Prevalence of Obstructive Sleep Apnoea in Glaucoma

Open Angle Glaucoma (OAG) is an eye disease which can lead to irreversible loss of vision caused by damage to the optic nerve at the back of the eye. It is often associated with raised fluid pressure in the eye and treated by lowering this pressure. However, despite treatment, some patients continue to lose vision and it is suspected that other factors are contributing to the optic nerve damage. Among them is Obstructive Sleep Apnoea (OSA), though the link between OAG and OSA is controversial. This study aims to determine whether the prevalence of OSA is higher in patients with OAG in comparison to people without glaucoma. In addition, it will establish whether OSA is an independent risk factor for OAG and whether a future randomised controlled trial assessing the impact of OSA treatment with Continues Positive Airway Pressure (CPAP) on OAG outcomes would be acceptable and feasible in this population. The usefulness of OSA screening tools, including oximetry and questionnaires will also be determined. We comprehensively phenotype glaucoma patients using novel techniques, which include angiographic ocular coherence tomography and retinal oximetry. Ocular perfusion pressure will be calculated based on central retinal vein pressure measured by ophthalmodynamometry. The study is a collaborative project between sleep specialists at Papworth Hospital and ophthalmologists at Hinchingbrooke Hospital and will involve patients attending glaucoma clinic and their relatives who will act as a control group. Two study visits will be required on consecutive days. Participants will undergo a comprehensive ocular examination and a sleep study in the form of respiratory polysomnography (respiratory PSG) at home. A brief medical history focused on cardiovascular and metabolic co-morbidities will be taken.