 Okay, so everything you ever wanted to know about visual fields So first of all, we'll start with kind of the basics of what is a visual field test? Why do we do it? How do we pick which test we're going to use all that stuff? so normal visual field is You know basically just limited by your anatomy So why does temporally and then narrowest because of your nose and your your eyebrows are limiting there But that's what a normal visual field is the vast majority of this Is just very unsensitive Areas of the retina so that's why we only test within the central 30 degrees because that's where most of the rental ganglion cells are located And even within that 30 degrees that peripheral edge of your 30 degree visual field isn't very sensitive So what is a permetry test? It's basically giving you a map of the visual field. There's two different kinds There's the kinetic which gives you a topographic map and then there's the static which gives you a vertical map What is an abnormal visual field? It's any defect or depression and sensitivity Compared to the normal hill of vision. So your sensitivity is basically your ability to detect light You can have a focal scatoma or diffuse relative or absolute scatoma And then this is the one the patients always want to know about well, how come I don't notice that I'm losing my vision It's because of the filling in effect, which is the same reason why you don't notice your own blind spot Your brain is taking your context clues from everything else that's around and filling in that gap does the same thing with glaucoma I tell I describe it to patients is like the photoshop effect. So it basically your brain is Taking what it thinks should be there and filling it in. That's why patients will sometimes When they are first noticing their glaucoma, they'll say hey like when I play tennis all of a sudden I feel like the ball is all of a sudden in my face and That's because they're not able to compensate anymore The movement of the ball is revealing all of their new visual field defects or why cars are like all of a sudden speaking up on them Their brain can't compensate for moving objects And so that unmasks their visual field defects So this is the diagram that you see in your books and I never really understood What this was the whole time I was a resident it made zero sense to me I was like, I don't understand what this is trying to show me basically If you think of your visual field as an island of vision in a sea of darkness It's this kind of thing Coming out of the water and there's different levels of the ability of your visual field to detect light So it can be measured in two different ways Like an airplane looking down doing an actual topographical map And that's your goldman field where the highest point in your visual field is your most sensitive That's the area that can detect light the best and then the lowest point is The peripheral field has the lowest sensitivity or like a ship at sea That's actually seeing an island come out of the water and that is a Humphrey visual field. That makes sense So there's your there's your island You're looking down on it from above you're slicing those layers into layers of the cake And then you get your topographical map and each one of those lines is an eye softer or a level of brightness. So This works, right? You guys know so the the far peripheral one is the brightest light and then moving in and in and in is increasing decreasing levels of brightness and And Then here is the vertical map. So in the middle So the island of vision is measured by depth of sensitivity So the highest most sensitive point is the apex of the hill, which is your macula And that's why the numbers in the middle of your visual field print out and the raw data are the biggest numbers Because it's the most sensitive part So you'll see there's naturally a drop-off if you look at the raw data in your visual field as you move From central to peripheral and that's not because there's any visual field defect there That's just because naturally that part of the eye is less sensitive Okay, so what are we measuring and how are we measuring it? The basic unit is the decibel and the apostelb The apostelb is a measure of the luminance of light, which is basically light intensity For Humphrey the maximum brightness is 10,000 apostelbs And then the decibel is a measure of attenuation of that light So light is attenuated within the visual field by using Neutral density filters the higher the decibel means the more attenuation So the dimmer the stimuli so a decibel of like 32 is a much dimmer stimuli than a decibel 10 if that makes sense and it's a logarithmic scale, which we'll get into in just a second So when you see on your raw data print out a decibel of zero It does not mean that the patient couldn't see that light It means the patient could see that light that had zero attenuation So the patient was able to see light without any attenuation at all the brightest stimulus the machine can provide When the machine gives you a value of Less than zero again, it doesn't mean that the patient is absolutely blind in that area It just means that patients not capable of seeing the brightest light that the machine can produce But if you take a fennhof and shine it in their eye, you know, they can see something And then we're measuring to find threshold which is the dimmer stimuli or the most attenuated amount of light that is seen by the patient 50 percent of the time And that's why patients hate this test is because they feel like they're constantly like Second guessing themselves. Did I miss something? Like I feel like I should be seeing more or I felt like maybe I saw that light But I'm not sure that's what the machine is trying to do is find that level where they can just barely see it Once I tell them that Oftentimes they feel a lot better about taking the test So sorry now, we know what we're measuring now. How do we choose the right test for the right patient? We talked about kinetic versus static. There are some Sometimes when a kinetic is the better choice for the patient Or you know one if you think they're they're faking it's a lot harder to fake A kinetic a goldmine that it is to fake a Humphrey So for non-organic vision loss really really severe vision loss where you feel like Your your fields are just blacked out on a Humphrey also oftentimes you'll be able to with that brightest stimulus And a goldmine still be able to find something that you can follow Or like disability certification things like that is better with kinetic static is pretty much used for everything else This is an example of a patient that I have in my clinic Who has black outfields both 24 dash 2 and 10 dash 2 He's also a really terrible test taker as you can see and that's not unsurprising and really severe glaucoma They're bad test takers not because they're not paying attention But just because the nature of glaucoma makes it difficult And so he's got 62 false negative rate and really high fixation losses Is basically no visual field left But we get a goldmine on him and you can see right eye compared to left eye left Eye he still has some reasonable feel that we can follow using this test and right eye is in a pretty bad state But I can follow him now with a goldmine once a year and still get some sense of if he's getting worse or not So choosing the right test you can choose a pattern dash 1 or dash 2 Does anybody know what dash 1 and dash 2 mean for the longest time? I thought it meant one eye or two like dash 1 dash 2 both eyes Yeah, not not what it means It's referring to the layout of where the dots are with respect to the horizontal and vertical meridians And so it used to be when you did a visual test There was a dot right on the meridians, but you can imagine if you have like a neurological defect That's that's respecting Anatomical pathways. It's going to be really difficult to assess defects right along that line, right? So now you if you straddle the line Then you get a sense of whether or not they truly are respecting the horizontal or vertical meridian. Does that make sense? So that's why everything that you order is a dash 2 because you get better information But that reason dash 1 isn't an option anymore. They've just taken it out And then you can vary the degrees of field tested 30 you can do 30 24 10 You can even do a central 5 if you wanted and this shows you what data you get with each test so This big one here is the 30 and then I drew in the line to show you what data you're getting with the 24 so the difference in Information that's gathered between a 24 dash 2 and a 30 dash 2 really isn't that much It's just that very far peripheral Rim of testing and you can see nasally You often you will always get the the nasal 30 degrees even in a 24 dash 2 so that you're not missing a nasal step The reason why 24 is now done instead of 30 is the vast majority of times you're getting defects in that very far periphery It's not Real it's artifactual due to decreased sensitivity of that part of the retina So they just figured you're getting a lot more false positives that way Let's just narrow the field bring it in by 1 and you get a 24 dash 2 which is more reliable And then the reason why we do a 10 dash 2 you can see the 10 dash 2 is is That area of a lot more dots in the next picture It gives you a lot more information in the central So you can see theoretically how you might miss small defects in the central vision If you're doing a 24 dash 2 compared to a 10 10, you're getting a lot more pieces of data Does the 10 still go out to 24? Is that what that's showing? No, it's showing it's showing what what like how how spaced out these data points are So if you're just getting 24 dash 2 then you're only getting within the central 10 degrees 1 2 3 4 5 6 You know these spots instead of all of these spots. Does that make sense? So in a patient where like if you had like a central defect right here It would be hard to know if it's getting worse just doing a 24 dash 2 with these points So you could do a 10 dash 2 and that would zoom in on that area and give you a lot more data points And you'd be able to better assess for progression Does that make sense? You can you can the problem you run into is so length Yeah, and so there are some people who say, you know, if you have patients with any type of central Or paracentral defects, they should be getting 10 dash 2s and 24 dash 2s every time you do a visual field test It ends up being most patients don't tolerate that I try and all like do like Try and do like a 10 dash 2 on a central defect patient like once every 18 months while I'm also doing 24 dash 2s So it ends up, you know I think you get really valuable data from it. Certainly if the only defect that they had was a 10 dash 2 Or was a central you could do 10 dash 2s and then maybe once in a while do a 24 dash 2 to make sure you're not You know missing new nasal steps The very newest Humphrey is coming up with some kind of modified hybrid between a 24 and a 10 Where the central testing has more data points in between But we don't have that best yet And so then you can also vary the size Standard size is a size three But you can increase it often times will bump it up to a size five and patients with really poor vision You can also do one two and four, but we just don't for some reason Those aren't used you can see relative the blind spot. They're all Much smaller than the relative blind spot and they all increase by a factor of four That's I think an okraps question So again choosing the right test you can see oftentimes when do we do a 10 dash 2 compared to a 24? Well, we'll usually do it on these central island patients because the 24 dash 2 Is not going to give you enough pieces information to assess whether or not that central defect is getting worse So you zoom in and you can see how much of a better picture it gives you And it's much easier to assess for progression and a 10 dash 2 And then when do we do a size 5 compared to a size 3? I think of that more as my I'll do like a 10 dash 2 say this patients 2020 with a central island, which is not uncommon Then I would do a 10 dash 2 with a size 3 Say this patients like 2100 because they also have angular degeneration or some other thing going on that can't see very well Usually for the patients with the poor vision is when you bump it up to the size 5 Compared to size 3 you could of course also do a size 5 10 dash 2 if you wanted But again, you can see by using a size 5 I've given myself better tool to assess this visual field and follow them in the future So you could do threshold versus super threshold super threshold is six decibels more intense Then the light that age match controls are guaranteed to see So it's pretty much a guarantee that you will see it the best way This is usually used. Um, it's like a bluff assessment where can you see it? Is it absolutely extinguished not you can see it? Okay, then your eyelid isn't in the way But it's really not useful for following glaucoma patients. So they get threshold testing and then Strategy it used to be everyone got a full threshold test but that was absolutely miserable into forever So everything's been replaced by the swedish interactive testing algorithm Which uses best gas data to present initial stimuli and it says all your You know 72 year old Gentlemen age match controls say this is where we should start you and you should be able to see this And then it varies what is presented next based on your initial responses So that's you can see how that would naturally cut down on testing quite a bit on testing time So is that like so it'll like shine a light of a certain intensity in one spot? And if they don't see it, it'll increase the intensity increase it Okay, what did the other ones do? They just they did all light intensities. Oh really even It was not adaptive. It wouldn't it would just be Like start would just be the same for everybody. Yeah, that's terrible Yeah, so you can see why it used to take forever Yeah, but the seeder Makes certain assumptions about spots in between your responses in other spots. Yeah, and so it it basically makes pre assumptions until it can miss smaller defects and okay um So the standard test Three seven minutes with a seed is standard because you'll you know what students we see is standard and seed of fast So that cuts it's pretty much cuts in half a full threshold test, which is nice You can make it even faster by using the seed of fast People will often think oh well my patients can't sit through they get distracted if they're doing a seed of standard So we should do a seed of fast True in some respects not true in others What a fast does is kind of cuts through and says Instead of starting at a light that I That age match data says you are guaranteed to see I'm going to start at a light that age match data says will be your threshold So it's skipping right to the really tough part of the test essentially And for that reason it's a little bit faster But also for that reason it's a little bit more frustrating for patients It's also less tolerant of mistakes So if you have a patient who is not doing well on a seed of standard and you think the answer is a seed of fast You might find that you do even worse on it because it's just more frustrating to them So in part of the deciding whether or not to do a standard or a fast ask them You know, is it a matter of you just having not having enough attention spin or you getting frustrated with the test? And then these are ones that are talked about a lot in like bcse and tested on That you don't really see all that much. There was some thinking swap shortwave automated perma tree. There was thinking that um The that testing for the blue visual field defects on a yellow background might help unmask earlier glaucoma changes um The more recent data doesn't really support this It I don't ever do it. I don't think I've ever seen any of my mentors do it It's not really used that much anymore. Um, you'll probably get you might get asked about it on the caps and then frequency doubling is Kind of what you'll see when you get the referrals from optometrists The ones that look like this where you're like, what kind of visual field test is this? And it's a really good Screening test, but it obviously doesn't give you enough data to follow Patience so it'll say hey, there's something wrong with your visual field goes to an ophthalmologist But beyond that it's not really useful Okay, so giving the test Basically, this is just a short slide to know that Having good staff give the test gets you better results And this has been validated in studies when the staff is well trained and invested in getting good data Data quality improves if you have a staff that isn't paying attention at all as the patient seeking the test Then reliability decreases it also helps um Data has shown that when patients fully understand the value of the test they get better results I feel like this is especially appropriate for utah because everyone loves essential oils here Okay, so what are we looking at now? We're now we're on to figuring out what this test is trying to show us the sink is called the sfa single field analysis report So you guys know where everything is patient and test data the reliability indices the raw data That shows you threshold sensitivities and then the grayscale map, which is a picture representation of the raw data And then your pattern maps and then your field indices and your gaze tracker So a lot of data sitting here on this one chart Obviously the first thing to do when you're going through this is just to make sure that the patient and test data is accurate I've had several Left eyes be tested as right eyes go back You want to make sure that the patient's age is in there correctly because this is all age match data, right? So if the age is entered incorrectly that will give you false information You know in the book you'll read about pupil size and how that can give you like a ring artifact if it's too small I don't know if that I've ever seen that and then it'll obviously tell you what test you're getting And then your reliability indices so starts with fixation losses They estimate fixation losses by projecting a light Where they've previously identified your blind spot to be and if you click then it says well You obviously are not fixated where you used to be because now you're seeing a light that is supposed to be in your blind spot It can be elevated in a lot of cases where it's not actually impacting the reliability of the field So of all the reliability indices, it's probably the least important And it can be artificially elevated because one maybe your blind spot wasn't identified correctly So maybe you're staring straight off and they haven't moved your eyes at all during the entire test But your blind spot was just identified incorrectly. And so it's reading your response as As a fixation loss and really you're just still looking straight ahead trigger happy patients are going to click even if they didn't see a light So that's going to be identified as a fixation loss and oftentimes, especially our older patients who have trouble Half the va who can't you know get into the machine comfortably or in a wheelchair they end up just kind of melting over time and Even though their gaze isn't moving their head is and so they're getting a lot of fixation losses from that for that reason Actually, I think the gaze tracker gives you a little bit better information because it shows you Where they're looking And how often they're looking away from where they should be fixating these are these are all rva lovely va patients when the gaze tracker When they when when you see something like that the gaze tracker is giving up Like it basically has just said I can't even identify where your eye is anymore because it's so far from Where it should be and every up deviation is Is a look away and the size of the up deviation is how far away you're looking and then down deviation is I like closed had a really good one where it's just like a bar of Down and that's where the patient fell asleep, but I can't find it You'll see that at the va not infrequently So then false positives that's the machine trying to trick you into responding when there really isn't a stimulus It's the most important reliability of the indices and we'll talk about why that is in a minute But anything really over 15 percent is Essentially garbage test and not reliable anymore balls negatives are found by presenting Super threshold stimuli in a location that we've already established You have normal sensitivity if that makes sense and then It's frequently elevated in glaucoma patients Even highly attentive ones just because the nature of those defects oftentimes if you're shining like right on the edge of a scatoma Sometimes they can see it and sometimes they can't it's not that they're Unreliable and taking the test. It's just they're just responding to the nature of their glaucoma Okay, so now we get to the data the raw threshold data and grayscale So when you get your print out and you see the numbers right next to your grayscale data That is just pure sensitivity in decibels. So that's where you'll see the numbers are highest here in the middle 34 33 That's your best sensitivity in your macula and then they fall off as you go towards the periphery Less than zero means you didn't respond to the brightest stimuli zero means you responded only to the brightest stimuli and then It's a logarithmic scale after that So 10 decibels is a brightness one tenth as bright as max 20 decibels is one 100th as bright as max And maximum threshold is about like 38 for young healthy individuals like us and then the grayscale map Is a visual representation of the raw threshold data Which is why you have to be cautious when you use the grayscale only if you're just looking at the grayscale to judge A visual field it's going to give you not all that reliable of data because you need that aged match so again just just as a reminder, so What do you think this patient sees they're less than zero everywhere Oh, no, oh, that's not that's my thing. So less than zero everywhere except for here two five three three How what guess the cutie? Yeah, because their foveal threshold just Is 28 so foveal threshold is the first part of the test where they test like your your fovea sensitivities and that Is not captured in this test. So this patient. Yeah, I can still see 2020 But that's why again the grayscale is unreliable because you show this to a patient. They think oh my god Blind which is you know good to scare them. But Then uh, why can I still see So we get to our deviation maps. There's This is the total deviation map And you have the numerical map on top and then the probability map on the bottom And what this is is comparing that raw data To your age match controls and saying what is the difference In sensitivity between what you responded and what someone your age should respond to so that's why this is almost always Slightly negative. You'll see these numbers if you look at them in our In our patients, you know, it's like minus one minus two or minus 20 or minus 30 depending on the depth of the defect so this um Every once in a while, you'll see a positive like up here This patient, maybe they had eyelid surgery compared to all their other age match peers Who have some ptosis and so they actually see a little bit better in this area Which is why these numbers are positive. So compared to their peers They see they have higher sensitivities here and then a little bit lower sensitivities everywhere else And then the question is well, is this just kind of like normal? amount of variation Or is this pathologic and that is what? The probability map is telling you is what is the chance that this is Pathologic compared to what normal is and so it's you know, it's graded There's a less than five percent chance that this is normal There's a less than two percent chance that this is normal less than one percent chance and less than 0.5 percent chance that this is normal. So That is what the probability map is showing you How does it how does it count? Yeah Magic I mean I feel like because like that total deviation map is like, okay, this is that's just so I mean they just had must have been like huge studies huge numbers. Yeah, okay I don't know. It's it would be interesting to look into how often those numbers are updated Like how often do you update your age match? Norms, I don't know the answer to that Not even age match norms, but the the probability of Yeah, the age match norms being pathological or not pathological. It's a lot of assumptions. It's a lot So then we go to our pattern deviation maps and Just like with your total deviation your pattern deviation gives you your numerical map on the top and then your Your probability map on the bottom And the difference between the two is the numerical map in the pattern deviation is adjusting for sensitivity Assuming an overall decline in vision. So it's saying We know that probably at your age Everyone's got a little bit of a cataract Or something there's some kind of maybe a media capacity And so we're gonna we're gonna screen that out. It takes the seventh most sensitive non-edge spot And since that is normal non-edge because these are often much less reliable So it doesn't want to use one of these It uses these kind of more central spots and since what is the seventh most sensitive spot in the field? We're gonna make that our new normal and set that as Zero so you can see here in the total deviation numerical map. This is a minus two It's been set to a zero now. So this is now the new baseline and everything else is compared to this So it's saying we expect overall That given this patient's overall decline in their field All these numbers can be subtracted by by minus two essentially and that will screen out whatever Media opacity is affecting their visual field and that leaves you that's why you'll see we often will look at the pattern deviation maps First because it screens out everything else that's going on in the eye and attempts to unmask their focal defects Well, that's why we say most clinically useful analysis negates worsening cataracts and also de-emphasizes Common artifactual patterns like eyelids or rim artifact. Does that make sense? This also explains why high false positives are the worst kind of error that you can make on a visual field because If you Are going along taking your test and you're clicking at everything The computer is going to measure your sensitivity as being A lot higher than what it should be And then it's going to take that Information when it's going from your total deviation to your pattern deviation and it's going to set an artificially high Number as the standard for your pattern deviation And then it's going to unmask defects that really aren't there at all If that's making sense. That's why when you see When you see these like big white spots over here where this means super high False positives or this means super high sensitivity. There's there's like no defects here at all It's unmasks this giant field defect here It's not even seen on your total deviation Because this patient responded with like, I don't know probably like a plus three or a plus four plus five Compared to age match controls that makes this whole field look bad once you set a plus four as the norm So that's why false positives make everything unreliable But those plus ones through fives or whatever are those on decibels also or are they some different scale? This is all this is on decibels. Okay. It's like the difference in decibels. So It's like a minus your minus one decibel from Your 34 in this spot or your 34 in that spot is two decibels higher than the age match controls So when you have a field that looks like that on the right that where the pattern deviation is Way worse. Yes. It like that's Reliable, right? Okay. You don't know like maybe they do have a defect there But you have no reliability to know what it looks like. What if the opposite is true? If the opposite is true, so if you have a ton of total deviation, but no pattern Then that points towards Okay, either global media opacity like cataract dry eye But I can't even like the seventh most corneal edema. Okay, usually that's what that means. Okay We'll talk about that right? Um, so when you compare total deviation pattern deviation, if they're identical That means there's no generalized depression present. So Like this those two maps are exactly identical. They have a small field defect looks like a little, you know Kind of nasally step there Um, but there's no other thing. There's no media opacity. Nothing else going on. You can have a Big total deviation depression without a focal pattern which points to media opacity Or you can have pattern deviation a lot worse than total deviation And that almost always points to a high false positive rate There's one instance where it doesn't If you know if the patient's like crazy reliable and they have amazing vision But they also have early glaucoma Every once in a while you'll see a pattern you'll see pattern Deviations show a defect that doesn't show up on total deviation The way you would know the difference is because you don't have a high false positive rate And then the last of the field indices is the glaucoma hemifield test Which is basically taking you know, it's splitting this test right down the middle and then comparing this to this This this this and saying is there any focal defect here? That's not seen here and it does this little fancy calculation and qualifies the field as being Outside normal limits borderline and then it can't qualify it when there's abnormally high sensitivity. So High false positive rates make this Unreliable or if it's like a very very depressed field They also can't do this test because there's just too much similarity between the two And then it'll qualify it as normal and it's very sensitive and specific So 94 specificity with borderline treated as normal and 84 specificity when borderline is treated as pathologic So this is a good thing just for like your normal patients or screening patients If the glaucoma hemifield test comes up as abnormal and more digging Then there's the visual field index. It's the newest of the indices. It's less affected by media opacities I kind of talked to it patients as like, you know, it's a percentage of your overall vision Um And it's designed to reflect ganglion cell loss, which is which makes sense because you want to follow that so it's center weighted So a small focal defect in the center will be weighted more than maybe a larger defect up here And then there's your mean deviation how much on average the whole field departs from age normal It's also center weighted and it's linear and it's useful in staging and tracking progression So it goes from a normal field having a mean deviation of zero decibels extreme field loss is minus 30 to 35 decibels You can see here this guy has essentially Nothing, you know, nothing left of his field up here. It's minus a bazillion up here His mean deviation fits. I think it's what minus 33 something his pattern deviation is Nothing, he has like no focal defects left. So why is that pattern standard deviation is a comparison of Points on this relative to other points. So it's looking for a difference between point a and point b Fields that are uniformly depressed have points that are the same So your pattern standard deviation is not going to find a big difference between the two So pattern deviation while mean deviation will go like this in glaucoma patients pattern will go Like this because as glaucoma gets worse and worse those focal defects become more and more global And the difference between the points next to each other gets less and less if that makes sense for that reason Is not something where you want to follow that number So interpreting the field It's best to just have kind of like reading an x-ray. It's best to have A flow of how you do it or a way of thinking about it Look at the patient demographics identify the field is the field reliable is the field normal or abnormal What is the pattern of abnormality is the abnormality real or is it artifact? Is the field getting worse and then is there clinical correlation? So we all know neurologic patterns how they look Retinol, you know, we don't do visual fields as often in retina But oftentimes our glaucoma patients will also have retinal disease. Yes phobia on phobia off it just it tests that central spot um and so it gives you valuable information even in Like that blackout field that that patient has phobia since to be was still 28 So for that reason we like it on um, I don't know why it gets turned off There should it should never get turned off. It should always just be on It's the very first part of the test if you've ever taken it or they have you look at like the little cross And then they have you fixate up glaucoma patterns of field loss They always respect the neurofiber layer. So if you know the anatomy of the neurofiber layer You know, you can decide whether or not a field defect is artifactual or not And so the biggest clue is Is it respecting this horizontal meridian? The basic patterns of glaucoma field loss nasal step arc would affect paracentral Altitudinal and end stage So classic nasal steps Respect this midline again classic nasal step respecting the midline here You can have an upper and a lower nasal step and it gets a little bit less clear But generally speaking early nasal nasal steps will always respect that horizontal meridian The arc you at skatoma again, respecting the horizontal meridian Paracentral skatoma also again, respecting the horizontal meridian And then end stage Okay, so common artifacts Incorrect patient. We talked about wrong age wrong prescription Learning effect our lid artifact room artifact slip blind spot is probably one you haven't heard of before And attend a patient and trigger happy patient. So this is a patient um who had Had um myopic myopic laser correction some big laser correction and In between their field Didn't tell anybody and they programmed their old Our old glasses prescription. Oh minus four or minus four. My hope program their old glasses prescription in and Had this funky looking visual field once they actually Said oh actually you don't need your glasses prescription anymore because you've had lasik their visual field goes to normal So it really does make a difference making sure that the glasses prescription is accurate So for us for our cataract surgery patients if they've had cataract surgery and they don't need the glasses anymore Making sure that we're the techs are at least updating the MRX entering it correctly Learning curve is a huge thing never trust a first field ever ever ever There are people who say you should get three fields in three months on patients where you're trying to decide if they have glaucoma just to see Whether these defects are reappearing. I don't do it quite that much, but I do try and get two fields in three months because of this because people take crap tests when they're first starting and then they figure it out and their test gets much better Lid artifacts. This is a classic lid artifact and the biggest thing is that it's not respecting There's no anatomical Like nerve fiber layer that this defect is respecting you can see how this is probably all eyelid And then you take their eyelid and boom they get better rim artifact Rim artifact is a bigger deal and a 30-2 then a 24-2, which is one of the other reasons why we switched over but the biggest way to To decide whether something's rim artifact is there's a huge drop off from normal to absolute Like in glaucoma, you don't often have things that are That are relatively normal sensitivities and then like You know, you might see the zeroes here That will tell you you went from it. That's that's like an eyelid, right? You can see Something's blocking you and you can't see so it's normal horribly abnormal in a very small area will tell you it's probably more something is blocking the vision there Slipped blind spot is something that happens when you're fixated in the wrong position So the foveal sensitivity test happens first and you're looking down at a little cross Sometimes patients will forget to refix it up on the gaze tracker part of it So if they're spending the whole time looking down here, it's going to show their blind spot being too low that's going to bring kind of Random retina into this top part of the field that shouldn't be in there. That's not as sensitive So you'll get these weird field defects that like this, you know, this doesn't fit anything But there's something there what do you make of it? Well, that's just because You know retina from here is being tested that isn't as reliable And sometimes you can have blind spots that are too high It's not as common because you know, oftentimes if they're fixing they're fixating on the on the little bogey cross instead But who knows sometimes they're looking up or looking wherever they're not fixated right on the gaze tracker Then their blind spot can appear in a random place And then we talked about trigger happy patients and why that's bad and it will give you these kind of weird pattern defects That don't show up on your total deviation It's the field progressing. This is where you use your field indices and your gut essentially so You know, obviously the mean deviation is getting worse Pattern deviation is getting worse. So this is like a mild moderate glaucoma patient that is progressing And then in this patient you can see The main deviation starting way down here instead of starting it You know one or two we're starting at 17 and it's continuing to just go downhill. This is bad news probably this patient should have gotten a trap about here And then the other thing that's bad news is that the pattern is actually going back up again So that means those vocal defects are now becoming like blackout fields So you can also use mean deviation and pattern deviation to tell you, you know What's going on with this patient their mean deviation is getting worse, but their pattern's not changing. Well, uh Maybe they had a cataract and then Maybe we took their cataracts out So you can see all that reflected Then there's the visual field index that you can track over time and it will give you Sometimes a nice little line here that tells you how about they're getting worse And relative to their age. So this if this was a 98 you might not care as much And if this was a 58 you might care a lot more. So it's helpful Do you have an idea of age and rate of progression? Then you can look at the maps So this is from the Iowa glaucoma Curriculum the sad story is that this is a patient who got a visual field literally every year But their pressures were always normal. So their doctor didn't look Yeah, he's like, well the pressures were normal. So I never looked at the field So look at look at your visual fields people And then again another example of just progression Using kind of gray scale in the maps to identify that. All right cases. How much time do we have? 10 minutes We can do it Do you have any questions about I know that was a lot of information Questions about the information. So 56 year old female presenting with two years of vision changes in the left eye Her vision is the right eye is 2020 left eye 2040 pressures are normal She has a 1 plus rpd in the left eye. So you're like, oh, I'm gonna get a visual field So field normal or abnormal Yes, abnormal. What is the pattern? Would you call that Yeah, her central early nasal step. Do you think this is real or artificial? She has zero fixation losses 1% false positive 3% false negative It's real. Yeah. So does she have glaucoma? She does This is a patient this is it's actually said this patient has been coming to us for two years complaining of visual Her visual field looks worse than this actually, but the story is is accurate The vision has been coming us for two years complaining of vision changes in her left eye We got we finally got a field on her and she has normal pressure glaucoma And has lost quite a bit of vision in her left eye But she has really tilted nerves. So it's hard to you know, it's hard to see cupping And for a long time her vision was still 2020 in this eye It wasn't until she had an ripd that you started and actually it's probably a little bit bigger rpd But We got a field So while the story if a patient complains of like funny vision problems in an eye Just get a visual field on them and make sure there's nothing funny going on Okay, so yeah paracentral scutomas most common in normal tension glaucoma and they can be really small but Since they're central they can really mess up a patient's vision Okay, case number two 51 year old male post motor vehicle accident with persistent headaches and vision problems He says he can't see anything He's 2100 in both eyes pressures are normal no ripd and you get a field on him So is the field normal or abnormal? Okay, what is this pattern It looks yeah, maybe a little nasal something it's kind of a weird Uh, do you think this is real or artifactual? False negatives are okay. Yeah Hello 33 Better than false positives is true. Yes How soon post the mba? I like six months still swollen We're all excited guessing ourselves. Yeah, it's not easy I mean feel some this feels aren't aren't always easy to interpret. So do you think he has glaucoma? This is nerve look like The nerve looks normal. Okay, totally healthy. Totally healthy. Totally healthy nerve Probably not real. I'm not glaucoma. She's a clover. Yeah. So clover leaves can be subtle. This is actually me Trying to do a clover Um, but they can be subtle the the biggest keys It's not there's this is kind of like Garbagey like she doesn't really respect this line here. I mean a little bit it does but False negatives are fine But also a sign of you know in someone where everything else looks normal But you would get an OCT on this patient and it would show totally healthy nerve And you'd be like what this and then you you would see the clover leaf So that's where your clinical context will come in as well And then the gauge tracker you could see I was really trying not to pay attention I tried to yeah I felt like I was closing it forever, but the gauge tracker was unimpressed So oftentimes the ones that you will see are these clover leaves and that's the the reason why they look like this often is because The first four stimuli are here here here and here and they're really bright So if you have a patient who just stops paying attention after those four That's why you'll get things that look like this because it's it's responding to like the first few stimuli that they're getting Okay Reliable or unreliable hard to assess from this normal or abnormal It's abnormal. Okay. What is the pattern rim artifact? Good job So it's a steep drop off from normal to abnormal you get these like block Really dark defects and then everything else is normal. This was a patient So then again, you correlate it like you ask the techs. Hey, were they sitting back from the lens that can give you rim artifact Or were they wearing their plus 10 a fake expects? giving them this huge rim defect okay case for 61 year old referred for glaucoma suspect with positive family history and Borderline iop. She's 2020 in both eyes pressures are 23 and 21. She's no r. A. P. D. Her r and a bell Um oct looks normal. Is this field normal or abnormal? It's mostly normal. What do you make of these right here? Oh smart She has high false positives 19 percent So do you think she has glaucoma? Maybe but not right now. Yeah Good job. There's a disconnect there. So again, this is a patient who was a little bit trigger happy She was maybe a little bit nervous. She doesn't have glaucoma yet. You still want to follow her Okay, is the field reliable? Yes, it was. Is the field normal or abnormal? It's abnormal. Obviously it's abnormal. What pattern is there? Right? So what do you think this patient has? Okay, oh this one apparently I didn't animate this one This one is you know, what do you notice here? There's all this generalized depression, right? But when you screen that generalized depression out, there's still this superior arcuate defect here So What do you think this is? Glaucoma and a cataract Take out the cataract. So that's what these look like a lot of total deviation When that screened out, you still have this nasal defect Partial arcuate same thing here a lot of deviation, but still have this defect here Okay This one's tricky. What is that? Is that this field is reliable? Is this normal or abnormal? Um, what is the pattern nasal step? Is this glaucoma? Yes This is I'll tell you why in just a second compared to this one Reliable abnormal nasal step is this glaucoma. Yes. Yes This just is not respecting this midline This nasal part here It's remember that's that's the only part of a 24-2 that's testing your 30 degrees. You're a lot more likely to just get Um, like a rim artifact if you're going to get it. We'll show up here and nowhere else. So be careful. Just So it's really unlikely to get like a like a upper and lower nasal step in early glaucoma In early glaucoma like this where there's nothing else Yeah, that would be really uncommon to just have one spot here and one spot here without really anything else And have it be that steep a minus 30 Would be would be uncommon And so this just shows you what a nasal step compared to rim looks like Is your slideshow done? Okay Four more of these ones are fast. Okay progression or no progression This was the field in december 2017. This is the field in july 2019 Do I need to do a trap on this patient? What do you think? It's certainly bad But then you look at her other eye And you realize she is having a stroke in your clinic and you sent her to the emergency room That actually happened Yeah, so just a reminder and I am guilty of this because especially in The way that we can look at things in epic through axis You're often when you're doing a side-by-side comparison You're not looking at I don't start always by looking at the two fields like the right and the left eye together I look at right. I compared to Previous right eye right because I'm always looking to see there's progression So don't forget to look at the field as a whole so that you can make sure your patient's not dying So this is october 2018 march 2019. Are they getting worse? Do I need to do a trap on this patient? This field looks a little bit different compared to this field, right? It's like what nine out of 14 fixation losses This field is a size five This field is a size three So this patient's seeing a lot better because the stimulus is you know bigger by a factor of 16 So this is just a reminder. You can't compare apples to oranges. You have to do the same test on the same patient Repeatedly again, this happens at the VA all the time Where we want a size five and they get a size three and it's just garbage You can't use it to compare or assess for progression So then you get her back doing her normal and her field looks great again And you've saved yourself from having to do surgery on this poor nice lady Okay, what about this one? April 2019 to july 2019. This was a guy that dr. C sent me and was like, hey, does he have glaucoma? This was the field he had coming to me and then when I repeated it like I said I do about three months later try and get a second field It looked like this And I had a minor heart attack Um, so what do you do? What do you do for this guy? Are all the I can't see any of the numbers are they all the same? He's pretty reliable. He's like one out of 23 4% false negatives What about what the size of the stimulus same everything's the same He did not fall asleep He just told me when I asked him I said your field looks a whole lot worse and I'm really worried about you He said I didn't feel like doing it. So Oh I didn't know why I was doing another one so soon and it annoyed me and I was mad Oh So I said well according to your field you're going blind and I need you to actually do it and I explained to him very carefully why it was important and his field went from this I said, I'm gonna make you come back in a month and do it again and prove to me that you can do it And then his field looked like this So again, don't trust progression until you confirm it So if you see a field and it's a lot worse than what it was before before you decide to do surgery on these patients Bring him back and make him do another time. I mean, he still has glaucoma, right? He still has glaucoma Yeah, he still has glaucoma. Okay He's also like 45 and he's probably Normal pressure glaucoma is a disaster If you suspect I can have normal results like that, how soon should you repeat it? I made him come back two weeks later I said I'm going to give you two week vacation to get over your bitterness about this test And then you're going to come back and take it or otherwise. I'm going to operate on your eye And he was like, all right, fine. I don't do that So how does he not have any like false negatives? He should really get it not I don't know. I mean that just goes to show you that This is this is we're objectifying a subjective experience and patients. I mean like You'll see field fluctuation with nor like Teresa brought me one from the VA the patient's a good test taker And from test to test went from horrible to great with no change in their reliability and disease So, you know, I don't know how they do it But they they can and it may seem that you don't know You don't know which one is the right one, right? Were you just having like a remarkable day or You know, which one is the real one? So that's why whenever you're not sure The moral of the story is repeat your fields Like just if you're if you if something's funny, just repeat it explain to the patient tell them why it's important They won't get mad at you repeat the field Yeah, I make the VA guys come back all the time Also, I will I will say one word if they have repeatedly shown you Would you guys notice like the eyebrows it really is true like eyebrow trends are like Normal and now like a bushy eyebrow is Super isn't it? Yeah, so they're saying if this trend continues Soon you're gonna have to be a super weird visual eyebrow We're gonna have to The other thing I will say I My rule is if you live to 90 your 90th birthday present is you don't have to take fields anymore As long as your pressures are like relatively well controlled because you know They're not 60 anymore. I don't have to keep them seeing 40 years I only have to keep them seeing 10 years Also, if you've proven time and time again that you are a bad visual field test taker and you just can't do it We shouldn't keep Making you do it. So at the VA in particular Be aggressive about saying hey this patient has never once had A quality field and yet we keep trying So when I say repeat the field repeat the field within reason But if you've done four fields on a patient and he just can't he's falling asleep every single time Don't make him do any more fields