When it’s not the moon…

That hits your eye that is.

Everything was fine when you went to bed last night. You woke up this morning and Cuddles’ eye was bright red, she was squinting and pawing at the eye as well. You called and the veterinarian had an opening so you rushed Cuddles right in. There was some testing, the veterinarian drew a picture, told you it was a “corneal ulcer” and then precribed medication that has to be applied 3 times a day. You get in the car, drive home and when you get there your family asks, “So what happened?” And you have no idea.

Bright red eyes are a fairly common problem in veterinary medcine. There are several reasons an eye, or both eyes for that matter, can turn red. If it is only one eye and it seemed to go from perfectly normal to a bright, angry red, I start to think about corneal ulcer or corneal erosion. A corneal ulcer or erosion is a disruption in the clear protective layer of the eye. When this layer becomes damaged for any reason it is extremely painful and will disrupt the architecture of the cornea. This will cause the surrounding tissues to turn that angry red color and they may even swell up a little bit.

Diagnosing a corneal ulcer is fairly straight forward and one of the more interesting things we get to do in routine exams. First the eye is examined thoroughly visually and then again using the ophthlamascope. We will then typically measure the eye’s tear production as a condition called dry eye may lead to corneal ulcers. Dry Eye Once the tear production has been measured we will place a small amount of a brightly colored stain in the eye, rinse the extra out, turn out the lights and look at the cornea using an ultraviolet light. This allows us to measure two things the first being the quality of tears produced and the second being whether or not there is an ulcer present. For the sake of this week’s post, you guessed it, there’s an ulcer. The stain will “stick” to the edges of the ulcer and may even stick to the bottom of the ulcer as well.

Treatment of an ulcer can be straight forward as well. The cells want to get to the right place and help to fill in the gap left by the ulcer. Utilizing a lubricating topical medication helps the cells do what they are supposed to do. We typically will prescribe an antibioitc eye ointment that will prevent subsequent infection (or treat a present infection) while allowing the cells that are laying down new cornea to migrate freely. The best way to use a medication like is is to apply it at least four times a day, preferably more. It is the very rare owner that has the time to apply medication to their pet’s eyes four times daily and it is an even more rare pet that tolerates this. For that reason we typically have to make due with three times daily. We also want to treat the pain associated with corneal ulcers. These things are really painful. Most of the pain is caused by the spasming of the iris, the colored part of the eye, in reaction to the inflammation associated with the ulcer. We stop this by paralyzing the iris with atropine. This causes the pupils to dilate so you might be careful about taking Cuddles out in the bright sun. This might also cause a cat to drool a bit after application, this is normal and will only last a few minutes. The pain relief on the other hand lasts for hours.

An Elizabethan collar (cone of shame) may be necessary to keep Cuddles from pawing at his eye while it is healing. If Cuddles has been pawing the eye or you are worried he might, a collar is a good way to get some piece of mind.

It is important that you have the eye rechecked every week or two until the ulcer is resolved. If the ulcer is not healing or the inflammation starts to spread we might have to be more aggressive with it. Some may even require surgery to protect the area of the cornea while the ulcer heals. Typically if an ulcer is not healing the way we think it should be, I start to talk about involving an ophthalmologist. Before we go down a long path of trying to make something work and potentially end up frustrated and with months worth of time and money invested, when the “usual” line of treatments don’t work, involving someone who has dedicated their entire profession to treating eyes is the most cost effective and efficient move.

Thanks for reading!