Lecture: Pediatric Cataract and Management

DR ADAMS: Good morning and thank you. It’s very lovely to be here. So the objectives that we want to cover in this lecture are an overview of the diagnosis of cataract and management. I’d like you to appreciate the impact of pediatric cataract on not only the patients but the parents and family. I want you to understand when we should intervene in pediatric cataract, whether to put an implant, an IOL in, or to leave the child aphakic. And then we want to look at the complications and the long-term follow-up needs. So we’ve got three questions, and the idea is that you try and have an answer to them now, and then we’ll see if you give the same answers later. And the first question is: Do all pediatric cataracts need surgery? The second one: Should all pediatric cataract patients have IOLs? And then the third one is: Should we discharge patients after 6 months? Okay. Just as an overview, pediatric cataract is a treatable cause of childhood blindness, and it accounts for about 15% of blind children, worldwide. And improving the outcomes is one of the Vision 2020 priorities. And obviously, if you don’t treat the cataract, you get stimulus deprivation amblyopia. So obviously the first way you’ll see it is by an absent or dim red reflex, and a retinoscope is a very good way of doing it. I think it’s better than a direct ophthalmoscope. A portable slit lamp, if you’ve got it. In a very small baby, you can put the baby under your arm and fly the baby into an adult-style slit lamp to have a look at it. And in an older child, a teenager, if they suddenly develop a cataract, think about diabetes, because it’s one of the causes of a child suddenly getting bilateral white cataracts in the space of a very short space of time. And remember to do an ultrasound to make sure that there’s no abnormality in the posterior pole. If a child got anterior lens opacities, the vast majority of them will not need surgery. So little white blobs, even in the central axis, are not usually visually damaging. But if these cataracts are dense and in the central area, and particularly if they’re in small children or babies, then they will require surgery. Always worth refracting, because they may in fact benefit from glasses, rather than from surgery. And if the cataract’s been present for a long time before you do surgery, the vision may not actually turn out to be very good, because the child may have stimulus deprivation amblyopia, and that may be a reason, in fact, for not doing surgery. This one will require surgery, but this one, I think, can be left. So a diagnosis of cataract doesn’t mean instant or essential surgery. So as I think they’ve made the point about pediatric glaucoma, pediatric cataract is entirely different. At Moorfields, only certain surgeons do pediatric cataract, and I haven’t done an adult cataract for over 20 years. So we’re very sharply delineated, because of the needs of the family and of the follow-up. They’re not common. And you need in many ways to find out why the child has got cataract. It may be familial. In other words, it may be passed through the family genetically. But it may also indicate a medical cause, which requires treatment. Unlike adult surgery, you have to be able to suture the corneal wound, and that’s often very difficult for people. And one of the major differences is the need for long-term follow-up, because of the complications. And it’s what we call long haul management. So the parents have to get to know you, because you may be following that child up for 16 years. And the other thing to remember is that the vision outcomes are not the same as in adult surgery. In adult surgery, you will expect 20/20. In pediatric cataract, the average outcome is 50% of that. And probably the most difficult thing that you have to learn to deal with is the parents. Now, we’ve had a look at the impact of a diagnosis of pediatric cataract on the parents and the family, and this may go some way to explaining why they can be so difficult to deal with. We looked at a large number of pediatric cataracts in the hospital, some of them unilateral, some of them bilateral, and the important thing was that they had all about 20/30 vision, overall. In other words, good, functioning vision. And that was from either treatment, surgery, or observation. And despite that, they all have a very reduced quality of life. And in fact, that affects the parents more than the children. So, in other words, they are more damaged in the quality of life, psychologically, than their children are, because the children have never known anything different. But the parents are bereaved, because they believe their child has lost something. And because of that, they are very depressed and very anxious about their children and their children’s future. And that explains why the parents are so difficult to manage. Because it’s not just something that comes with aging, which is normal. It’s something that’s not normal, and is very distressing. Now, the impact of pediatric cataract is the same as having a child who needs a liver transplant or has severe congenital heart disease. Or having acute leukemia. So, in other words, it’s a very negative impact. You think — you say to the parents — your kid’s got a cataract. I can treat that. That’s not the message they’re getting. The message is: Your kid’s got cataracts, and your child is going to suffer. And the parents are very upset, and as I said, that makes them very often very difficult to deal with. So what do you need to do obviously, is your ophthalmology assessment, and that will include looking at the cornea, looking at the lens, looking at the anterior chamber depth, look at your ultrasound to measure axial length, look for PHPV, look for retinal detachment. Biometry. We use the Hoffer Q for children, because they usually have small eyes. You’ve got to get them reviewed by the pediatrician. We get them counseled by the family support team, and when they sign the consent form, they’ve got to understand what they’re letting themselves in for. Now, the thing to remember is that whatever information you give them, they’re only going to partially listen to. You’ve all got mobile phones. So do most patients. And most patients will look up Dr. Google. They will look up pediatric cataract, congenital cataract, on the internet, and then they’ll come back with some barking mad idea. So I’ve been asked: Why am I not putting multifocals into a 2-month-old baby? And they want to know what you’re doing, how you’re doing it, because they’ve Googled something which is totally inappropriate. But remember, if you don’t know, you’ll simply put it in onto the search engine, and come out with some interesting ideas, including stem cell therapy, which has been the latest one, and bifocal and trifocal lenses, and also why can’t they have bilateral surgery, simultaneously. So when it comes to timing, for uniocular cataracts, this is a graph which shows you how, if you wait too long, your chances of getting good vision go down. So we think you’ve probably got approximately 6 weeks. Possibly 10 weeks after birth. For bilateral, you’ve probably got longer, because it’s a bilateral condition. But if you’re going to do dense bilateral cataracts, you’ve got to leave a short interval between them — preferably about a week. Because the risk is that if you do bilateral simultaneous that you get infection. So we prefer not to do that on the same day. Pediatric cataract requires general anesthesia, not local anesthesia. The eyes are small, so be careful of the type of speculum you put in. Because otherwise you’ll get pooling of fluid. So you want one that doesn’t lift up. The eye is very small and very soft. You’ve got a very small anterior chamber. It’s about 1.2 millimeters. So you haven’t got a margin for error when you put any blade in. And the pupils don’t dilate well. So intracameral phenylephrine is probably really worth thinking about. And then you’ve got to make a decision as to whether you’re going to leave the child aphakic or use an implant. Okay. So you shouldn’t do surgery for dense bilateral congenital cataracts within the first 4 weeks of life, because it’s been shown to be highly associated with aphakic glaucoma. You need to dilate them preoperatively. And we use topical Voltarol, as well as an antiinflammatory, because it also helps. We use povidone-iodine, 5%, in the conjunctival sac, to sterilize the eye, and obviously povidone to clean the eye. I put heparin, 2500 units, in a 500-unit bag of BSS, because that reduces the inflammation, and we put half an ampule of adrenaline in, because that helps dilate in the irrigating fluid. I put intracameral phenylephrine in. So as I say, for dense congenital bilateral cataracts, you wait for 4 weeks after birth, to reduce the risk of getting aphakic glaucoma. We dilate preoperatively, and we also use Voltarol and intracameral phenylephrine. That’s 7 drops of phenylephrine to 1 mil of saline. I put heparin and adrenaline in the infusion bag, and that helps to reduce inflammation and to keep the pupil dilated. You’ve got to suture the wounds with 10-0 vicryl to prevent prolapse. And I tend to use VisionBlue for every case, because the capsule is very different from that of an adult. You’ve got to be very careful when you use irrigation/aspiration. I don’t use phaco, because the power can blow the back of the capsule. And if you remember, many of these children will have very weak posterior capsules. So if you hydrodissect or use phaco power, you can actually open that up and make a huge hole with vitreous prolapse. I use GV. Healon GV, if I’m putting in an IOL. And I put triamcinolone, neat triamcinolone, not dilute triamcinolone, in as a wash or an emulsion. Because that helps to reduce AC activity. It helps to reduce membrane formation. And it also means if the child doesn’t get as many drops in as they should, that they have quite a lot of steroid in the AC already. I use intracameral cefuroxime at the end of surgery, and we use 10-0 vicryl. I put an air bubble in at the end of congenital cataract surgery, because one of the things that children sometimes do is they’ve got a very shallow AC, and the one thing you’ve got to prevent is iris touching the corneal endothelium. Because I think if you do that, you’re gonna get aphakic glaucoma. You can put Healon GV in, but then the pressure may well go up to 50, and then you have to sit it out for at least 3 to 5 days. And then subconjunctival steroid at the end. Postoperatively, you need long-term follow-up. And they need visual rehabilitation. You need to refract and give glasses, because even with an IOL, these children will need some distance prescription, a middle distance prescription, and a reading distance prescription. And then you need to monitor long-term for glaucoma. And that’s a particular problem with the very young congenital cataracts. And occlusion therapy, particularly if it’s uniocular, is a huge and long-term part of the management. And then management of the strabismus. And for bilateral cataracts, you can either — young cataracts — you can either give them aphakic glasses or you can give them aphakic contact lenses. And remember that the contact lens prescription is much higher than the glasses prescription, because it’s a hyperopic prescription. And for babies, you set it at middle distance, so you don’t take anything off your retinoscopy. You simply do the retinoscopy and that is the prescription you use. And once they start to walk, you need a distance prescription, and then you need reading glasses on top. And some of the children, when they’re older, they can use a varifocal, once they can learn to move their head up and down. Multifocal IOLs — no. Because one of the problems about IOLs — multifocals in adults have a number of problems anyway. But if you look at multifocals in children, one of the problems is that the lenses often get a bit decentered by fibrosis, and near is up here for a multifocal. Middle distance is there. So they’re really not a good idea for children. So for — if you’re going to put an implant in, I think you should consider that once the child is over 7 months of age. Under that, it’s actually very difficult to get a decent implant. And if you’ve got very darkly pigmented eyes, you’ve got to be aware of the increased incidence of inflammation, cyclitic membrane. So you need a lot of heavy antiinflammatory treatment, both perioperatively and postoperatively. And if you do get a cyclitic membrane in a heavily pigmented eye, the best thing to break it is TPA. Injected into the anterior chamber. But you can’t do that for a week after surgery, because of the risk of bleeding. And if you’ve got a small eye, with a diameter of less than 9 millimeters, I wouldn’t advise an implant, because you basically won’t be able to get it into the eye very easily, without creating a lot of damage. And the infant aphakia trial from the States has highlighted very well the problems with IOLs. They get far more returns to theater, they get posterior capsule opacification virtually all the time. So they’ve got more anesthesia time, which has got concerns about neurodevelopment. And it is just more expensive. So there are quite a lot of issues. They may sound a better idea. They’re not actually always a better idea. And you’ve got to be able to deal with posterior capsule opacification, if you put an implant in. Now, I’m very lucky. I have a theater horizontal YAG. So I use the YAG machine for these kids, lying flat. If you haven’t, you’ve got to be very happy to be able to tip the IOL and do a surgical capsulotomy with a vitrector. But that means more — opening the eye up again. And then don’t use multifocals. Now, when you calculate the implant, you’ve got to remember the age of the child. Because the child’s eye is going to grow, so the lens implant should be set for when they’re an adult. Because they’re going to live more time as an adult than as a child. So you’ve got to calculate that. And this is one way of calculating it. But if they are one year old, you should make them +6, postoperatively. And I make them approximately emmetropic, looking at the refraction on the other side, at 6. And basically I sort of subtract 1. So at 2, I’ll make them 5. At 3, I’ll make them 4. 4, I’ll make them 3. Just on the curve. But the biggest growth is in the first two years in life. And we use the Hoffer Q, because it’s designed for small eyes. We do virtually all our biometry preoperatively. We measure the axial lengths through closed eyelids, and then we do handheld keratometry and calculate it that way. So you don’t need a general anesthetic to calculate your biometry. Now, any sensible parent will want to know what the vision outcome is likely to be. And so the average outcomes after surgery are about — in bilateral cases — are about 50% of normal. And they’re 10% of normal for a uniocular cataract. Six years after surgery. This is in LogMAR, so it’s 0.48. So many of these children will meet the requirements for being sight-impaired. But at least they’ve had a chance of sight. Because if you leave them with their cataracts, they’re probably going to be blind. So it’s better, but it’s not normal. So this is the American IATS study. And their median acuity was 0.9 LogMAR. So, in other words, one line better than 6/60. 20/200. So it’s about 20/160. So they showed what I think is well known — that you have more complications if you put an implant in. Particularly posterior capsule opacification. And they said that there was no benefit to implanting a lens implant. So the obvious things you’ve got to look for when you do a child are infection — because the child isn’t going to tell you that their vision is blurred, because it’s going to be blurred anyway. You’ve got to look for a wound leak. So when you see an oval pupil, you’ve got to ask yourself: Why is it peaked? Is their iris prolapsing through the wound superiorly? And you can see the visual axis opacification behind the implant there, and that’s 100%. It just depends how long it takes to occur. Then you’ve got glaucoma, retinal detachment. That tends to be a late complication. Approximately 12, 15 years after surgery. And then you’ve got strabismus and amblyopia. Now, glaucoma is a major, major problem after congenital cataract surgery. They’re saying 17% five years after surgery in the American study. The British study had 10%. It is commoner in the very young children, and particularly if you operate before 4 weeks of life. And the other thing is small eyes and persistent fetal vasculature or PHPV. So you have to monitor for glaucoma. And the thing is: The child isn’t going to tell you that they feel any pain or any problem. So you actually have to measure the pressure. And I always find that if you’ve got a parent who keeps crying after their child’s surgery, when it’s gone well, it tends to mean that there’s something probably — they’re gonna get glaucoma. So the Icare is a very good way of measuring pressure. Makes it very easy. The other thing you can do is measure serial axial lengths, because if the eye grows too fast, that’s probably glaucoma. You can look at the optic nerve heads. But remember that many of these children will have very thick corneas. And when you’ve got very thick corneas, you get a false elevation in intraocular pressure. So you may think the pressure’s raised. But in fact, you have to subtract about 7 millimeters from the number, because of the thick cornea. And if you’re in doubt, you have to do an examination under anesthetic, and measure under ketamine, ideally, although many anesthetists now won’t use that. So you have to get in there very early, before the sevoflurane kicks in. So 100% of uniocular cataracts will have strabismus. Now, it may be small, it can be big, but they will all have it. And about — anything up to 90% of your bilateral cataracts will have a strabismus. And about 60% of those with strabismus will have amblyopia on top of their vision reduction from the cataract. And it can be quite a small deviation. And on top of nystagmus, which many of them will have, it can be very difficult to diagnose. Occlusion is needed until about 6. And this is the thing which really gets most of the parents. And that’s the reason uniocular cataracts get a bad result. Because most people can’t keep up 2 to 6 hours of occlusion a day for six years. So I think the sort of take-home points are that: Pediatric cataract surgery is completely different to adult cataract surgery. It’s got different stresses and it’s got different strains. It has a huge major negative impact on the parents and the families of the children with cataract. And that probably explains why the parents are so distressed, because it’s the same as diagnosing their child with leukemia. It’s far better to have good aphakia with a clear axis than to have bad pseudophakia on a cloudy visual axis. You can use IOLs in the older child, but not in the younger child. And you’ve got to remember, in the IOL calculation, look at the age of the child to calculate how hyperopic you want to make them. Don’t implant if it’s chronic uveitis, very small eye, PHPV. And the clue to getting a good result with a uniocular cataract is occlusion, occlusion, occlusion. And glaucoma needs long-term follow-up. So do all pediatric cataracts need surgery? No. Because it depends on whether they’re disturbing the vision. Should every pediatric cataract have an IOL? No. And they can be discharged after 6 months? No. Because they need long-term follow-up for glaucoma.