Abstract
Abstract: :
Purpose:To compare the values measured for retinal macular thickness with the first and last generations of the Optical Coherence Tomograph (OCT1 and 3). Methods:Fifty–nine eyes were examined : 17 had normal macula and 42, diabetic macular edema. Retinal macular thickness was mapped for in each eye, using OCT1 and OCT3. Mean retinal thickness (RT) was measured automatically in the 9 macular Early Treatment Diabetic Retinopathy Study (ETDRS) areas and at the foveal center. The mean RT values for each area were compared, both before and after the exclusion of areas with artifactual measurements. The type and rate of artifacts were also compared. Results:Of the 590 automatic measurements, 505 had no artifact, either with OCT1 or OCT3. Mean RT value for the area of 6mm in diameter was 308.8 ±116.8 µm with OCT1, and 333.8 ±126.7 µm with OCT3. These values were highly correlated (p<0.0001) but slightly different. The mean difference between the OCT1 and OCT3 measurements was 25 ±26.2 µm (p<0.0001), and with OCT3, RT values were 8.1 ±7.8 % higher than with OCT1. Artifacts were only observed in cases with diabetic macular edema and were significantly more frequent with OCT1 than OCT3 (10.5% versus 4.4, p<0.0001). These artifacts led to underestimation of RT in two thirds of cases with both OCT1 and OCT3. Conclusions:Macular retinal thickness values measured with OCT3 are significantly higher than those measured with OCT1, by 8.1 ±7.8 %. OCT3 also has the advantage of producing fewer artifacts than OCT1 in pathologic cases.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)