Quantifying birefringence in the retinas of AMD patients using polarization sensitive optical coherence tomography (Conference Presentation)

A depth-multiplexed fiber-based PS-OCT system is used to extract local polarization information of retinas of age-related macular degeneration (AMD) patients in different stages. In the end stage of wet AMD, retinal structures are replaced with fibrous tissue which leads to irreversible loss of vision. Accurate imaging and evaluation of the lesions is important for reliable diagnosis and treatment of AMD. However, no imaging techniques exist which can clearly distinguish a fibrotic lesion from non-fibrotic neovascular tissue which is still active. With PS-OCT fibrous tissue in the retina of AMD patients can be detected and quantified using its birefringent properties. Images from previous research often show cumulative phase retardation, where the polarization state of every pixel is compared to the polarization state at the surface of the retina. However, a quantity which is linearly related to the amount of birefringent tissue is more desirable for clinical interpretations. In the presented research, a new method is used to obtain depth-resolved local birefringence images which has only been used on breast tissue before. In this method, the birefringent quantities (linear phase retardation) are extracted from the differential Mueller matrix. In the images of retinas from AMD patients, fibrotic lesion areas can be recognized and separated from non-fibrotic areas. An improvement to localize birefingence in depth while maintaining similar image quality is demonstrated. This provides new possibilities for clinical research to monitor the development of AMD and to assess the response to treatment.