Examination of the Eye with an Ophthalmoscope

hello and welcome back to my channel my name is dr james gill and you join me for another video on looking at the deeper side of clinical skills i've been joined by derek's shorter cousin phyllis here who's going to help us out using the ophthalmoscope and how to look at the back of a patient's eye so before we kick off with looking at the back of the orbit i suppose we should get the ophthalmoscope and actually work out what it is that we're doing with the thing so i'm using a um a hein mini lux otoscope and this looks a little bit old because well honestly it is um this particular set uh looked after my grandparents looked after my parents and looked after me when i was a baby and was given to me by our family gp before i came to medical school because i was the first doctor in the family for a long period of time so even though this is older than i am at 37 years of age the technology is still the same we've got a couple of batteries powering a bulb that bounces through a mirror and a lens so on the front of the ophthalmoscope we've got the shutter which we can move down like so we can then switch it on at the back to give our light we've got a dial at the front which will change the different apertures that we are seeing and then round on this side there is a white dial again which allows us to set the magnification of the lenses in use which we can see through this window here and obviously at the top is this the ophthalmoscope itself that we'll be looking through to check the patient's retina so with that in mind we want to check the ophthalmoscope has power which we'd normally do by shining it on our hand and then we want to set the correct aperture so i can set it to a wide beam i can set it to a narrow beam i can set it to a half cut and also a green light i personally would use the the larger of the beams and we want to rotate the lens disc around the maximum setting so in this one it's 20 and that would allow us to set this as a magnifying glass giving us the best view of the anterior surface of the eye if you're wearing spectacles for a near sided reading then you'd want to move that dial so it gives you your correct prescription for that magnifying glass conversely when it comes to looking at the back of the eye we want to set the ophthalmoscope to the zero setting and that should hopefully give us a good view at the back there with that in mind you'd then take the ophthalmoscope and approach the patient having prepared our kit we want to alcohol jail our hands as we would do on every consultation and then introduce ourselves to the patient phyllis here isn't particularly talkative but nevertheless we would still attempt to get her name and date of birth we confirmed that we were going to have a look at the back of her eyes and because we were likely doing it in the gp surgery we wouldn't be dilating her eyes with drops now i highlight that because it is very difficult to look at the back of a patient's eye without anything to stop their iris contracting that's why the vast majority of times if you're seen in the outpatient department they'll ask someone to drive you in and drive you home because they'll put these dilating drops in your eye which will mean you won't really be safe to drive because the bright lights and a slight impact on your ability to focus but that doesn't happen in gp very often but we still want to highlight the facts to our patient so with that in mind we've confirmed what we're going to do and we're going to highlight the patient that we will approach them very closely nearly putting our head toward theirs that's important because whilst we won't be dilating their eyes we will certainly be lowering the lights in the room we're going to approach the patient using our left eye to their left eye that should mean that our faces should cross and we shouldn't have any problems some of you will have noticed when we did the cranial nerve examination i didn't follow that protocol when i was observing cranial nerve two the reason being is i had optic neuritis as a baby and that eye is ever so slightly affected so i'll tend to use the same eye on both sides of the patient although i will often highlight that to them first because i have to get a little bit closer than would be ideal with that in mind we're going to look around the eye and we want to do that systematically so we're going to have a look at the eyelashes we're going to have a look at the eyelids we want to pull the eyelid down and have a look at the conjunctiva and then we're going to look up into the eye itself at the anterior of the eye so having a look at the cornea and around the pupil if the patient has commented that they think they've scratched their eye which is incredibly painful then we can confirm this by putting a drop of fluorescein drop or stain into the eye that will turn the eye a very halloween yellow but will mean if i shine a purple light on it then it will fluoresce shine bright green wherever the scratch is we'll similarly use this if there's something called a dendritic ulcer effect in the eye which can be an exceptionally painful complication of wearing contact lenses sometimes if we've not found anything on toward there then we're going to want to change again the dial on the ophthalmoscope to enable us to bring the back of the eye into focus now when it comes to trying to orientate ourselves on the patient's retina what we want to try and do is find the fundus or the optic disk often that's a very difficult thing to do so we'll get the patient to look at one location in the room so the top corner of the room would often be a good start that fixes their gaze in one location this means that we would then be able to look into the eye and hopefully find some blood vessels and we'll follow those blood vessels along to find the optic disc once we've found the optic disc we want to be able to characterize it does it have nice sharp borders does it look a little bit fluffy around the edges is it paler than we might expect or does it look swollen all of these are potential complications that we need to be very very conscious of with regard to pathology of the eye diabetes is a very common condition and a lot of the time we consider it to be a body-wide issue perhaps a better way of considering diabetes is as a blood vessel and a neurological or nervous issue what i mean by that is that we're going to see changes on the retina with the microvasculature due to the damage from the diabetes and the eye is actually one of the few places in the body where we can observe those micro blood vessels easily so having looked at the fundus we then need to move back over there to try and assess the fovea this is the most concentrated area of cells in the eye and we're going to get the patient to do that by asking them to look directly into the light now we're only going to do that for a couple of seconds but that should be sufficient for us to get a good view over this area and as we're tracking the blood vessels around the eye trying to get to our optic disk that's where we're going to ask the patient to keep looking in one location and we're going to move our head around trying to look up down and around inside the patient's eye through their pupil i'm sure you can imagine that it's going to be much easier to look out of a window and into that room if that window is a big window hence why in ophthalmology we'd want to dilate the patient's eye rather than gp where we'll just struggle squinting through a smaller window so with that in mind we would thank the patient for their time and make sure that we've covered any questions and that would then complete our examination as we switched the lights back on and helped make sure the patient was able to leave the room with that in mind let's try and have a look at how we'd actually go about that now in terms of examining the patient the very first thing we want to do is actually switch the lights in the room off and shine the light in the patient's eye from about 10 centimeters back as we look through the ophthalmoscope this is to try and elicit the red reflex i'm going to approach the patient and i'm putting my hand on their forehead and i'm going to use my right eye approaching their right side from about 10 centimeters back i'm looking to see if i can see their red reflex which i can i'm going to swap over again hand on the forehead left eye to left eye and seeing that i can confirm the red reflex now it's not something that we commonly see day to day often seen in old cameras where people would have bright red eyes and that's because the light is actually fixed very close to the lens in those old cameras the place that you're much more likely to be aware of this red reflex out in the world is the shiny of cats eyes when you hit them with a light or torch when you're out in the garden or perhaps your headlights illuminates them we're looking for that same feature showing that we can see the nice red back of the retina now it's important and we do this check in children because we can have something called a retinoblastoma where we get a cancer on the back of the retina meaning that red reflex is absent and is a very worrying sign having looked at the red reflex we want to with our magnifying setting we want to move close to the patient and we're going to place our hand on their forehead to make sure that we don't accidentally come too close and bang into them as we do that we're going to look at the anterior of the eye so once again going back and i'm using the right eye to their right eye i'm going in straight asking the patient to look at something in the top left of the room so i'm having a look at the eyelids i'm checking the eyelashes i'm looking over the pupil and the iris making sure there's no problems with the cornea and also looking at the conjunctiva from there we want to turn our dial again to try and bring the back of the eye the fundus into focus if that's not possible then we want to try and focus on a blood vessel that we may see as we're moving through the different lenses so moving the disc i'm now going to have a look at the back of the patient's eye trying to bring the disc into focus and finding that i'm going to look around tracing the blood vessels back to the center of the um the eye and the optic disc we want to again turn the lens dial so that we can try and try and bring the the retina and the optic disc into focus and asking to focus on a side part of the room that will allow us to shine the light into their eye and concentrate on what it is that we're seeing without you know dazzling the patient as much now it's possible that we may not be able to see the optic disc straight off but as we're moving through the focus wheel we may notice a blood vessel comes into focus we can follow this blood vessel back centrally to find the optic disc adjusting our focal points as we go and to clarify with that point when i say following the blood vessel we're going to be following it in the direction opposite to which it branches that central direction should lead us back to the optic disc once we've found the optic disc we want to pay attention to four features the shape of the disc the edges of the disc the color and also what is the cup like there are many diseases in the body that can be seen in the optic disc sometimes at early onset and sometimes in much more advanced cases diabetes is a good example of that whereby we don't see changes in early disease but it is certainly a marker of the severity of diabetes depending on what we see in the eye once we've looked at the optic disc we want to make sure we're covering the four quadrants of the retina very much in the same way as we're going to assess the visual fields in our cranial nerve examination we want to look at the areas of the retina and we're going to do that by moving our ophthalmoscope around like a torch we then want to check all four quadrants of the retina to ask the patient to change their fields of view so looking to the top right the top left the bottom left and the bottom right in terms of helping us visualize those four quadrants the final thing that we would need to get the patient to do which can be the most uncomfortable for the patient is to look directly into the light that's going to allow us to look directly into the back of their eye at a place called the macula this is where we have our central and sharpest vision hence why when we have things like macular degeneration where people are losing the center the most sensitive the core part of our vision it can be so devastating for a patient with that complete we would switch the lights back on and thank the patient for their time and make sure that their vision has returned to normal before they leave the room so just to wrap up a few bits there on the retina and the optic disc we talked about myself having had optic neuritis now when we have a look at the optic disc as mentioned we want to comment about the edges the power the size and the shape well if you have optic neuritis then that will in the acute stage cause an inflamed and a poorly defined and ill-distinct fluffiness to the optic disc so if you have an optic neuritis that will cause a swelling to the optic disc which well we're going to see it becoming larger but we may see those edges become less defined but at that time the color will be the same subsequently once that inflammation has settled down and everything has resolved the optic disc will hopefully go back to normal but we will from thence on see a pale optic disc such as you see in my right eye and going back to our cranial nerve examination when i do a the red hat pin to comment about color and i have red desaturation in my right eye so the various things that might cause the optic disc the visual part of the optic nerve to swell one of the classic ones at medical school would be increased pressure so termed papillary edema raise pressure in the skull causing that swelling of the optic disc but there you'll often see that in both eyes when it's unilateral that tends to be more effective so things like lyme's disease syphilis meningitis or the optic neuritis as i mentioned myself staying with the bilateral causes they were talking hypertensive retinopathies diabetic retinopathies we may also have as mentioned tumors causing pressure on the brain in terms of the color we can look at changes or to the power of the optic disk based upon trauma compression neurological metabolic and infective causes so again it's those and inflammatory causes for that matter so again it's those big ones meningitis for our inflammation diabetic for our metabolic although thyroid i think can also go in there straightforward trauma and compressive issues in terms of brain tumors etc so one may be causing a swelling of the disc but we may also be seeing a change in color of the disc based upon those same pathologies well i hope that's been a useful overview of using the ophthalmoscope please drop down any questions you've got below more importantly give us a shout out in the comments if you'd like us to try and do some dedicated videos on looking at the pathologies of the retina there's quite a lot to get through there which we don't have time to touch on with this focused video so we'll leave you there have a good evening good day good night whenever it is you're listening and revising with this take care and please if this has been useful consider liking and subscribing take care cheerio you