Sticky eyes occur when a hamster sleeps for a long time and the natural lubrication of his eyes dries to form a crust, sealing his eyes shut. Sticky eyes can also be caused by a small piece of debris irritating the eye, causing it to leak more.
Although rare, sticky eyes can be a symptom of conjunctivitis. The infection causes discharge to leak around the eye constantly. Colds and allergies also cause a hamster's eyes to stick shut, as can dehydration. Infections are more likely to occur when the tear ducts are blocked.
To open a hamster's eyes, soak a small piece of cotton or wool in warm water and gently wipe it along his eyes. If this is not sufficient, carefully pull the eyelid open after and use the cloth to wipe the area clean. Use a separate, clean cloth for each eye. If the tissue surrounding the eye is swollen and red, the hamster is most likely suffering from conjunctivitis and may need to see a vet for oral antibiotics and eye medications.
As a hamster ages, he becomes more prone to excess discharge and may need more help opening his eyes. Some think this occurs because older hamsters sleep more than younger ones do, causing more fluid to build up and dry out.