A simplified method to measure choroidal thickness using adaptive compensation in enhanced depth imaging optical
Preeti Gupta1, Elizabeth Sidhartha1, Michael J A Girard2
1Singapore Eye Research Institute and Singapore National Eye Centre, Singapore, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore, Singapore.
Plos One
|May 7, 2014
Summary
A simplified method using enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT) significantly improves choroidal thickness (CT) measurement reliability. This efficient technique enhances image quality and measurement precision for clinical use.
Area of Science:
- Ophthalmology
- Medical Imaging
- Biomedical Engineering
Background:
- Accurate measurement of choroidal thickness (CT) is crucial for diagnosing and monitoring various ocular diseases.
- Enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT) is a valuable tool for visualizing the choroid.
- Current CT measurement methods can be limited by image quality and inter-observer variability.
Purpose of the Study:
- To evaluate a simplified, post-processing compensation algorithm for enhancing choroidal images obtained via EDI SD-OCT.
- To assess the reliability and efficiency of this simplified method for measuring choroidal thickness (CT).
Main Methods:
- Choroidal thickness (CT) was measured in 31 healthy subjects using Spectralis EDI SD-OCT.
- A post-processing adaptive compensation algorithm was applied to enhance the choroid-scleral interface.
- Image analysis was performed using Adobe Photoshop, with independent grading for inter- and intra-grader reliability using intra-class correlation coefficients (ICC) and Bland-Altman plots.
Main Results:
- The simplified method with adaptive compensation demonstrated perfect intra-grader (ICC: 0.95–0.97) and inter-grader (ICC: 0.93–0.97) reliability across five measurement locations.
- Conventional manual CT measurements showed lower reliability (intra-grader ICC: 0.87–0.94; inter-grader ICC: 0.90–0.93).
- Mean differences for sub-foveal CT measurements using adaptive compensation were minimal (-1.3 µm and -1.2 µm for intra- and inter-grader, respectively).
Conclusions:
- The simplified CT measurement method using EDI SD-OCT is highly reliable and efficient.
- This practical approach enhances choroidal image quality and improves the precision of CT measurements.
- The proposed technique offers a valuable improvement for clinical OCT analysis.
