From simple refractive issues to dry eye to age-related cataracts to emergencies such as retinal detachment, the causes of painless fuzzy vision vary widely in urgency. Ophthalmologist Madeline Yung, MD, delineates a straightforward path to evaluating this common complaint and provides keys to recognizing when a patient’s condition indicates the need to assess for stroke.
Um, so today I'm going to be talking about painless decreased vision. I'm just gonna take a quick moment to acknowledge, uh, the cohort at the UCSF Berkeley site. Um, we have an amazing staff consisting of faculty optometrists from the Berkeley School of Optometry as well as a bunch of different specialists, um, in a wide array of subspecialties in ophthalmology. Here are the upcoming topics and presenters. In terms of disclosures, I'm a consult uh for Iota Biosciences, which has no relevance to this talk. This presentation is by no way exhaustive, but I'm trying to give you a framework for how to approach a vision evaluation. So, hopefully all of these, uh, topics are things that you've heard of before. I'm just trying to organize it in a better way. So here's the scenario. You have a patient who comes to your office and they say, Doctor, my vision is blurry. You take a look at the patient, they're in no acute distress. The eyes look completely white, quiet. Patient looks fine, no pain, uh, but their vision is. Blurry. How do you approach this type of patient? So by the end of this talk, hopefully, you'll be able to list the differential for painless blurry vision. You'll be able to perform some basic screening maneuvers even though you're in a non-ophthalmology clinic, and you'll know when and where to refer these types of patients. So the first branch in the diagnostic algorithm is, is the blurry vision constant? If it is, it might be refractive error like a glasses prescription. It could be due to cataract, macular degeneration, retinal detachment, central retinal artery occlusion, or giant cell arteritis. But if the patient says, no, sometimes my vision is actually pretty good. It's only sometimes that I have fluctuations where my vision is poor. You might think about Dry eye, papilledema, or amaurosis fugax. Now you might think, OK, dry eye, refracted air, not a big deal, but some of these, um, are, uh, conditions that might tighten, uh, the anal sphincter, right? You might want to refer them emergently to the emergency department. So the next question to ask is, is the blurry vision sudden, severe? Or unilateral. And if it is, you might be thinking of intraocular emergencies like retinal detachment, central retinal artery occlusion, giant cell arteritis, and amaurosis fugax. Just like, uh, most of the complaints that come through your office, if it's sudden and severe, it probably means that there's an emergency going on. So let's go back to that first branch point of constant blurry vision. One of the most common causes of constant blurry vision is refractive error. It's non-emergent, and it happens when the focusing structures of the eye, the cornea, and the lens are unable to properly focus the light rays onto the retina. So what does that mean? Here is a cross section of the eye, and the cornea is that very, very front layer that it's thin and transparent. It lets through light and it also bends the light rays into focus for clear vision. Underneath the cornea, you can actually see the colored portion of the eye called the iris, and the reason why you see mainly the iris is because the cornea is clear. In the middle is the pupil, and behind that since the lens of the eye, which similar to the cornea is clear and curved. In the back of the eye, you have the layer um that covers the entire um inner wall called the retina. This is a light sensitive layer that collects all of the light information and sends it as a light signal for vision into the brain via the optic nerve. So in order to see, you need to have good focus. You need to bend those rays of light into a clear focal point that intersects with the retina. You want the image to form on the retina itself, and the cornea and the lens are the ones, um, uh, the structures in the eye that are responsible for this. So, um, good focus is when you're aligned with the retina. When you are not aligned with the retina, you might need additional glasses to, uh, uh, correct the focus so that you do have, um, a, a focal point that is. alignment with the retina. So going back to the glasses prescription, you can see that the focus is all scattered, um, there's no clear focal point and the image that ends up, um, uh, forming on the retina is very out of focus. All right. So, um, things that you, uh, might suggest that the patient has refractive error include, uh, includes how old their current correction is. Our bodies are always changing and so, uh, do our eye shape and glasses prescription. Um, so if they're wearing glasses that are 234 years old, maybe it's time for an updated prescription. Also, um, if the patient is younger, the prescription can continue to shift naturally as the whole body grows until adulthood. If the patient is middle aged, they may be experiencing presbyopia, which is the need for reading glasses because of Loss of the ability of the lens inside the eye to focus between far and near. So these middle-aged patients will tell you, well, my distance vision is OK, but I just can't see up close. So over the counter reading glasses and an updated prescription can help with that. And finally, in older patients, a cataract might be starting to form. Cataracts can cause refractive shifts before they start blurring the vision out even with glasses. Now, the key with refractive error is that it improves with pinhole, and if the patient has blurry vision in both eyes that is constant and improves with pinhole, you can be reasonably certain that they have refractive error and can go to optometry non-urgently for an updated prescription. So let's talk about pinhole visual acuity. So remember that light gets scattered in patients who have refractive error, but you can see that that center line, the line that does not need to be bent in order to focus, is actually able to transfer the image directly onto the retina. It's really those peripheral rays. that are being bent improperly that are causing the light scatter. So if you put a pinhole in front of the eye and you block all those other peripheral rays that are getting bent, and you only allow those straight on rays, even though the vision is dimmer, less light is being let into the eye, you can actually improve the vision with pinhole visual acuity. So just to review, checking vision is one eye at a time. Sometimes I see that um the vision is checked with both eyes open. This will give the vision of the better eye only. So you wanna check with one eye at a time and you wanna check with whatever glasses um the patient is, uh, needing to wear. If they, if you're Checking vision for far away, they need to wear glasses for distance. If you are checking vision up close, they need to wear reading glasses. For example, if you check vision without glasses, but they have the glasses sitting in their pocket, the vision is going to be, uh, poor because they're not wearing their glasses. So it's not really helpful to check vision without glasses if they need them. Um, and you also wanna check with and without pinhole occlusion. All right, so you might say, OK, that sounds great, but I don't have an eye chart in my office. How am I supposed to check vision? I'm not going to, you know, go out of my way and delay my entire clinic to check it. So here are some good approximations for visual acuity. If you happen to have an iPhone, the small letters that are underneath the icon, so here you can see FaceTime, calendar, photos, camera, those are pretty small print, and if you, if you can get a patient to see them, that's at least 20-30 vision. You know that their vision is pretty good. You want to do this holding the iPhone approximately 14 inches away. If the patient needs to hold it closer, then just via distance, the letters are larger than if they were holding it farther away. So you know that if they hold it like half as far away, like 7 inches instead of 14 inches, you go from 20/30 to say 2060 vision. It's a little bit worse. Now for medium vision, um, if you look at the letters of a standard keyboard at approximately 14 inches away, that correlates to approximately 2150. If you hold the keyboard further, then the vision is better. If you hold the keyboard closer, then the vision is estimated to be worse. Now you know the patient has very bad vision if they can't read any letters at all, but you can at least maybe check to see if they can, you know, count a couple fingers or if they can even see some movements of your hand. Now you might say, OK, that sounds good, but I don't have a pinhole in my office. What do I do without pinhole occlusion? So if you can't, you can actually still check pinhole, um, even without an occluder. Uh, what you can do is have the patients use their hands or fingers to make a pinhole themselves. The caveat is you just wanna make sure that pinhole that they make is not gigantic, so this is probably too large, that's almost like the size of an eye. You want to make sure that the pinhole is at least approximately like 1 millimeter in diameter so that you're actually able to get rid of those peripheral rays. So one way is to really squeeze your fingers in or you can even make a pinhole by pinching your fingers together and have the patient look through that, um, at something. So, um, if any of you wear, uh, refractive corrections such as glasses, I challenge you, um, to take off those glasses, look at something, uh, around you in the room, and try that pinhole, see if you can actually get your vision to improve, um, when you're looking through a small aperture. All right, so let's move on from refractive air. Cataract is another uh cause of constant blurry vision that is non-emergent due to likely age-related opacification of the lens, although there can be secondary causes. So, uh, here is just a, uh, pretty, uh, extreme example of a cataract. You can see that the lens which sits behind the pupil on the, uh, left side of the screen is very white, very cloudy from the dense white cataract. This patient, when she presented to my clinic was hand Emotions and vision. She couldn't read anything and she couldn't even count my fingers. After cataract surgery, you can see that that opacity has been completely removed and replaced with a new intraocular lens that is artificial, and her vision improved to twenty-twenty after surgery. So how do you know a patient has a cataract? Well, they'll typically tell you that their vision has been slowly getting worse over time. It's slowly progressive. Other, uh, visual symptoms that are specific to cataracts include decreased nighttime vision. The cataract is opaque, so you're just getting less light into the eyes, so in dim lighting, you can't see anything. You might have glare, and these patients tend to be on the older side. Now, even without a bio microscope like the one sitting behind me, you can actually see a cataract if you get close enough. If you get a light source and you look at the pupil, you can possibly perceive mild to moderate to even severe cataracts, obviously, um, if the lens looks maybe milky gray brown instead of being just a black, maybe bluish black pupil. Um, you might also note that the red reflex is decreased in adults. Now, the caveat is that the red reflex, which is decreased in children, is retinoblastoma until proven otherwise, so this conversation applies strictly to adults. Now the recommendation here is to refer to ophthalmology as a non-urgent cataract referral. So here is a um comparison of on the left top hand side of a pupil that is completely dark. It's normal, there's no cataract there. Um, if you look a little bit closer at a patient who has blurry vision and you see that the, um, lens that's sitting behind the pupil is starting to look a little bit yellowish, maybe a little bit whitish grayish, then they might have moderate cataracts. If their pupil looks completely white, then it's a severe cataract. Um, and then here is, um, a red reflex comparison between, um, the, uh, right eye which is pictured on the left and the left eye which is pictured on the right. Sorry to be confusing, and that you can have a good red reflex, which means that there are no lens opacities versus a bad red reflex that could potentially mean a cataract. All right, so the next on the differential is age-related macular degeneration that can cause constant blurry vision. Uh, usually this is non-emergent unless it is changing rapidly. So going back to the sudden and severe, um, uh, uh, uh etiologies that require, uh, more urgent or emergent referral. So, uh, macula, uh, refers to the center of the vision, center of the retina, and age-related degeneration, um, uh, uh, only affects the central retina and affects the central vision, but not the peripheral vision. So here for comparison on the left side, you have a normal retina. You can see that The macula has a different pigmentation and it sits next to the optic nerve. Now, in the middle, you have someone with a dry macular degeneration, um, and you can see that there is atrophy, um, you know, it just looks different. It looks scarred, maybe some of the retina is missing. This is usually treated with, um, eye vitamins and it's slowly progressive. We don't have Great treatments at this time. Now, in very advanced cases, you can have so much degeneration that you start to have bleeding in the retina, and this is called wet from the bleeding. Um, you know, when you have a bleed, the blood vessel pops and then it goes. So this typically will cause sudden, um, and sometimes severe losses of vision. Um, this is treated with retinal injections and often requires an urgent referral. So, uh, macular degeneration causes central blurry spot because it happens in the center vision in the macula. Typically, these patients have a positive family history. They're typically Caucasian, and since it's age-related, they're typically older. One way to check for macular degeneration is with an Amsler grid. You can pull this up via Google. There are many different images, and the way you do it is checking one eye at a time. As the patient to look at that central black dot. Then you can ask, are any of the lines, uh, wavy instead of being straight, or any of the lines missing? And, um, this grid checks the center 20 degrees of vision. So, um, the patient, uh, should get an ophthalmology referral non-urgently unless there is a recent and rapid change. All right. Um, moving on, we're going to next talk about retinal detachment, which is another cause of constant blurry vision. Now retinal detachments are emergent because they often require surgical correction, and the earlier that you can, uh, correct it, the less likely that the retinal detachment has time to grow and expand and involve the entire retina. A retinal detachment typically occurs when the retina has a hole or a tear, and then fluid goes into that hole in between the retina and the wall of the eye, so the retina starts coming off as a detachment. This typically starts in the peripheral vision. So the patient might say, OK, I had some flashes and floaters, um, flashes of light because the retina, which senses light, was stimulated, so you have this, um, artifice inside the eye of a flash of light. They might have floaters because of release of, uh, subretinal pigment into the eye, um, or just changes in the vitreous. Um, and then they might start seeing that detachment itself as a shadow in the vision, and remember this is constant. Once it is detached, it doesn't go back, so that shadow stays there and it can get larger as the detachment progresses, and that's when we're saying, did you see a curtain come over your vision? So red flag symptoms for retinal detachment include floaters, flashing lights, curtain in one eye. Sudden, unilateral, and sometimes can have severe vision loss. Now remember, if it's temporal or peripheral, um, the vision loss might not be affected yet, but they might still say that they see that shadow. So in this case, it might not be severe but still be emergent. You can actually visualize retinal detachment on ultrasound and you need an emergent um ophthalmology referral um or referral to the emergency department for possible surgical repair. Now for those of you who have ultrasounds in the office, um, you can actually visualize the retinal detachment itself. So you wanna take a linear transducer, you know, like the long like thin rectangular ones. They might seem too large for the eye, but it's better than The, um, like more rectangular, like square squarish looking ones. So you want the linear transducer. You have the patient close their eyelid, make sure that they have like some tissues on hand. I, we always have tissues in clinics, so it's like literally just sitting right there for me. Um, Uh, just because you can have them wipe the ultrasound jelly off after your examination, and once you have the, uh, transducer on the eye, you wanna adjust the depth so that you can easily visualize the whole eye, but you don't really need much more than that. Next, you want to increase your gain. Typically, you want the gain to be relatively high, maybe 90 or 100. You can go as high as you can and then turn it down slowly so that the inside of the eyeball generally just looks, just becomes black. Um, otherwise it'll be too dark. So you want the gain to be relatively up. Up is better than down, um, but you don't wanna have it too high, so you wanna turn it down until the inside of the eyeball just turns black. And then on the right side, you can see a couple of pictures, examples of retinal detachments. You can see the retina itself as this wavy line inside of the eye that is actually uh separated from the wall. If you're not really sure what's going on, you could always compare it to the normal eye. It's very um unlikely that the patient has bilateral retinal detachments. So if you're seeing something weird in one eye, if it's present in the other eye, that's probably not a retinal detachment. All right, getting to the super big emergencies, central retinal artery occlusion or CRAO causes severe, severe, severe vision loss because the entire retina has become ischemic. So these patients typically have count fingers, hand motion, or light perception vision. They can't read any letters at all. This is an um ocular and also a systemic emergency. This results from the occlusion of the central retinal artery. It's the artery that supplies the entirety of the blood vessels to the retina. It enters the eye through the optic nerve. So you can see here a picture of the back of the eye and you can that yellow portion is the um optic nerve, the yellow circle, and you can see all these blood vessels coming out. Um, these blood vessels all are derived from that central retinal artery, and you can see here that they're very attenuated, and the retina, instead of looking nice and healthy and red, is actually quite ischemic. It's swollen, um, and it's pale. All right, so, um, these patients tend to be vasculopaths, they have, um, hypercoagulable risk factors, or they have other risk factors for vascular occlusion like GCA. These patients will typically have an afferent pupillary defect, and they need emergent referral to the emergency department, so it's not helpful to just refer them to an ophthalmologist because you need to find out why they're occluding their vessels. They might need a stroke evaluation. These patients have poor prognosis, so the, um, ocular um therapies listed down below are typically heroic measures but don't tend to make much difference. Um, it, uh, is kind of like a stroke in which you have a neurologic defect that doesn't necessarily reverse if you're outside a certain time window, in this case, approximately 90 minutes. All right. So, um, that is a central, uh, retinal artery occlusion. Uh, next, uh, let's cover giant cell arteritis or temporal arteritis. Again, can cause severe and constant blurry vision. Again, is an emergency. Um, this is, uh, giant cell arteritis, as you, uh, well know, is granulomatous inflammation of medium to large arteries, including the arteries, uh, that supply the optic nerve. So you can have ischemia of the optic nerve. Typically. The prognosis for the involved eye is very poor. The reason why this condition is emergent is because you want to prevent vision loss of the other eye, the normal eye. This is a systemic disease and you can involve the patient's eyes bilaterally. Giant cell harderitis has a lot of uh specific signs and symptoms. It will cause sudden severe unilateral vision loss, usually worse than 2200. Typically, these patients are above 70 years old, although 50 years old is the formal cutoff, we typically only see patients who are greater than 70. They may have a prodrome of other weird come and go eye symptoms like amaurosis fugax or double vision. They, uh, will often have jaw claudication where I ask, do you have, uh, trouble chewing so much so that you have to stop because it hurts your jaw to chew. They have scalp tenderness often associated with polymyalgia, rheumatica, fevers, weight loss, you name it, systemic symptoms. These patients have a definite large afferent pupillary defect as well as loss of the temporal artery pulse right here. Their inflammatory markers are extremely elevated with ESR often greater than 50, CRP greater than 2.4, and they require emergent referral to the emergency department for IV steroids and rheumatology evaluation to transition them to an immu immuno immunomodulator after discharge. All right. So we've covered all of the constant blurry vision, and now we're in the home stretch. We're gonna talk about fluctuating, uh, blurry vision. So there are 3 main ones that I wanna cover today, which is dry eye, papilledema, and amaurosis fugax. So dry eye is very, very common these days, and I, uh, can bet that the vast majority of patients, at least who come to my clinic with fluctuating blurry vision, um, have it due to dry eye. It comes and goes. It's non-urgent, and it's because you need tears to see clearly. The eye is always covered by a thin layer of tear film, um, and if this tear film starts breaking up, it's going to scatter light and you're going to lose vision because of it. Now, one thing that throws people off is a lot of times, especially when people are older, they don't feel dry, they just have blurry vision, and that is actually quite common. Um, so I want to explain that tears have some main components. One is obviously water, uh, produced, uh, mainly by the lacrimal gland, but you can also have oil glands in the tear foam, um, that are produced by mbomian glands in the eyelid. And if you have a deficiency of the water of the eye, you typically will have dry eye worse in the evening because your eye has been open all day, all the water has evaporated, so you're feeling more dry by the end. Um, if you are having an oil dysfunction, when you close your eyes, you're no longer blinking your eyes, you're not squeezing the oil glands in your eyelids out. All those oils are accumulating in the eyelids kind of like pimples, um, and they accumulate and they start, uh, squeezing out of your eyelids like this gross picture inferiorly, and so you'll get crusting and irritation, especially in the morning. It's typically worse with concentration because when we're concentrating, we're not blinking. It's like having a staring contest with your computer. Um, so typically patients will say, OK, I have fluctuating blurry vision, sometimes my vision is great, but then towards the end of the day or maybe when I'm reading, I'm going to have blurry vision and it gets better when I blink or when I take a rest. So mild fluctuating blurry vision, worse with prolonged reading, or anything that just exacerbates it like AC or wind drying the eye out. Um, the recommendation would be to consider an optometry referral, um, and to start the patient on artificial tears, just replacing the, um, aqueous component of their tears, as well as warm compresses to, uh, loosen up those oils that are trapped in their, um, eyelid glands. Next, we have papilloedema. Um, this is a, a type of fluctuating blurry vision resulting from swelling of the optic nerve head secondary to increased intracranial pressure. This is relatively urgent just because you want to make sure that whatever is causing the intracranial pressure, um, is, uh, evaluated. So, um, Uh, the papilledema causes bilateral transient blurry vision. It typically lasts for seconds. It's worse when you're increasing pressure to the head, so you think about prostural headaches, worse with lying down, worse with sleeping, um, worse in the morning, worse with bending over. You might hear, um, headaches or tinnitus, um, associated with this, and the patient needs to be referred either urgently to ophthalmology to evaluate for papilledema or to the emergency department um for further evaluation of increased intracranial pressure. Typically, we'll start off with an MRI and um MRV um to look for mass or duo venous uh thrombosis, as well as a lumbar puncture just to see what the opening pressure is. Um, if there's no identifiable cause, this is likely due to increased, um, uh, pressure from idiopathic intracranial hypertension, IIH, otherwise known colloquially as pseudotumor cerebrae. All right, uh, home stretch here, so the last cause of fluctuating blurry vision is amaurosis fugax. It comes and goes, so it can throw off people because when the patient comes to you, their vision is actually normal. They had an episode maybe one week ago. Or this morning and it's completely resolved. Um, this is due to carotid artery stenosis resulting in transient episodes of ocular ischemia. Sometimes, um, it can be due to GCA but usually these patients have vasculopathic risk factors. So it's unilateral. Typically, the vision blacks out or at least has very severe blurry vision. It typically lasts for 3 to 5 minutes and then goes back to normal. If you look at the eye itself, it's actually a completely normal eye examination, which can be confusing to a provider, but you actually need to take these patients and refer them for um a relatively urgent carotid ultrasound, possible stroke evaluation, and carotid endarterectomy. All right. So in summary, um, we've talked about painless blurry vision, which can be divided into constant versus fluctuating, uh, um, classes. In the constant category, we have refractive error, cataract, macular degeneration, as well as some, um, more severe, uh, syndromes that require a referral emergently, such as retinal detachment, central retinal artery occlusion, and giant cell arteritis. Now, the patient can also have fluctuating blurry vision, which can be dry due to dry eye, papilloedema, or amaurosis fugax. So this is the evaluation of painless blurry vision. You might note that you can think of a bunch of other um uh diagnoses. Uh, that are also emergent referrals, um, or it can cause blurry vision. Um, those, uh, potential causes are likely painful. Um, we're just covering painless blurry vision today. That patient who comes in in a note acute distress saying, Doctor, my vision is blurry, what do I do? Um, as a quick, uh, reminder, refractive air is better with pinhole. Cataract, you can look really close at that pupil, try to see if it's milky or not. In macular degeneration, it affects the central vision. You might have wiggly lines. Retinal detachment, as for floaters, flashes, or that shadow curtain getting larger and larger. Uh, central retinal artery occlusion, they have an, uh, APD, pupil defect. They are vasculopath, giant cell arteritis, pupil defect, and jaw claudication is one of the most specific symptoms associated with it. Dry eyes are better with blinking and rest. Papilledema lasts for seconds, and is postural worse when you have your head down. Amaurosis lasts for minutes and these patients tend to be vasculopaths. All right, so, um, we've reached the end of the talk. Um, hopefully now you have a better idea of how to make a differential for painless blurry vision. You know some basic vision screening maneuvers for a non-ophthalmology clinic. Remember the phone and the keyboard are your friend. Know when and where to refer these patients. OK. All right. Thank you so much.
