Abstract
Purpose: :
It is well known that different optical coherence tomography (OCT) systems provide different retinal thickness (RT) measurements. However, it was anticipated that there is a systemic difference in RT measurements. It was the aim of this study to evaluate the impact of antiangiogenetic therapy on the differences in retinal thickness measurements performed with two different OCT systems from the same manufacturer.
Methods: :
Data were obtained by two different OCT systems in a group of 20 Patients with neovascular age-related macular degeneration (nAMD) before and following three intravitreal treatments with Ranibizumab in monthly intervals. Imaging was performed using the time domain (TD) Stratus® and the spectral domain (SD) Cirrus® OCT system (both systems are manufactured by Carl Zeiss Meditec). Retinal Voulme (RV), central retinal thickness and central millimeter thickness analyses were carried out using the latest software available.
Results: :
Mean RT and RV revealed to be significantly lower in conventional TD-OCT parameters than in SD-OCT parameters before and after treatment with Ranibizumab (p<0,002). Differences in all morphological parameters varied stronger in patients examined before than after treatment, demonstrating higher Standard Deviation (SD) previous to treatment. Most interestingly, the difference between TD- and SD-OCT retinal thickness measurements before and following antiangiogenetic therapy were highly significant (p < 0,01) and significantly lower than before the therapeutic intervention.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • age-related macular degeneration • imaging/image analysis: clinical