The Relationship Between Macular Sensitivity and Retinal Thickness in Eyes With Diabetic Macular Edema

PURPOSE: To investigate relationship between macular sensitivity and retinal thickness in diabetic macular edema (DME). DESIGN: Prospective observational study. METHODS: SETTINGS: University-based retina practice. PATIENTS: Twenty-two eyes of 11 patients with DME. PROCEDURE: Fundus microperimetry and retinal thickness tomography were performed simultaneously using an automatic fundus perimetry/tomography system. MAIN OUTCOME MEASURES: Quantification of macular sensitivity, fixation pattern, and relationship: between macular sensitivity and retinal thickness. RESULTS: Fixation stability revealed that 21 eyes (95.4%) had stable fixation (>75% within central 2 degrees of point of fixation) and 1 eye (4.5%) had relatively unstable fixation (<75% of fixation points located within 2 degrees, >75% located within 4 degrees). Evaluation of fixation location revealed that 15 eyes (68.2%) had central (>50% of fixation points within 0.5 mm of fovea), 3 eyes (13.6%) pericentral (25% to 50% within 0.5 mm of fovea), and 4 eyes (18.2%) eccentric (<25% of fixation points within 0.5 mm of fovea) fixation location. Macular sensitivity increased by an average of 0.03 decibel (dB) (95% confidence interval [CI]: 0.00, 0.06) per 1-micron (mu m) increase in retinal thickness for thickness values <= 280 mu m measured with the OPKO/OTI spectral-domain OCT. The macular sensitivity decreased by an average 0.05 dB (95% CI: -0.08, -0.02) per 1-mu m increase in thickness for thickness values >280 mu m. CONCLUSIONS: In this pilot study, the majority of eyes with DME had stable, central fixation. Macular sensitivity varied depending on the thickness of the retina. Additional studies are needed to determine the role of microperimetry in eyes with DME. (Am J Ophthalmol 2011;152:400-405. (C) 2011 by Elsevier Inc. All rights reserved.)