This retrospective cohort study examines whether the kidney complications of diabetes (diabetic nephropathy) and blood-sugar control before surgery help predict swelling of the central retina, called pseudophakic macular edema (PME), after cataract surgery in people with type 2 diabetes.

PME is a common cause of blurred vision after otherwise successful cataract surgery, and people with diabetes are at higher risk. Doctors currently estimate this risk mainly from the HbA1c blood-sugar level and the stage of diabetic eye disease (retinopathy). It is not yet known whether diabetic kidney disease, measured by the urine albumin-to-creatinine ratio (UACR) and estimated kidney function (eGFR), adds independent information about who will develop PME.

Using medical records already collected during routine care at Thammasat University Hospital, the investigators will measure central retinal thickness on optical coherence tomography (OCT) scans before uncomplicated phacoemulsification cataract surgery with a lens implant, and again 1 and 3 months afterward. PME is defined as at least a 30% increase in central macular thickness. Patients with and without baseline diabetic nephropathy will be compared, and statistical modeling will identify the best preoperative HbA1c threshold for predicting PME.

The results are intended to improve preoperative risk counseling and to help identify diabetic patients who may need closer monitoring after cataract surgery. Because only existing records are used, the study involves no additional visits, tests, or risks for patients.