title: Retinal hemodynamics in early diabetic macular edema.
abstract: The objective of this study was to establish the baseline retinal hemodynamic characteristics of stratified groups of diabetic patients at increasing risk for the development of diabetic macular edema (DME). Group 1 had 50 control subjects, group 2 had 56 diabetic patients without clinically visible retinopathy, group 3 had 54 diabetic patients with microaneurysms and/or hard exudates within two disc diameters of the fovea in the absence of clinically manifest DME, and group 4 had 40 patients with clinically manifest DME. Retinal hemodynamics (diameter, velocity, maximum-to-minimum velocity ratio, and flow) were assessed. Intraocular pressure, blood pressure, and relevant systemic markers of diabetes control and complications were also undertaken. The maximum-to-minimum velocity ratio was elevated with increasing risk of clinically significant DME (P < 0.0001). No significant differences were found between the groups with respect to diameter, velocity, or flow. The maximum-to-minimum velocity ratio was correlated to age, duration of diabetes, blood pressure, pulse rate, intraocular pressure, and serum potassium levels. In conclusion, the maximum-to-minimum velocity ratio was significantly increased with increasing risk of development of DME. Retinal arteriolar hemodynamics were positively correlated to age, duration of diabetes, and blood pressure. These findings suggest a reduction in the compliance (i.e., an increase of vascular rigidity) of the arteriolar circulation with increasing risk of DME.
authors.affiliation: Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario M5T 2S8, Canada.
authors.forename: Kit
authors.initials: K
authors.lastname: Guan
authors.forename: Chris
authors.initials: C
authors.lastname: Hudson
authors.forename: Tien
authors.initials: T
authors.lastname: Wong
authors.forename: Mila
authors.initials: M
authors.lastname: Kisilevsky
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Nrusimhadevara
authors.forename: Wai Ching
authors.initials: WC
authors.lastname: Lam
authors.forename: Mark
authors.initials: M
authors.lastname: Mandelcorn
authors.forename: Robert G
authors.initials: RG
authors.lastname: Devenyi
authors.forename: John G
authors.initials: JG
authors.lastname: Flanagan
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D003930:Diabetic Retinopathy / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D008269:Macular Edema / Q000209:etiology* / Q000503:physiopathology; D008875:Middle Aged; D015999:Multivariate Analysis; D012160:Retina / Q000503:physiopathology*; D012307:Risk Factors