Diabetic Macular Edema: Symptoms and Treatment

Diabetes mellitus causes global disease and continues to be a public health threat. Among Americans aged 18 to 64, it is the leading cause of new blindness cases annually. Diabetes triggers diabetic retinopathy, damage to the blood vessels and nerve at the back of the eye. It may lead to diabetic macular edema, the leading trigger of blindness in patients with diabetes. Early and regular eye evaluations can identify these conditions before blindness ensues.

Current estimates demonstrate that 9–12% of the U.S. population have diabetes mellitus (DM). The current U.S. population is just over 340,000,000 and climbing, according to the Worldometer. Therefore, as of August 2023, 31–40 million Americans currently have DM.

Ocular complications of DM

Much attention in healthcare is paid to preventing chronic diseases, especially the development of DM. Diabetes mellitus refers to individuals who either cannot make enough insulin (type 1) or cannot use insulin properly (type 2). When people with DM also have underlying conditions such as elevated triglycerides and cholesterol, they are at higher risk for stroke, kidney disease, heart disease, or blindness.

Diabetes mellitus afflicts over 30 million Americans annually. Once DM has developed, and often before diagnosis, chronic changes to the body, including ill effects on the kidneys, nerves, and eyes, have already occurred.

DME vs. diabetic retinopathy

People with DM are at risk for several conditions that negatively affect the eyes, including cataracts, open-angle glaucoma, diabetic retinopathy (DR), and diabetic macular edema (DME). Recognizing signs of eye problems early is crucial to preserve vision, prevent complications, and ensure one receives the eye healthcare they need.

The retina makes up the innermost portion of the eye. It is the connection between the outside world and the brain. It takes images we look at and processes them (through photoreceptors) so that we can visually understand and interpret the world around us. Vision can be distorted or lost without a well-functioning, intact retina, and secondary to DM, we see chronic eye changes that may permanently affect one’s ability to see the world around them.

Diabetic retinopathy (DR)

Retinopathy is a weakening of the retina’s blood vessels. This can occur in babies born prematurely as well as secondary to DM. Diabetic-induced retinopathy (DR) also impairs the neurological workings of the retina — blindness results without proper treatment. Thus, patients at risk of DM or with active disease want to ensure that they receive regular eye exams and follow all healthcare provider recommendations to manage their DM or pre-DM state.

The damage caused to the eyes and specifically the retina in patients with DM is multifactorial and a combination of nerve and inflammatory insults combined with the metabolic consequences of the disease, triggered by the failure of sufficient sugar (energy) to make it into one’s cells.

Risk factors for DR

Risk factors for developing DR include clinical DM symptoms and disease duration. Some people may be genetically more predisposed to the development of DR, and anyone with concurrent conditions or risk factors involving any of the following is at higher risk:

Diabetic macular edema (DME)

According to the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR), DME is the most common cause of vision loss in diabetic patients. Further, without the proper treatment, up to 30% of patients will lose at least three fields of vision within the first three years. Without treatment, it will lead to permanent vision loss.

Patients with DR may subsequently develop DME, a fluid buildup in the back of the eye, centrally located in the macula. The macula is a key structure at the retina’s center and is crucial to one’s vision. As fluid builds up, it causes swelling, and the macula thickens, leading to blurred vision. It can develop at any time, but unless routine eye visits occur, it can be missed until it is already advanced. If fluid continues to build up without treatment, it will cause permanent blindness.

Symptoms of DME/DR

The symptoms of DME (and DR) vary from patient to patient. However, signs typically include changes in vision, including blurriness or double vision. Additionally, patients may notice the following:

• Spots in one's vision
• Distortion
• Difficulty with fine details or working
• Flashes

DR and DME diagnosis

Diabetic retinopathy and DME diagnoses are based on a thorough physical exam of the back of the eye, often with special equipment, stains, and other means. Changes in one’s vision may occur before the onset of visible changes to the back of the eye, further emphasizing the need to control DM as soon as possible and before changes worsen, risking vision loss.

People diagnosed with diabetes should have their eyes evaluated as soon as possible and then at regular intervals (depending on the type of diabetes you have) thereafter.

Treatment and prevention are possible

Thankfully, because DR and DME are so common, numerous treatment options are available or currently in development. So, with early recognition and intervention, blindness doesn’t have to be a given. If you or a family member is diagnosed with DM, along with all the education, nutritional information, medication literature, and other materials and advice you receive, schedule an appointment with the ophthalmologist ASAP. Follow up regularly and follow all medical recommendations to maintain control of your DM to help prevent complications such as vision loss.

The thought of vision loss is a scary one. Not only does it confer the obvious, the inability to see the world around us, but it can be accompanied by a sense of losing one's independence. This often negatively affects the quality of life and may lead to depression and increased anxiety. However, receiving a DR and even a DME diagnosis doesn't mean that blindness is inevitable. You may need to step up your DM management and prioritize it. However, you can take measures, including improving your DM control and talking with healthcare providers, dietitians, and your ophthalmologist to permit vision preservation.