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 the cohort at the UCSF Berkeley site. Um We have an amazing staff consisting of faculty optometrist from the Berklee 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 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 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 there in no acute distress, the eyes look completely white, quiet patient looks fine, no pain 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 a 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 arthritis. But if the patient says no, sometimes my vision is actually pretty good. It's only sometimes that have fluctuations where my vision is poor. You might think about dry eye to pull edema or Amoros is few jacks. Now you might think okay dry eye refractive error not a big deal but some of these are conditions that might tighten, tighten the anal sphincter right? You might want to refer them urgently 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 intra ocular emergencies like retinal detachment, central retinal artery occlusion. Giant cell arthritis and Amoros issue jacks. Just like 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 um 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 irises because the cornea is clear in the middle of 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 that covers the entire inner wall called the retina. This is the 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 the structures in the eye that are responsible for this. So um good focuses when you're aligned with the retina, when you are not aligned with the retina, you might need additional glasses to uh correct the focus so that you do have a focal point that is in 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 forming on the retina is very out of focus. Alright so um things that you might suggest that the patient has refractive error include uh includes how old their current correction is. Our bodies are always changing and so do our eye shape and glasses prescription. Um So if there were 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. As the patient is middle age, 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 okay 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 shift 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 rate 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 raise 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 the vision is checked with both eyes open. This will give the vision of the better. I only. So you want to check with one eye at a time and you want to check with whatever glasses um the patient is needing to wear if they if you're checking vision for far away, they need to wear glasses for a 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 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 want to check with and without pinhole occlusion. Alright so you might say okay 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 2030 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 seven inches instead of 14 inches you go from 2030 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 21 50. 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 of fingers or if they can even see some movements of your hand. Now you might say okay that sounds good but I don't have a pinhole in my office. What do I do without pinhole occlusion? So if you can you can actually still check pinhole um even without an include er what you can do is have the patients use their hands or fingers to make a pinhole themselves. The caveat is you just want to 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 you want to make sure that the pinhole is at least approximately like one millimeter in diameter so that you're actually able to get rid of those peripheral raise. 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 refractive correction such as glasses, I challenge you to take off those glasses, look at something around you in the room and try that pinholes. See if you can actually get your vision to improve um when you're looking through a small aperture. Alright so let's move on from refractive error. Cataract is another cause of constant blurry vision that is non emergent due to likely age related or pacification of the lens although there can be secondary causes. So here is just a pretty extreme example of a cataract. You can see that the lens which sits behind the pupil on the 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 intra ocular lens that is artificial and her vision improved to 2020 after surgery. So how do you know a patient has a cataract? Well though typically tell you that their vision has been slowly getting worse over time, it slowly progressive. Other visual symptoms that are specific to cataract include decreased nighttime vision. The cataract is opaque, so you're just getting less light into the eyes on 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 and 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 has 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 comparison of on the left top hand side uh pupil that is completely dark, it's normal, there's no cataract there. Um If you look a little bit closer out, 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 a red reflex comparison between the right eye which is pictured on the left and the left eye which is pictured on the right. Started to be confusing and you can have a good red reflex which means that there are no lens capacities versus a bad red reflex. That could potentially mean a cataract. Alright, 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 ideologies that require 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 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 I vitamins and is 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 objections and often requires an urgent referral. So macular degeneration causes central blurry spot because it happens in the center vision in the macula. Typically these patients have a positive family history there 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. Ask the patient to look at that central black dot. Then you can ask any of the lines wavy instead of being straight or any of the lines missing. And um this grid checks the center 20 degrees of vision, so the patient should get an ophthalmology referral non urgently unless there is a recent and rapid change. Alright, 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 correct it, the less likely that the retinal detachment has time to grow and expand and involved entire retina. A retinal detachment typically occurs when the retina has a hole or a tear and the 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, okay, I had some flashes and floaters, flashes of light because the retina, which senses light was stimulated. So you have this artifice inside the eye of a flash of light. They might have floaters because of release of sub retinal pigment into the eye 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 ophthalmology referral 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 want to 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, like more rectangular, like square squarish looking one. So you want the linear transducer, You have the patient, close their eyelid, make sure that they have like some tissues on hand. We always have tissues and clinics, it's like literally just sitting right there for me. Um uh just because you can have them with the ultrasound jelly off after your examination and once you have the transducer on the eye, you want to 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 game 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 game to be relatively up up is better than down. Um But you don't want to have it too high so you want to 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 detachment. You can see the retina itself as this wavy line inside of the eye that is actually separated from the wall. If you're not really sure what's going on, you could always compare it to the normal. I it's very unlikely that the patient has bilateral retinal detachment. 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. Alright getting to the super big emergencies central retinal artery occlusion or C. R. A. O. 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 ocular and also a systemic emergency. This results from the inclusion 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 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 vascular past. They have um hiker co global risk factors or they have other risk factors for vascular occlusion like G. C. A. These patients will typically have an Afrin people every 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 including their vessels. They might need a stroke evaluation. These patients have poor prognosis. So the ocular therapy is listed down below are typically heroic measures but don't tend to make much difference. Um it 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. Alright. So that is central retinal artery occlusion. Uh Next let's cover giant cell artery. Itis or temporal artery itis again can cause severe and constant blurry vision again is an emergency. Um This is giant cell arthritis as you well know is granny, luminous inflammation of medium to large arteries, including the arteries that supply the optic nerve. So you can have ischemia of the optic nerve tipping the prognosis for the involved I is very poor. The reason why this condition is emergent is because you want to prevent vision loss of the other eye. The normal I this is a systemic disease and you can involve the patient's eyes bilaterally. Giant cell Margaritis has a lot of 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 cut off. We typically only see patients who are greater than 70. They may have a program of other weird come and go i, symptoms like Amoros is few jacks or double vision. They will often have jaw clarification where I asked do you have trouble chewing so much so that you have to stop because it hurts your jaw to chew. They have scalp tenderness often associated with poly rheumatic fevers, Weight loss, you name it systemic symptoms. These patients have a definite large affluent people every defect as well as loss of the temporal artery pulse right here. Their inflammatory markers are extremely elevated with E. S. Are often greater than 50 crp greater than 2.4. And they require emergent referral to the emergency department for I. V. Steroids and rheumatology evaluation to transition them to a mono immuno modulator after discharge. Alright so we've covered all of the constant blurry vision and now we're in the homestretch we're gonna talk about fluctuating blurry vision. So there are three main ones that I want to cover today which is dry I papa adama and Amoros issue Jacks. So dry eye is very very common these days and I 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 i 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 produced mainly by the lack of gland but you can also have oil glands in the tear film um that are produced by glands in the eyelids. And if you have 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 squeezing out of your eyelids like this gross picture inferior early 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 okay 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 works with prolonged reading or anything that just exacerbates it like a seer, 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 acquis component of their tears as well as warm compresses to loosen up those oils that are trapped in their eyelid glands. Next we have papa adama. Um This is 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 evaluated. So um the popular edema 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 postural headaches worse with lying down, worse with sleeping um worse in the morning, worse with bending over. You might hear headaches or tinnitus associated with this. And the patient needs to be. He referred either urgently to ophthalmology to evaluate for papa adama or to the emergency department for further evaluation of increased intracranial pressure. Typically will start off with an M. R. I. And MRV. Um To look for mass or dural venous 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 uh pressure from idiopathic intracranial hypertension II h otherwise known colloquially as pseudo tumor cerebral high. Alright home stretch here. So the last cause of fluctuating blurry vision is Amoros is food ax. 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 the this morning and it's completely resolved. Um This is due to carotid artery stenosis resulting in transient episodes of ocular ischemia. Sometimes it can be due to G. C. A. But usually these patients have vascular empathic risk factors So it's unilateral. Typically the vision blacks out or it at least has very severe blurry vision. It typically lasts for 3-5 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 a relatively urgent carotid ultrasound, possible stroke evaluation and carotid endarterectomy. Alright so in summary we've talked about painless blurry vision which can be divided into constant versus fluctuating uh classes in the constant category we have refractive error, cataract macular degeneration as well as some more severe syndromes that require referral emergent lee such as retinal detachment, central retinal artery occlusion and giant cell artery itis. Now the patient can also have fluctuating blurry vision which can be dry due to dry i, Patel edema or Amoros issue Jacks. So this is the evaluation of painless blurry vision. You might note that you can think of a bunch of other um diagnoses that are also emergent referrals or can cause blurry vision. Um Those potential causes are likely painful. Um We're just covering painless blurry vision today That patient who comes in and a note to distressing doctor my vision is blurry. What do I do um as a quick reminder. Refractive error is better with pinhole cataract. You can look really close at that pupils. Try to see if it's milky or not in macular degeneration. It affects the central vision, you might have wiggly lines, retinal detachment. Ask for floaters, flashes or that shadow curtain getting larger and larger. Uh central retinal artery occlusion. They have an A. P. D. Pupil defect. Their vascular path giant cell arthritis, pupil defect and draw clarification is one of the most specific symptoms associated with it. Drives are better with blinking and rest. Popular. Gmail lasts for seconds and is postural worse when you have your head down and neurosis last for minutes and these patients tend to be vascular paths. Alright, so we've reached the end of the talk um Hopefully now you have a better idea of how to make a differential for a 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? Okay. Alright, thank you so much