Polarization-sensitive OCT is a specialised form of optical coherence tomography that records changes in light polarisation as it passes through ocular tissues. It provides additional contrast related to tissue birefringence and composition.
Principles
Certain structures, such as nerve fibre layers and collagen-rich tissues, alter the polarisation state of light. By analysing these changes, polarization-sensitive OCT can map features like fibre orientation, depolarising lesions, or melanin-containing layers.
- Extends standard structural OCT with polarisation contrast information
- Produces images of phase retardation, degree of polarisation, and related metrics
- Particularly sensitive to retinal nerve fibre layer and retinal pigment epithelium
- Data acquisition and processing are more complex than conventional OCT
Potential Uses
This technology is being investigated for enhanced assessment of glaucoma, age-related macular degeneration, and other conditions where tissue organisation is important. It may help differentiate lesion types or detect early structural changes.
- Could offer more specific markers of nerve damage than thickness alone
- May improve visualisation of fibrous or scarred tissues
- Currently mainly used in research rather than routine practice
- Further validation is needed before widespread clinical adoption
