Definition

Diabetic retinopathy is an ocular condition resulting from complications associated with uncontrolled diabetes mellitus. Elevated blood sugar levels in diabetes lead to damage in the retinal blood vessels, which comprise the light-sensitive layer at the back of the eye responsible for transmitting signals to the brain.

Causes

Diabetes mellitus causes blockages in the retinal blood vessels, depriving the retina of essential nutrients. To compensate, the retina forms new blood vessels. However, these new vessels have fragile walls, making them prone to dilation and rupture.

When a blood vessel ruptures, blood leaks into the vitreous, the clear fluid filling the back of the eyeball. This vitreous hemorrhage causes patients to see black spots or floaters in their vision. The bleeding can also lead to retinal inflammation and swelling, which, upon healing, forms scar tissue. Scar tissue formation increases the risk of retinal tearing or detachment (retinal detachment). These changes can result in vision loss for patients with diabetic retinopathy.

Risk Factor

All individuals with diabetes are at risk of developing diabetic retinopathy, including those with type 1, type 2 diabetes, and gestational diabetes occurring during pregnancy. The risk is increased if the diabetic patient also has the following conditions:

• High cholesterol levels
• High blood pressure
• Smoking

Symptoms

In the early stages, diabetic retinopathy often presents with mild symptoms or none at all, leading to a lack of awareness about the condition. Some patients may initially notice blurred vision when looking at distant objects. As the disease progresses, patients may experience:

• Gradual vision decline
• Blurred vision, with occasional clarity
• Seeing thread-like spots or floaters
• Seeing black spots in the visual field
• Perception of empty or dark areas in the visual field
• Eye redness, with or without pain
• Worsened night vision
• Fading color vision
• Vision loss

Symptoms of diabetic retinopathy typically affect both eyes.

Diagnosis

Diagnosis involves assessing the history of diabetes, conducting laboratory tests, and performing eye examinations. Checking HbA1c levels (glucose-bound hemoglobin) is crucial in managing patients with diabetes and diabetic retinopathy. An eye examination with an ophthalmoscope is conducted to inspect the eye. Prior to this examination, the doctor administers special eye drops to dilate the pupil (the black part in the eye's center), allowing a clearer view of the retina.

This examination can reveal several signs of diabetic retinopathy, such as:

• Abnormal blood vessels
• Swelling and accumulation of blood or fat on the retina
• New blood vessels and scar tissue on the retina
• Vitreous hemorrhage
• Retinal detachment
• Optic nerve abnormalities

Further tests may also include:

• Fluorescein Angiography

In this test, dye is injected into a vein in the arm. A special camera captures images as the dye passes through the ocular blood vessels, highlighting blockages or leakages.

• Optical Coherence Tomography (OCT)

This test measures the retinal thickness and detects retinal swelling. It can also identify fluid leakage in retinal tissue and evaluate treatment efficacy.

Management

Control Blood Sugar

The primary therapy for all diabetic retinopathy patients involves controlling blood sugar and blood pressure levels. Doctors will advise consuming low-sugar and low-fat foods, along with taking prescribed diabetes medications as directed. Effective blood sugar control can potentially restore some vision or at least prevent further vision deterioration.

Medicines

In advanced stages, doctors may administer intraocular injections to reduce macular swelling, which affects the central area of the retinal layer. The specific dosage and frequency of these injections will be determined by the physician.

Laser Surgery

Laser surgery is performed to seal leaking blood vessels, thereby reducing retinal swelling. It can also shrink existing blood vessels and prevent the formation of new ones. Multiple laser surgery sessions may be required to achieve optimal results.

Vitrectomy

For late-stage diabetic retinopathy, a vitrectomy might be recommended. This surgical procedure involves removing the vitreous gel from within the eye. It addresses various vision problems originating from the back of the eye by clearing the vitreous fluid and blood from leaking vessels, allowing light to properly focus on the retina. Additionally, scar tissue on the retina can be excised during this procedure.

Complications

Untreated diabetic retinopathy can progress into severe conditions, such as:

• Diabetic Macular Edema

This occurs when blood leaks from the retinal vessels into the macular area, the central part of the retina responsible for vision clarity, leading to blurred vision.

• Neovascular Glaucoma

This type of glaucoma arises when new, abnormal blood vessels block tear flow in diabetic retinopathy, potentially causing blindness.

• Retinal Detachment

In diabetic retinopathy, scar tissue formation on the retina can lead to retinal detachment, where the retinal layer is pulled away from its underlying support, resulting in blindness.

Prevention

For diabetes mellitus patients, the best preventive measure against diabetic retinopathy is controlling blood sugar levels. Strategies for maintaining blood sugar control include:

• Regular blood sugar monitoring
• Consuming low-sugar, low-fat foods
• Adhering to prescribed diabetes medications
• Maintaining an ideal body weight
• Engaging in light exercise 3-5 times per week for 30 minutes

Beyond blood sugar control, patients should take additional precautions:

• Be vigilant about any visual disturbances
• Maintain normal blood pressure and cholesterol levels
• Undergo comprehensive eye exams at least once a year

If diagnosed with diabetic retinopathy, the following steps can help prevent vision loss:

• Discuss with your doctor strategies for early blood sugar management to prevent retinal vessel damage and subsequent vision loss.
• Address accompanying conditions such as high blood pressure or kidney issues with your doctor.
• Regularly visit an eye specialist for ophthalmoscopic examinations to detect diabetic retinopathy before significant vision changes occur.
• Immediately contact your eye doctor if you notice any vision changes in one or both eyes.
• Prompt treatment of diabetic retinopathy can avert vision loss.

When to See a Doctor?

Seek immediate medical consultation if you experience:

• Gradual vision decline
• Sudden vision loss
• Floaters (thread-like spots or lines floating in your vision)
• Blurred vision or black areas in your visual field
• Eye pain and redness

While other eye diseases can present similar symptoms to diabetic retinopathy, it is crucial to get checked promptly without waiting for a scheduled follow-up appointment.

Looking for more information about other diseases? Click here!