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.

Inclusion Criteria:

1. Patients aged between 18 and 80 years.
2. Diagnosed with Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS)(apnea-hypopnea index≥5/h).
3. First-time diagnosis, with no previous surgical interventions or CPAP treatment for OSA.
4. Ability and willingness to provide informed consent for participation in the study.

Exclusion Criteria:

1. History of severe stroke or cerebral hemorrhage, or presence of neurological or psychiatric conditions that could affect study results.
2. Presence of active malignancies or other severe underlying diseases, such as severe liver or kidney dysfunction. Diagnosed with diabetes or other significant vascular diseases.
3. Presence of severe chronic obstructive pulmonary disease (COPD), severe asthma, severe pulmonary hypertension, or heart failure caused by any condition.
4. Pregnancy or having other conditions that make participation in this study unsuitable.
5. Extremely debilitated patients or those with severe underlying conditions.

The individual participant data will not be shared. The informed consent will be ansigned before enrolled in the study and ensured to keep personal information confidential.