Physical Exam: Eye Eye

September 3, 2007

Though it seems a small part, the eye exam is a very important part of the routine of the exam. Often in the doctor’s notes you will read:

Eyes: PERRLA, EOMI, Anicteric

This translates: Pupils Equal, Round, Reactive to Light and Accommodation, no yellowing of the eyes.

Pupil Exam

No, this is not the kind of pupil exam I am referring to.

If you hold up a light to a person’s eye, the pupil will get smaller. That is what is meant by reactive to light. In certain circumstances, they don’t react to light as well:

• A person on narcotics will have their pupils very small. If someone is comatose and has constricted pupils, chances are good it is an opioid overdose.
• A person who has had a seizure or who a head injury may have very sluggish reactions to light.
• A person who is taking medications with anticholinergic properties (such as antihistamines) can have a dilated (enlarged) pupil. Interestingly, women of past eras used to put drops in their eyes to dilate the pupils. This was felt to be a sign of beauty, and so the medications used to do this are now referred to as bella donna (beautiful woman) alkaloids. I guess it beats a Brazilian butt lift.
• When one pupil is exposed to light, the other will also constrict. This is called a consensual response. If a pupil responds consensually but not to direct light, it is called a marcus-gunn pupil, and it is a sign of multiple sclerosis.
• It is relatively common for people to have one pupil larger than the other, a condition known as anisocoria (which came close to making my list of words fun to say aloud). When you shine a light on both eyes, they both constrict down to the same size, however. There is no danger in having this condition.
• When a person is comatose and one pupil gets much larger than the other, it is a sign of serious problems with the brain - called a herniation. This is an ominous sign referred to by the physicians as “blowing a pupil.” If immediate action is not taken, the person is likely to die.

Pupils also constrict when a person focuses at closer points. This is what is called accommodation. I have found little use for checking accommodation on exams, so I usually write “PERRL” instead of “PERRLA”

EOMI

Extra-ocular eye muscles are the muscles that let you look in different directions. In children, the main problem with them is that the eyes don’t line up with each other properly. This is what is called a strabismus. If a strabismus is not caught and treated at an early enough age, one eye generally becomes dominant and the other eye cannot see. This condition is called amblyopia.

The interesting thing about this is that the eye itself functions perfectly well. It is actually the mapping of the input from the eye that is not proper in the non-dominant eye. This is why children are sometimes patched over one eye - it forces the non-dominant eye to have enough input of stimuli until the eye muscles can be surgically repaired.

In adults, there are a number of things that can mess up the extra-ocular muscles, the most common being a stroke.

Irises

The iris is the part of the eye that gives eye color. There is not much significant to say about the iris exam, except eye-color is often a question pediatricians get very early. For most Caucasians, babies start out with blue eyes. Brown eyes become apparent within the first few months of life, while the changing of the eye from blue to green is a much slower process. Generally eye color is set by three months, but can even change in adulthood (according to some sources).

Let me add here that those contact lenses that change eye color look really creepy up close. I have on patient who wears blue-eyed contact lenses that are too small and this leaves a rim of brown around the blue iris. It does not look human. Kind of like that spooky Elmo picture I used in an earlier post.

Conjunctiva

Pink eye.

Those two words that strike terror into the hearts of parents and daycare workers across the country.

HIV. Ebola Virus. Small Pox. Hepatitis B. All pale in comparison with that horrible plague: Viral Conjunctivitis.

I am not certain why this perception seems to be entrenched in the population. Yes, viral conjunctivitis is quite contagious. It can run rampant through a classroom very quickly. Yet it is only eye redness with discharge. It does not cause blindness. It goes away without treatment. Yet parents are told by daycare centers and schools that they must go to the doctor to get antibiotic eye drops before the child will be permitted back. This is the case despite the fact that eye drops do not make conjunctivitis less contagious. They just prevent the progression of viral conjunctivitis to bacterial conjunctivitis.

So what should a pediatrician do: prescribe an unnecessary eye drop, or hold the scientific high ground and let the eye get better on its own? I bite the bullet and give the eye drops. So far, education of the schools and daycare centers has proved fruitless.

It is far easier to quell the terror than it is to educate the educators.

Red Eye

An acute red eye can actually be quite significant. If someone has one eye become red and painful, they need immediate attention, as it could constitute an emergency.

Several things in the history can create more concern on the part of the doctor:

• Pain in the eye
• Blurred vision
• Double vision
• A crowbar sticking out of the eye socket.

While the last of these has yet to come into my office (thankfully), the other three could mean several things. The first concern is acute angle-closure glaucoma. Some people have eyes with an iris that bulges forward. This means that the angle between the iris and the front of the eye (the cornea) is very small. Under certain circumstances, this can lead to an abrupt rise in pressure in that eye that can only be relieved with surgery.

Another red eye phenomenon that we have seen is an infection with a herpes virus. This can cause significant redness and is generally painful. In one child it actually spread back to the retina and would have caused blindness had my partner not acted quickly and got him immediate attention by an ophthalmologist.

Yes, you can get an ophthalmologist out of bed at night.

The Retina

The retina is the only part of the brain that can be viewed with the naked eye. When you take a flash picture of a person it can result in “red eye.” This is the blood of the retina that you are seeing. Disgusting, isn’t it?

The retina exam is actually one of the more difficult parts of the exam for me. My ophthalmology friends say that it is a veritable wealth of diagnostic information, but it just looks about the same every time I look (if patients don’t have cataracts that block the view). My diabetic patients are sent to the eye doctor every year to screen for diabetic retinopathy - a condition that is the leading preventable cause of blindness.

The simplest version of the retina exam has yielded me the most dramatic outcome. The “red reflex” is the exam finding in infants when I shine the light on the baby’s eyes and look for the red-eye response. While newborns can have a significant amount of swelling of the lid and make this exam difficult, I repeat the exam at every visit for children under 12 months to look for something called retinoblastoma. Retinoblastoma is a tumor that occurs in the retinae of very young children. It is an aggressive tumor that can not only lead to blindness in the child, it can become metastatic and lead to death.

I did diagnose this once in a child on their two month exam. I did pretty much the ritual exam I had done for many years prior to that, including looking for the red reflex in the child. One of the eyes was obviously white, and not red. The child was immediately sent for treatment and actually did very well. This is clearly a case where doing the same thing a thousand times made discovering the abnormal much easier.

Wrap-up

OK, my eyes are starting to get heavy. There is more I could cover, but I suspect you’d start to get that cross-eyed thing you get when you are falling asleep while reading.

The eye exam is often simply relegated to PERRLA EOMI, but the abnormals that do walk into the office can make life quite interesting for a doctor.

As long as you keep your eyes open.

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