Diabetic Retinopathy

People with diabetes can have an eye disease called diabetic retinopathy. If you have diabetes mellitus, your body does not properly regulate your blood sugar levels. High blood-sugar levels can damage blood vessels throughout your body, but especially vulnerable are the blood vessels in the retina (nerve layer at the back of the eye). The blood vessels of the retina can swell and leak, or they can constrict, thereby prohibiting blood flow. Sometimes abnormal new blood vessels grow on the retina. Any of these changes can steal your vision.

Diabetic retinopathy can be broadly categorized into two types:

Diabetic retinopathy is a progressive process, and, in general, the progression goes from non-proliferative to the more severe proliferative diabetic retinopathy, though this is not inevitable.

What is non-proliferative diabetic retinopathy?

Non-proliferative diabetic retinopathy (NPDR) is commonly known as background retinopathy.  It is an early stage of diabetic retinopathy. Many people with diabetes have it, and it usually does not affect their vision.

In this early stage, tiny blood vessels within the retina begin to leak blood or fluid. This leaking fluid causes the retina to swell and/or to form hard deposits called exudates.

As vision becomes diminished, it is the result of macular edema and/or macular ischemia.

What is proliferative diabetic retinopathy?

Proliferative diabetic retinopathy (PDR) may cause more severe vision loss than NPDR because it affects both central and peripheral vision.

As diabetic retinopathy progresses, the retinal blood vessels continue to weaken, narrowing and eventually closing. As the blood vessels close, they can no longer carry oxygen to the retinal tissue. Once deprived of sufficient oxygen and nutrients to maintain normal health and functioning, the retina responds by attempting to compensate by growing abnormal new blood vessels – a process called neovascularization. The condition characterized by the presence of retinal neovascularization is known as proliferative diabetic retinopathy.

While new blood vessel growth, or neovascularization, might seem like a beneficial event, these new blood vessels are extremely fragile and tend to break easily, leading to hemorrhage. If left untreated, proliferative diabetic retinopathy will, in fact, result in hemorrhage that leads to scarring and ultimately to retinal detachment with profound vision loss. Proliferative diabetic retinopathy is treated with either laser treatment or laser treatment in conjunction with a surgical procedure called a vitrectomy. The retinal surgeon will perform a vitrectomy to remove the vitreous that has become filled with blood or scar tissue.

Sometimes it may be possible for patients to have proliferative diabetic retinopathy and neovascularization and yet still have good vision. It is critical that, to maintain good vision, neovascularization be treated as quickly as possible, even if it appears to be causing any vision loss.

The ophthalmologists at East Valley Ophthalmology can often diagnose and treat severe retinopathy before you are aware of any vision problems. A comprehensive medical eye examination, which includes a dilated retinal examination, is essential for detecting changes within your eye. Your ophthalmologist will dilate your pupil and examine the inside of your eye using special equipment and lenses. Additional support tests may be required depending on the severity of the retinopathy that is discovered. These may include color fundus photography, fluorescein angiography, and ultrasonography.

Unfortunately, because visual loss is often a late symptom of advanced retinopathy, many patients remain undiagnosed and are examined only after the optimal time for treatment has passed. Many complications can be prevented if retinopathy is detected early enough for treatment. The optimal time for treatment is before you experience visual symptoms.

Patients with diabetes must be diligent and attentive to their eye care throughout their lives. The American Diabetes Association (ADA) recommends yearly eye examinations for all diabetic patients to detect blood vessel leakage and the presence of diabetic retinopathy in its earliest stages. While screening photographs, even through a dilated pupil may be of some use, it is not a substitute for a comprehensive diabetic eye examination by an ophthalmologist.

Diabetic patients may also be more prone to other significant eye problems, such as glaucoma and cataracts; thus, a comprehensive eye examination is necessary. Depending on the severity and progression of diabetic retinopathy, it may be required to undergo an intravenous fluorescein angiogram (IVF) regularly to monitor and record any changes in retinal circulation. In general, most insurance carriers endorse and cover regular annual diabetic eye exams, including intravenous fluorescein angiography, as often as needed to help patients preserve their vision. High-quality diabetic eye care is a crucial component for all diabetic patients.

Treatments are highly effective in reducing vision loss associated with this disease. In fact, even people with advanced retinopathy have at least a 90 percent chance of keeping their vision if they get treatment before the retina is severely damaged. Treatments include:

Laser treatments:

Laser treatments are available for:

Are there any studies on laser treatments for diabetic retinopathy?

Three major clinical trials have conclusively demonstrated the value of argon laser photocoagulation surgery in reducing the rate of severe visual loss in patients with advanced diabetic retinopathy, as well as in earlier stages of the disease and for the treatment of macular edema. Earlier surgery for severe proliferative retinopathy and vitreous hemorrhage has also been recommended.

The aforementioned clinical trials have demonstrated that individuals who receive appropriate treatment are more likely to achieve better visual outcomes than those who do not. Panretinal scatter photocoagulation using the Argon laser reduces the rate of severe visual loss by over 50%. In this outpatient procedure, laser light is directed into the eye through a special contact lens held on the eye while the patient sits at a slit lamp. Between 1000 and 2000 burns, a fraction of a millimeter in size, are evenly placed across the entire peripheral retina. This destruction of retinal tissue causes the proliferating vessels to disappear by a poorly understood mechanism.

Laser treatment of clinically significant macular edema also substantially reduces the rate of subsequent visual loss. In this case, the leaking microaneurysms are treated directly with the argon laser to seal them, allowing the edema to be resorbed and preventing further vision loss. Vitrectomy and retinal detachment surgery may become necessary in cases of persistent, non-clearing vitreous hemorrhage and for traction retinal detachment due to scarring.

Vitrectomy

Instead of laser surgery, a vitrectomy may be needed to restore sight. A vitrectomy is a surgical procedure in which the vitreous humor gel that fills the eye cavity is removed and replaced with a special salt solution, providing better access to the retina. It is performed in cases where there is a significant amount of blood in the vitreous.

The ideal treatment for diabetic retinopathy is to prevent the disease from developing as much as possible, thereby maintaining vision and preventing severe vision loss in many patients. Strict control of your blood sugar will significantly reduce the long-term risk of vision loss from diabetic retinopathy. If high blood pressure and kidney problems are present, they need to be treated.