Ischemic optic neuropathy (ION) is damage to the optic nerve caused by ischemia and hypoxia of the optic nerve due to an impairment of the blood supply to the optic nerve from the arteries. Obstructive Sleep Apnea Hypoventilation Syndrome (OSAHS) is a sleep-breathing disorder characterized by recurrent upper airway obstruction and apnea during sleep, leading to recurrent intermittent hypoxemia with fragmented sleep and daytime sleepiness. Due to the lack of accurate methods to evaluate blood flow, the correlation between the two is unclear and uncertain. The study will enroll 80 patients from the First Affiliated Hospital of Nanjing Medical University and categorize them into mild, moderate, and severe OSA groups according to their apnea-hypopnea index (AHI). Participants will undergo a baseline evaluation, including polysomnography (PSG) and ophthalmologic examinations such as optic nerve and macular blood flow OCT, visual acuity, refraction, intraocular pressure, and visual fields. Eligible patients will be treated with CPAP for 3 months, after which their PSG and ophthalmologic examination-related results will be re-evaluated to assess treatment efficacy.
Ischemic optic neuropathy (ION) is damage to the optic nerve caused by ischemia and hypoxia in the optic nerve due to impairment of the blood supply of the arteries supplying the optic nerve. ION is an important blinding eye disease. It has been found that patients with OSAHS are often misdiagnosed as having normotensive glaucoma due to chronic hypoxia resulting in optic nerve ischemia and hypoxia, leading to the development of ION. However, the correlation between the two has been poorly studied and is uncertain due to the lack of accurate methods to evaluate blood flow. The study will enroll 80 patients from the First Affiliated Hospital of Nanjing Medical University between the ages of 18-80 years. Participants will be diagnosed with OSA according to established guidelines and must be first-time visitors with no prior history of OSA surgery or CPAP treatment. Patients with severe cerebrovascular disease, psychiatric disorders, diagnosed diabetes mellitus with severe vascular complications, severe COPD, pulmonary hypertension, heart failure, or pregnancy will be excluded. All participants will undergo a polysomnography (PSG) to determine the Apnea Hypopnea Index (AHI) and will be categorized into mild, moderate, or severe OSA groups. Ophthalmologic-related examinations will be performed to measure ocular parameters such as optic nerve and macular blood flow OCT, visual acuity, refraction, intraocular pressure (IOP), visual fields, and IOLMaster measurements of the eye axis. Eligible patients will receive CPAP treatment for 3 months. After 3 months of CPAP treatment, participants will undergo another PSG examination with ophthalmologic correlation to re-evaluate sleep parameters and ocular parameters. The collected data will be analyzed using SPSS software. Correlation analysis will be performed to assess the relationship between AHI, minimum SPO2, hypoxic load, respiratory load, blood pressure variability, heart rate variability, pulse wave amplitude decline index, ESS drowsiness score, and the following ophthalmologic parameters: optic nerve and macular blood flow OCT, visual acuity, refraction, intraocular pressure, visual field, and eye axis as measured by IOLMaster. Paired t-tests will be performed to analyze the changes in the above indexes before and after CPAP treatment; ANOVA with repeated measurements will be performed to analyze the long-term changes in the above indexes. The aim of this study is to analyze the relationship between sleep apnea severity hypoxia indexes and ION in OSAHS patients. To analyze the improvement of ischemic optic neuropathy (ION) after 3 months of CPAP treatment and to establish a long-term cohort to observe the occurrence of ION in patients with OSA of different severities, as well as the improvement of ION with long-term CPAP treatment.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
80
CPAP therapy will be administered to patients for 3 months. The CPAP device will be set to deliver a continuous flow of air at a prescribed pressure to keep the patient's airway open during sleep.
The First Affiliated Hospital of Nanjing Medical University
Nanjing, Jiangsu, China
RECRUITINGOptic nerve and macular blood flow
Changes in optic nerve and macular blood flow in patients with OSA of varying severity were measured using blood flow optical coherence tomography (blood flow OCT).
Time frame: Baseline and 3 months of CPAP therapy
Apnea Hypopnea Index (AHI)
Number of apneas and hypoventilations per hour of sleep
Time frame: Baseline and 3 months of CPAP therapy
Hypoxic Burden（HB）
The sum of the area between the SpO2 trace and the desaturation baseline associated with all apnoea and hypopnoea events is divided by the total time of sleep.
Time frame: Baseline and 3 months of CPAP therapy
Ventilatory burden
The average ventilatory burden per event was defined as the multiplication of the average ventilation during the respiratory event and average duration of respiratory events. The total ventilatory burden for each participant was defined as the multiplication of respiratory event rate and average ventilatory area per event.
Time frame: Baseline and 3 months of CPAP therapy
Blood pressure variability
The main studies were on ultrashort-term variability (blood pressure variability between each heart beat) and short-term variability (blood pressure variability over a 24-hour period).
Time frame: Baseline and 3 months of CPAP therapy
Heart rate variability
Heart rate variability (HRV) is the variation of differences between consecutive cardiac cycles. For example, the standard deviation of NN intervals in 24 h (SDNN), the standard deviation of the mean of NN intervals per 5 min (SDANN), and the SDNN during wakefulness and sleep.
Time frame: Baseline and 3 months of CPAP therapy
Pulse Wave Amplitude Drops Index
The number of decreases (\>30%) in pulse wave amplitude per hour detected by pulse oximetry based on photoplethysmographic volumetric tracing (PPG) signals during sleep.
Time frame: Baseline and 3 months of CPAP therapy
Time below 90% Saturation
Percentage of total time with oxygen saturation below 90% of total monitoring time.
Time frame: Baseline and 3 months of CPAP therapy
Lowest SpO2 at night
The lowest SpO2 value recorded during the nightly test.
Time frame: Baseline and 3 months of CPAP therapy
Mean SpO2
Mean SpO2 values during nighttime monitoring.
Time frame: Baseline and 3 months of CPAP therapy
Oxygen Desaturation Index
The number of oxygen desaturation events per hour of sleep.The desaturation thresholds of 3% (ODI3) or 4% (ODI4) are commonly chosen in the analysis of OSA.
Time frame: Baseline and 3 months of CPAP therapy
Vision
The patient's naked eye visual acuity in the right and left eyes was checked using a visual acuity chart.
Time frame: Baseline and 3 months of CPAP therapy
Diopter
Qualitative and quantitative analysis of the refractive status of the eye under test using computerized optometry.
Time frame: Baseline and 3 months of CPAP therapy
Intraocular pressure
Measurement of intraocular pressure (IOP) in the eye under test using a non-contact tonometer.
Time frame: Baseline and 3 months of CPAP therapy
Field of view
An automated visual field meter was used to detect the total loss of the visual field and the extent and depth of limiting defects in the tested eye.
Time frame: Baseline and 3 months of CPAP therapy
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Axon of the eye
The IOLMaster was utilized to measure the eye axis of the tested eye.
Time frame: Baseline and 3 months of CPAP therapy