Q&A: Jay Chhablani, MD, discusses 3D choroidal vasculature analysis

Photo of Jay Chhablani, MD, at Retina World Congress 2025

Jay Chhablani, MD, from the University of Pittsburgh Medical Center's Vision Institute discusses 3D choroidal vessel segmentation technology. Using advanced Plex elite Zeiss swept-source OCT imaging, his team has created a new tool to visualize and analyze Haller vessels in 3 dimensions – overcoming previous limitations of 2D imaging.

Note: The following conversation has been lightly edited for clarity.

Ophthalmology Times: Can you speak to the development of this 3-dimensional imaging?

Jay Chhablani, MD: We have been focused on choroid for more than a decade. Our team, along with machine learning engineers and clinical research fellows, have been working on choroid over the last few years, we have reported multiple choroidal biomarkers.

This year is very exciting, because last year we could achieve the 3D choroidal vessel segmentation, which is based on Plex elite Zeiss images, because it is the swept source OCT system, which allows us to see the choroid and choroidal vessels very much in clearly. So by using the deep learning methods our team has defined, or I should say, invented, a way to look at the 3D choroidal vessels. And we are right now focused only on Haller vessels, because the visualization of choroid capillaries is very poor. So we just wanted to focus on one layer. And we identified Haller vessel layer.

At this meeting at Retina World Congress, I'll be primarily talking about all our work, which we have done in last several years, along with I'll be showing what 3D choroidal vascularization helps us in terms of clinical diseases such as age-related macular degeneration, central serous chorioretinopathy, as well as diabetic retinopathy.

OT: Can you highlight a few takeaways from your presentation?

Chhablani: When we really started doing this 3D choroidal vessel visualization... So we have created a tool where we can actually see these 3D vessels, and it allows us to do the vessel diameter manually and different points; it allows us to see the tortuosity. So we have been doing this manual measurements of the diameter of these choroidal vessels. And we have tried to define the 3D choroidal vessel diameter, as well as intervessel distance. So we looked into several cohorts of macular degeneration, dry AMD, wet AMD, as well as bilateral AMD, with dry one eye and fallow eye wet macular degeneration, as well as diabetic retinopathy.

So the key learning points, what we had was that as the disease starts in macular degeneration, these choroidal vessels start dilating, and the inter vessel distance starts coming down. And we saw this happening starting at very early stage to all the way to the...late AMD, including both geographic atrophy, as well as wet macular degeneration. We also compared the two eyes of the same patient, having one eye dry and one eye wet, and again, we saw that there was difference between these two eyes.

Talking about central serous chorioretinopathy, we saw that as the disease is getting more chronic, these choroidal vessels are becoming much larger, the inter vessel distance is coming down, and that is where probably will explain the pachychoroid mechanism.

Talking about diabetic retinopathy, we saw that, in contrary to AMD and CSC, the vessel diameter is actually coming down, and that something which we understand that this has also been reported in histological studies of diabetic retinopathy patients. So we are yet to learn that how, what is the impact of proliferative diabetic retinopathy, as well as laser. And when we really think about macular degeneration over the most recent study, which we have submitted for review, is that when we picked up our early macular degeneration cases, followed them up for a year, and we saw that the choroidal vessels were the only changes which happened over 1 year – [the] rest of the retina looked absolutely same.

So it looks like that...the choroid is playing a very, very important role in all the diseases as so far we have focused only on these 3 diseases, but we will be able to explore this into various ocular diseases, as well as in systemic diseases such as cardiovascular disease or kidney diseases, which will definitely show us the changes in the choroid. Because, as we know that the choroidal vasculature is very much connected to the systemic vasculature.

OT: What benefits do you find in this 3D imaging over 2D imaging that could benefit patients and their care?

Chhablani: When we really compare between 2D and 3D imaging, so our lab has been working on this one several years, I have been focused on choroidal vessels since 2010 where we did not have these cool imaging. So we were doing only 2D imaging, and we did a lot of work in terms of cross sectional B scan, en face scan, but there was always something missing because we were not able to get the depth information, we were always getting the cross section. So we knew that there is definitely something. And you can imagine that the choroid itself is a vascular structure, and the vasculature in the choroid does not follow the layered configuration as we see on retina. Instead the choroidal vessels, they really go around, they don't follow a path. So when they don't follow a path, you have to really track them down. And I think 3D visualization is the only way to learn about choroidal vessels.

OT: In your time as an ophthalmologist, how has advancing imaging changed the way patients are diagnosed?

Chhablani: I think that I always say that I've been lucky that I was born as a retina specialist in the OCT era. So the OCT actually made our life really simple. I think that advancement, what we started with Stratus OCT, time-domain OCT, to now what we have swept-source OCT. And then think about imaging, doing only 35 degrees or 50 degrees angiography. So now we have this wide-field imaging.

The biggest advantage, I see that has happened in last 10 years or 15 years, has actually let us diagnose newer diseases. It has let us follow up our patients really well. We are able to treat our patients much sooner. We are able to relate it with more systemic information. I think that now, I feel that we are now able to approach our patient more comprehensively compared to what we were doing maybe 2, 3 decades ago. So I'm sure that this will go on and we will learn more and more about the diseases.