Abstract
Purpose: :
To report normal macular thickness measurements in healthy eyes using spectral-domain OCT (Spectralis, Heidelberg Engineering) and to compare obtained data with time-domain OCT (Stratus, Zeiss).
Methods: :
50 Eyes of 50 healthy patients, mean age 48,6 ± 23,5 yrs, underwent a complete ophthalmologic examination, including OCT performed by two different instruments: a time-domain OCT(Stratus, Zeiss) and a spectral-domain OCT(Spectralis, Heidelberg Engineering).Using time-domain we chose "Fast Macular Thickness" scan-protocol and "Cross-Hair" scan-protocol; using spectral-domain we chose a (6x6)mm Volume scan-protocol consting of 25 lines. Retinal thickness was automatically calculated by OCT mapping software. Measurements were displayed as the mean and SD for central region (1 mm).Moreover we considered measurements of minimum foveal thickness obtained with horizontal line scan.
Results: :
Mean central macular thickness of normal eyes measured with time-domain OCT and with spectral-domain OCT resulted 201,8±16,2 and 275±17,7 respectively. Mean difference between measurements obtained by two different domains is 73.8±9.7 µm. Mean minimum foveal thickness of normal eyes measured with time-domain OCT and with spectral-domain OCT resulted 147,2±12,3 and 226,3±13,2. Mean difference between these measurements is 79,1±13
Conclusions: :
Central macular(1mm) and minimum foveal thickness resulted thicker using spectral-domain OCT because of the predefined position of the marking line set above the RPE in time-domain’s software and under RPE in Spectral-domain’s software. Therefore we regarded necessary to consider these important differences between two of the most common acquisition protocols of retinal thickness.
Keywords: macula/fovea • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina