May 21, 2024

Diabetic Retinopathy: A Silent Threat To Vision

Diabetes is a chronic condition that affects millions of people worldwide. While diabetes is commonly known to impact organs like the kidneys, heart and nerves, one organ that is severely damaged by prolonged high blood sugar levels is the eyes. Diabetic retinopathy refers to damage caused to the retinal blood vessels due to diabetes. It is a leading cause of blindness among working-age adults. In this article, we explore the key facts about diabetic retinopathy, its symptoms, stages of progression and treatment options.

What is diabetic retinopathy?
High blood sugar levels over time can damage the tiny blood vessels inside the retina (back portion of the eye). The retinal blood vessels may swell and leak fluid or they may become blocked. Diabetic retinopathy occurs when these small blood vessels in the retina are damaged due to long standing high blood sugar levels.

The exact cause of damage is not clearly understood, but long-term high blood sugar is known to induce various changes like thickening of the basement membrane of blood vessels and appearance of acellular capillaries. These changes interfere with the normal functioning of blood vessels leading to progression of retinopathy. It generally takes 5-10 years after the diagnosis of diabetes for any signs of retinopathy to appear.

Stages of Diabetic Retinopathy
Diabetic retinopathy progresses through different stages with varying levels of severity:

Non-Proliferative Retinopathy
In the early stages called non-proliferative diabetic retinopathy (NPDR), microaneurysms (tiny bulges in weak blood vessels), hemorrhages (bleeding), hard exudates (leaked lipid deposits) appear as signs of damage. The NPDR stage is further categorized into mild, moderate and severe forms.

Proliferative Retinopathy
The most advanced stage is called proliferative diabetic retinopathy (PDR). In this stage, the loss of blood vessels triggers the growth of new fragile blood vessels (neovascularization) on the surface of the retina and at the optic disk. These new blood vessels are more susceptible to bleed and lead to scarring which can detach the retina. Scarring can also cause traction retinal detachment where the retina is pulled from its position by the scar tissue. This can cause permanent and profound vision loss.

Symptoms of diabetic retinopathy
Early stages may not show any visible symptoms. But as it progresses, symptoms may include:

– Blurred or fuzzy vision
– Difficulty in seeing clearly in dim light or night time
– Floaters (spots or wisps in vision)
– Flashes of light in the field of vision
– Poor night and side vision
– Dark or empty areas in the field of vision
– Perception of straight lines as wavy

These symptoms may appear gradually or suddenly, depending on the severity and stage of retinopathy. Anyone with diabetes should get regular eye screening tests done to detect retinopathy early even before symptoms develop.

Risk factors for development
Some risk factors that increase the chances of developing diabetic retinopathy include:

– Long duration of diabetes – Risk starts rising after 5 years of diagnosis and keeps increasing with time.
– Poorly controlled blood sugar levels – Studies show intensive control can reduce risk by 40%.
– High blood pressure – Uncontrolled hypertension further damages retinal blood vessels.
– High cholesterol levels
– Pregnancy – Rapid fluctuations in hormones and blood sugar levels during pregnancy can worsen retinopathy in diabetic women.
– Kidney disease – Diabetics with chronic kidney disease have higher risk.
– Genetic factors
– Obesity
– Smoking

People with both type 1 and type 2 diabetes are at equal risk of developing retinopathy. So ensuring tight blood sugar and blood pressure control is key to reducing the risk.

Diagnosis and screening
Diabetic retinopathy can only be diagnosed by a comprehensive dilated eye exam by an ophthalmologist. For screening and periodic monitoring, the following tests may be used:

– Dilated fundus exam – Eye drops are used to dilate the pupil allowing internal examination of the retina using an ophthalmoscope or slit lamp bio-microscope. This remains the gold standard.

– Fundus photography – High resolution photos of the retina are captured and studied for signs like microaneurysms, hemorrhages, exudates etc.

– Optical coherence tomography (OCT) – A non-invasive imaging technique that uses light waves to capture high resolution cross sectional retinal images. It can detect signs not visible on fundus exams like opaque swelling.

– Fluorescein angiography – A dye is injected intravenously and its progress through the retinal vessels is photographed under ultraviolet light. It reveals vascular leakage and blockages very clearly.

All people with diabetes are recommended to undergo a comprehensive dilated eye exam at the time of diagnosis and then annually to screen for retinopathy. More frequent monitoring may be needed depending on severity and progression. Early detection and timely treatment are key to preserving vision.

Treatment approaches
Treatment is aimed at stopping progression of retinopathy and preserving vision. Management involves:

– Strict blood sugar and blood pressure control – This remains the cornerstone of management to prevent and slow progression.

– Laser photocoagulation surgery – laser beams are carefully aimed at areas of retina leaking fluid to seal leaky vessels and prevent further damage. It is very effective if done timely in early stages.

– Intravitreal injections – For diabetic macular edema, injections of anti-VEGF (Vascular Endothelial Growth Factor) drugs like ranibizumab, bevacizumab and aflibercept directly into the eye are effective. They inhibit VEGF which causes growth of abnormal fragile vessels.

– Vitrectomy surgery – For more advanced cases with bleeding, scarring or retinal detachment involving the macula, vitrectomy helps remove vitreous hemorrhage/scar tissue and reattach retina to vision.

– Cataract surgery – Common cataract surgery is safe in diabetics but requires intensive pre and post-operative sugar control.

With advances in therapy and early detection, diabetic retinopathy is no longer a inevitable cause of blindness in developed countries. But diligent management and close monitoring remain key. With increasing prevalence of diabetes, it remains a leading global cause of vision loss which can be prevented with awareness and timely screening.

1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it