How does sleep apnoea reduce your vision?
Although no one is 100 per cent sure, sleep apnoea is thought to damage your sight for the following reasons:
- A decline in the oxygen level in your eyes during apnoeas directly damages nerves.
- A build up of fatty deposits in the blood vessels that supply blood to the eye narrows them so less blood reaches or drains from the eye. This also damages nerves.
- High blood pressure within you eyes places pressure on the nerves.
- High blood pressure in your head squeezes the fluid in your eyes, placing pressure on the nerves.
- If you are obese, excessive fatty tissue within the eye can also increase the pressure within the eye.
Sleep apnoea and eye diseases
If you have sleep apnoea you are more likely to develop the following eye diseases:
Glaucoma – a build up of excess fluid in one or both of your eyes. This extra fluid places pressure on the nerves in your eyes, eventually leading to blindness.
Non arteritic ischaemic optic neuropathy (NAION) – the major nerve in one or both of your eyes is starved of oxygen leading to a reduction in sight.
Retinal vein occlusion – a blockage in a vein that removes blood from the retina, a membrane at the back of the eye that helps you to see. The retina becomes bruised and swollen causing a reduction in vision.
Central serous retinopathy – fluid builds up underneath the retina and a small part detaches from the back of the eye. This leads to a reduction in sight.
Effects of continuous positive airway pressure (CPAP)
A CPAP machine is used to treat obstructive sleep apnoea. It prevents full or partial airway closures and enables you to gain good quality sleep.
While most people with eye diseases get on well with CPAP, on some occasions it can actually increase the pressure in your eyes. It is important to tell your sleep specialist about any problems you have with your eyes before you start treatment. You should also receive regular eye examinations while you are using CPAP to ensure the condition of your eyes does not deteriorate.
