Purpose
We previously suggested a 6 radial scan protocol, which simply generates a topographic map of choroidal thickness and volume on a commercial spectral-domain optical coherence tomography (SD-OCT) device. Recently, swept-source OCT using long wavelength is introduced and expected to visualize choroidal tissue more clearly. In this study, we compared choroidal thickness map data by SD-OCT and recently introduced swept-source OCT (SS-OCT)
Methods
Thirty-two eyes of 32 volunteers underwent both a 6 radial scanning protocol using a SD-OCT with enhanced depth imaging (EDI) technique and a 6 x 6 mm 3D volume map protocol using a SS-OCT device. A topographic map of choroidal thickness was automatically generated by built-in software according to the Early Treatment Diabetic Retinopathy Study (ETDRS) layout. A statistical analysis was conducted to compare the choroidal thickness map measurements for each ETDRS subfield between SD-OCT and SS-OCT.
Results
The mean choroidal thickness of all ETDRS subfield was 257.25 ± 36.0 μm by SD-OCT and 261.8 ± 35.2 μm by SS-OCT, which was not statistically significant. Except three outer subfields, 6 of total 9 ETDRS subfields including central subfield showed no statistical difference in choroidal thickness between two OCT devices. Also, both OCTs demonstrated similar topographic choroidal thickness pattern.
Conclusions
Compared to SD-OCT, recently developed SS-OCT is faster and can visualize the entire choroid more precisely in one session, but this OCT is not widely used currently. In this study, the choroidal map data in healthy eyes was similar between two OCT devices. We suggest that the 6 radial protocol using widely used SD-OCT is comparable to SS-OCT and appropriate method for instantly obtaining choroidal thickness map.
Keywords: 550 imaging/image analysis: clinical •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)