Macular Layer Thickness with Spectral-Domain and High-Resolution OCT

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Imaging

Background:

• High-resolution optical coherence tomography (HR-OCT) offers improved axial resolution over standard spectral-domain OCT (SD-OCT).
• Accurate segmentation of retinal layers is crucial for monitoring diseases like glaucoma.
• Understanding inter-device differences in OCT measurements is vital for longitudinal patient follow-up.

Purpose of the Study:

• To compare retinal layer thickness measurements between HR-OCT and SD-OCT.
• To assess the clinical significance of differences in segmentation for monitoring disease progression.
• To evaluate the impact of switching OCT devices on patient monitoring.

Main Methods:

• A prospective cross-sectional study involving glaucoma patients and healthy controls.
• Macular scans were acquired using both SD-OCT and HR-OCT on the same eyes.
• Automated segmentation analyzed the thickness of six retinal layers across 97 B-scans.

Main Results:

• Mean differences in retinal layer thickness between SD-OCT and HR-OCT ranged from -2.65 to 2.02 μm.
• Hyper-reflective layers appeared thicker with SD-OCT, while hyporeflective layers appeared thicker with HR-OCT.
• Intra-device differences were within ±1 μm; image quality did not significantly predict inter-device differences.

Conclusions:

• Small but consistent inter-device differences exist between SD-OCT and HR-OCT retinal layer thickness measurements.
• These differences, particularly the alternating pattern, may be due to variations in axial resolution and border definition.
• Switching between SD-OCT and HR-OCT for patient follow-up requires careful consideration of potential masking or masquerading of disease progression due to measurement discrepancies.