Cataracts and special lenses webinar transcript
Good evening and thank you for joining us on tonight's webinar on cataracts. My name is Louise King and I'm your host. Our expert presenter this evening is Mr Damian Lake he's our Consultant Ophthalmic Surgeon at Benenden Hospital. The presentation this evening will last approximately 25-30 minutes and then there'll be time for a Q&A session. You may ask questions throughout the presentation, using the Q&A at the bottom of the screen or you can ask them at the end. It'd be better if you could use the Q&A button, not the chat, if possible, just so we can manage the amount of questions.
This webinar is being recorded and other attendees won't know you are attending unless, when you do a question, you include your name. So, if you want to be anonymous, please don't include your name. I'll now hand over to Mr Lake and you'll hear from me again shortly. Thank you very much, over to you.
Mr Damian Lake
Thank you very much. Welcome everybody to this webinar on cataract removal and information about special lenses and the service at Benenden Hospital. My name is Damian Lake. I've been a Consultant Ophthalmologist (which is an eye surgeon) for the past 15 years and 10 years training before that.
I'm a member of these prestigious academies: American Academy, The Royal College of Ophthalmology, the European and UK Society of Cataract and Refractive Surgeons - upon which I've served as council member - The British Refractive Society and the Cornea Society in America.
And as part of my membership and council membership of these bodies I've presented both here and internationally on subjects related to cataract surgery.
Now just a brief overview of the anatomy of the of the eye. So, most people have two eyes, and it looks like this in cross section. The front window of the eye we call the cornea. Then there's a front chamber called the anterior chamber. The coloured material inside your eyes is muscle called the iris. And the hole in the iris is the pupil. Just behind that is your natural lens, which sits in a very thin capsule bag, suspended on a muscle called the ciliary muscle by these tiny little strings we call zonules.
Now behind your natural lens here is this cavity called the vitreous cavity, which is filled with a mainly clear jelly - although occasionally you can get floaters, which cause people a lot of consternation - in that jelly. And then behind the jelly is a membrane at the back of the eye called the retina. And the eye is analogous to an old-fashioned camera, in as much as it's got a got two lenses; a fixed lens at the front, a mobile lens in the middle and then a film which picks up the light at the back of the eye. And we're going to talk about these later when we discuss the procedure.
When examining the eye, the doctor asks you to put your chin onto a machine called a slit lamp and there's an oblique light and then we look through a microscope to examine the eye and this is what we can see. So, we see the top lid here and the bottom lid down here, there's the pupil in the centre with the coloured iris and the clear window called the cornea over this and the white of the eye called the sclera and a thin membrane called the conjunctiva above that. And it's important in our examination that we that we check that these are all healthy, prior to them cataracts or lens-based surgery, so we can properly discuss with you all the risks and benefits of the procedure.
As part of the assessment at Benenden Hospital you'll come to the hospital, you’ll be asked some questions by the nurses and have some tests performed. Some of those tests you'll be familiar with because you have them performed when you go to the opticians, like reading the letters on the chart. Others you'll be less familiar with, but I'll give some examples here.
Now you can see, we initially start with what we call cornea mapping, so the cornea is that clear window at the front of the eye, and we take a rotating photograph of the cornea and we do that so that we can ascertain how thick the cornea is and the shape of the cornea, because that's going to help inform our choices as to what lens at the time of cataract surgery we might suggest to you.
Now this is the screen that we see, and we can see the shape of the cornea, we can see how thick the cornea is, and we can see the depth of the front chamber of the eye to help that cataract plan.
Here you can see that these circles are projected onto the cornea, and this is a technique to enable us to work out the shape of the cornea. So, if you project circles onto the cornea, if it's irregular or steep in one direction and flat in the other it will distort these circles and it will give us an idea of the shape of your cornea.
So, when the cornea is misshapen like this so steep in one direction and flat in another, we call that astigmatism. Now astigmatism is important if it degrades your vision, so your visual quality is not quite as good, and we can correct that during the cataract surgery and provide lenses which will give you an optimal outcome. As you can see here again this test merely involves you putting your chin on a machine and having a light shone on the eye, there's no touching of the eye or anything like this.
This is a picture of the eye with a circle superimposed on the surface, and you can see that there's some distortion of those circles, and that helps us work out in our planning - which goes into a formula - to work out what style of lens that we can offer to you.
Now once we have all of those images, those are passed through to the surgeon and you can see at the bottom here is the images that have just been performed on the patient before. And we get four maps; this one is the curvature of the cornea, this one is the front steepness of the cornea, the back steepness of the cornea, bottom right, and the thickness of the cornea.
Now these are relevant to us because you can see on the top left map that there's a sort of increased red colour in this direction here, but a yellow colour in that direction there. And this equates to this scale here, so the red areas are curved, steeply curved areas, and the yellow area is a flat curve. And that's the astigmatism. Now those readings can then go into a formula up here, along with the length of the eye, the curve of the eye, the front depth anterior chamber and it goes into a mathematical formula which then gives us the power of the lens that we would need to order and then implant during the cataract surgery and the expected outcome. Now all of these measurements are performed with something called biometry which uses laser and a special light, infrared light, to measure the eye. And this all takes less than one minute to do, so I'll show you a demonstration of that.
This equipment is very expensive and has been purchased by Benenden Hospital within the last year. So, you can see the eye up here and it's projecting dots onto the surface to measure the curvature. You can see the front chamber of the eye here: this is the pupil; this is the lens - or the cataract when it's gone cloudy - so that's all the first measurements done in under 20 seconds.
We then move on to the other eye. This is all done automatically, again measuring the curvature of the eye. This is the front chamber of the eye, this is the cataract, this is the pupil, and you can see that all of those measurements are done in just over 30 seconds. The computer then calculates the power of the lens - all of this is done without touching your eye, just with lights - and that's all done in less than 45 seconds. So very quick very simple; there aren’t multiple repeat readings, it’s very accurate, the latest equipment available and very simple.
Now after we've had all of these assessments and you've answered the questionnaire so we can understand what your needs, what your visual needs are and what your pastimes are, we then move on to a consultation with the surgeon, like me, who would examine the eye to make sure that your eye is healthy. But particularly we're looking at the front chamber of the eye, we're looking at the cataract - if the lens has gone cloudy - and the health of the back of the eye. Now a cataract is when that usually clear lens becomes cloudy. Now the symptoms that you may suffer from, due to cataracts, would be that the vision becomes gradually blurry or the image becomes very washed out and yellow or you get a lot of glare and - depending on where exactly the cataract is within the lens - different people will have different symptoms.
The procedure itself at Benenden Hospital is predominantly done with local anaesthetic. That means eye drops only. So, 99.99 percent of cases are performed with eye drops only and so you have eye drops to numb the eye, a drop to clean the eye and a little pellet is placed just inside the eyelid, which releases medicine over about 30 minutes to help the pupil dilate. Then, during the procedure, you're sitting in a chair that reclines like a dental chair and we clean around the eye with iodine and cover the lashes with a drape and there's a little clip to keep the eyelid open.
We'll then ask you to lie still and to stare straight ahead at a bright light and then during the procedure, what we do is we make a tiny incision on the edge of the cornea - which is 2.2 millimetres wide only - and we then fill the front chamber with an artificial jelly to maintain the depth of the eye and we make a little circular opening on the front of the cataract.
We then use a machine called phacoemulsification. Now this machine produces sound waves, which break up the cataract and it also has a vacuum to aspirate away the cataract segments. And that then leaves an empty capsule bag inside the eye. And, into that capsule bag, we inject a new plastic lens. So that plastic lens is made from a malleable acrylic, which rolls up into a little cartridge like a cigarette paper and we simply inject that into the eye. Once it's in the eye, it unfurls inside the capsule bag, and it's held in place by two little arms that we call haptics. And - at the conclusion of the surgery - we put antibiotics into the eye and take away the drape and the clip and the surgery is all finished.
For those patients who have decided that they'd like to get both eyes done on the same day, we would then move on to the other eye and the same procedure is performed again.
This is the machine that removes the cataract. It's called a phacoemulsification machine. At Benenden Hospital we have the latest generation of that machine called the Centurion which is produced by an American company called Alcon. It's the latest machine because it has a pump inside there, which is controlled by three sensors in the tip of the phacoemulsification probe, which then dictate how these pumps in this computer segment here work. And these are set by the surgeon, so we can set the pressure inside the eye and the power of the vacuum and also the power of the ultrasound that breaks up the cataract.
This machine was developed by Alcon and there's a big international body of consultants who advise Alcon on the machine and how to improve it. And you can see that this is me at the back here as part of that panel to provide the best machine possible for you potentially if you come to Benenden Hospital.
Now when we when we take away the cataract, the cataracts prior to becoming cloudy was a clear lens which helped you focus your vision. Once we removed that cataract, you need to have a replacement lens for you to be able to focus your vision again. Now those lenses come in different styles with different advantages and compromises. Most probably the commonest intraocular lens which is used is something called a monofocal lens or a standard lens which would be commonly used in the health service and that lens is a very good lens, but it has limitations in that the focus is only at one plane which is - for most people - usually in the distance. And then they would need to use glasses like varifocal glasses to be able to read up close or in the middle. And for people with astigmatism, it wouldn't correct that and therefore they would need glasses all the time.
At Benenden Hospital we can offer other lenses, which we call premium lenses or special lenses including multifocal lenses. You can see on this multifocal lens that there's a number of rings, and those rings allow you to focus up close in the middle and in the distance, so you're less reliant on spectacles. This is a close-up image of those lenses so you can see feint, milled circles on the lens, so the advantage of that is distance, middle and near vision. But the compromise of these lenses is that when you look at bright lights in the evening, you may see some circling around lights and in low levels of light it's a bit more difficult to read, so you need to turn the lights up. But nonetheless these are a very popular lens and have lots of advantages to them and if you're if you're happy with the compromises, then it may be the lens for you.
The lens itself - this graph is a bit complicated - but basically it shows that the light from a multifocal lens is split into three - so a trifocal lens - predominantly in the far vision and in the near vision. So, it allows you distance and near (the near being about 40 centimetres away) with some intermediate vision, so approximately the distance of your laptop from your eyes. It gives functional vision for what most people do nowadays, which is look in the distance when they're driving, look at their laptop when they're on the internet and when you're reading a book to be able to read up close. This is a different lens but with similar outcomes which shows that most people who have multifocal lenses, who have been counselled properly pre-operatively to expect the compromises and the advantages, and would elect to have the implanted lens again, and there's a very high satisfaction rate with those lenses.
Post-treatment, immediately as you finish it'll be a bit blurry, but not so blurry that you can't walk around and navigate. You're provided with refreshments and tea or coffee or whatever you need and biscuits while you watch a video on your post-operative care, which involves eye drops for one month to keep the eye uninflamed and clean with antibiotics. And you're phoned later by our nurses to make sure that everything's okay, and with the special lenses you come in to see our optometrist to check the outcome of the lens.
And this is what we see when we're looking down slit lamp, you can see - this is called a retro illumination photograph - so the light that enters the eye, bounces off the retina and comes back and enters the camera. And then you can see that this is the edge of the lens here, this is the dilated pupil, and you can see the faint circles on the lens which indicate that this is a multifocal lens - but it's nicely centred and no issues at all there.
This is a closer view of that with an oblique light you can see those circles on the lens which give the multi-focality but it's well centred, this is a dilated pupil, and everything looks fine.
For those people who have corneal astigmatism, which means a curve on the on the cornea, you can see on the map on the left-hand side this red line means that the cornea is very steep in the 90-degree axis and very flat in approximately the zero axis. So, the curvature that's mapped initially at the consultation is then put into a program and we put the astigmatism figures into this algorithm, which then allows us to calculate your special lens, and the lens has to be implanted at a certain angle inside the eye. So for those people with astigmatism, the surgery is pretty much the same with one minor difference in that just before the surgery happens (after the anaesthetic drops have been applied) you put a little mark on this very surface of the eye with a an instrument to mark the axis of the astigmatism, so that when you're lying down we can orientate the special lens with your astigmatism.
Now the special lens looks like this. So, it looks pretty much the same as a monofocal lens, but you can see up in the top left and the bottom right here there are these additional marks on the lens, which indicate that it's a toric lens for correcting astigmatism. So, these marks need to be orientated with the ink marks placed on the surface of the eye. This is what they look like in close-up, so it just takes a few extra minutes during the surgery to do that, but for people with corneal astigmatism it will give them a much better outcome and less dependent on spectacles. The compromise with this is there's just a small chance, about two percent that these lenses can move in the early post-operative period, in which case that will necessitate a second procedure just to reorientate the lens back into position afterwards.
Now one of the risks of cataract surgery is that the focus isn't quite perfect after the initial surgery and that may be that it leaves you a little bit short-sighted or a little bit long-sighted. In that circumstance it may require a second procedure.
The two things that we can do to change that are to either laser the very surface of the eye or to insert a secondary lens to correct that residual, what we call refractive error. And the way that we perform that is we use a laser to create a little flap on the surface of the eye. Now the flap is created about 270 degrees, with a little hinge here which we then lift up, so the flap is retracted. And then a second laser will reshape the cornea based on the refractive error or the v-focus that you have. Once that second laser has reshaped the cornea, we can then put the flap back down and that's the procedure finished. And that can help just perfect the outcome.
If you're not suitable for that then the alternative would be to implant a second lens which we can either attach to the iris like this claw lens or just slips behind the pupil a very simple procedure - takes about five to ten minutes - very similar to the cataract surgery but with less risk attached.
And post-treatment this is what the eye looks like. So, you can see this secondary lens connected to the iris here. Now this is the pupil and the top lid. It's very simple.
So. in summary, we provide cataract surgery at Benenden Hospital. As opposed to NHS hospitals, we can provide special lenses which give a greater outcome than simple, standard monofocal lenses.
The advantages are that we can correct those people who have astigmatism, we can provide multi-focal lenses which will give people less dependence on spectacles post-operatively, and we provide a safe service which we audit annually - we've achieved quality benchmarks - we have a team of surgeons including myself that are nationally and internationally recognised and provide services both at Benenden Hospital and in various NHS hospitals in the South East. And I think a marker of the trust that people have in our services when people choose to come and have surgery with us, this is the Chairman of one of the hospitals I worked in previously who came to have surgery with me. So I think that if your if your Chairman is choosing to have surgery with you, then it's probably a trustworthy service.
This is a survey of other doctors in the UK that selected the best surgeons in the country, of which I featured. So, if you're considering having cataract surgery and you have a problem, then I would suggest to you that you at least book a consultation to find out what the options are, we'll do an in-depth examination of your eyes with the most high-tech equipment, with the best surgeons and we'll give you a truthful and honest appraisal of what's best for you and we can discuss between us what you would like to choose, and whether this is possible and take it forward from there. So, thank you very much for attending tonight and I look forward to answering your questions.
Wonderful. Thank you, Mr Lake. Okay, so we do have some questions and the first is from Sandra. She says, are there different quality of replacement lenses? She had a consultation with another company, and they informed her that they're the only organisation that used a particular high-quality lens.
Mr Damian Lake
I think the lenses are a bit like television sets, so I think that they've been a mature technology probably over the past 20 years.
So, the first multifocal lenses appeared in the early 1990s and they've developed since then, and the technology has got to a level where there are very small differences between any of the multifocal lenses. So, it's a bit like when I used to go to John Lewis to pick a television set in the TV department and it used to take me about two hours, because they all look nice, and they all look shiny, and they've all got a great picture. And it's very difficult to choose between them because they're all very similar really. And I think it's the same with lenses, really, I think they're all very good. There are minor differences between them which some eye surgeons may see as being significant. Personally, I think that what's important is that your surgeon is very comfortable with the lens that they use and they're familiar with it. What you don't really want them doing is practicing on you and doing something new on the day.
The lenses that we use are tried and tested. The material has got a long history which is safe, the technology is the latest for the lens and other companies have actually copied that technology and been sued for it, in fact. So, I think that any claims that they're the only ones that use the best lens etc I would take with a hefty pinch of salt really.
Thank you, okay and we have a very different type of question now from Roger. He is an insulin dependent diabetic. Would he be suitable for a varifocal lens, or would he need a monofocal lens?
Mr Damian Lake
It's a good question, and it depends upon an examination of the eye. Diabetes can be a serious condition and you can get a lot of eye complications from that, and you may have required treatment inside the eye from the diabetes. So, if it's not necessarily a contraindication against multifocal lenses if you're diabetic, but it would depend upon the examination.
So, we would look at the retina in particular to see if there's any what we call retinopathy from the diabetes. So, the diabetes causes leaky blood vessels, it causes new blood vessels and - if there's been any laser on the retina in the past - that would probably be an exclusion. So, in short, it might be a contraindication, it might be an exclusion for multifocal lenses, but it might not. It's individual and it'll depend upon the patient and what the findings are at the pre-operative examination.
Okay thank you. Okay we have a slightly longer question here. Anonymous attendee says in recent years they've noticed that whenever they're reading, even for fairly short periods of time, it then takes several minutes for their eyes to readjust to distance vision - during which time they have quite blurred vision. Is this likely to be a problem with the eye lens e.g., hardening or is it more likely to be poor eye muscle control? And is this problem likely to improve or go away if they had lens replacement surgery?
Mr Damian Lake
And it sounds like this person is in middle age and what they're describing is symptoms of what we call presbyopia. What happens is that the lens naturally - our natural lens - becomes harder over time and bigger and the muscle that presses on that lens has less room to act. And therefore, the zoom function of the natural lens is impaired. It's very frustrating, and it's likely to get worse as time goes on. When you have a lens replacement with a multifocal lens, the optics are different. So, the three focal points are presented to the retina all at once and the brain separates out which image it wants to use at any one time. So, it'll be it will be a different perception than you have at the moment. I hope that answers the question.
Thank you, we have another question. During the summer they occasionally get hay fever and sore eyes, can lens replacement be disturbed or displaced if someone inadvertently rubbed their eyes during bouts of hay fever?
Mr Damian Lake
I think, in the early post-operative period if you had a toric lens for astigmatism, rubbing the eyes is definitely not a good idea. And, in fact for anyone with lens replacement or cataract extraction. But in the long term you'd have to be, you know, very, very vigorous to move and interrupt intraocular lens by rubbing the eye due to them being itchy. So, I think that that's not, it's not a common problem that we see at all.
Okay another question. What is the typical lifespan of replacement lenses?
Mr Damian Lake
I think that they've got a half-life of probably a few thousand years, so once we're all dust there'll be little discs of plastic in the ground. They last a lifetime!
Cool, okay. What options are there for someone who requires excellent close vision for work or who used to get very close vision and poor distance vision. So, they're used to very good close vision and poor distance. What options are there out there if they also have cataracts?
Mr Damian Lake
Then they'll need to work out whether, as I said, we can either do a monofocal lens in both eyes - where they're either focused at near and then they wear glasses for the distance, or they’re focused for distance and wear near reading glasses. Or the other option is to have one eye for short distance and one eye for distance. We call that monovision although I don't usually recommend that for people who are not used to it.
So many people use that solution with their contact lenses, and they're adjusted to it, but if we do it with intraocular lenses, lenses inside the eye, it can lead to about one in eight people getting double vision if they're not used to it. So, unless you're used to it with your contact lenses, I wouldn't recommend it.
The alternative otherwise would be multifocal lenses, which give you near, middle and distance vision - although you'd need to accept that there are compromises such as the glare and halos and also the vision in low levels of light is not so good, so you need to turn the lights up.
Okay thank you, just a few more questions. Someone has recently developed a cataract in their right eye. Are cataracts treatable medicinally or naturally without the need for surgery?
Mr Damian Lake
There are no proven treatments for cataracts except for surgery. So no eye exercises, no creams, no drops - despite intermittent press reports of this and that - the only proven treatment for cataracts is surgery, I'm afraid.
Okay, and this person has had a varifocal lens inserted many years ago, a cataract formed in the meantime, and it was lasered. They have some cobwebs coming again can they be lasered to help clear them again and how many times can this be done going forward?
Mr Damian Lake
We'd need to examine the eye to work out exactly what's happening there and if they're vitreous floaters then they can be lasered, but not at Benenden. You'd need a different type of laser. But if you've had a cataract surgery done before, then it's - you know - it's probably in the in the vitreous jelly so you would you would need to go to somewhere that's got a YAG vitreolysis laser, which is quite rare.
Okay, thank you just three more questions. Is it normal to have double vision with a cataract?
Mr Damian Lake
Preoperatively it's possible that you can get what we call monocular diplopia so if you cover one eye, in the eye that's got the cataract you may get a slight doubling of the image. If you've got clear vision in one eye and then clear vision in the other eye, but with both eyes open you've got double vision, then that would indicate that it's not cataracts and it's actually an eye muscle problem which is a different assessment and a different procedure.
Okay, thank you. Okay this person wears glasses and they have a cataract in their left eye. What special lens could they have fitted to no longer need glasses?
Mr Damian Lake
If they wear glasses, if they've only got cataract in one eye, then the decision will be whether to have the cataract operated on and a lens put in that eye and then to leave the other eye and have surgery in the future when you do have cataract - or whether to have surgery in both eyes, so that you've got an even visual experience. Because otherwise, if one eye gets operated on and the other eye doesn't, then often there can be a big discrepancy between the two eyes which people find difficult to cope with.
So, the solutions for the cataract eye are as above really which are still multifocal lenses for distance, middle and near or a standard lens to match the other eye and then you just carry on with your glasses. If you want to get rid of the glasses, then you would probably go for the multifocal lens and accept that you'd have to have surgery on the non-cataract eye fairly soon to even up that experience.
Okay, last question, hopefully an easy one, once they've had the cataracts removed how long will they have to wait to wash their hair and wear makeup?
Mr Damian Lake
Well, we usually say washing hair a few days afterwards, but it's a good idea to wash your hair the night before the surgery and then maybe you don't need to do that again until you know three or four days afterwards. And for makeup, you can put on makeup the day after - but no eye makeup for two weeks. And preferably no foundation either because it tends to find its way into the tear film quite a lot.
Okay, so no foundation for two weeks either?
Mr Damian Lake
I would say not.
Okay thank you, well that's all the questions we've received, so that was a great varied range of questions, so that was really good and, thank you very much everyone in the audience for sending those in, and thank you very much for your great answers.
After this, as you see on the on the screen, there's a phone number that you could call if you wanted to book a consultation. You will get through to a lovely lady called Emma and if you're interested in special lenses, you will also speak to a Debbie.
After this you receive a short survey and I'd be really grateful if you could fill that in, as it helps improve our future events, it helps us learn of anything that you did like particularly like or you didn't like,
Our next webinar is on heartburn and acid reflux. That's on the 28th of April and that's with Ahmed Hamouda and Abuchi Okaro, they're both Consultant Surgeons.
So, on behalf of myself, Mr Lake and the team at Benenden Hospital, thank you very much for attending this evening and you know using your time for that and we look forward to seeing you again soon either at the hospital or at another event so thank you very much, bye.