Diabetic Retinopathy – Signs and Symptoms

The first sign of diabetic retinopathy (DR) is often blurry vision, but this disorder can present with a number of symptoms. Read on to learn more.

Blurry vision

Blurry vision is the first tangible symptom of diabetic retinopathy. The human eye is supplied by blood vessels through the optic nerve, which travels throughout the inside of the eye up to muscles at the front of the eye that control eye functioning. DR is the leaking of blood and other fluids from these blood vessels into the eye. This causes the tissues surrounding the inside of the eye to swell, resulting in blurred vision.

However, it should be noted that it is possible for this first stage of diabetic retinopathy to show no signs or symptoms and go completely undetected. This is known as non-proliferative diabetic retinopathy (NPDR).

Non-proliferative diabetic retinopathy (NPDR)

Non-proliferative diabetic retinopathy has no symptoms. Patients can have normal vision and will only know that there is a problem through fundus photography. This will identify tiny aneurisms in the eye. Diagnosis is more common when symptoms are reported during the second stage referred to as proliferative diabetic retinopathy (PDR).

What are the symptoms of diabetic retinopathy?

Proliferative diabetic retinopathy (PDR) is the second stage of this condition. The more apparent symptoms during this stage enable a diagnosis. During this stage, abnormal new blood vessels form at the back of the eye. This is referred to as neovascularization. These abnormal vessels are fragile and can easily burst and bleed, leading to blurry vision. This is referred to as vitreous haemorrhage.

Such bleeding may be very minor in the first instance leaving just a few specks of blood that will go away after a few hours. These may cause a few floating spots in a person’s visual field but will not be permanent. Over the next few days or weeks, the bleeding from these fragile vessels will increase, leading to blurry vision. In the worst case, patients will only be able to differentiate between dark and light in the affected eye. This damage can take years to clear up on its own and may not clear up at all. These haemorrhages tend to reoccur, most frequently during sleep.

In severe cases, damage is caused to the macula. This is at the centre of the retina and is linked to accurate vision.

Diagnosis

Assuming the condition is at the second stage, a doctor will use a funduscopic exam to look for signs of damaged arteries. The funduscopic exam can see inside the structures of the eye. The doctor will look for “cotton wool spots” which are fluffy white patches on the retina caused by damage to nerve fibres.  These patches indicate accumulations of nerve material within the optic nerve and are an indication of haemorrhage.

Doctors will also look for flame haemorrhages and dot-blot haemorrhages.

Symptoms

Diabetic retinopathy is the leading cause of blindness in the United States. Symptoms include blurred vision, difficulty seeing colours, floaters, and even total loss of vision.

Causes

Diabetic retinopathy causes are well understood. Chronically high blood glucose levels weaken and damage the small blood vessels within the eye. The resulting haemorrhages reduce the amount of oxygen available to the retina leading to the growth of abnormal vessels.

Treatment

There are three main treatments for diabetic retinopathy. Most patients will see success and not experience blindness. The first of these is laser surgery.

Laser surgery

For proliferative diabetic retinopathy, laser surgery can be used to treat the abnormal vessels growing within the eye.

Injections

For more severe cases of proliferative diabetic retinopathy, injection of corticosteroids or other agents into the eye can be used to repair the macula. These injections are used in more severe cases when sight is threatened.

Vitrectomy

If retinopathy is too advanced, laser surgery may not be possible. In such cases, a surgery referred to as a vitrectomy is performed to remove blood or scar tissue from the eye.

What are the four stages of diabetic retinopathy?

To better understand the progression of this condition and which course of treatment to pursue, the following section of this article describes the four stages of diabetic retinopathy:

Mild Nonproliferative Retinopathy

At this initial stage, tiny parts of the vessels may leak, and these leakages are called microaneurysms. These are very small instances of swelling in the area’s tiny blood vessels. Patients are unlikely to experience symptoms.

Moderate Nonproliferative Retinopathy

Moderate Nonproliferative Retinopathy manifests as blocking of the blood vessels that nourish the retina. Again, patients are unlikely to experience any major symptoms.

Severe Nonproliferative Retinopathy

At this stage, a greater number of blood vessels become blocked, depriving the retina of blood supply and therefore oxygen. The blocked areas of the retina send messages to the body for the growing of new blood vessels.

Proliferative Retinopathy

At the fourth stage, the messages sent by the retina for new blood vessels are responded to and new blood vessels grow. These vessels are abnormal and fragile, growing along the retina and along the inside of the eye. Due to their fragility, they are likely to leak blood. These haemorrhages cause noticeable symptoms such as loss of vision and, if untreated, possible blindness.

Summary

Diabetic retinopathy is a serious condition that affects a significant proportion of diabetic patients. It is caused by chronically high blood glucose levels and is the body’s way of responding to a lack of oxygen supplied to parts of the eye. Though serious, patients need not experience long-term loss of vision provided adequate medical care is taken. Regardless of the stage, several options are available for diagnosis and treatment with few patients having to experience long-term loss of vision or blindness.