Comparison of Spectral-Domain and Time-Domain Optical Coherence Tomography for Evaluation of Macular Thickness and Peripapillary Retinal Nerve Fiber Layer in Healthy Subjects

Abstract

Purpose: : To compare Cirrus fourier-domain optical coherence tomography (OCT) with Stratus time-domain OCT for measuring retinal thickness in the macular area and the peripapillary retinal nerve fiber layer (RNFL).

Methods: : One hundred and twenty eyes from 120 healthy subjects were prospective and consecutively selected. All of them were scanned using a Cirrus OCT system (Carl Zeiss Meditec, Inc.) and afterward with a Stratus OCT (Carl Zeiss Meditec, Inc.). The 512x128 volume cube and fast macular were the scan protocols used for acquiring the macular images, whereas the optic disc cube 200x200 and the fast RNFL thickness (3.46) were the scan acquisition protocols used for measuring the peripapillary RNFL thickness, respectively. Total and regional macular thickness and RNFL average and quadrant thickness were compared between both devices.

Results: : 34 men (28.2%) and 86 women (71.8%) were included, age ranged from 19 to 60 years. The macular thickness measurements were approximately 64.18 µm larger for Cirrus OCT than for Stratus OCT (265.82 µm vs 201.64 µm, respectively)(p<0.0001). The differences between both equipments showed a mild decrease with eccentricity (differences were 53 µm in perifoveal values vs 43 µm in parafoveal ones). The average thickness in the optic cube was 96.9 µm using the Cirrus OCT and 99.7 µm using the Stratus OCT (p=0.035). Values representing RNFL in the superior, nasal, inferior and temporal quadrants showed no significant differences using both methods.

Conclusions: : Spectral-domain OCT had different references for macular thickness than Stratus OCT, showing higher measurements for Cirrus OCT. RNFL thickness surrounding the optic nerve head showed no differences using both methods.

Keywords: macula/fovea • retina • nerve fiber layer