The Latest Advancements in Diagnostic Imaging, Surgical Innovations, and Treatment Options for Anterior Segment Conditions
Francis Mah, MD, of the Scripps Clinic in La Jolla, California, talks about where the field is heading for anterior segment diseases.
Next, Dr. Mah talks about using AS-OCT for surgical planning and more.
Question:
What are the latest trends and advancements in the anterior segment of the eye?
Francis S. Mah, MD:
As far as OCT, so there are huge advances. I think the main area of advances is improving the resolution and high definition, especially as it pertains to the surface of the cornea. We’re talking the epithelium, and then anything that’s abnormal on the epithelium. For example, cancers, ocular surface, neoplasias, those have a specific pattern. The resolution is increasing there any other tissues, melanoma, for example, and then even normal tissues like pterygias and differentiating between scars versus more abnormal like the cancers and melanomas and so forth. I think that’s really entered into more the mainstream for cornea experts.
I think the other area that is improving, again, in terms of the resolution and the ability to visualize the areas of the cornea are, for example, like the tear film. Not that you can identify the specific particles, but you can actually resolve the tear film layer.
In the future, it may help define specific types of dry eyes. For example, evaporative versus more aqueous versus other types that we haven’t even described. But now that we have the ability, for example, to visualize the surface of the cornea, that we’d be better able to describe them.
In addition, for example, there’s been a lot of work on limbal stem cell deficiency and differentiating between the tissues there. I think this would be beneficial to be able to define it a little bit better in terms of making the diagnosis of limbal stem cell deficiency.
There are different groups. I think the most in the literature is Sophie Deng, MD, PhD, out of UCLA, has been using OCT and describing OCT as far as her day-to-day workflow for limbal stem cell deficiency. There are various different advancements in OCT on the corneal side of things as well. Mainly, I focus on the anterior surface, but there are things that are advancing on the anterior chamber as well.
As far as the advancements on the anterior segment, again, as a cornea specialist, the first things that I’ll talk about are corneal transplants. Ever since 1905, with Eduard Zirm, we were doing penetrating keratoplasties, and that advanced really until the late 20th century where we started doing lamellar types of procedures, and specifically anterior lamellar, but also more significantly posterior lamellar keratoplasties. That’s when we really had DLEK and then DSEK, DMEK, those types of transplants.
I think the next wave are going to be more the cellular level. The majority of transplants that are happening these days, at least in developed countries, is due to endothelial either trauma or issues, Fuchs’ dystrophy, for example. There are a couple of new technologies that are coming down the pipeline looking at trying to improve upon DSEK and DMEK, which is actually a pretty high bar if you think about it.
DMEK, nowadays, people get 20/20 vision. It’s pretty … I don’t want to say routine, but it’s definitely a lot simpler in terms of the management, and people get faster visual recovery. To improve on that is really going to be, I think, impressive. I think some of the technologies that are coming down the pipe where we may not have to do these procedures in the office, we may be able to do them repeatedly, for example, maybe injections in the office. I think those technologies are super exciting.
Down the road, as the costs come down and the technology is scalable, it may impact the rest of the world as well. I think that’s really exciting.
As far as refractive surgery, I think refractive surgery, I would say, 20 years ago, was primarily keratorefractive surgery, LASIK, PRK. We even have SMILE these days. I think, in general, as the accuracy and outcomes of lens-based surgery is improving, I think it might be even more preferred. Some of the optics are pretty excellent in terms of the implant lenses versus changing the contour of the cornea.
Then you’ve got the intraocular lenses, for example, the EVO ICL. These are various different technologies, I think, from a refractive. I think we not necessarily are moving away from the cornea, but I think we’re expanding other areas of refractive surgery. I think it’s due to the safety and improved outcomes and technology of the lenses that are coming out that are reasons why things are expanding inside the eye as well.
I’m not really a glaucoma person, but, in general, glaucoma in the past decade, we saw a huge explosion of MIGS and other surgical technologies that were minimally invasive, which is part of the MIGS term. That really helped to improve upon safety as well as lifestyle. I think, in general, there seems to be a lot of technology which is out there, especially this kind of watershed moment.
The final area is just presbyopia. I think we found our first presbyopia-correcting drop and topically. I think there are several more technologies which are coming down the pipeline, and hopefully we continue to refine this area, because obviously there’s a huge amount of interest. It impacts almost 2 billion people worldwide.
As far as clinical trials, I think a lot of the clinical trials that I’m involved in, again as a cornea specialist, I kind of fall in line with the ocular surface. We saw a huge success with cenegermin, which is Dompe’s product, the brand name’s OXERVATE, for neurotrophic keratitis.
Due to this success and obviously the patients that are benefiting, there are other drugs that are coming down the pipeline, multiple drugs, looking at things like persistent corneal epithelial defects. I think there’s at least 4 studies that are being done. One that I’m participating in is the Kala study, which uses a novel mesenchymal stem cell secretome. There are other drugs looking at the neurotrophic keratitis as well.
Internally, there are technologies looking at endothelial cells. We talked about the transplants and ex vivo expansion, but there are drugs that are potentially going to either allow for expansion of innate endothelial cells or provide movement of these cells. One of the earliest technologies are these ROCK inhibitors that are FDA-approved for glaucoma. There are some that are being used off-label to try to help the endothelial cells move in, for example, Fuchs’ dystrophy. These are different areas of advancement and technology for the next several years for cornea specialists.
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