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Dr. Brenda Bohnsack: we are at the forefront of a lot of these molecular therapies. And so for instance, a lot of the retinal dystrophy, those were some of the first diseases in which we are applying gene therapies for. And revolutionizing not only eyecare in terms of these eye diseases, but also just in terms of medicine Lurie Children's Division of Ophthalmology provides a range of eye care for children from those who need to correct their vision with glasses, to those who endure eye trauma, to those with serious congenital disorders and pediatric glaucoma. The division's head, Dr. Brenda Bohnsack, is a physician researcher who specializes in complex eye problems in children, sometimes restoring vision in children who would otherwise be blind. We'll talk with her today about her clinical work and also her research investigating new treatments for children with the most severe eye disorders.

Scott Webb: This is Precision: Perspectives on Children's Surgery, the podcast of Lurie Children's Hospital. I'm Scott Webb. Doctor, thanks so much for your time today. I know you're a specialist in complex pediatric eye disorders. So what conditions do the children you see typically have?

Dr. Brenda Bohnsack: So my expertise is predominantly in congenital eye diseases that affect the front part of the eye or what we call the anterior segment. And a lot of what I deal with is are kids who have glaucoma.

Scott Webb: Certainly through some family members, I have some familiarity with glaucoma and I know that you're dealing with relatively rare eye conditions. So how did you choose to get into this specialty?

Dr. Brenda Bohnsack: Well, that's very long story, but I'll try to make it as short as possible. So the field of pediatric glaucoma is actually very specialized and kind of falls between two subspecialties in ophthalmology, both pediatrics as well as glaucoma. And it is one of those fields where not a lot of people like to do it because adult glaucoma specialists, they tend not to really want to be dealing with children. And then, pediatric ophthalmologists really typically don't want to be dealing with glaucoma. And so, when I was in training, I had this love of glaucoma as well as pediatrics. And then on top of that, my basic science research is on anterior segment development, which is rooted in a lot of the pediatric glaucomas. And so, it all kind of came together as a serendipitous moment of this was my calling and this is what I was supposed to be doing.

Scott Webb: Yeah, I love that word. That's one of my favorite words, serendipity, serendipitous. And I know that you have a medical degree and a PhD in molecular and cellular biology. So that's pretty ambitious of you. How does your PhD enhance your expertise in the field?

Dr. Brenda Bohnsack: So my PhD, as you said, it was in molecular and cellular biology. But really, what it was in was in developmental biology. And at first and foremost, as a researcher, I consider myself a developmental biologist. And what that means to me is understanding the processes that happen during development when the eye is forming, is really what I'm interested in.

In terms of congenital eye diseases, something went wrong during development. And so some sort of molecular signal didn't happen or didn't occur the way it was supposed to and then tissues didn't form properly. And so understanding that at a molecular and developmental level really helps me treat these kids, because I understand it not just from a clinical standpoint, but understand it from why did this happen and then also, the question after that is are there better treatments for these diseases? And so that's really what my research ventures are about, is understanding why it happened and, more importantly, are there genetic type treatments such as stem cells or gene therapies that someday we'll be able to apply two congenital eye diseases to at least halt the disease progress and potentially even cure them.

Scott Webb: It's encouraging to feel like that someday is getting closer and closer. And I'm sure it's very rewarding for you, even where we are today, to be able to help restore and improve vision for children, right?

Dr. Brenda Bohnsack: Oh, of course. I mean, that's really what it's all about.

Scott Webb: Yeah, absolutely. So I want to have you tell us more details about your current research that you're involved in, how you think it might impact diagnosis, outcomes, treatment for children, you know, especially in your area, which is the complex eye disorders.

Dr. Brenda Bohnsack: Like I said, my lab is actually in the Stanley Manne Research Institute and what my lab studies is a cell population called the neural crest. The neural crest is a transient stem cell in the embryo, which gives rise to many parts of the eye including parts of the cornea, the iris, the ciliary body, the sclera. And so, those are all really important structures in the eye. And so what we are doing is trying to figure out the molecular signals that control specifically the ocular neural crest, what causes these cells to form these parts of the eye, and then what goes wrong in diseases such as like Peters anomaly, Axenfeld-Rieger syndrome, aniridia, what happened at a molecular level and then a cellular level. With this information, we use two different models. We use a zebra fish model as our in vivo animal based model. And then, another thing which we are interested in in which we're working on is using human embryonic stem cells as a human model that goes side by side with our in vivo zebrafish model.

So step one is to understand the genetics of these diseases and understand what went wrong in terms of the developmental processes. And then step two is to then figure out, can we fix those processes? Now, it's one thing to say, "Oh, can we fix it during development?" And obviously, that gets difficult, especially with the eyes, because a lot of times unlike congenital heart diseases where they can be diagnosed in utero from ultrasounds, a lot of times the congenital eye diseases aren't diagnosed in utero, they're diagnosed postnatal. But we do know that the ocular tissues aren't fully developed at birth and that there's probably a four to six-month period or window where we may be able to redirect or at least halt some of the abnormal processes. And so like I said, things such as stem cells or gene therapy may be able to be applied during this early postnatal phase and then prevent vision loss or even potentially, you know, reverse the effects of the congenital eye disease.

Scott Webb: That's really amazing. You see the value if you get to early diagnosis, right? So right after a child is born and you could halt, you know, the progression or prevent it maybe, it's really amazing. And it does feel like the entire field has advanced so much from 10, 20 years ago. What's your optimism level for the future?

Dr. Brenda Bohnsack: Oh, it's great. The interesting thing about ophthalmology and specifically the eyes is that, as a field, we are at the forefront of a lot of these molecular therapies. And so for instance, a lot of the retinal dystrophy, those were some of the first diseases in which we are applying gene therapies for. And revolutionizing not only eyecare in terms of these eye diseases, but also just in terms of medicine and so specifically doing gene therapy, where we're doing subretinal injections in order to give back the gene that was mutated and disease-causing. So that's being done already at the retinal level. And so the question is, can we apply this to other aspects of the eye.

Scott Webb: Yeah. And of course, you know, there's so many questions, but every day, through your research and working with patients, you know, you're getting closer and closer to answering those questions and finding answers. And I know that Lurie Children's is home to specialists in other fields and that you work closely with your patients, whether it's oncology, neurology. How do you think it enhances care for patients to have all those specialists working together?

Dr. Brenda Bohnsack: Well, I mean, it's critical, especially with complex diseases. One, just to be able to coordinate the care of these kids. You know, we have kids who come from hours and hours and hours away. And so if we can help coordinate their care so that there's less travel time, that there's less time away from school or work for the parents, just making things easier just logistically, it benefits everybody. So in that regards, just coordinating care between different disciplines, but also just the communication, you know, that being able to pick up the phone and call colleagues and we can all talk on the same level and be able to discuss the care and what's going to be the options for these kids and, you know, really not only in terms of from an eye standpoint, but overall medical standpoint. So it's very beneficial to have the specialists in all fields at your fingertips.

Scott Webb: Yeah, it really is. Well, this has been really educational. I wish we could stay on for hours and talk about this. As you say, there's so many questions and search of so many answers. But for today, thanks for your expertise and compassion. You stay well.

Dr. Brenda Bohnsack: All right. Thank you so much.

Scott Webb: And for more information visit luriechildrens.org/eye. And if you found this podcast helpful, please share on your social channels and check out the full podcast library for additional topics of interest. This is Precision: Perspectives on Children's Surgery, the podcast from Lurie Children's Hospital. I'm Scott Webb. Stay well.