Abstract
Purpose:
The conventional imaging technique Optical Coherence Tomography (OCT) images the anterior structures of the macula such as vitreoretinal interface. The Enhanced Depth Imaging (EDI) function offers higher clarity in visualizing the choroid and scleral line. The aim of our study was to assess the efficacy of a novel method of OCT imaging that allows uniform definition of all layers.
Methods:
Our study included images on 25 eyes in patients with various retino-choroidal disorders. All eyes underwent conventional retinal scans, EDI and the combined scan technique using Spectral Domain (SD) OCT (Spectralis, Heidelberg) as part of routine clinical practice. One scan was taken through the fovea using 100 single frames, averaged to create one image. This was repeated using the EDI function to provide greater visualization of the choroid. A further scan was taken that used 50 scans of conventional retinal imaging and combined it with 50 scans of EDI imaging to create one image with uniform clarity. The thickness of the retina in the subfoveal, nasal (1mm and 3mm) and temporal (1 mm and 3 mm) areas were measured using the conventional OCT image. These exact points were replicated in the EDI image where the choroidal thickness was measured. The sum of the retinal and choroidal thickness at these points was compared to the corresponding thickness in the combined image from the vitreo-retinal interface to the posterior scleral line.
Results:
The sum of the thickness of the retinal and EDI scans did not vary significantly (p= 0.77- 0.94) from the thickness in the corresponding areas in the combined scan. For example, the average of the sum of the retinal and choroidal thickness using conventional OCT and EDI 3mm temporal to foveal centre was 619.5±124.2 µm while it measured 621.7+126 µm with the combined technique (p=0.95).
Conclusions:
This combined imaging method can accurately replace individual conventional retinal imaging and EDI imaging in each patient.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
550 imaging/image analysis: clinical •
549 image processing