If you often wake up with red, gritty, or irritated eyes, it might not just be from screen time or a fan. Sometimes, the real cause is obstructive sleep apnoea (OSA) — a breathing disorder that can quietly affect your eye health too.
How Sleep Apnoea Itself Can Cause Dry Eyes
Oxygen Drops and Inflammation
When breathing repeatedly stops during sleep, oxygen levels fall and the body triggers inflammation. This can affect the tear glands and eye surface, leading to dryness, burning, and redness.
Floppy Eyelid Syndrome
A strong link exists between OSA and floppy eyelid syndrome (FES) — a condition where the upper eyelid becomes loose and flips open during sleep. Tears evaporate, leaving the eyes sore and sticky in the morning. Up to 90% of people with FES have OSA, so eye doctors often refer these patients for a sleep study.
Sleep Position and Eyelid Opening
People with untreated OSA often toss and turn or sleep in awkward positions that help them breathe but cause partial eyelid opening (nocturnal lagophthalmos). This lets tears dry out overnight and can make morning irritation worse.
Shared Risk Factors
OSA and dry eye disease often occur together because they share risk factors such as:
- Age over 40
- Obesity
- Diabetes or high blood pressure
- Male sex (though risk rises for women after menopause)
How CPAP Therapy Can Also Cause Dry Eyes
For people using CPAP (Continuous Positive Airway Pressure) to treat OSA, eye dryness can sometimes still occur — but for different reasons.
Why CPAP Can Dry the Eyes
- Mask leaks: Escaping air blowing toward the eyes overnight.
- Low humidity: Dry pressurised air without enough moisture.
- Mask type: Full-face masks leak upward more easily than nasal designs.
How to Fix It
- Re-fit or replace cushions if leaks occur.
- Use the heated humidifier on your CPAP device.
- Try a mask liner or nasal-only mask if suitable.
- Use lubricating eye ointment or moisture goggles overnight.
When to Seek Advice
- If your eyes are persistently dry, red, or irritated:
- See an optometrist or ophthalmologist to assess eye surface health.
- Ask your sleep clinician about an at-home sleep study or CPAP check-up.
- Treating OSA can improve not only your energy and focus but also your eye comfort and overall wellbeing.
References
- McNab AA. Floppy eyelid syndrome and obstructive sleep apnoea. Ophthalmic Plast Reconstr Surg. 1997;13(2):98–114.
- Kadyan A et al. Ocular findings in sleep apnoea patients using continuous positive airway pressure. Eye (Lond). 2010;24(5):843–850.
- Karaca EE et al. The effect of obstructive sleep apnoea syndrome on ocular surface and intraocular pressure. Curr Eye Res. 2014;39(6):561–566.
- Lupi O et al. Relationship between dry eye disease and sleep quality. Ocul Surf. 2020;18(2):366–374.