Comparison of time-domain OCT and fundus photographic assessments of retinal thickening in eyes with diabetic macular edema.
OBJECTIVE
To explore the correlation between optical coherence tomography (OCT) and stereoscopic fundus photographs (FP) for the assessment of retinal thickening (RT) in diabetic macular edema (DME) within a clinical trial.


METHODS
OCT, FP, and best corrected visual acuity (VA) measurements were obtained in both eyes of 263 participants in a trial comparing two photocoagulation techniques for DME. Correlation coefficients (r) were calculated comparing RT measured by OCT, RT estimated from FP, and VA. Principal variables were central subfield retinal thickness (CSRT) obtained from the OCT fast macular map and DME severity assessed by a reading center using a seven-step photographic scale combining the area of thickened retina within 1 disc diameter of the foveal center and thickening at the center.


RESULTS
Medians (quartiles) for retinal thickness within the center subfield by OCT at baseline increased from 236 (214, 264) microm in the lowest level of the photographic scale to 517 (455, 598) microm in the highest level (r = 0.67). However, CSRT interquartile ranges were broad and overlapping between FP scale levels, and there were many outliers. Correlations between either modality and VA were weaker (r = 0.57 for CSRT, and r = 0.47 for the FP scale). OCT appeared to be more reproducible and more sensitive to change in RT between baseline and 1 year than was FP.


CONCLUSIONS
There was a moderate correlation between OCT and FP assessments of RT in patients with DME and slightly less correlation of either measure with VA. OCT and FP provide complementary information but neither is a reliable surrogate for VA.
Davis
Matthew D
MD
Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI, USA.
Bressler
Susan B
SB
Aiello
Lloyd Paul
LP
Bressler
Neil M
NM
Browning
David J
DJ
Flaxel
Christina J
CJ
Fong
Donald S
DS
Foster
William J
WJ
Glassman
Adam R
AR
Hartnett
Mary Elizabeth R
ME
Kollman
Craig
C
Li
Helen K
HK
Qin
Haijing
H
Scott
Ingrid U
IU
D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000601:surgery; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005654:Fundus Oculi; D006801:Humans; D017075:Laser Coagulation; D008269:Macular Edema / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000379:methods*; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology