Navigating Pediatric Early Onset Cataract Diagnosis and Treatment
Courtney Kraus, MD:
I am Dr. Courtney Kraus. I’m a pediatric ophthalmologist and pediatric anterior segment disease specialist at the Wilmer Eye Institute at Johns Hopkins.
Question:
What are the common signs and symptoms of pediatric early-onset cataract and how does it differ from cataracts in adults?
Courtney Kraus, MD:
Probably the most poignant thing that we always tell people is that kids are not just small adults and that definitely applies when we start to think about pediatric cataracts. So for the first part, babies can’t talk and tell us that they have trouble seeing and so most of our grandparents, they’re getting followed regularly by an eyecare professional or they start to notice that their vision just wasn’t what it used to be. A baby can’t tell us that.
So 90% of the way that early onset, congenital cataracts are discovered is by a informed newborn exam or in those early appointments with the pediatrician. Parents are often, many times, the people that kind of sound the alarm, noticing that there’s a white reflex, where we kind of counsel them there should be a red reflex or the easy sort of black pupil that we kind of think of seeing. So most of the time with a congenital onset cataract, it’s the observation of a white pupil.
Question:
What are the most prevalent risk factors associated with pediatric cataracts and are there any preventive measures that can be taken?
Courtney Kraus, MD:
So we often break down pediatric cataracts into thinking about one-third as being sporadic with no known genetic predisposition or inheritance pattern. One-third are usually due to some form of familial hereditary cataract gene pattern and one-third are secondary to other types of causes. That can either be something that they acquire later in childhood like diabetes or trauma, for example, or it can be secondary to a systemic condition that they inherit at birth or shortly thereafter.
I think when we think of the most common things that you can do for prevention, acquired cataracts, the most common, is definitely traumatically acquired cataracts. So all of those things that we counsel kids to do to really avoid traumatic eye injury, obviously not putting themselves in harm’s way whenever that’s possible. We’re always singing the praises of safety glasses whenever that’s indicated and just eye safety in general.
And then, some of these congenitally acquired secondary syndromes, they can be associated with things that you can screen for in utero or moms can make sure that they’re getting their vaccines for, rubella being one of them. So moms being vaccinated against rubella can ensure that they do not acquire it while their baby is in utero and then you can avoid the secondary cataracts that you can get as a result.
Question:
How is the diagnosis of pediatric cataracts different from diagnosing cataracts in adults and what are the key diagnostic tools and techniques used?
Courtney Kraus, MD:
As mentioned before, in a pre-verbal child, 90% is your clinical exam. So that includes just observing that the cataract is there. That’s done by either the parent, pediatrician, or someone sounding the alarm that it looks like there is something wrong with the red reflex. And then by the time they get to my office, then I actually usually use a tool that’s called a retina scope. A retina scope is used in my practice as a means of determining a child’s need for glasses, but it’s also a really handy, non-threatening tool for me to just get a better sense of what the red reflex is like. It also gives me a sense of how much of the pupil the cataract is taking up because one of the main things that we’ll take into consideration in terms of whether a cataract is operative or non-operative, so how much space the cataract takes up within the visual axis.
Where the cataract seems to be, sometimes I describe a cataract as being sort of like a peanut M&M. There can be a candy coating, the chocolate or the peanut, and the cataract can kind of occur in any of those parts of the lens. And depending on where, even the front part of the candy coating versus the back part of the candy coating, those are actually different in terms of their visual significance. So things that are located on the front part of the lens are much less likely to be impactful to the vision and need to be removed than some that are located in the back part. So that’s something that’s important.
The density of the opacity also starts to be important, and I always say if I can’t see into the back of the eye, we gauge that your child can’t see out. But if I can see, I can get a glasses prescription or look at their optic nerve, then I can usually assume that that child has some potential to see out. And especially in cases of bilateral cataracts, we may favor observation over intervention.
Question:
What are the primary challenges in managing and treating pediatric early-onset cataracts and how do these challenges differ from treating cataracts in adults?
Courtney Kraus, MD:
Well, part of being a pediatric ophthalmologist is being very comfortable with the fact that our children aren’t necessarily going to answer us or give us some of our exam findings readily. So that’s something I think all of us are well-versed in and part of what actually brings joy to the practice of managing pediatric ophthalmologic patients. What actually makes pediatric cataracts particularly unique is the fact that unlike your grandparents whose eyes are done growing, who’ve actually probably gone through something called presbyopia where they’ve started needing reading glasses, if you take out a child’s natural lens, you’ve taken out a very important offset to the natural growth that they’re supposed to have over the next 20 years of their life. And taking it out in early childhood in ways we’re still coming to terms with understanding changes the growth trajectory of the eye and also introduces a need for countering that removal and compensating for that loss of a very dynamic lens.
In addition, because they’re not presbyopic, you’re going to remove this ability to not only see far away, but also then focus up close. You’re going to take a child who’s very good at being able to do both of those things, maybe with only a slightly reduced visual acuity because of the cataract, and you’re going to make them dependent on reading glasses. So for that reason, in verbal children especially, I usually have a visual acuity cutoff that’s a little more generous than those we use in adults. In adults, we may choose to intervene when the cataract starts to give them some nighttime glare, but maybe their vision’s 20/25, so not that far off from perfect. For kids, we tend to wait until their visual acuity is a little bit worse because, again, we are introducing this absolute dependency on reading glasses.
And then, if I didn’t hammer home, we are also having to choose a refractive error for them to become. So in very young children, we often choose for them to become very farsighted to sort of help us compensate for that growth of the eye that’s going to occur and we hope we get it right. If we guess the right amount of farsightedness to leave them, then as they grow and become adults, we actually will find that they actually outgrow that farsightedness and end up with a very little need for glasses when all of this is said and done.
So that’s kind of part of the fun, but definitely also the big challenge of pediatric cataract surgery is that we kind of have to predict the future and sometimes, I tell parents it’s like trying to predict the shoe size your child will wear on their wedding day. We can make some good inferences, maybe based on how tall you guys are as the parents and how tall they are as a two-year-old, but you’re not going to get it perfectly right every time.
Question:
Are there any specific genetic or hereditary factors linked to pediatric cataracts and how does this impact the approach to treatment?
Courtney Kraus, MD:
Yeah, so there are definitely lineages of familial hereditary cataracts, and you will find mom had cataracts, dad does not, but it’s autosomal dominance in its inheritance. So many times, their offspring share about a 50% risk of being born with bilateral cataracts. These kids are usually easy because the mom or the dad, whoever’s the affected one, knows the drill when it comes to dealing with cataracts. And so they’re in our office, if not with their firstborn, definitely with their second, third once they’ve met a nice pediatric ophthalmologist.
There are other syndromic conditions, both ocular and systemic, that can also present with cataracts. And you’ll find that many times, we work pretty in sync with ocular geneticists or just pediatric geneticists, particularly when kind of trying to piece together the puzzles. Perhaps the cataract is the early identified piece and then down the line, you realize that a child also has GI distress that’s sort of non-specific and lo and behold, they have a diagnosis of cerebral [inaudible]. So something you wouldn’t have necessarily thought of screening for based on GI symptoms alone, but the cataracts really made it useful. So I think that’s some of the things that we tend to think of.
Other times, we have conditions that we just know have a higher risk of presenting with a cataract or developing a cataract and we screen appropriately.
Question:
Can you discuss the range of treatment options available for pediatric cataracts, including both surgical and non-surgical approaches? What factors determine the choice of treatment?
Courtney Kraus, MD:
Yeah, so many of those things that I mentioned before when talking about the evaluation of a pre-verbal child, the size, location, density, laterality, those all play a role in whether a cataract is deemed surgical or non-surgical. Those same cataracts that I said are on the front part of the eye of the lens and are often not surgical, many times can induce what we call anisometropia or a need for glasses that’s greater on that side that has that non-surgical cataract. So in a way, we would say giving that child glasses is compensating for the induced refractive error and that’s how you’re managing it.
Other times, we find that a cataract is present, but again, I can see to the back of the eye and I don’t find it dense enough to warrant surgery, but it is enough that it’s giving the child a reason to have an eye preference. Maybe it’s, again, unilateral or a little bit asymmetric. In those circumstances, if glasses aren’t warranted, we may introduce patching and we’ll patch the eye that has every reason to be the more favored eye by the brain to encourage the brain to then devote equal amounts of attention to this eye with a milder opacity. And glasses and patching are something that we use even if a kid has undergone surgery, but they are something that we can definitely make use of as non-surgical interventions.
And then finally, you’ll see that sometimes, we will introduce a dilating eye drop that parents will instill a couple times a day. If, for example, the opacity is not dense enough, but perhaps just a little bit more central than we’d like and we’d like to increase the size of the pupi,l so it doesn’t take up so much real estate and we get more vision into the back of the kid’s eye.
Question:
What are the potential complications associated with pediatric cataract surgery and how can these be minimized or managed?
Courtney Kraus, MD:
Yeah, so I think the scariest thing that we really talk about and we really do see is glaucoma. Glaucoma following cataract surgery is its own entity of pediatric glaucoma, and it has been probably the best studied out of the sort of forms of pediatric glaucoma that we see. We seem to understand that the timing of pediatric cataract surgery really gives you an insight into whether that child’s at higher risk for developing glaucoma and for that reason, even in those really, really young babies, we don’t intervene right at day of life one because it seems to be that if you intervene before four weeks of age, you’re going to end up seeing that they end up developing glaucoma at a higher rate than if you just push that surgery back to maybe four to six weeks of age.
So we’ve really tried to skew the surgical operative timeline closer to that four to six weeks time period for a unilateral cataract, eight to even 12 weeks for bilateral cataracts. And then, we really have seen some really nice data saying that in those kids that are seven months or older when they undergo cataract surgery, their risk of glaucoma is much lower.
Of course, anyone that I counsel about undergoing surgery, there are always the risks. Everyone needs to know what’s done using general anesthesia, and it can be scary to have your baby undergo that, but we always work with excellent pediatric anesthesiologists that do a really good job putting kids to sleep. Infections, things like retinal detachments can happen, but those are also really rare in the pediatric cataract surgery literature.
Question:
How does the age of the child at the time of diagnosis influence the treatment decisions and overall prognosis?
Courtney Kraus, MD:
Well, the age of the child, as I mentioned in terms of their risk for glaucoma, does kind of affect your surgical planning as well as kind of their overall risk for that is a complication. The age of the child also affects how much ocular growth is still going to happen and therefore, how much intentional hyperopia I may leave for a child. Older kids, teenagers, I think some of us are starting to think that they may have the potential for some of the newer types of lenses that are out there, maybe even some with correction for astigmatism and other sort of things that are almost more like what we approach doing in the adult world where we compensate for a lot of the other factors that can go on like trying to optimize refractive error outcomes.
Question:
Are there any long-term implications or potential visual outcomes for children with early-onset cataracts? How does early intervention impact their vision development?
Courtney Kraus, MD:
Yeah, so we think of intervention in terms of managing the critical period. The critical period of visual development we think of more or less extends on up to age seven. Definitely continues up past then, but up to age seven is really where we start to see slowdowns in responses to amblyopia treatments. For pediatric cataracts, the type of amblyopia that they get if they have a really, really dense white cataract is called deprivational amblyopia, and it’s far more difficult to reverse.
So that’s where I mentioned those timelines for a dense unilateral cataract needing to come out in that first four to six weeks of age, and for bilateral cataracts, even though the eyes aren’t going to be competing against each other, the brain’s not going to plug in and pay attention to those eyes if it doesn’t get some clear visual images before about 12 weeks of age. As we extend further out, past that first birthday or so, they can tolerate weeks at a time, but months are certainly important. And then, as we sort of start tracking out beyond about four to five, usually if the cataract is developing after about three, four, or five, you definitely still have time. Amblyopia isn’t quite as critical, but even among those traumatic cataracts that we see in that sort of early childhood age group, we do see that even with optimized surgical outcomes, the brain does start to pay more attention to that kind of non-involved eye, but less so than you would absolutely see at younger ages.
Question:
How important is collaborative care and interdisciplinary communication when managing pediatric cataracts, particularly in cases involving other health conditions or syndromes?
Courtney Kraus, MD:
Yeah, well, you already mentioned, heard me mention how much I love working with our geneticists. I think that they hold such a key piece of the puzzle in telling me which kids to be screening because they have a higher risk for presenting with cataracts, but also with me providing some ocular data and then them adding that to the complex pool. I mentioned pediatric anesthesiologists as another critical member of the team because these kids often do need early anesthesia in order to have their cataracts managed. And again, with some of these kids who have other medical conditions, it can be really challenging to put them to sleep and carry them through the surgical journey safely.
Conditions like Lowe syndrome, for example, that ends up affecting and creating congenital cataracts, but it also affects the kidneys and they can have really devastating kidney disease. So just again, as the ophthalmologist, we might see the cataracts first because that presents much more obvious than the renal disease. But if something doesn’t look right, then I’m definitely going to involve the pediatrician and we’re going to start to sort of activate that search for what else about this kid? Are they meeting their motor and developmental milestones? Are they someone we would consider a failure to thrive? They’re not gaining weight as we would expect them to be. Are they jaundiced? All these little pieces. So the pediatrician is really the link that keeps all of the things going when I see bilateral cases.
