BLOG: Patients win when device makers respond to surgeon feedback
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Ophthalmology is one of the most technologically driven subspecialties in medicine.
From examination techniques to treatments with pharmaceutical, laser and surgical technologies, every aspect of our management relies on advanced innovations, regardless of the disease process.
The technological advancements of glaucoma management have been practically breathtaking. When I started practicing almost 3 decades ago, the disease’s management paradigm was pretty straightforward: We used a centuries-old diagnostic approach, gave patients a rote treatment cascade of drops followed by laser trabeculoplasty as a stopgap measure and then moved on to a risky filtration procedure. Today, we have so many more options to offer our patients, which has freed us from a management paradigm that may not meet our patients’ best interests.
I believe that in the future our strategies will be driven by artificial intelligence based on large data sets acquired through registries (such as the American Academy of Ophthalmology’s IRIS Registry). Technological advancements allow us to further personalize therapy. Today, our surgical goals in glaucoma management are not only to achieve a predefined target pressure but also to perform procedures that allow for a faster recuperation and return to a preoperative level of function relatively quickly. Plus, in the setting of COVID-19, we also seek to take advantage of technologies that reduce patients’ risk for exposure by decreasing the need for multiple office follow-up visits.
For all these reasons, MicroPulse transscleral laser therapy (MicroPulse TLT, Iridex) is highly appealing and advantageous.
Tweaking technology once it is on the market
When it comes to any new technology, it’s not unusual for a manufacturer to make tweaks once the product is in the marketplace. Consider modern pharmaceutical agents with reduced preservative content, adjusted active drug concentrations and modern delivery vehicles. Although valuable and ingenious, these are sometimes relatively easy changes. A bottle, after all, has a short shelf life. Once it’s gone, a pharmaceutical company can reintroduce a new formulation. After the hard work has been done in the lab and the next-generation agent is FDA cleared, the new product comes to market and the old one goes away.
Now, consider microinvasive glaucoma surgery. These procedures are constantly evolving to improve ergonomics, stability of the device in the eye or efficacy. In some cases, better efficacy can also be obtained by injecting multiple devices. Thanks to collaboration between biomedical engineers and surgeons, these adjustments are accomplished with relative efficiency. Again, once that inventory is gone, industry can simply reintroduce the new device.
But a laser — a relatively expensive piece of equipment — that enters the marketplace presents a different challenge. The original idea of MicroPulse TLT was to have a relatively non-incisional treatment that could reduce morbidity and therefore shift laser treatment to an earlier stage in the disease process. The device, however, is a “closed box” that the surgeons have made a significant investment in. When improvements and revisions are needed, the manufacturer has to figure out a way to make it seamless for physicians to “upgrade” their technology.
Improved handpiece, refined treatment parameters
Iridex was aware of this when it introduced the revised MicroPulse P3 delivery device for MicroPulse TLT. Its initial approach had been cautiousness — do the most amount of good and the least amount of harm. Initially, it thought that enhancing the energy transfer, with the original dosing parameters of 2,000 mW at 50 seconds per hemisphere with five sweeps of 10 seconds duration, would be an adequate starting dose. Early data did demonstrate an approximate 20% reduction in IOP, but there was too much variability in outcomes. Since then, based on clinician input and newly designed computer tissue modeling, the starting dose was reassessed. A dose-escalation methodology was also devised to allow clinicians the opportunity to achieve the effectiveness and safety they wanted for their patients.
Slowing the sweep speed was found to be the most important variable in tissue uptake of thermal energy and the transfer of energy to a larger area of adjacent tissue. The “tipping point” to achieve a therapeutic durable dose was found to be 20 seconds per pass for a hemisphere. So, recommended settings are now 20 seconds per pass with a small increase in power to 2,500 mW. Total sweeps can be adjusted to between three to five sweeps per hemisphere depending on surgeon preference and target IOP goals (I personally use five sweeps per hemisphere).
An industry fixture and longtime friend, Kevin LaMarche, director of glaucoma clinical affairs at Iridex, described it to me using this analogy: Think of passing your finger through a candle’s flame to visualize tissue response. If you run your finger through the flame quickly, you don’t feel the heat, but as you begin to slow your finger down, the heat intensifies.
My experience, which is also being noted by others around the country, is that these adjusted parameters provide an efficient treatment with improved efficacy. These tweaks are not unique to MicroPulse TLT — think about the variability still today when it comes to treatment settings for selective laser trabeculoplasty. Power settings and treatment area (180° vs. 360°) are commonly different depending on the surgeon’s preference or individual patient.
Optimizing laser therapy
The revised MicroPulse P3 delivery device provides a smaller footprint with improved ergonomics for the surgeon. It allows for increased visibility of the treatment area and better limbal access in eyes with tight lid fissures or in eyes that are deep set. On both fronts, the new delivery device and adjusted parameters, Iridex has done an excellent job of bringing to market a great tool while at the same time making necessary adjustments to fine-tune the device’s capabilities. Particularly in the COVID environment, MicroPulse TLT is a valuable treatment approach for doctors to consider. Kudos to Iridex for listening to its customers and optimizing the existing platform.
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