Which reflex would the nurse assess for when using an ophthalmoscope

Hi.  My name is doctor Errol Ozdalga.  I'm a doctor at the Stanford School of Medicine, a hospitalist and also a member of the Stanford Medicine 25.  The purpose of this video is to teach you the approach to looking at your patient’s retina. Normally we think of eye doctors as the ones who are looking in patients’ retinas.  However if you're taking care of a patient we want you to also be comfortable doing the same thing so that's the purpose of this video.  So let's get started. 

Before we can do anything else we have to talk about the equipment. Usually we use direct ophthalmoscopes.  Indirect ophthalmoscopes are the type of gear that the eye specialists wear on their head.  These direct ophthalmoscopes come in a couple different forms and twoof the most common ones I'm holding in my hands. You have the traditional one here and also the pan optic. For the purpose of this video we're going to be mostly sticking with the pan optic because one, it's easier to use and two, has a greater field of view.   Now I should also mention while we'll go over the mechanics of using the pan optic it's essentially the same thing as this ophthalmoscope as well and we'll talk about that in a second.

Now for the ophthalmoscope there's three main things to know. 

The first one is light or brightness.  So for the brightness all you need to do is press the little button and twist it and the more you twist it the brighter the light will become.  There's two things to remember when dealing with brightness.  Number one: the brighter you make it the more pupil constriction you may get if you're not using a dilator. Number two: the brighter it is the more painful it will be for the patient so you won't be able to visualize the retina as long.  The second thing to know about the ophthalmoscope is this carousel setting right here and this carousel setting allows you to change the different types of light coming out of the scope, so the most important thing to know is this green line here. 

This green line will provide a medium-sized circle which is what I recommend most people use. If you slide the green line to the right or to the left you'll get varying sizes of that circle, a larger one or a smaller one.  The purpose of that is simply that if a patient's more dilated or more constricted you can check it. 

You can adjust the light as needed. You'll also see here a tiny slit lamp to look for variations in contour.  The second thing you can also see is a blue cobalt filter.  Certain scopes have that, certain come with that and certain don't, so if yours has that, it allows you to look at abrasions on the cornea if you add a Fluorescein dye.  There's a green light that comes out and that's the red-free filter.  The purpose of that is to see better contrast on the red blood vessels in the back of the eye.

Right now the third and final setting to know about the pan optic is regarding these numbers here.  The purpose of this third setting is to focus--if you the health care provider or your patient is too nearsighted or too farsighted this setting can actually be used to figure out what your prescription is. All you have to do is look through the scope at something about ten to fifteen feet away and move this knob until it comes in focus and if it comes in focus a little bit towards the red setting that's actually your prescription in diopters.  For someone who's nearsighted or having difficulty seeing far away, another thing to remember is that the pan optic scope is actually very similar to the more traditional direct ophthalmoscope. This knob here correlates very well with this knob here and this setting here that you adjust for near-sighted and far-sighted is very similar to this one here, same idea.

Otherwise one last thing to mention: if you're a healthcare provider and you're very nearsighted and you have to adjust this for yourself, usually you don't have to worry about the patient being nearsighted or farsighted with the pan optic unless they're extremely nearsighted or farsighted. You actually can set it for yourself and not touch it again. For this scope you may have to adjust it more for the patient. That's another advantage of this scope.

So before we start the demonstration I need to make sure that this setting is adjusted for my vision.  So I look at something about 10 to 15 feet away and make sure it's in focus.  After that it's very unlikely I need to touch this setting again. Unless the patient's extremely nearsighted or farsighted you usually can set it for yourself and not have to worry about it again.  If you have 20/20 vision or you have contacts in that lead you to have 20/20 vision you actually don't have to do anything other than leave it right at the zero. 

So we have Jocelyn here and we're examining Jocelyn's right now.  So if you're using the pan optic it comes with this little cup here which allows you to go as close as you want without worrying about running into the patient's eye.  If you're going to use this I recommend maybe just putting it on the patient and getting them used to it so they're not flinching the first time you look at it.  So to do that we're actually going to use an additional adapter called the eye examiner which allows us to attach an iPhone to the pan optic and take video images or stills of her retina.  And the great thing about it as well is it’s great for teaching. You can tell if somebody is actually looking at the retina when they're going in there to do that.  All we do is simply turn on the phone, make sure the setting here is at zero and we leave it at the green setting, the medium-sized circle.  Turn the video on and turn on the light.

So the other important thing to keep in mind is patient positioning. Whenever you're looking at someone's retina you have to make sure that your positioning of the ophthalmoscope is equal to the height of their eyes, whether they're sitting or standing. Sometimes they need to be sitting or standing to make the right position, especially if you're a different height from your patient.  So we want to make sure you're at the same height as them and what I usually ask the patient to do is to ask you to take your thumb and stick it straight out ahead of you, great.  So I'll have her stick her right thumb out if I'm going to look in her left eye and the next thing I'm going to do is make sure my level is the same height. I'm going to come about 15 degrees from center and look for something called the red reflex.

The red reflex is important for two reasons.  It tells you that basically from the camera of this phone all the way to the back of a retina is intact, there's nothing obscuring that such as a cancer in the back of the retina like a retinal blastoma if your patient’s young, or cataracts blurring the lens.  The second thing is it tells you that your angle is perfect for actually visualizing the retina. So the last thing to do is simply go in and visualize the retina.  You just go in and follow that red reflex.  If you lose the red reflex, no problem, just come back, find the red reflex and go back. And again you get closer and closer and closer. You see it there, see the optic disc and a little bit of the bright optic cup within the optic disc and you see the patient's blinking, which is very common.  Sometimes they get uncomfortable and you lose the view. No problem, come back again. Jocelyn is doing great I just want to demonstrate that sometimes you lose it. Excellent.  Same thing come back in there and visualize the optic disc just like that.

Perfect.

Now a couple of things to remember when we're going in.  We're looking, we're going straight for the optic disc.  The optic disc is the best place to visualize because number one, it can be associated with a lot of pathology, a lot of medical pathology.  And number two, there's no rods or cones there so it's going to cause the least amount of pain and least amount of pupil constriction.  If you're focusing light in that area, if you want to visualize other aspects of the retina for the pan optic you simply have the patient look a little bit up to see up, have them look down to see down, medial to see medial, and lateral to see lateral.  Lastly if you're

trying to visualize the fovea or macula you have them look directly at the light.

So now let's talk about abnormal findings.  By far and away when you're looking at the optic disc one of the important things you want to look for is optic disc blurring.  Optic disc blurring in the setting of increased intracranial pressure is referred to as papilledema.  Papilledema can be caused by anything that causes increased pressure in the brain such as brain tumors, pseudotumor cerebri, sinus thrombosis, hydrocephalus, meningitis or encephalitis, malignant hypertension. It should also be noted that while optic neuritis causes optic disc blurring, that's caused by inflammation of the optic nerve, not from increased pressure in the brain. Other abnormal findings you can see in the retina include roth spots as you see here caused by patient presented to Stanford with endocarditis, hypertensive and diabetic retinopathy, and cholesterol emboli also known as Hollen horse black. 

Well that's it, thanks so much for watching the video.  Please join us at the Stanford medicine 25 website to learn more on the retinal exam and a whole host of other bedside exam techniques. The preceding program is copyrighted by the Board of Trustees of the Leland Stanford junior University please visit us at med.stanford.edu.

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