"Development of En Face Optical Coherence Tomography for Accurate Detection of Early Retinal Damage in Glaucoma "
Lead Research Organisation:
University of Bradford
Department Name: Faculty of Life Sciences
Abstract
This project will produce technology to meet the need for improved eye imaging techniques for accurate, early diagnosis of the common eye disease glaucoma. Our technology makes innovative use of existing imaging devices already in widespread clinical use, requiring no new hardware. We thereby bring benefits to patients for minimal new financial investment from health services.
Glaucoma is the world's leading cause of irreversible blindness, affecting 3% of those aged over 40 in the UK. Glaucoma is becoming more common as our population ages, with 112 million people worldwide predicted to be affected by 2040. Effective treatment of glaucoma requires accurate early diagnosis as sight lost cannot be restored and early-moderate stages produce no symptoms.
Existing diagnostic imaging for glaucoma uses optical coherence tomography (OCT) which is fast, non-invasive, straightforward to use and comfortable for patients. This technology is now in routine clinical use for glaucoma diagnosis and follow-up. However, partly due to previous technical limitations, use of OCT has thus far focussed on measuring thinning of retinal tissue in cross-sectional (front-to-back) slices.
This current use of OCT produces many false positives (misidentifying healthy eyes as glaucoma), contributing to 17-63% of early cases in UK glaucoma clinics being present unnecessarily, costing the NHS over £36M per year. Current use of OCT also misses 20-30% of true cases, contributing to preventable sight loss.
We have developed a new method of constructing and automatically analysing 3-D images from the cross-sectional scans captured by existing OCT devices. Our method rotates the view to become front-on, which enables measurement and visualisation of glaucomatous changes to the appearance (reflectance) of retinal tissue at varying depths below the surface. This allows us to assess not only the thickness of the tissue as conventionally measured, but also its appearance.
This enhanced method allows us to detect defects in the retina that are not captured by current OCT techniques. Further, unlike current OCT methods, the defects identified by our technology can be directly corroborated with defects measured separately by visual field tests (which measure sensitivity to light). This corroboration of defects found by two different test types has potential to vastly reduce the false positives produced by each test used in isolation.
Our technology has undergone initial development, proof-of-concept and early-stage validation. This project will comprise necessary further refinements and validations of our method for translation to clinical use. We will:
Simplify the method of image capture, making it faster and easier to use in busy clinics.
Refine our image processing and analysis to improve image quality and further improve identification of defects.
Assess and correct for effects of healthy ageing and cataract (clouding of the eye lens) on our images, such that the technology can be robustly applied to patients over a wide range of ages.
Measure how our images vary over repeated measurements in the same patients.
Evaluate how well our final, refined technology performs in accurately diagnosing glaucoma compared to current tests.
Upon completion, we will have produced a refined version of our technology and data demonstrating its validity, robustness and efficacy. The technology will be ready for a larger clinical trial following on from this project which will represent the final step before being ready to use in clinics, where it will benefit patients and reduce the backlogs caused by unnecessary referrals and follow-ups.
Glaucoma is the world's leading cause of irreversible blindness, affecting 3% of those aged over 40 in the UK. Glaucoma is becoming more common as our population ages, with 112 million people worldwide predicted to be affected by 2040. Effective treatment of glaucoma requires accurate early diagnosis as sight lost cannot be restored and early-moderate stages produce no symptoms.
Existing diagnostic imaging for glaucoma uses optical coherence tomography (OCT) which is fast, non-invasive, straightforward to use and comfortable for patients. This technology is now in routine clinical use for glaucoma diagnosis and follow-up. However, partly due to previous technical limitations, use of OCT has thus far focussed on measuring thinning of retinal tissue in cross-sectional (front-to-back) slices.
This current use of OCT produces many false positives (misidentifying healthy eyes as glaucoma), contributing to 17-63% of early cases in UK glaucoma clinics being present unnecessarily, costing the NHS over £36M per year. Current use of OCT also misses 20-30% of true cases, contributing to preventable sight loss.
We have developed a new method of constructing and automatically analysing 3-D images from the cross-sectional scans captured by existing OCT devices. Our method rotates the view to become front-on, which enables measurement and visualisation of glaucomatous changes to the appearance (reflectance) of retinal tissue at varying depths below the surface. This allows us to assess not only the thickness of the tissue as conventionally measured, but also its appearance.
This enhanced method allows us to detect defects in the retina that are not captured by current OCT techniques. Further, unlike current OCT methods, the defects identified by our technology can be directly corroborated with defects measured separately by visual field tests (which measure sensitivity to light). This corroboration of defects found by two different test types has potential to vastly reduce the false positives produced by each test used in isolation.
Our technology has undergone initial development, proof-of-concept and early-stage validation. This project will comprise necessary further refinements and validations of our method for translation to clinical use. We will:
Simplify the method of image capture, making it faster and easier to use in busy clinics.
Refine our image processing and analysis to improve image quality and further improve identification of defects.
Assess and correct for effects of healthy ageing and cataract (clouding of the eye lens) on our images, such that the technology can be robustly applied to patients over a wide range of ages.
Measure how our images vary over repeated measurements in the same patients.
Evaluate how well our final, refined technology performs in accurately diagnosing glaucoma compared to current tests.
Upon completion, we will have produced a refined version of our technology and data demonstrating its validity, robustness and efficacy. The technology will be ready for a larger clinical trial following on from this project which will represent the final step before being ready to use in clinics, where it will benefit patients and reduce the backlogs caused by unnecessary referrals and follow-ups.
