Information - Diabetic Retinopathy

The retina is a layer of special light-sensitive tissue at the back of the eye that sends nerve impulses up the optic nerve to the brain. This process is responsible for vision. If the retina becomes damaged by disease, then the quality of vision is affected or even lost.

In people with diabetes, tiny blood vessels in the retina may become diseased and damaged due to the effects of diabetes. Diabetes can cause the blood vessels to swell and leak blood or fluid around the retina. As they heal, scar tissue forms on the retina. These problems can damage the retina so badly that the retina functions less effectively and vision is impaired.

Diabetic retinopathy usually affects the retina slowly. All people with diabetes are at risk of developing retinopathy to some degree, whether or not they are insulin dependent. If retinopathy is not treated, the patient risks serious damage to vision that can lead to blindness.

If the retina becomes damaged so badly that sight is affected, no surgical or medical treatment can restore the lost vision. Diabetic retinopathy doesn’t cause pain, and the person may not notice any changes to vision until the disease has caused severe damage to the retina. This is why a person with diabetes should have an eye examination with their optometrist every year.

 

 

The two types of retinopathy are non-proliferative (or “background) retinopathy and proliferative retinopathy.

Non-Proliferative Retinopathy

This is the early stage of the disease and typical signs include tiny areas of bleeding or leaking from blood vessels. Most people don’t notice changes in vision at this stage, although damage may be occurring; hence the need for regular exams by your optometrist.

Proliferative Retinopathy

As the disease worsens, new blood vessels grow in an attempt to provide a better blood supply for the retina. As these blood vessels are weak and bleed easily without warning into the eye, vision becomes blurred. Impaired vision can take weeks or months to improve as the blood is slowly restored by the body.

Other Eye Diseases

People with diabetes have a higher risk of developing other eye diseases. Also, cataracts tend to develop at a younger age in a diabetic person. The longer the person has had diabetes, the greater the risk of cataract or glaucoma.

Diabetic retinopathy cannot be fully prevented, but the risk of impaired vision or blindness can be greatly reduced by good management of diabetes. People with diabetes who keep their blood sugar levels, blood fats and blood pressure as normal as possible have less risk of retinal disease in the long term.

Diagnosis

Your optometrist will give you a vision test and a full eye examination. Drops are put in the eyes to enlarge the pupils. A scope with a bright light is used to examine the retina. Fluid pressure inside the eye is checked, and photographs of the retina may be taken. An OCT (optical cohence tomography) machine can also be used to determine if signs of retinal swelling due to leaky blood vessels is evident. Another test called fluorescein angiography may also be needed in some cases where a special yellow dye is injected into a vein in the arm or hand entering the bloodstream, whilst photos are taken to detect whether dye has leaked from the retinal blood vessels. This however must be performed by a retinal specialist.

Surgery to Treat Retinopathy

There are two surgical treatments for diabetic retinopathy, slowing or preventing further vision loss but unfortunately, not curing it.

·        Laser Treatment (Photocoagulation): Drops to enlarge the pupil are put in your eye, giving the optometrist a better view of the retina. A special lens is held to the eye to stop the eye blinking and to help the optometrist see the retina. The retinal specialist uses the laser beam to seal leaking blood vessels and to shrink abnormal vessels. The multiple, more complicated and longer treatment to shrink blood vessels in proliferative disease can cause discomfort. When a lot of blood has leaked into he eye, and vision doesn’t clear or the retina has detached, a vitrectomy may be needed.

 

 

·        Vitrectomy: The surgeon uses an operating microscope to see the retina and other structures inside the eye. Tiny cuts are made in the white of the eye and special instruments and a bright fibreoptic light are then inserted into the vitreous cavity. Vitreous contaminated with blood is removed with a hand-held cutting device and replaced with a clear salt solution similar to the liquid removed from the eye that absorbs over time, slowly replaced by fluid produced by the eye. The surgeon may remove retinal scar tissue if any is present and causing a problem. The cuts are closed with fine stitches that dissolve and don’t need to be removed.

 

 

Recovery after Laser Treatment or Vitrectomy

After laser treatment, the pupils will remain dilated for a few hours, and vision may be blurred temporarily. You may have a headache if the treatment was length and the eye may feel irritated for the rest of the day. Pain-relieving medication can be taken. You may notice that vision is not as good as it was before treatment, but vision usually improves in a few days or weeks.

After vitrectomy, you may experience some discomfort for several days after surgery and your eye will be red and feel scratchy. The redness will gradually disappear. Some pain is normal but pain-relieving medication should control this. There may also be some swelling around the eye. You may need to wear and eye patch for a few days or weeks and antibiotic eye drops are used to protect against infection. Avoid bending, strenuous activity and lifting heavy objects for one week.

Possible Complications of Surgery

While your eye doctor makes every attempt to minimise risks, complications can occur. It is important that you have enough information about side effects and complications to fully weigh up the benefits and risks of surgery. If you have particular concerns about possible complications, discuss them with your optometrist. If vision worsens following treatment, it may be caused by the retinopathy rather than the treatment. Any serious complication could cause poor vision, blindness or even loss of the eye.

General risks of surgery:

·        Infection – can be treated with antibiotics.

·        Bleeding that may require reoperation.

·        Complications related to the anaesthesia.

Possible side effects of laser treatment:

·        Vision can be blurred for weeks, although in most patients it usually improves within hours or days.

·        Some loss of side (peripheral) vision.

·        Increased sensitivity to glare.

·        Central vision may not be as good as before – only temporary.

·        A slight risk of damage to the macula; this may reduce central vision.

Possible side effects of vitrectomy:

·        Quality of vision may not be as good as before.

·        Bleeding into the vitreous may continue.

·        Intraocular gas used during vitrectomy may promote (or worsen) a cataract and may cause elevated pressure in the eye (glaucoma).

·        Silicone oil used in vitrectomy may promote (or worsen) a cataract, cause glaucoma and damage the cornea.

·        Within 6 months of vitrectomy, about one eye in every 4 that have been operated on develops some degree of cataract.

·        Scarring or glaucoma after the operation can cause reduced vision or blindness.