There are some common signs that can indicate your horse may have a problem with its eye.  These include:

• Discharge from the eye – a tiny amount of  dried mucous at the inside corner is normal, but anything more may reflect a problem.
• Closed eyelids – if your horse is holding one eye tightly closed, or even just slightly more closed than the other, this probably means he has a painful eye.
• Photophobia – this means your horse doesn’t like bright light, and can mean their eye is painful.
• Closed pupil – if your horse’s pupil is very small on one side compared with the other then it may reflect pain.
• Opacity on cornea – the front of your horse’s eye should be totally clear.  Any cloudiness or discolourations need to be examined.
• Swelling – swelling of the eyelids or conjunctiva can reflect a problem.