Diabetes and Your Eyes
Over 100 million adults in the U.S. are living with diabetes or have been diagnosed with prediabetes. Beyond that, as many as 8 million more may be undiagnosed in this country. Diabetes can wreak havoc on any organ of the body but is known to be devastating to a person’s vision, if not well controlled. Diabetic retinopathy (bleeding in the back of the eye), glaucoma, diabetic macular edema ( swelling of the macula), and cataracts, can all lead to irreversible blindness if not diagnosed and treated in a their early stages. 75% of those with diabetes will develop diabetic retinopathy within 20 years of their initial diagnosis. 80 % of these cases will progress from mild to moderate retinopathy over this same time period. If left untreated, 60% of these cases will progress to severe retinopathy leading to permanent vision loss. Slightly more than 10% of those patients will go on to develop diabetic macular edema. The macula is the most sensitive part of the retina, in that it is responsible for the central 10 degrees of your visual field and your ability to see detail. Anything that affects the normal anatomy of this area of your retina can be devastating to your vision.
Optometrists represent the frontline of diabetic eye care and patient education and are able to identify when diabetic retinopathy or diabetic macular edema have advanced to the point of needing the care of a retinal specialist. With the advent of newer technology, fundus cameras, and ultra-wide field retinal scanners, it is easier than ever to refer to retinal specialists much sooner than would have been recommended a decade ago, based on the clinical data we now have.
Earlier treatment with medications that stop the growth of leaky blood vessels in the retina has proven to be beneficial in patients with moderate to severe diabetic retinopathy. Remember, retinopathy is bleeding and leakage of fluid within the retina (the lining inside the eye); you can’t see through blood. Patients with moderate diabetic retinopathy without macular swelling can still progress rapidly to severe retinopathy before their next eye exam. As many as 30% of patients with moderate retinopathy without macular swelling will still progress to severe retinopathy within 1 year. All patients with clinically significant diabetic macular edema (swelling) should be referred in a timely fashion to preserve their central vision.
Monitoring the overall medical state of these patients is critical. Patients should make it a point to know their blood pressure status, cholesterol levels, and A1C levels, as all of these play a part in the health of the retina.
It is also important for the patient to realize that if they are under the care of a retinal specialist, they do not typically do evaluations of the front part of the eye; they are usually only evaluating and treating the back of the eye. So, for example, if a patient is also a glaucoma suspect, or has a corneal condition that needs regular follow-up, they still need to continue seeing their referring doctor to manage those conditions.
Cataracts are also known to grow more rapidly in diabetic patients vs. nondiabetics. Diabetics are 5 times more likely to grow a visually significant cataract compared to those without the disease. If the patient’s prescription has to be updated more than twice in a given year due to cataract growth, I will usually go ahead and refer that patient to a cataract surgeon to address the real problem. Once the cataracts are removed, it is usually safe to go ahead and update the prescription as long as other diabetic related eye issues are stable as well. As an optometrist, I would not prescribe new glasses to a patient with moderate to severe retinopathy until I received clearance from the retinal specialist that the patient’s retinal condition was stable enough to prescribe lenses.
Patients with diabetes need annual eye exams, whether they notice a change in their vision or not, as early diabetic retinopathy oftentimes does not noticeably affect their vision. Sadly, many of these patients are not compliant with their yearly exams. Keeping your annual appointment acts as a safety net in that you can be sure that you are receiving the care you need in a timely fashion.