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Glaucoma – Advanced, LAbel-free High resolution Automated OCT Diagnostics

Periodic Reporting for period 2 - GALAHAD (Glaucoma – Advanced, LAbel-free High resolution Automated OCT Diagnostics)

Reporting period: 2018-06-01 to 2019-11-30

The project GALAHAD targets the critical need for better glaucoma diagnostic systems. Glaucoma is an age related
major cause of blindness. The eye disease is characterized by an irreversible damage to the optic nerve head
caused by increased intra-ocular pressure. The current screening and basic diagnostics for the disease involve intraocular
pressure measurement, visual field tests and detection of structural damage to the optic nerve head and
retinal nerve fibre layer. The present methods have high rates of false positive or false negative results since the in
depth analysis of optical nerve head damage is not possible due to the poor resolution of available optical
technologies. A leading candidate is optical coherence tomography (OCT), but the required axial resolution is ~1
μm, well beyond the 3-5 μm resolution of commercial systems. GALAHAD aims to develop a label free, compact
and easy to operate high resolution diagnostic OCT system. The multiband and multimodal system will use
submicron ultra-high resolution polarisation sensitive OCT (UHR PS OCT). The key breakthrough elements are: (i)
A revolutionary low cost multiband supercontinuum light source. (ii.) Ground-breaking ultra-broadband photonic
components required to exploit such a source. (iii.) Automated glaucoma screening algorithms: using end user
evaluation of cell and animal models and tissue samples, automated algorithms will be developed, trained and
tested so that non-expert operators will be able to perform glaucoma screening. The GALAHAD in depth glaucoma
diagnostics after a positive screening with conventional methods will dramatically reduce false positive and false
negative screening results and decrease the number of patients suffering from glaucoma-related disability. The
project is driven by world leading companies and manufacturers of OCT systems and guided by requirement
specifications and validated by high ranking clinical and experimental ophthalmologists in their clinical settings.
GALAHAD finished on schedule at the end of November 2019. Over the last 36 months the project has had a major impact on the development of ultra-high resolution polarisation sensitive optical coherence tomography (UHR-PS-OCT), from advances in components to automated algorithms to process the results. GALAHAD has been very successful in developing components, sub-systems, operational systems (1 µm axial resolution), processes and software related to OCT and has achieved some important results in applying them to glaucoma screening. The key advances include:

Hardware for UHR-PS-OCT

-Components (already available as products from G&H)
-G&H has set the new state-of-the-art in both SM and PM broadband fused fibre components and has a wide range of new products already on the market
-PM and SM collimators
-SM and PM delay lines
-Motorised polarization controller
-Variable dispersion compensator
-Sources (products planned to be released in 2020 by NKT)
-NKT Photonics has developed the first polarised supercontinuum source with a long lifetime and robust polarisation extinction ratio (>25 dB PER for >2200 h successful operation)
-Technical University of Denmark (DTU) made fundamental advances in the understanding of noise processes in supercontinuum sources
-Spectrometers (customized products available from Ibsen Photonics)
-Ibsen has improved its technology from the large area etch process for its gratings to improved thermal stability for its spectrometers

Software for UHR-PS-OCT
-DTU developed numerical all-depth OCT dispersion compensation software
-Universitat Politècnica de València (UPV) developed algorithms which set the new state-of-the-art in several areas:
-Retinal layer segmentation algorithms for in vivo and ex vivo rodent OCT images
-Computer-aided diagnosis algorithms for glaucoma from human OCT images
-Epidermis and hair follicle segmentation algorithms for human skin OCT images
-Gloucestershire Hospitals NHS Foundation Trust has made available a large anonymised human glaucoma OCT database
-Standards for UHR-PS-OCT
-University of Münster (WWU) delivered permanent tissue-like test standards for UHR-PS-OCT testing
-WWU reported the first measurement of retinal refractive index as a function of wavelength
-Systems for UHR-PS-OCT
-Optos assembled two final systems which were characterised with axial resolutions of 1.25 µm (GALAHAD-1) and 1.39 µm (GALAHAD-2)
-Preliminary observations with the GALAHAD UHR-PS-OCT systems
->150 OCT measurements from various glaucoma models were performed
-GALAHAD standard mouse retina models at WWU
-Standard test targets and in vivo rodent retina models at the Rigshospitalet, Copenhagen
-Thanks to excellent progress and efforts at Optos, it was possible to demonstrate the systems on a human volunteer
-This work has already contributed to analytical procedures for the refined analysis prediction of visual field characteristics by Rigshospitalet
-Demonstration of GALAHAD UHR-PS-OCT system
-This live demonstration, on a human volunteer, formed part of the workshop on 8 January 2020 to an audience of researchers and clinicians
-This went significantly beyond the planned project scope and was a highly satisfactory conclusion to the project.

More detail may be found at the project website: https://galahad-project.eu
GALAHAD has advanced the stat-of-the-art in several areas relating to components and hardware for OCT systems, software for OCT image analysis and complete systems:

-G&H has set the new state-of-the-art in both SM and PM broadband fused fibre components in terms of wavelength-dependent loss and bandwidth (300 nm)
-NKT Photonics developed the first polarised supercontinuum source with a long lifetime and robust polarisation extinction ratio (>25 dB PER for >2200 h successful operation)
-Technical University of Denmark (DTU) made fundamental advances in the understanding of noise processes in supercontinuum sources
-Universitat Politècnica de València (UPV) developed algorithms which set the new state-of-the-art in several areas:
-Retinal layer segmentation algorithms for in vivo and ex vivo rodent OCT images
-Computer-aided diagnosis algorithms for glaucoma from human OCT images
-Epidermis and hair follicle segmentation algorithms for human skin OCT images
-University of Münster (WWU) delivered permanent tissue-like test standards for UHR-PS-OCT testing
-WWU reported the first measurement of retinal refractive index as a function of wavelength
-Optos assembled two final systems which were characterised with axial resolutions of 1.25 µm (GALAHAD-1) and 1.39 µm (GALAHAD-2) demonstrated on a human volunteer, which the consortium believes sets a new state-of-the-art for PS OCT systems.

More detail may be found at the project website: https://galahad-project.eu
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