Updated: Feb 21, 2020
Buckle up, as this is a long one. I address the many causes of vision dysphotopsias such as glare, halos, the problems of contrast sensitivity and the many, many causes of these issues such as dry eyes and tear film instability, corneal scarring and previous corneal refractive surgeries such as LASIK, PRK, RK, as well as cataract with or without YAG laser treatment for posterior capsular opacification (PCO). But wait, there's more. A very common age-related event, the posterior vitreous detachment (PVD) can also cause visual problems such as glare. Unlike the other conditions, a PVD causes a dynamic fluctuation of glare that varies from moment to moment as with eye and head movements. PVDs can also alter contrast sensitivity and reduce it by about 50%. This is something that is not tested by your optician, optometrist, or ophthalmologist at a typical eye examination. Lately, those with cataract surgery are 'pressured' (or, at least stongly directed) toward the significant 'out-of-pocket' expense for the "premium" lenses that are multifocal lens options. These have the potential for getting you out of glasses for distance AND near vision - but not without sacrifice. The cost is more than just financial, as there can be significant increases in halos, starbursts and other visual dysphotopsias. I also address the issue of when your optician tries to upsell you with an antiglare coating for your eyeglasses correction. These antiglare coatings generally do not reduce glare but they can reduce the reflection off the surface of the glasses which doesn't benefit you all that much, the person wearing the glasses, but instead improves the appearance of the glasses to the person looking at you as they see less reflection off the front surface of the glass. This is a lengthy one, but if you're frustrated and aren't sure why you're having vision problems and your doctor says everything is fine because you are seeing 20/20, well now you have a vocabulary and understanding to describe your problem.
Here is a transcript of the video:
Glare, Halos, and other Vision Problems - Multifocal IOLs & Opticians Upselling Anti-Glare Coatings
Most people are aware of the measurement of visual acuity. When you go to your doctor, you sit in the chair, they project some letters up on a wall and you read them and they'll tell you, you are 20-40 or 20-20 or 20-15. I won't get into what those numbers mean, but you know, generally 20-20 is good vision and 20-15 even better, elsewhere in other countries they use the metric system.
But that's really only part of what we would call quality of vision issues. There are other things we're going to talk about which are the category of dysphotopsias which includes other things such as color vision, the balance between the two eyes, seeing single or double vision? It also includes glare, contrast sensitivity, and many of these other things have to do with the quality of vision.
Hi, I'm Dr. James Johnson. I am medical director of vitreous floater solutions and all I do is treat floaters in my sub-specialty medical practice, I'm known as the floater doctor. But I'm not going to talk strictly about floaters. First, I'm going to talk about some of these other factors, which can affect the quality of vision. And this might also explain why the doctor might say, well, very good, you're seeing 20/20. And you're like, ‘Yeah, but there's this other quality vision thing that I don't really have words to explain’. And then he or she says, ‘Yeah, but you're seeing 20/20’. It's like you're speaking different languages. And this might help you understand why it's possible to have 20/20 vision, but still complaining about the quality of vision. That's certainly true in the case of floaters, but it's also true with a lot of other things.
For instance, if you've had refractive surgery, if you've had cataract surgery, if you've had some injuries or even dry eye can cause a number of these things. And this presentation will not necessarily arm you with all of the vocabulary to explain that and describe that, but it might help you understand it somewhat. So, we can break down these quality vision issues, dysphotopsias into maybe three main groups and I'll put examples of each of these. There's glare or flare, halos, and starburst.
Glare can occur when you have your black letters against a white background with what we will call foreground and background. And that edge should be clear and dark and sharp and very well defined when you start to get sort of a softening of that and less distinct definition of the foreground versus background or the letter versus the white background. That can occur with a number of conditions, for instance, refractive error, (if you're very nearsighted if you're very farsighted or if you have astigmatism), it can also be caused by ocular surface issues such as very dry eye or irregular tear film as can occur after LASIK or with autoimmune disorders, injuries, scarring and things like that. Estrogen issues with postmenopausal women, anything that disturbs or makes the tear film, less stable from blink to blink can cause a glare. You can also occur with posterior capsule opacification after cataract surgery, this back membrane here (the posterior capsule of the lens) can start become kind of cloudy, sometimes it's called a secondary cataract, not technically a cataract, but that can cause some of those problems as well.
In the case of my practice, I see this a lot when people have had a posterior vitreous detachment where this vitreous pulls away, fluid gets behind that, and you have this less clear membrane kind of billowing around in that back fluid space.
Essentially what a lot of these are (other than the defocus of being nearsighted or far-sighted) is whenever you have light entering into this camera-like system all those light rays are not being focused into one place. If 95% of that light is being focused to one place, but 5% or more or so is being sort of scattered and diffracted around that you're going to get that kind of soft little halo, but a soft little glow around that defined edge. And that's where I see this in my practice a lot. All of these other conditions, for instance, the irregular cornea, posterior capsule opacification, cataract, those are static and stable conditions.
In other words, from moment to moment, blink to blink, eye movement-to-eye movement, it doesn't really change. It's not stable in the sense that over months, and maybe even years or so yeah, that can certainly get worse, but not from moment to moment. The only other condition that does give you some moment to moment change would be an irregular or unstable tear film. That will give you some instability, you know, in between blinks, you blink it's a little bit better and then within just a few seconds you can kind of blink and kind of re-wet that again, it's kind of unstable.
The thing about the vitreous detachment and floaters and cloudy floaters and such is that it truly has a dynamic nature to it so when you turn your head and that that cloudiness and that glare will sort of move across you might have moments of clarity and then it swings across there and you have that glare.
Halos again, (sample of the halo here) is a bit different. I will see this more so in multifocal intraocular lens implants. So, with cataract surgery, cataract is a clouding of this lens right here. It's a yellowing clouding haziness, which can also give you glare. When they replaced those intraocular lenses, it used to be there was a standard single focus monofocal lens that would be placed in there. So, in the last several 10 years or so, these multi-focal intraocular lens have become much more popular. And the way they work is they take basically 100% of the light rays entering into this system, and we’ll say 50% of it is focused here, and then 50% of it is focused slightly in front of that.
And then when you, so if you're looking at an object at distance, half of the light rays are focused here, half of it is in this halo-ey you’ll kind of ring around there. Then when you focus on something closer to you, there's a shift and it's half in focus. And then there's another 'glarey' Halo that surrounds that, that's kind of unique to these multifocal lenses where you have two distinct focal points. That's something that may not have been explained to you. The manufacturers will show you a brochure, the representative or the doctor will show you a brochure and says, “look, you know, you we can get you out of glasses, you can see distance and you can see me and you're not going to be stuck with reading glasses like I am. And that's amazing. Oh, and by the way, it's a little extra money, maybe you know, $3000-$4,000 out of pocket, but it'll be high definition vision. It'll be amazing”. That's kind of how it's sold it you know, sidebar over here little comment is, you know, they're very well designed, but I think they just don't really explain to you that there might be this quality of vision, a dysphotopsia that will go along with those intraocular lenses. And so, you know, caveat emptor, buyer beware, this is part of you doing your due diligence to sort that out, you know is the benefit of being mostly functional without glasses. Is it worth the decrease in the quality of vision?, I don't know, it kind of depends on you and your personality? If you are a software engineer, if you do a lot of reading a lot of work on your computer, a lot of detail work at a set fixed distance. Having that issue may not be good enough for you. If on the other hand, you just want to be out and about, you just want to be able to grab your phone and take a look at you want to look at your watch, you want to grab a menu real quick. You just want to be really really functional without glasses. That might work quite nice for you. But there's trade offs, you know, as in life, you can't have it all. And these multifocal lenses, truly you can't have it all.
Now, starbursts (again, sample here). Starburst, can be seen with refractive error again, nearsighted farsighted can be seen with ocular surface disorders, bad tear film, blepharitis. Again, all the things that could cause problems with your tear film and can be seen with different types of multifocal lenses with these newer diffractive style lenses, and again, this is sort of the newer phase of that. So, you know, whether you have halos or Starburst, both of those are qualitative changes to your quality of vision that will occur with these newer highly promoted multifocal lenses that either have or you know, you'll be sold on. So that's a very brief you know, kind of overview on dysphotopsias which is quality of vision. There's more than just Snellen visual acuity chart vision, but these dysphotopsias.
Now, let me shift a little bit and talk a little bit about contrast sensitivity. So, this is again, one of the quality of vision issues. Contrast sensitivity is your ability to distinguish gray on gray. Okay, so when you sit down in the chair at your doctor's office, and they put 100% black letters on a 100% white background, that's essentially 100% contrast, right? And the brighter the light environment, the better your eye’s contrast will be. Same thing with photography, right? In low light, it's hard to get really good quality images, they get a little grainy, especially with a digital. And the brighter the light is you can change the ISO to your favor, you get just you just get better quality images in the brighter the light is, and the eyes are the same way.
And so, contrast sensitivity is a very important part of what we call the quality of vision. And, and so example you know, black on white, and better lighting will give you better contrast and dimmer, dark environments and or gray on gray. So, if you are in the high latitudes in the wintertime at dusk, and there's a woman wearing gray pushing a gray stroller and it's foggy, and that's a very, very low contrast situation. The vision is not going to be very good. If you have some of these other conditions, which can affect contrast sensitivity, the vision is going to be is going to be even more poor.
Now, where the floaters come in. One aspect of changes to the vitreous that can take place is what is called a posterior vitreous detachment, again, as I explained earlier, that's when that vitreous pulls away from the retina. Now, we're not even talking about specific floaters, we're just talking about a PVD. How common is that? 25% of 60-year olds will have a PVD and this is just randomly chosen off the street we find a bunch of 60 year olds we do measurements we do the examination will find a good 25% of them will have had a posterior vitreous detachment that goes up with age with same grab a bunch of 80 year olds do the examination that rate goes up to 60%. So, it is clearly an age-related phenomena. The older you are, the more likely you are to have a PVD. Again, not even talking about the floaters, specific clouds and strands and things like that. So, Dr. Sebag in Huntington Beach was a retinal specialist, he did a study. And he showed that just the presence of the PVD alone will decrease your contrast sensitivity by about 50%. That's a lot. And again, it's one of those things that people have a very hard time trying to describe. Doctor, My vision is not clear. Yeah, but you're reading 20/20 it's that whole thing back and forth again.
Now, kind of related to this, let's say you have glare, from whatever source you've got glare, you know you have glare, you're driving into the car headlights, the street lamps, the setting sun, those types of things are causing a lot a lot of glare. Well, if it's cataract, and it's bad enough, well, you're you can get cataract surgery and get that improved. But let's just say you have glare and your eyeglass prescription is changing, it's time to get that fixed. So, you go to the local optometrist, and they do their refraction. And they say, Well, you know, you're refraction has changed a quarter diopter, which is nothing, half a diopter, whatever. I'm going to write you a prescription for some glasses. And by the way, let me guide you over to our own optical shop over here where you can choose from our assortment of expensive frames (Am I sounding cynical? I hope not) where you can choose from our frames, and and choose that. And then they say, “Oh, and by the way, I would highly recommend our anti-glare coating”. At that point. There should be red flags, right? But there isn't. We'd like to recommend this anti-glare coating so you have less glare and you're saying “Great because I've got glare right, this is going to help me”, Well hang on there. What they're really promoting is an anti-reflective coating. Now there's a difference. Okay?
An anti-reflective coating, you can sometimes see it because if you just kind of shine some light in there you can look at the surface there. It has a little bit of a blue green color I'm reflecting it actually off my light right here is I'm looking at that has kind of a blue green color to it, and it's a little bit of a matte finish to it, rather than a very bright reflection on there. That's the anti-reflective coating, right. It's really not changing the glare because light has to pass through all of these surfaces here has to pass through your tear film has to pass through your cornea and has to pass through your lens, it has to pass through any posterior capsule opacification (PCO), if you have that, it has to pass through your vitreous detachment. And this is where all the diffraction of the glare comes from. Putting a pair of glasses in there is not going to change that the light still has to pass through these, right here. So, let me just say the anti-glare coding really only benefits somebody else looking at you.
So if I'm in a big box store, or I'm doing a presentation in the corporate setting, and there's these new bright fluorescent lights all over the place, that light is going to reflect off my glasses and is going to reflect off to the observer you out sitting out there. Or if I'm having photographs taken, and you have the reflection coming off that that, it will help reduce some of that reflection to you, the observer, it really doesn't change my glare, or it doesn't really improve glare, if that's what I suffer.
So, I'm not saying it's a bad thing. I'm just saying again, information: You're better armed with information when you go in and do that and you might still say, hey, it's worth the extra, I don't know what it is $50 $60 whatever it is that they charge for the anti-glare. Maybe it's only $20 I don't know. It may be worth it to you. I have anti-glare on here as well. I don't have problems with glare. You know, I don't like the reflection coming off the glasses. So bottom line is there's lots of things that affect the quality of vision, some that you can do something about. If you have a bad tear film, there's often times things that you can do about that. And cataract if it gets bad enough you can have cataract surgery, depending on which intraocular lens you put in there that might affect whether you have things like halos and starbursts. If you've had a posterior vitreous detachment can't do much about that to tell you the truth you cannot get that vitreous to reattach there's, there's no way to do so it just doesn't right. So that's bad.
Well, no, I take that back. There is a procedure for that.
If somebody has really bad floaters, you can justify a floater-only vitrectomy , without much detail, they go in and they basically remove all of this fluid and replace it with the saline fluid. It's invasive, it’s got its risk. It's got its challenges. I’ll talk about that in another video. So, there are there are some things you can do about this.
Contrast sensitivity, again, better lighting if you're going to read you know, have lighting not coming at you this way but from behind you. Just be aware of some of these things. And if you are at a point where you're developing cataract, and the doctors are strongly promoting these multifocal lenses, I might as well talk about some of that right now. I've got a few more minutes. I'm not against the multi-focal lenses, but you need to know what you're getting into. Choose wisely. I will say this: I don't think they can really justify the cost, the additional cost. It used to be that the insurance companies and Medicare here in the United States paid for cataract surgery. And that was it. The company's lobbied 10 years ago or something they said we now have this better technology. We'd like you to still pay for the cataract surgery. But because this is our research and to develop these things, it's expensive technology. We'd like to be able to charge the patient for the difference. And the regulatory Medicare who generally sort of leads the pathway and all this, they said, “All right, that sounds right.” And so the doctor can basically charge anything for that.
But to put a multifocal lens in the eye - There's no additional equipment, there's no additional or different preoperative evaluation or measurements. The surgery? You cannot tell the difference between the surgery. It's the exact same surgery. Post-op care is the same and same post up medications. Everything is the exact same as if they put a single focus lens in place. Yeah, the lenses are more expensive, but it's a piece of plastic.
Can you justify the cost of $3500 to $4,000 that I hear people paying for these two eyes now you're getting into $8,000 or so? That's for you to decide. It's not my position to say you should or should not. I will tell you this though, when my mother and my ex-mother-in-law, and anybody else who would ask me said, “What should I do?” I said, You know what, I'd go the single focus lens, I think they can dial that in better. I think the results are more predictable. Yeah, you might still need reading glasses. That's what I do. You know, I'm of that age, I need them. I'm used to that. And that way, I know that both of my eyes are focused in the same place that they're either focused for distance without, I put on my reading glasses. I could see up close, it's all good.
And there's workarounds for that as well. For instance, myself, when I go out socially or go on a date or something like that, I will put a single contact lens and just when I that one gives me a little bit of power for up close. So, I can see for distance both eyes open, I can see up close both eyes open, my brain kind of shifts its emphasis from one to the other. And it's called monovision. And that's something that just about anybody can do. And the nice thing about it is I can see for distance when I'm playing sports like tennis and I can put on my reading glasses, and I can see up close with both eyes balanced. And then under certain circumstances, without an absolute commitment, I can put a contact lens in one eye and be able to see distance in the air, but I'm not committed to that.
So, for me, that works, that's an option worth discussing with your doctor. And by the way, that's also possible with an implant lens where you have one lens implanted, which is for distance, the other one for near so you can do monovision with the implant lenses. And that way, you're kind of avoiding some of these problems with halos and Starburst that you get with the implanted multifocal lenses.
Just my opinion, okay, I don't do cataract surgery anymore and haven't done so for a while. So I've got no skin in that game. It's just my opinion for what it's worth.
Anyways, I hope you found this helpful.
If you did, and if you if you'd like to hear more of this on, on both on floaters as well as just sort of general ophthalmology, I'll ask you to subscribe and recommend this channel to anybody else. And if you do have floaters, I am the floater doctor. That's all I do is treat floaters here in Southern California.
So, if you have floaters, and you need an evaluation and possible treatment, I'm the guy. Anyways, it's a pleasure. As always, thank you for your interest in my practice, and I hope you learned a little bit of something.
And by the way, if you have, if you have suggestions, or if you have questions, you can send them to write up in the comments here. Go to my website, there's a contact form, you can contact me. That's where I get ideas for this. I think I had a conversation with somebody about glare, glare glare and that was the catalyst for this whole presentation. So, I really do read these I tried to put time into answer them and all to help Expand your visual consciousness. All right. Anyways, have a great day. Thank you again. Talk to you later.