– In today’s video we’re gonna be discussing how to assess eye position in your patients, and why it’s important for those who are applying clinical neuroscience in their practice. Hello, my name’s Dr. Freddy Garcia, today we’re joined by Dr. Jessica Lofgren. We are gonna be talking eye position in our patients, and a device that we like to use called the Maddox rod. Dr. Lofgren, how are you doin’ today?
– Good good, how are you doing today?
– I’m doing great. Okay, so give me the scoop, what is this Maddox rod, where’d it come from?
– Yeah, so the Maddox rod, it was created in 1890 by an english surgeon and ophthalmologist, E.E Madox, and at the time he was known as an expert in the field of phorias and eye deviations. So what it is, it’s just a color tinted glass. It can come in any color, reds, greens are the common ones. And we discussed why you’d use other colors in our clinical neuroscience program. But what it is, it’s just different cylinders lined up about three millimeters apart, and when you bring it up to the eye and shine a light through it, it creates a dissimilar image which is good for our clinical examination.
– So what is it’s prime purpose? What type of information am I looking to get from the use of a Maddox rod?
– Yeah, so the only information that you get from the Maddox rod is eye position. The ability of both eyes to fixate on the same object. Traditionally, it was only used to decide what kind of prisms they’re gonna use in the ophthalmology clinic, now we use it functionally as a way to assess how the cortical and sub cortical regions are functioning as well as the eye muscle integrity that controls the ocular movements.
– Right, so I guess a Maddox rod prepared along with a good physical, neurological examination give you kind of insight into the person’s nervous system, and how well it could be functioning.
– But it’s soul purpose first, eye position, and then along with everything else, we get a little bit of more information from it.
– Exactly, yep.
– Sounds pretty good, alright, well I guess the next thing we should do is learn how to use it.
– Yeah, let’s do it.
– Okay, Dr. Lofgren, I want to use how to use this Maddox rod, how does it work?
– Yeah, so we are going to test horizontal deviations first. So what we see with many practitioners is that they will take the Maddox rod, and they’ll test both eyes. But the correct protocol to do this with is just to use the right eye during all of your Maddox rod testing. All it is is because if we’re doing both eyes, it’s just giving us the same results, and it sort of just takes up more time than we need to be using because all the Maddox rod is doing, it’s just creating a dissimilar image. So it’s just converting the light source into a line, so we see the right eye’s looking at a line, and the left eye is looking at a light. So really, just the right eye is all we need. So for horizontal, we’ll start with those first.
– So, for a horizontal deviation, the doctor is gonna be looking at horizontal lines, and the patient is gonna see a vertical line.
– So what we’re gonna do, we’re testing near first. So I’m gonna hold up the Maddox rod right up to the patient’s right eye, and I’m gonna shine the light about 33 centimeters away from them.
– So, let’s turn on our light. I’m looking at horizontal lines. I hold my light source up, and I ask the patient now, “Do you see a red line, “and a white light?”
– Alright, I see a vertical red line.
– And I see a white light.
– Perfect, now where is the light in relation to the line?
– I see the white light just a little bit past to the right of that vertical line.
– So the light is to the right of the line?
– Yep, just a little bit.
– Perfect, so there are three possibilities that we can get from looking at horizontal deviations.
– So, the first possibility, we have the red line, and the white lieu directly on top of the red line.
– That wasn’t me this time.
-So that is a normal, that means that both eyes are looking at the same
– Oh, not normal, okay.
– object. So, Dr. Garcia is not normal.
– We all knew that.
– The second outcome that we can get is having the red line, and the white light to the right of that line. That is gonna tell us that the patient has a slight exodeviation, or exophoria on the right side, or they have an esophoria on the left side.
– Got it, and figure out which one I have, we wanna follow it up with more testing. Typically, I believe it’s cover-uncover, and cross cover testing, right?
– Correct, yep.
– Sounds like we’ll have to do a future video on that.
– Definitely, let’s do a different video on that later.
– And now there’s one more response you can get, and so that would be a red line with a light on the inside, or to the left of the line. That will give you a esophoria, or esodeviation on the right eye, or an exophoria on the left eye. Again, cross cover, or cover-uncover tests it’s gonna give you which eye it is, and give you more information about it.
– Got it, well what about vertical, the vertical aspects, how do we get that?
– Yep, so vertical’s not too hard to change. So we had the horizontal lines, and we are looking for horizontal deviations. Now we’re just gonna flip it over, and we’re gonna be looking at vertical lines, so that the patient is looking at one horizontal line.
– So, same thing as before, I’m using the right eye. I’m gonna hold it up so I’m seeing vertical lines, and then I’m gonna bring the light up. And again, ask the patient, “Do you see one horizontal “line in the light?”
– Yep, I see a horizontal line, and this time the light is right on that line for me.
– Great, so Dr. Garcia is normal in the vertical plane. So he is seeing both images in the same location.
– There are three responses for that as well.
– Okay, what are those?
– So, same ones as before. So we have a horizontal line now that they’re looking at, if the light is right on the horizontal line, it’s normal, just like Dr. Garcia was. If it is above the line, it is gonna be a hyper deviation, and if it’s below the line, it is a hypo deviation. Now be aware, that’s a deviation in relative to the other eye.
– Got it.
– So, it’s a hyper deviation relative to the left eye.
– So then, we have to do future testing to find out whether it’s actually a hyper of the right eye, or hypo of the left eye?
– And again, is it cross cover-uncover, and cross cover testing for that?
– Yep, those are the same tests that we would use, and remember we always reference the hyper deviated eye when we’re doing our exam findings.
– Okay, excellent. Dr. Lofgren, that was really good explanation. I’ve always been you know, kind of confused about how to do appropriate Maddox rod testing, but I love the way you explained it. I think we have a follow up video ’cause we should definitely show everybody at home how to do appropriate cover-uncover, and cross cover testing. But for now, this is great. Thank you so much.
– You’re welcome.
– Alright guys, that’s all today on the Maddox rod and eye positioning. Until next time, this is CITV, we had Dr.Lofgren, and my name’s Dr. Garcia, we’ll catch you next time.