Kim KL, et al. - In this study with 30 patients who have diabetic macular edema (DME) and 35 controls, researchers compared vitamin D levels in serum and aqueous humor (AH). Hypertension, dyslipidemia, or diabetes mellitus without diabetic retinopathy were present as underlying diseases in one-third of the control group. A higher AH level of vitamin D was found in eyes with DME vs control eyes. A significant association of AH vitamin D level with the presence of DME was evident. The DME group vs control group showed no significant difference in serum vitamin D levels. Systemic vitamin D level had no impact on localized vitamin D level in the eye. Localized vitamin D level in the eye could be an indicator of DME severity.