or type 2 diabetes is at risk of diabetic retinopathy.
People who are at a greater risk are the ones who:
- have had diabetes for a long time
- have a persistently high blood sugar (blood glucose) level
- have high blood pressure
- have high cholesterol
Diabetic retinopathy is a leading cause of blindness. Initially, diabetic retinopathy, may not show significant symptoms but over time, it can get worse and cause vision loss. Diabetic retinopathy usually affects both eyes.
Four Stages of Diabetic Retinopathy are:
- Mild Nonproliferative Retinopathy
- Moderate Nonproliferative Retinopathy
- Severe Nonproliferative Retinopathy
- Proliferative Retinopathy.
Mild Nonproliferative Retinopathy is the earliest stage which shows the presence of small areas of balloon-like swelling in the retina’s tiny blood vessels.
Moderate Nonproliferative Retinopathy is the second stage which shows blockage of some blood vessels that nourish the retina as the disease progresses.
Severe Nonproliferative Retinopathy is the third stage where in more blood vessels are blocked, depriving several areas of the retina of their blood supply. These areas send signals to the body to grow new blood vessels for nourishment.
Proliferative Retinopathy is the fourth and the advanced stage where the signals sent by the retina help new blood vessels to grow.
These new blood vessels are abnormal and fragile.
The new blood vessels grow along the retina and the surface of the vitreous gel which occupies the area inside the eye.
On their own, these blood vessels do not cause symptoms or vision loss. But as they have thin, fragile walls, blood leakage can result in to severe vision loss and even blindness.
Causes of Diabetic Retinopathy:
The primary cause of diabetic retinopathy is diabetes. Increased sugar levels can damage the small blood vessels that nourish the retina and may in some cases block them completely.
As a result, the blood supply to the retina from these damaged blood vessels is cut off and vision is affected.
Due to the lack of blood supply, the eye may create growth factors that lead to diabetic macular edema, resulting in decreased vision, or proliferative diabetic retinopathy, which can lead to retinal detachment and vision loss.
Diagnosis of Diabetic Retinopathy:
A dilated eye exam is the best way of diagnosing diabetic retinopathy. In this test, the physician puts drops in the eyes to dilate the pupils dilate so as to allow a better view of the inside of the eye, especially the retina tissue.
The physician will look for:
- Swelling in the retina (diabetic macular edema)
- Abnormal blood vessels that may predict an increased risk of developing new blood vessels
- The actual presence of new blood vessels or scar tissue on the surface of the retina (proliferative diabetic retinopathy)
- The physician may take fundus photographs of the back of the eye to facilitate detection of diabetic retinopathy. These photos help the physician to track the disease on subsequent visits to monitor its progress.
- Fluorescein angiography is a retinal photography test conducted as a supplementary eye exam. In this test, post dilating the pupil, the physician injects a dye into the patient’s arm which then circulates through the eyes. The dye does not affect the kidneys and is not like the dye that is used with MRIs or CAT scans.
- As the dye circulates, the physician takes pictures of the retina to accurately detect blood vessels that are closed, damaged, or leaking. The pictures are black and white to facilitate the detection of these changes, but the process is not the same as having an x-ray. Prior to examination, ask your physician about the risks and benefits of this test.
- The physician may also suggest an optical coherence tomography (OCT) exam which provides cross-sectional images of the retina that show its thickness, helping to determine if fluid has leaked into retinal tissue.
With proper examinations, the earliest signs of diabetic retinopathy in the retina can be detected before vision loss begins.