Skip to main content
What Exactly Are Doctors Trying to Find in My Eye?

You are listening to Health Library:

What Exactly Are Doctors Trying to Find in My Eye?

Oct 31, 2018

Sometimes when you pay the doctor a visit, he’ll hold a little flashlight up to your eye and joke that he's looking into your soul. But what are doctors really trying to find when they look into your eyes? Emergency room physician Dr. Troy Madsen talks about the situations that would cause him to pull out his little flashlight, and you might be surprise to learn that the two top reasons have nothing to do with the eye itself.

Episode Transcript

Interviewer: What is a physician trying to find when they look into your eyes? That's next on The Scope.

Announcer: Medical news and research from University of Utah physicians and specialists you can use for a happier and healthier life. You're listening to The Scope.

Interviewer: A lot of times on TV you'll see, or if you've ever even gone to the doctor yourself, they got the little flashlight and they start looking in your eyes and I've always wondered, what are they looking for? We're with Dr. Troy Madsen, emergency medicine at the University of Utah Hospital. In your particular situation, in the emergency room, if you get out the light and are looking into somebody's eyes, what are you trying to figure out?

Dr. Madsen:It's going to vary depending on who I'm looking at. But it's just part of a standard physical exam that when I see a patient I will document something that says on the chart, PERRL. What that stands for is the pupils are equal and reactive to light. And the pupil is the black part of your eye so I'm looking at that. I'm looking at are they the same size, and when I shine a light into it does it close? Does it react to that light and constrict like you'd expect?

And the relevance of that kind of varies from person to person. I mean, in the average person, it's not really a big issue. I can just kind of look at you and look at your eyes and say, "Oh, yeah, they look fine." But in different situations I'm looking for different things.

So if someone comes in after a head injury and they've been in a trauma, I really want to get a good look at those eyes to make sure the pupils are equal, because if they're not, that can be the sign of potentially something very serious in the brain that is affecting the brain's ability to send that message to the eye to have that pupil squeeze down and constrict. That can be a sign of some kind of bleeding in the brain, which is the more serious thing I'm really looking for there. So that's kind of the number one thing I'm looking when I do that.

The other thing I'm looking for often times, and this is a tough thing to do sometimes in the E.R., but sometimes I'll try and get a look at the back of the eye at what's called the fundus of the eye, called a fundoscopic exam, where I'm looking at optic nerve, so where the nerve inserts into the back of the eye. And if a person has a lot of pressure in their brain from bleeding in the brain or something like that, I can actually see swelling on that nerve. So that for me says this person potentially has something that's raising the pressure in their brain, like bleeding, a tumor, something like that. So that's kind of the other big thing I'm looking for when I do that.

Interviewer: All right. So two reasons you would look into somebody's eyes, none of them related to the eyes. Are there things you're looking in somebody's eyes for if they have an eye issue?

Dr. Madsen: Oh, certainly. Yep. And that's one of these things where if someone . . . and usually there I need to have something that's going to push me toward that, someone saying I'm having a lot of pain in my eye or I feel like just something is scratching my eye. And there, I'm going to do an even more detailed exam. I'll kind of flip their eyelid out, kind of like kids do to gross people out. So I'm doing that to look for some kind of piece of dirt or a splinter or something like that in the eyelid itself that's scratching the eye.

Interviewer: And that actually happens?

Dr. Madsen: It does.

Interviewer: That's gross.

Dr. Madsen: Oh, it does, yeah. And then I'm looking at the cornea, so the front part of the eye and sometimes you'll look at that, you'll see little pieces of metal that are stuck on there, say, from a welder or someone who is working with metal. I can see that. Sometimes I'll see a rust ring there. You can actually see rust on the eye itself from a piece of metal that may have been there and then came off.

And then I'll do a very detailed exam, something called a slit lamp exam. It's basically a microscope where I'm sitting down kind of with this microscope that focuses right on the person's eye. I'm looking in the front part of the eye for any, what we call just any cells, any inflammation there that would suggest a lot of irritation in the eye itself. And then I actually put a little thing on the eye that's kind of like a dye that will light up to look for any scratches.

Interviewer: Okay.

Dr. Madsen: Which is what's called a corneal abrasion.

Interviewer: Sure.

Dr. Madsen: So lots of different things you're looking for there on the eye.

Interviewer: So any of these tricks that people can try at home? For example, taking the flashlight and if a person's pupils aren't dilating properly, knowing that you might potentially have an issue?

Dr. Madsen: Yeah, and that's something you can do. If you've had a head injury and you feel comfortable looking at that, you can even look at your own eyes in a mirror and just say, "Do my pupils look like they're the same size?" If you have a family member who's had a head injury, you can shine a light in their eye, just watch, does that pupil squeeze down? And at the same time that one squeezes down does the other one do the same thing? And if it's not, those are concerning things.

Interviewer: Is time of the essence for any sort of eye injuries, generally?

Dr. Madsen: It is, yeah. So time is really of the essence for eye injuries if you actually have something that cuts the eye open. So if we have what's called an open globe injury, so the globe being the eye, the big eyeball, if something actually gets in there and cuts that where there's fluid coming out, time is absolutely of the essence. You need to get to the emergency department. We call our ophthalmologist and they'll oftentimes get you to the operating room to repair that emergently.

Interviewer: All right. Any final thoughts on the eyes?

Dr. Madsen: Final thoughts on the eyes. Obviously, a lot of these things are things we are going to need to do in the E.R. but, like you said, you can kind of take a look at the eyes at home. And certainly if anything comes up, make sure you come in so we can evaluate you further.

Announcer: Have a question about a medical procedure? Want to learn more about a health condition? With over 2,000 interviews with our physicians and specialists, there’s a pretty good chance you’ll find what you want to know. Check it out at

updated: October 31, 2018
originally published: March 19, 2014