Is it Myopia or Glaucoma? Clinical Tools to Identify the Disease

• Applicant: Dr. Jasmin Rezapour
• Subject Area: Ophthalmology
• Term: from 2019 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 422530480

Glaucoma is a chronic, progressive eye disease, characterized by retinal ganglion cell damage, which presents with a pathognomonic appearance of the optic disc and visual field loss. It is the second most common cause of irreversible blindness worldwide. The total number of people with glaucoma was estimated to be 64 million in 2013 and is expected to increase to 80 million by 2020.Myopia or nearsightedness is a condition where distant objects appear blurry. Myopia occurs when light is focused anterior to the retina and is usually associated with axial length above the norm. The prevalence of myopia is rapidly increasing from ~1.4 billion worldwide in 2010, to an estimated 5 billion by 2050.Individuals with myopia are 2.5 times more likely to have glaucoma than those without myopia. However, the clinical challenge is that the myopic optic nerve head mimics glaucomatous damage to the optic disc, which makes it difficult to diagnose glaucoma in myopes. At the same time a myopic optic disc may mistakenly be interpreted as glaucoma and even result in overdiagnosis and overtreatment of glaucoma in healthy myopes.The objective of this study is to differentiate accurately between myopia with and without glaucoma. We hypothesize that unique features of the myopic optic disc, identified by optical coherence tomography (OCT) and OCT-Angiography (OCTA) could be used to differentiate between myopic eyes with and without glaucoma.OCT and OCTA are two retinal imaging modalities that are used extensively in routine ophthalmic examinations and considered the standard of care for management of glaucoma and other retinal diseases. OCT is used to visualize and measure different layers of the retina, while OCTA visualizes choroidal and retinal vasculature. The parapapillary atrophy zone is a chorioretinal atrophy zone around the optic disc, which can be categorized into subtypes parapapillary atrophy zone-α, zone-β and zone-γ by OCT but not by clinical examination. Recent studies suggest that parapapillary atrophy zone-β is more strongly associated with myopia and glaucoma and parapapillary atrophy zone-γ with myopia and no glaucoma. We hypothesize that parapapillary atrophy along with other OCT parameters such as optic disc tilt, ovality index, fovea to disc angle and distance, optic nerve head choroidal thickness and OCTA measurements could be used to differentiate between myopic eyes with glaucoma and myopic eyes without glaucoma. If our hypothesis is correct, these OCT and OCTA parameters can then be used to develop clinical decision support algorithms to improve detection of glaucoma in individuals with myopia. Finally, these new clinical decision support tools will help to prevent functional impairment and blindness caused by glaucoma in patients with myopia and on the other hand will help to prevent overdiagnosis and overtreatment in healthy myopes, improve quality of life and reduce health care costs due to overtreatment.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Linda Zangwill, Ph.D.