Obstructive sleep apnea is a common disorder linked to serious long-term adverse health consequences; such as hypertension, metabolic dysfunction, cardiovascular disease. Retinal vascular occlusion is related to many systemic illnesses especially hypertension. Obstructive sleep apnea is also related to vascular endothelial dysfunction and vascular endothelial growth factor elevation which causes vision threatening complications of retinal vascular occlusion. Therefore the relationship between obstructive sleep apnea and retinal vascular occlusion should be studied.

Inclusion Criteria:

• Any patient who visits outpatient clinic and diagnosed as retinal vascular occlusion which occurred within recent 3 months

Exclusion Criteria:

• Any ocular disease other than retinal vascular occlusion (for example: floppy eyelid syndrome, uveitis, glaucoma, other retinal diseases)
• Patient who has difficulty answering the questionnaires or portable sleep monitoring
• Patient who refuses the study enroll