Eye-specific measurements may be better at predicting conditions that can cause vision loss in people with diabetes than standard measures of diabetes control and general health, according to a new study published in the journal Diabetes Care.
Eye complications of diabetes, such as diabetic retinopathy, are a leading cause of blindness worldwide. They typically develop when tiny blood vessels in the eyes become damaged due to elevated blood glucose levels, which can lead to different kinds of dysfunction in the various structures of the eyes. Unfortunately, many people with diabetes aren’t aware that they’re developing eye complications until they actually experience vision problems — a point in time where it’s much harder to address these problems than earlier in the course of their development. But right now, aside from standard vision and eye exams, there aren’t many eye-specific indicators of potential vision problems in people with diabetes. Most health care providers rely instead largely on overall measures of diabetes control, such as A1C (a measure of long-term blood glucose control), to estimate a person’s risk for vision problems.
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For the latest study, researchers looked at 172 people with type 2 diabetes and mild diabetic retinopathy, whose ages ranged from 42 to 82 and whose A1C level was no higher than 10%. Participants were followed for five years or until they developed at least one of the following problems: clinically significant macular edema (CSME), center-involved macular edema (CIME), or proliferative diabetic retinopathy (PDR). Macular edema is the buildup of fluid in the macula, an area of the eye at the center of the retina. Proliferative diabetic retinopathy is an advanced form of this complication. During the study period, participants received a complete eye exam each year, which included assessment of needed vision correction, a slit lamp exam, eye pressure measurement, color vision assessment, and optical coherence tomography (which creates a three-dimensional image of the retina). Each participant had only one eye examined as part of the study.
Several factors linked to increased risk of eye problems
By the end of the study, 14 participants (8%) had developed CSME, 10 participants (6%) had developed CIME, and four participants (2%) had developed PDR. One of these participants developed both CSME and PDR. By looking at as much data from participants as possible, the researchers found several factors that predicted the development of these eye problems. Those who developed CSME or PDR tended to have a younger age, a lower body-mass index (BMI, a measure of body weight that takes height into account), higher A1C levels, and higher LDL (low-density lipoprotein, or “bad”) cholesterol levels. Those who developed CIME tended to have lower blood pressure.
When it came to measurements from eye exams that predicted the development of eye problems, the researchers found that higher values of microaneurysm turnover (MAT) helped predict CSME and PDR, while higher central retinal thickness (CRT) helped predict both CIME and CSME. These measurements remained significant predictors of eye problems even after adjusting for other factors, such as age, A1C, and BMI. Adjusting for age reduced the predictive value of these measurements the most, meaning that both these measurements and the risk for eye problems increased with older age.
The researchers concluded that certain measurements from eye exams would help predict the development of macular edema or worsening diabetic retinopathy in people with mild diabetic retinopathy, beyond what standard measurements like age, A1C, or BMI can help predict. The researchers noted that relatively few people int he study developed the eye problems they were interested in studying, possibly because they had fairly well controlled diabetes. More studies that include people whose diabetes isn’t as well controlled could help researchers find out if the same measurements from eye exams help predict eye problems in this group, as well.
Want to learn more about keeping your eyes healthy with diabetes? Read “Diabetic Eye Exams: What to Know,” “Eating for Better Vision and Healthy Eyes,” and “Keeping Your Eyes Healthy” and watch “Diabetes and Your Eyes.”