What Is Diabetic Retinopathy?

Diabetic retinopathy is a critical eye condition that affects individuals with diabetes. It occurs when high blood glucose levels damage the blood vessels in the retina, leading to vision impairment and, if left untreated, even blindness. In this comprehensive article, we will explore the disease in detail including management and treatment options and we will also cover some of the frequently asked questions. By understanding this condition better, individuals can take preemptive steps to prevent its onset and seek timely medical intervention.

Overview

Diabetic retinopathy is a progressive eye disease that causes vision loss and blindness in people primarily affected by diabetes. The vital component of an eye, the retina, is responsible for the transmission of visual information to the brain. Due to prolonged exposure to high blood sugar levels, the retina may suffer damage. Over time, this can decline the functionality of the eyes by blocking the blood vessels, leading to poor circulation and impaired vision. According to the National Eye Institute, people with diabetes must get their comprehensive diabetic eye screening test done at least once a year.¹

Types of diabetic retinopathy

There are two main types of diabetic retinopathy - non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). NPDR is an early stage of diabetic retinopathy which is characterised by increased deposition of exudates and fluid within the retina.²  Moreover, it is also manifested as occlusion (blocking) of tiny blood vessels in the retina, causing reduced blood flow.³

Proliferative diabetic retinopathy, on the other hand, is a more advanced stage where new, abnormal blood vessels grow on the retina's surface, leading to bleeding and scarring. This state also occurs when the retina gets detached from the underlying epithelial pigment due to the traction present in the retinal membranes.⁴

The most common cause of vision loss in diabetic retinopathy is macular oedema, which is described as the swelling of the macula due to the accumulation of fluid in the retina. This macular oedema can result in distorted visual images and reduced visual sharpness.²

Causes/risk factors of diabetic retinopathy

This table includes some common causes and risk factors associated with diabetic retinopathy, but it is not an exhaustive list. It's essential to consult with a healthcare professional for a comprehensive understanding of the condition and its causes. Moreover, if you have one or more causes/risk factors of diabetic retinopathy, it is imperative to take appropriate measures to prevent or delay the progression of the disease. 

Signs and symptoms of diabetic retinopathy

Individuals with diabetic retinopathy usually show no symptoms in the early stages. However, with the progression of the disease, people may experience certain symptoms. These include:

• Fluctuating vision
• Floaters
• Empty/dark areas in the visual field
• Impaired colour recognition
• Blurred vision
• Difficulty reading/seeing in dim light or seeing faraway objects

It is recommended by the National Eye Institute to get a medical consultation and treatment as soon as possible because, without medical attention, blood vessels may begin bleeding which may cause further complications.¹

The signs observed on the fundus examination include: 

• Microaneurysms (lesions)
• Soft and hard exudates
• Microvascular abnormalities 
• Venous (dilation and bleeding) and arterial (peripheral narrowing) changes
• Haemorrhages⁵

Diagnosis of diabetic retinopathy

As recommended by the National Eye Institute, a detailed diabetic eye screening test is used to diagnose diabetic retinopathy. There are various tests undertaken in the comprehensive exam which are as follows: 

1. Visual Acuity Test: This test is performed to examine the clarity and sharpness of an individual’s vision through an eye chart. This test helps determine the level of visual impairment⁶
2. Dilated Eye Exam: For this exam, dilating eye drops are used to enlarge the pupils. This is done to get a better picture of the internal structures of the eye including the retina which helps to diagnose retinopathy
3. Optical Coherence Tomography (OCT) Scan: This is a non-invasive procedure done to view eye structures. This allows professionals to assess the size of the retina and detect any abnormalities within it
4. Fluorescein Angiography: An invasive and costly procedure that detects changes in the vascular system of the eye due to the rupture of the retinal barrier that prevents the accumulation of fluid in the retina⁷

Early diagnosis of diabetic retinopathy is significant to prevent the complications of the disease and eventually reduces the risk of vision loss and blindness.

Complications

Diabetic retinopathy, if left untreated, can lead to serious complications which may even steal an individual’s sight and vision. These complications are: 

1. Diabetic macular oedema: The central part of the retina is called the macula which is responsible for vision sharpness. Due to excessive accumulation of fluid, the macula swells which may result in blurred vision, double views, and increased floaters
2. Vitreous Haemorrhage: The new blood vessels developed in the proliferative diabetic retinopathy may rupture and bleed into a gel-like substance. This gel substance (vitreous gel) may fill the centre of the eye causing dark spots and vision impairment
3. Retinal Detachment: The new blood vessels developed are weak and thus, they may detach the retina from the underlying pigment
4. Neovascular Glaucoma: This is manifested as increased eye pressure due to the burden of new blood vessels developed over the retinal surface

Early detection and appropriate medical intervention minimise the risk of complications associated with diabetic retinopathy.

Management and treatment for diabetic retinopathy

The management and treatment of diabetic retinopathy aim to slow down its progression, prevent further damage, and restore vision whenever possible. Managing diabetes through tight blood sugar control, blood pressure control, and cholesterol management is crucial. Additionally, lifestyle modifications such as regular exercise, a healthy diet, smoking cessation, and limited alcohol consumption can significantly reduce the risk and progression of diabetic retinopathy.⁸

Treatment options for diabetic retinopathy include: 

1. Laser Photocoagulation: Laser treatment helps seal leaking blood vessels
2. Intravitreal Injections: Injections slow down the growth of abnormal blood vessels
3. Vitrectomy: A procedure to remove blood and scar tissue from the eye and restore vision²

FAQs

How can I prevent diabetic retinopathy?

To prevent diabetic retinopathy, it's essential to manage diabetes diligently by maintaining blood sugar, blood pressure, and cholesterol within recommended limits. Routine eye check-ups play a pivotal role in detecting any early signs and ensuring prompt treatment. Embracing a healthy lifestyle, encompassing a nutritious diet, consistent physical activity, and steering clear of smoking and excessive alcohol, can greatly diminish the chances of contracting diabetic retinopathy.

How common is diabetic retinopathy?

A study reports that the incidence of diabetic retinopathy is estimated to be 34.6%, worldwide.⁹ In the UK, the general prevalence of the disease has gradually increased in the last ten years. Therefore, in the UK, it is advised to get diabetic retinopathy screening annually using digital technologies for individuals who are more than 12 years of age and have diabetes.

When should I see a doctor?

For those with diabetes, an annual comprehensive dilated eye exam with an eye care specialist is highly advised. If you encounter vision alterations, like blurriness, the appearance of floaters, or any visual impairments, it's essential to promptly consult a healthcare expert. Early identification and appropriate care can halt additional complications and maintain your eyesight.

Summary

Diabetic retinopathy is a complication of diabetes whereby the eyes of affected individuals are impacted. It is caused by prolonged exposure to high blood sugar levels, which damages the blood vessels in the retina. Understanding the different types, causes, signs and symptoms, management and treatment options, diagnosis procedures, associated risk factors, and potential complications of diabetic retinopathy is crucial for individuals with diabetes. By prioritising proper diabetes management, adopting a healthy lifestyle, and seeking regular eye examinations, individuals can take proactive steps to prevent diabetic retinopathy or detect and manage it in its early stages, preserving their vision and overall eye health.