Prevalence of Obstructive Sleep Apnoea in Glaucoma (POSAG)

POSAG: Prevalence of Obstructive Sleep Apnoea in Glaucoma

This study aims to investigate a potential link between Obstructive Sleep Apnoea (OSA) and Open Angle Glaucoma (OAG); initially by determining whether the prevalence of OSA is higher in patients with OAG in comparison to people without glaucoma and if OSA is an independent risk factor for OAG. It will comprehensively phenotype glaucoma patients for variables that may be associated with both OSA and OAG.

Study Overview

• Status: Completed
• Conditions: Open Angle Glaucoma; Obstructive Sleep Apnoea

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 403

Contacts and Locations

Study Locations

• United Kingdom
  • Cambridgeshire
    • Huntingdon, Cambridgeshire, United Kingdom, PE29 6NT
      • Hinchingbrooke Hospital NHS Foundation Trust

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients and healthy volunteers

Description

Inclusion Criteria:

Glaucoma patients:

1. Open angle glaucoma (including primary open angle glaucoma, normal tension glaucoma and pseudoexfoliation glaucoma) in either eye.
2. Age ≥18 years
3. Able to give informed consent and attend at the required frequency for the duration of the study.

Control group:

1. Age ≥18 years
2. Able to give informed consent and attend at the required frequency for the duration of the study.

Exclusion Criteria:

Glaucoma patients:

1. Unable to perform reliable visual field testing (>15% false positives, >20% fixation losses. However, if fixation losses are >20%, the eye tracker may be used to assess reliability)
2. Known or suspected pregnancy.
3. Tracheostomy
4. Use of nocturnal oxygen for indications other than sleep related breathing disorders (SBD).

Control group:

1. Known or suspected pregnancy
2. Known or suspected glaucoma (participants with glaucoma diagnosed during screening ophthalmic examination and newly identified glaucoma 'suspects' will also be excluded)
3. Inability to undergo screening ophthalmic examination
4. Tracheostomy
5. Use of nocturnal oxygen for indications other than sleep related breathing disorders (SBD).

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Patients with OAG; Patients with a diagnosis of Open Angle Glaucoma
Controls; Controls without a diagnosis of Open Angle Glaucoma

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnosis of OSA	Clinical diagnosis of OSA defined as apnoea hypopnoea index (AHI) >5	Within 24 hours of recruitment on to study (cross-sectional)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
OSA severity	OSA severity will be determined by Apnoea-Hypopnea Index (AHI) and nocturnal oxygen desaturation levels (recording from nocturnal oximetry), which are used to indicate the severity of obstructive sleep apnoea.	24 hours
Glaucoma severity	Glaucoma severity measured by mean deviation (MD) derived from visual fields examination	24 hours
Ocular perfusion pressure (OPP)	Ocular perfusion pressure will be calculated based on the following formula : OPP=2/3MAP-CVRP where MAP is mean arterial pressure and CVRP is central retinal venous pressure measured by ophthalmodymamometry.	24 hours
Postural changes in intraocular pressure (IOP)	Postural changes of IOP will be measured as the difference between IOP in the upright position and then supine position.	24 hours
Optic nerve head perfusion	Optic nerve head flow index will be measured non-invasively by Angiographic Ocular Coherence Tomography (aOCT)	24 hours
Structural changes of the optic nerve	Structural changes of the optic nerve will be characterised by retinal nerve fibre layer (RNFL) thickness measured by Ocular Coherence Tomography	24 hours
Stop-Bang questionnaire as screening tool	Sensitivity and specificity of Stop-Bang questionnaire in detecting OSA in OAG, using Stop-Bang questionnaire summary score.	24 hours
Nocturnal oximetry as screening tool	Sensitivity and specificity of nocturnal oximetry in detecting OSA in OAG	24 hours
Diagnosis of obstructive sleep apnoea syndrome (OSAS)	Prevalence of OSAS in OAG patients	24 hours

Collaborators and Investigators

• Sponsor: Papworth Hospital NHS Foundation Trust
• Collaborators: Anglia Ruskin University; Hinchingbrooke Healthcare NHS Trust

Study record dates

Study Major Dates

• Study Start: March 1, 2016
• Primary Completion (Actual): September 14, 2017
• Study Completion (Actual): September 14, 2017

Study Registration Dates

• First Submitted: January 25, 2016
• First Submitted That Met QC Criteria: March 14, 2016
• First Posted (Estimate): March 18, 2016

Study Record Updates

• Last Update Posted (Actual): December 2, 2017
• Last Update Submitted That Met QC Criteria: November 29, 2017
• Last Verified: November 1, 2017

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Eye Diseases; Ocular Hypertension; Signs and Symptoms, Respiratory; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Glaucoma; Glaucoma, Open-Angle; Apnea
• Other Study ID Numbers: P02058

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No
• IPD Plan Description: Will not be sharing individual participant data. All study data will be anonymised.