How 3D printers could help improve access to eye care

Dec 29, 2023

In recent years, the use of 3D printing in healthcare has seen an increase.

3D printing has already been used for creating certain implants and prosthetics. And research is currently under way on ways to use 3D printing for human organs and tissues as well as drugs.

Now, scientists from the Centre for Ocular Research & Education (CORE) at the University of Waterloo in Ontario, Canada, recently presented research during the ARVO 2023 Annual Meeting showcasing how 3D printing could potentially be used in eye care.

Potential 3D printing applications included ocular drug delivery, biodegradable contact lenses, and a 3D bioprinted eye model that could be used to test drugs delivered through the eye.

The findings haven't been published yet in a peer-reviewed journal.

Unlike a standard printer that prints words and photos onto a flat sheet of paper, 3D printing creates an actual three-dimensional item.

The 3D printer does this by using "printing" layers of material. These layers continue to build and shape into the object it is printing. Because of this, 3D printing is considered an additive technology.

A variety of materials including plastics, metals, composites, and ceramics can be used to 3D print objects.

For 3D printing medical devices, the Food & Drug Administration (FDA) currently regulates these items through its Center for Devices and Radiological Health (CDRH).

According to Dr. Alex Hui, the head of biosciences at the Centre for Ocular Research & Education (CORE) at the University of Waterloo, the key benefit of 3D printing is flexibility.

"3D printing opens new avenues for rapid, on-demand, and custom manufacturing of ocular devices, ranging from glasses, contact lenses, or drug-delivering ocular inserts," he told Medical News Today. "We can also leverage this technology to make better in vitro eye models to screen drugs or test new ocular products."

"While the potential of 3D printing in eye care is quite promising, we are still quite far away from this reality," Hui added. "That is precisely why we have decided to pursue this research, helping bridge the gap between 3D printing and ophthalmic applications."

This is not the first time scientists have looked at 3D printing in eye health. A study in December 2022 showed how 3D bioprinting could be used to create eye tissue. Other research has examined 3D printing for contact lenses and intraocular lenses.

"From a consumer perspective, 3D printing allows for medical devices to potentially be produced at the point of care — e.g., in the office or home," Hui said. "The most useful application will be for situations needing a customized, one-off, or specialty design for a unique patient. We envision this technology could be impactful in scleral lenses, orthokeratology, and drug delivery where custom and personalized products are highly desirable. Products that have a short shelf life or products that take weeks or months to produce may also benefit from this technology."

Three of the 3D printing innovations revolved around the making and use of 3D-printed polydimethyl siloxane (PDMS) microfluidic chips.

Researchers looked at using this chip to test eye cell responses to certain conditions, as well as using the chip to make a contact lens that can test medications administered through the eyes.

Additionally, scientists were able to incorporate human corneal epithelial cells (HCECs) into the PDMS chip for use in cell biological studies.

"Microfluidic devices are a common tool used in research and diagnostics," Hui explained. "For example, consider COVID test strips that use similar principles, where only a small amount of fluid is leveraged for information. Those made from PDMS are primarily used for research containing cells, but the traditional process to make PDMS microfluidic devices is quite lengthy and expensive."

"CORE leveraged 3D printing as a way to help facilitate this process, enabling us to create design elements that would normally not be possible using traditional approaches," he continued. "We utilize these PDMS chips to help test and screen new drugs and products on cells in terms of safety and efficacy. We can also design these chips in the future as a diagnostic tool, such as detecting tear film biomarkers for specific eye diseases, in a relatively rapid fashion from design to the first prototypes."

Another study focused on the development of a biodegradable bioink for 3D printing ophthalmic devices.

In this study, researchers used the bioink to 3D print materials that can be used to make biodegradable contact lenses.

"Bioinks are materials that have a compatible biological profile that can also be printed using a 3D printer," Hui said. "We want to utilize this technology to print biodegradable ocular inserts for drug delivery, and their geometrical designs are quite simple, making this straightforward."

"As a learning exercise, we also wanted to see if we could print a soft contact lens, which (is) very thin and soft, and for which there are numerous challenges to have it print properly," he added. "We will use the lessons learned and apply them for 3D printing hard lenses — i.e., scleral lenses and ortho-K lenses."

CORE researchers also developed a soft hydrogel eye model with surfaces mimicking the natural surfaces of the cornea and sclera. The model also has an internal chamber to mimic the natural interior of the eye.

Researchers believe this type of eye model could be used for testing the administration of eye medications and how they are absorbed through the cornea.

"There are a lot of studies that require us to understand how drugs diffuse and penetrate to the back of the eye, and there has been no way to simulate that," Hui explained. "By experimenting with different bioink formulations, we can now 3D print a hydrogel eyeball with hollow structures that simulate the anterior and posterior chambers. Further advances will help us study various drug delivery methods to the back of the eye. As our work develops, we hope to produce models for not only research but also educational purposes, allowing clinicians to learn and practice techniques on them prior to patient interactions."

Medical News Today also spoke with Dr. Benjamin Bert, an ophthalmologist at MemorialCare Orange Coast Medical Center in California, about this research.

"Any application of new technologies that we’re able to use to try to improve the care that we provide and brings things into the future is always beneficial and always very exciting," said Bert, who was not involved in this particular research.

When speaking of the benefits 3D printing may offer eye care professionals in the future, Bert said it will open up accessibility.

"So you can have a technology that is developed in one part of the world, and then by being able to print it with just having access to a 3D printer, that means you can bring it into even very remote parts and still have access to this highly advanced technology," he said.

"I think it is a very interesting technology," Bert added. "It has a lot of future applications. And this was kind of the first step in introducing some of the things where it may be able to be utilized. I think we’ll be hearing a lot more about it as time passes and as the research continues to progress."