Comparison of the Foveal Average Retinal Thickness in Diabetic Mcular Edema in Two Different Spectral-Domain Optical Coherence Tomography

Abstract

Purpose: : To evaluate and compare the foveal average retinal thickness in diabetic macular edema in two different spectral-domain optical coherence tomography (SD-OCT).

Methods: : This retrospective study was conducted on 72 eyes of 37 patients with diabetic macular edema who were measured the foveal average retinal thickness in Cirrus and Spectralis OCT at the same day from September 2008 to May 2009. The relationships between the foveal average retinal thickness and best-corrected visual acuity (BCVA) were evaluated.

Results: : The mean age was 61± years (mean±standard deviation). The mean foveal retinal thickness was 390 ±138µm in Cirrus OCT and 402±141µm Spectralis OCT. The measured values of Spectralis OCT were significantly thicker than those of Cirrus OCT (P=0.002). BCVA over 4/20 were 56 eyes and BCVA under 4/20 were 16 eyes. In BCVA over 4/20, the mean foveal retinal thickness in Cirrus OCT was 396±143µm and in Spectralis OCT was 408±143µm. As previous described, the measured values of Spectralis OCT were significantly thicker than those of Cirrus OCT (P=0.00013). In BCVA under 4/20, the mean foveal retinal thickness in Cirrus OCT was 359±111µm and in Spectralis OCT was 375±127µm, but the difference was not significant (P=0.19). In a case of poor fixation, measured values might be not confidence.

Conclusions: : It is possible that measured value of the foveal retinal thickness have dispersion among models of SD-OCT. So we should be careful to compare the measured values among different models.

Keywords: diabetic retinopathy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • edema