Relationship of macular microcirculation and retinal thickness with visual acuity in diabetic macular edema.
OBJECTIVE
To assess perifoveal capillary blood flow velocity (BFV), capillary occlusion, and retinal thickness at the central fovea in diabetic patients with or without clinically significant macular edema; to examine the relationships of these variables with visual acuity (VA); and to identify their contributions to visual outcome and diabetic macular edema.


METHODS
Comparative cross-sectional prospective study.


METHODS
Diabetic patients with clinically significant macular edema (CSME) (n = 22), matched diabetic patients without CSME (n = 22), and healthy volunteers (n = 16).


METHODS
Capillary BFV was measured by fluorescein angiography using a scanning laser ophthalmoscope and was analyzed by the tracing method. Severity of perifoveal capillary abnormalities was classified by the size and outline of the foveal avascular zone (FAZ) and extent of foveal capillary loss. Macular thickness was measured by optical coherence tomography. Each subject underwent a complete ophthalmic evaluation, and best-corrected VA (BCVA) was converted to the logarithm of the minimum angle of resolution scale.


METHODS
Relationship of perifoveal capillary BFV, capillary occlusion, and foveal thickness with VA.


RESULTS
Best-corrected VA significantly differed among all 3 groups (P<0.0001). Best-corrected VA correlated negatively with BFV (r = -0.644, P<0.0001) among all subjects and positively with retinal thickness at the central fovea in diabetic patients with CSME (r = 0.640, P = 0.0013). There was a positive correlation between BCVA and severity in the size of the FAZ (r = 0.484, P = 0.0015), outline of the FAZ (r = 0.542, P = 0.0004), and extent of foveal capillary loss (r = 0.585, P = 0.0001) among all diabetic subjects. Multiple regression analysis showed that retinal thickness at the central fovea was the only variable that significantly predicted VA (standardized regression coefficient, 0.635; P = 0.0001).


CONCLUSIONS
Best-corrected VA was associated with perifoveal capillary BFV, severity of perifoveal capillary occlusion, and retinal thickness at the central fovea in diabetic patients, but the greatest contributing factor was only the retinal thickness.
Sakata
Kumi
K
Department of Ophthalmology, Tokyo Women's Medical University, Tokyo, Japan. sakata@oph.twmu.ac.jp
Funatsu
Hideharu
H
Harino
Seiyo
S
Noma
Hidetaka
H
Hori
Sadao
S
D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology; D002196:Capillaries / Q000502:physiology; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D005451:Fluorescein Angiography; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008266:Macula Lutea / Q000098:blood supply*; D008269:Macular Edema / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy; D011446:Prospective Studies; D012160:Retina / Q000473:pathology*; D015356:Retinal Artery Occlusion / Q000503:physiopathology; D012170:Retinal Vein Occlusion / Q000503:physiopathology; D012171:Retinal Vessels / Q000502:physiology*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology*
D006442:Glycated Hemoglobin