Abaqus/Explicit Helps Give the Gift of Sight

By Jim Romeo

Subham Sett, Dassault Systèmes Simulia Corp.

In the lens of the human eyes, cataracts sometimes develop and degrade a person’s vision. Cataracts are opaque areas in the lens that obstruct and disseminate some of the light, causing a blurred and unfocused vision.

  Dassault Systèmes’ Simulia Abaqus FEA (finite element analysis) suite has been used to model intraocular lenses (IOLs) for corneal transplant surgery.

  To gain more insight into Dassault’s work with Bausch and Lomb, Inc., we recently spoke to Subham Sett, the Life Sciences industry lead for Dassault Systèmes Simulia Corp. in Providence, RI.

Q: What were some of the more challenging aspects to the design of the IOL and the inserters used during cataract surgery?
A: From an ophthalmologist’s point of view,  the surgery is outpatient and typically takes less than 10 minutes.
From an engineering perspective, however, the procedure is quite challenging, given the geometry: An industry-standard precision lens has a 6mm diameter, a center thickness of 1mm, and four haptics; an average incision is 2.8mm. According to the client, it’s like trying to suck a Frisbee through a vacuum. During the insertion, the lens can experience strains in excess of 60%.

Q: How did the Abaqus/Explicit software help in the design?
A: The analysis is highly non-linear with large deformations, difficult self-contact, sliding contact and hyper-elastic material properties. Our software allows the end-user to handle all of these complex features in a single analysis.

Q: Is designing a medical product different from designing other products?
A:  In most cases, medical products are designed to be used within the human body. The interaction between the device and the human aspect makes it distinctly different from designing other products. There is a lot of uncertainty and a lack of biological data, so product design relies on making assumptions about the biological environment in which it operates.

Q: For this particular application, how did the human element come into play?
A: The application design required a strong interface of Abaqus with SolidWorks, where the 3D models were generated and then linked with the Abaqus/CAE Interactive product for realistic simulation. The strong interface between design and engineering software allows designers and engineers to iterate efficiently during product development.

Q: Is breakthrough medical technology reliant on top-quality design software?
A: Most conventional engineering product designs today are heavily reliant on top quality design software during their development phase. The reliance on pure, real-world testing methods to validate and come up with new designs has been significantly reduced. Medical device companies have, in recent years, ramped up their investment in quality design and engineering software to accelerate their product development cycles—and lead to breakthrough medical technology.

Q: For this particular application, what are some of the things that the client was able to achieve, and how does it affect the ultimate end user?
A: The client was able to arrive at validated models that helped capture parameters crucial to the IOL design, such as insertion force, and measuring device strain while visualizing the deformations as it moves through the inserter. Such measurements, observations and validations allow the designers to create devices with less likelihood of failure during surgery, and design next-generation IOLs and inserters that will allow surgeons to operate with even smaller incisions during surgery. All of this has had a positive effect on patient experience, surgical outcome and patient recovery.

Q: What is the most important thing about developing engineering software products for the medical market?
A:  Engineering software products must provide accurate solution results for the medical market. The accuracy of these numerical solutions is key to arriving at test data validation. Because medical devices can save patient lives and promote long-term health, engineering software solutions must be validated before they can be used for such life-critical devices.

More Info:
Dassault Systèmes

Jim Romeo is based in Chesapeake, VA. Contact him via [email protected].