Chinchillas have beautiful, dark eyes that compliment their big ears and tiny paws. These beautiful eyes are usually problem free but occasionally you may run into an issue with them and have to take them to see their vet.
There are a plethora of diseases that affect the eyes of chinchillas but some are seen more often than others in the vet clinic.
• Corneal Ulcers - Sometimes eyes get scratched or irritated by hay, hair, dust, or even after a struggle with another chinchilla. These scratches or irritations can cause a defect on the cornea of your chinchilla's eye known as a corneal ulcer. An ulcer is a painful defect and may cause a bit of cloudiness or redness to the eye. Your chinchilla may paw at the hurt eye, keep his eye closed, or even rub it on the ground. The pain may cause him to stop eating and even develop ileus if it is really bad. Corneal ulcers may be treated with special eye ointments. Some of these ointments are antibiotics and some are made specifically to heal ulcers. If the ulcer is really bad or hasn't healed after the use of some medications your vet may draw some of your chinchilla's blood, centrifuge it, and use the serum that is produced as eye drops to help the ulcer heal. If the ulcer still hasn't healed, a grid keratotomy may need to be performed on the eye to encourage healing. This procedure is done under anesthesia.
• Eye Infections - If an eye gets irritated for some reason or exposed to excessive amounts of bacteria or fungal spores it can get infected. Bacterial and fungal infections can affect one or both eyes and need to be treated with the appropriate antibacterial or antifungal medications. Your chinchilla may have hair loss around his eye, redness (conjunctivitis), discharge, swelling, and even keep his eye shut. Your exotics vet may choose to treat the eye without obtaining a culture first but if it does not resolve, or if you want to do the best thing possible for your chinchilla, a bacterial and/or fungal culture should be obtained. The culture will tell your vet exactly what bacteria or fungus is growing around the eye and will allow him to pick the correct treatment for your chinchilla. If your chinchilla has a lot of discharge from his eye and it is crusting shut you can use a warm, damp, cloth to gently clean it until you can see your vet. 
• Overgrown Teeth - Chinchilla teeth don't technically have roots but the part of the incisors that would normally be considered roots can grow into the nasal-lacrimal duct and cause your chin's eye to weep.
• Tumors - Sometimes tumors will develop behind the eyes of chinchillas. These tumors can cause an eye to bulge, swell, and be very uncomfortable. Sometimes radiographs (x-rays) will show a suspected tumor on the skull and your vet may want to send the radiographs off to be read by a radiologist to confirm it. If nothing shows on an x-ray an MRI may be recommended. Many other problems can arise with your pet chinchilla's eyes but regardless of the issue, if you think something is wrong with your little friend make an appointment with your exotics vet as soon as possible.
From: http://exoticpets.about.com/od/Health/a/Chinchilla-Eye-Diseases.htm
