The Bulging Rat Eye: Why Does One Eye Look Bigger than the Other?

healthy rat eyes

Normally, both eyes of a rat are relatively even, sitting on top of the head like small, delicate glass beads. Then, one day you wake up to find a terrifying, disturbing problem has occurred: one of your rat’s eyes is now bigger than the other and bulging, as if it was swollen and ready to pop! Is it possible that the rat has an infected eye? Is it cancer? This really is a creepy situation. Every time I see it, it STILL scares me. I always feel as if the eyeball could pop out, and the imagined visuals are enough to make you cringe. However, I don’t intend to make you hyperventilate and trip over your own two feet in an effort to grab the travel kennel and do 90 MPH on your way to the emergency vet. Let’s take a moment and look at what COULD be going on.






Sometimes, rats' eyes will bulge; and when they look like this, it is enough to give you a heart attack. This ratty was well taken care of, judging by the other pictures on xxchelle's Photobucket account! Photo credit: xxchelle on Photobucket

Sometimes, rats’ eyes will bulge; and when they look like this, it is enough to give you a heart attack. This ratty was well taken care of, judging by the other pictures on xxchelle’s Photobucket account! Photo credit: xxchelle on Photobucket

Is the Bulging Eye Infected? Oozing, Weeping, Crying, Crusty, Gunky, or Goopy?

The very first thing to look for is ANY sign of infection. As far as the eyeball’s health is concerned, infection is what you really have to worry about. If the eyeball seems to be oozing or weeping, clean the gunky build up away from the eye as much as possible. Use a rat eye wash recipe in order to cleanse the eyeball, or a saline wash like the one to the right. Once all of the crusty funk is gone, check for cuts, scrapes, or scratches on the eyeball’s surface. Also, check to see if the inside of the eyeball is cloudy. If it is, chances are the rat has already (or will) lose vision in that eye. An infection is going to require some proper antibiotics for treatment.

Is There An Inner Ear Infection That Is Causing the Bulge in the Eye?

healthy rat eyes

This is what the normal eye of a healthy rat should look like

One of the less serious causes of a bulging eyeball is the typical inner ear infection. Now, don’t let this fool you: inner ear infections should NEVER be taken lightly. They require medical treatment, or complications will occur. These include but are not limited to: respiratory infection, deafness, infection of the blood, and potentially death.  This cause is usually associated with head tilt, or wry neck. The rat will keep its head tilted, turned, and pulled to one side of the body. It will also seem to be in a drunken stupor, stumbling around the cage. This is because when the inner ear becomes infected, the rat loses its sense of balance and much of its hearing. Your rat could go from seeming normal to being in this pitiful state within hours. It will alarm you, but just remember to remain calm and treat him or her with medicine regularly. Once the infection of the inner ear is under control, the eyeball should return to normal. I will say that this is also a common secondary infection that commonly results from respiratory infections, which are characterized by excessive rattling and a greatly increased production of red colored tears.

This rat has a much less serious case of bulging than the previous rat. As you can see, the swollen eyeball has some clouding. this can signal infection, blindness, or both. Photo Credit: Nickelrat on Photobucket

This rat has a much less serious case of bulging than the previous rat. As you can see, the swollen eyeball has some clouding. this can signal infection, blindness, or both. Photo Credit: Nickelrat on Photobucket





Does a Rat’s Eye Push Out of It’s Head When There is a Brain or Pituitary Tumor?

Unfortunately, one of the most dreadful causes of a bulging eye is the brain or Pituitary tumor. These tumors are pretty much a death sentence for any rat, as it is extremely tricky to remove or treat them. You can usually distinguish yourself between the different causes of bulging eyes, but this one could come with a long list of accompanying symptoms.

Sleeping rat has its eyes closed. Sometimes, rats will sleep with their eyes open; but it isn't very common. Photo Credit: Starsandspirals via Flickr

Sleeping rat has its eyes closed. Sometimes, rats will sleep with their eyes open; but it isn’t very common. Photo Credit: Starsandspirals via Flickr

First, you need to ask yourself if the rat has been acting strangely in recent weeks. Unusual aggression, depression, odd eating habits, new quirks, and new social patterns can all signal a potential tumor. As these little odd things occur, you may not notice them. Then, the bigger symptoms start. One or both eyes may seem to protrude farther. The rat might run a weird schedule (trouble sleeping, awake at odd hours), and he or she may seem to lose balance more frequently. As it worsens further, the rat will likely become unable to climb or utilize fine motor skills, and could even begin running in circles. In other cases, the rat may simply stop breathing one day, as the area of the brain that controls vital organ functions may be suffocated. It always depends on the location of the tumor within the brain.