Researchers from the University of Hong Kong (HKU) and the Chinese University of Hong Kong (CUHK) have jointly developed an advanced imaging technique for retinal nerve fibre layer optical texture analysis (ROTA) that can improve the detection of early optic nerve damage in glaucoma.
<Published in MIMS, 29 September 2022 >
Currently, ROTA is patented (US patent number 10,918,275) and available as part of glaucoma assessment at HKU Eye Centre and Southern District Hong Kong Eye Survey. “I am glad that ROTA developed by CUHK and HKU can be used in clinical practice. Advanced imaging techniques are important tools for early diagnosis of glaucoma and detection of its progression,” highlighted Professor Clement Tham of Department of Ophthalmology and Visual Sciences, CUHK.
Conventional diagnosis of glaucoma involves the use of optical coherence tomography (OCT). However, detection sensitivity of OCT is limited by measurement of retinal nerve fibre layer (RNFL) thickness without considering physiological variations of axonal-fibre-bundle distribution in the optic-nerve head and fovea. With ROTA, an algorithm integrates data on RNFL thickness and reflectance from standard OCT scans, and optical diagnosis can be improved by optical texture and trajectories in widefield imaging of the retina. [Nat Biomed Eng 2022;6:593-604]
The diagnostic performance of ROTA and conventional analyses were compared in an adult cohort including 363 patients with glaucoma (531 eyes; mean age, 58.4 years) and 177 healthy individuals (315 eyes; mean age, 59.7 years). Of all glaucomatous eyes, 34.5 percent were in early stage (visual field mean deviation [VF MD], ≥-6 dB), and the remaining were in intermediate or advanced stage (VF MD, <-6 dB).
For early glaucoma detection, ROTA showed higher specificity (94.3 percent vs 78.1–87.9 percent) and sensitivity (97.3 percent vs 91.8–92.3 percent) vs conventional analyses, with visual field (VF) testing as the reference standard. At a specificity of 95 percent, ROC regression analysis revealed significantly higher sensitivity with ROTA (97.3 percent vs 82.0 percent; p=0.002) vs conventional analyses.
“With high sensitivity and specificity in detection of RNFL defects, ROTA represents a new paradigm in the diagnostic evaluation of glaucoma and other optical neuropathies,” the researchers suggested.
With ROTA, the researchers were able to further identify signatures of optical neuropathy with axonal-fibre-bundle trajectories not captured by conventional analyses. A recent ROTA study (n=171; 204 eyes; mean VF MD, -3.20 dB; mean age, 55.5 years) revealed papillomacular bundle defects (71.6 percent) and papillofoveal bundle defects (17.2 percent) as common patterns of early glaucoma. These patterns were also associated with central VF sensitivity loss at the corresponding locations in VF tests. [Ophthalmology 2022;129:1043-1055]
“We are delighted to collaborate with CUHK to develop ROTA, bringing new hope to early identification and timely treatment for glaucoma,” added Professor Christopher Leung of Department of Ophthalmology, HKU. “Our next steps include longitudinal studies of ROTA for detection of glaucoma progression and collaboration with OCT industry partners to deploy ROTA in clinical care.”
ROTA will also be available through the Advanced Nerve and Glaucoma Imaging (ANGI) Network, a global partnership of leading hospitals and clinical centres, for the diagnosis of glaucoma and optical neuropathies.