Patients with diabetes face a higher risk of vision problems after cataract surgery if their blood sugar levels are not well controlled, according to new research published in Clinical Ophthalmology.
The study, led by Rui Ding and colleagues at Lanzhou Bright Eyesight Hospital in China, looked at the connection between blood glucose levels and two common eye issues after cataract surgery: cystoid macular edema (CME) and central macular thickening (CMT).
“Macular edema after cataract surgery can affect vision, especially in older diabetic patients,” the researchers wrote. They added that keeping blood sugar between 80 and 180 mg/dL after surgery appears to lead to better outcomes. Still, few studies have closely examined how post-surgery blood sugar levels affect complications.
To explore this, Ding and colleagues analyzed medical records from 80 diabetic patients who had cataract surgery and intraocular lens (IOL) implantation between December 2018 and December 2023.
The patients were split into two groups:
- Intensive treatment group (56 patients): Blood sugar well-controlled with HbA1c at or below 7%. These patients used both insulin and oral medications.
- Standard treatment group (24 patients): HbA1c above 7%. These patients used only oral medications.
Results showed that in the standard group, central macular thickness increased significantly at 3 and 6 months after surgery compared to before surgery. In the intensive group, CMT rose slightly after surgery, but not significantly.
At the start of the study, no patients had CME. In the standard group, CME improved at 3 and 6 months compared to one week after surgery. In contrast, the intensive group had only a mild increase in CME, which was not statistically significant.
The team also analyzed how well HbA1c levels could predict macular changes. They found that an HbA1c level of 6.125 mmol/L or higher could signal a higher risk for CMT thickening and CME. This threshold had a sensitivity of 43.24% and a specificity of 88.37%.
The researchers proposed that poor blood sugar control may limit oxygen delivery to tissues, worsen inflammation, and increase stress on the eye after surgery. These factors could damage blood vessels in the eye, leading to swelling and thickening of the macula.
Based on their findings, the researchers recommend keeping HbA1c below 7% after surgery to support better healing and reduce complications.
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