Ultrahigh resolution retinal imaging by visible light OCT with longitudinal achromatization

Area of Science:

• Ophthalmic imaging
• Optical coherence tomography
• Biomedical optics

Background:

• Chromatic aberrations are critical in high-resolution visible light imaging systems.
• Longitudinal chromatic aberration (LCA) in the human eye affects ophthalmic imaging quality.
• Existing OCT systems may not fully compensate for ocular aberrations.

Purpose of the Study:

• To develop and evaluate a fiber-based, visible light OCT ophthalmoscope with chromatic aberration correction.
• To assess the impact of achromatization on in vivo retinal image quality and resolution.
• To enable detailed imaging and morphometry of retinal structures.

Main Methods:

• Developed a fiber-based spectral/Fourier domain, visible light OCT system.
• Incorporated correction for the average longitudinal chromatic aberration (LCA) of the human eye.
• Analyzed speckle characteristics and visualized retinal layers in human subjects.

Main Results:

• Achromatization narrowed the axial speckle autocorrelation function by ~20%.
• Distinct separation of Bruch's membrane (BM), retinal pigment epithelium (RPE), and outer segment tips was achieved across a 6.5 mm field-of-view.
• High-resolution cross-sectional images revealed distinct inner retinal layers.
• Enabled segmentation and morphometry of BM and RPE.

Conclusions:

• Visible light OCT with chromatic aberration compensation achieves high retinal image quality.
• The system's performance matches or exceeds ultrahigh-resolution near-infrared OCT systems.
• This technology offers improved diagnostic capabilities for retinal diseases.