Performing cataract surgery at a more physiologic IOP offers benefits
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As ophthalmologists, we face almost daily pressure to adopt the latest and greatest technologies and techniques. With so much competing information, it can be challenging to know what new innovations are truly worth pursuing.
Trying out the newest gadget or using a new surgical technique is exciting, but the bottom line is this: If it does not improve patient outcomes or increase efficiencies in my practice, as evidenced by scientific data, then I move on to the next new thing.
There is one such technique that has been picking up steam that I am particularly passionate about: operating at a more physiologic IOP during cataract surgery.
Changing my tune on phaco
Phacoemulsification has long been performed using passive irrigation systems that rely on gravity to move fluid through the eye and do not adjust for IOP changes in real time caused by variables such as incision leakage, post-occlusion surge and aspiration flow. The technological limitations of these passive fluidics’ models are compensated for by operating at a significantly elevated IOP (approximately 50 mm Hg or higher) and lower vacuum levels to protect against the shallowing of the anterior chamber.
I operated at higher IOP settings for much of my career; 3 to 6 months postop, most patients’ outcomes were normal, and most ended their cataract journeys seeming happy enough. The reality is, when you are performing dozens of surgeries each surgical day with “good enough” results, it is easy to sink into your normal routine and forgo incremental improvements in technique and technology that could lead to better outcomes on behalf of your patients.
Since then, my go-to strategy for surgery has changed, and I do not settle for “the norm.” The goal for patients should not be standard visual outcomes — the goal is the best possible vision as soon as possible after surgery.
The same thing is true for intraoperative patient comfort. We live in an age of exceptional advancements in medicine. There is no reason that a patient in my operating room should experience more discomfort than is medically necessary.
Solving for the unmet need
An innovation such as the Centurion Vision System (Alcon) with Active Sentry solves this unmet need. Centurion Vision System with Active Sentry is the first and only phacoemulsification technology that combines Active Fluidics with a handpiece that has a built-in fluidics pressure sensor. The device leverages technological innovation to allow surgeons to operate at significantly higher vacuum levels without compromising anterior chamber stability.
The Active Sentry handpiece first signals to Centurion to indicate when adjustments are needed to ensure consistent IOP. The pressure sensor then detects changes in the anterior chamber stability as they occur, while the Active Fluidics uses compression plates to adjust the pressure on the BSS (Alcon) bag, compensating for changes in the eye. QuickValve technology then releases fluid into the aspiration line and minimizes occlusion break. Through this process, surgeons can operate at a lower, more physiologic IOP that, in turn, supports ocular safety and provides a more comfortable procedure for patients.
Adjusting to a lower, more physiologic IOP may be particularly beneficial for patients who are more vulnerable to ocular pain and have a higher preoperative IOP, greater anterior chamber depth and greater axial length.
Why more stability is critical
In my experience, operating at a more physiologic IOP has resulted in faster healing time and improved comfort because of how well the anterior chamber is stabilized.
Multiple studies conducted between 2009 and 2017 support this, revealing that the standard method of operating at a higher IOP can negatively affect corneal tissue and the anterior chamber, resulting in postoperative outcomes that can include a higher instance of corneal edema as shown by an increase in corneal volume at 1 month, an increase in central corneal thickness at days 1 and 7, a reduction of corneal clarity at day 1, and a higher presence of Descemet’s folds at day 1.
These studies also demonstrated that patients who received surgery performed at higher IOP experienced greater anterior segment inflammation, as indicated by the presence of flare and cells at day 1.
In contrast, another study conducted in 2022 revealed that a more physiologic IOP (approximately 20 mm Hg) supports a higher protection rate of endothelial cell density at day 4 and month 3 following surgery compared with cases that were performed at a higher IOP.
Additionally, notable data show that intraoperative patient pain tends to peak during the phacoemulsification stage. Therefore, operating at a lower IOP, especially for myopic patients with large anterior segments who tend to be more sensitive to IOP fluctuations, has done wonders for their intraprocedural comfort and their overall postop satisfaction.
Improving your practice
So, is operating at a more physiologic IOP worth it? I would say so.
Patients want to recover faster than ever, with as little intraoperative and postoperative discomfort as possible. In our era of highly advanced medicine, we have the power to make that a reality for cataract patients with more physiologic IOP supported by new surgical advancements.
However, no matter your experience level, adopting any new surgical technique can be unsettling. It is important to remember that by letting these innovations improve your practice, you can help ensure that your practice — and your patients — are not left behind as ophthalmology barrels toward a more advanced, patient-focused era.
- References:
- Bajwa SJS, et al. Indian J Anaesth. 2021;doi:10.4103/ija.ija_866_21.
- Centurion vision system with Active Sentry. https://www.myalcon.com/professional/cataract-surgery/surgical-equipment/centurion/. Accessed Oct. 9. 2024.
- Cyril D, et al. J Cataract Refract Surg. 2022;doi:10.1097/j.jcrs.0000000000000769.
- Hou CH, et al. Eye (Lond). 2012;doi:10.1038/eye.2012.29.
- Kokubun T, et al. The protective effect of normal-IOP cataract surgery on the corneal endothelium. Presented at: 125th annual meeting of Japanese Ophthalmological Society.
- Kokubun T, et al. Verification for the usefulness of normal tension cataract surgery. Presented at: Japanese Ophthalmological Society annual meeting; April 14-17, 2022; Osaka, Japan.
- Liu Y, et al. Front Med (Lausanne). 2023;doi:10.3389/fmed.2023.1294808.
- Nicoli CM, et al. J Cataract Refract Surg. 2016;doi:10.1016/j.jcrs.2015.08.017.
- O’Brien PD, et al. J Cataract Refract Surg. 2001;doi:10.1016/s0886-3350(00)00757-4.
- Scarfone HA, et al. J Cataract Refract Surg. 2024;doi:10.1097/j.jcrs.0000000000001359.
- Suzuki H, et al. J Cataract Refract Surg. 2009;doi:10.1016/j.jcrs.2009.05.057.
- Thorne A, et al. J Cataract Refract Surg. 2018;doi:10.1016/j.jcrs.2018.01.032.
- Vasavada AR, et al. J Cataract Refract Surg. 2010;doi:10.1016/j.jcrs.2009.11.009.
- Vasavada V, et al. J Refract Surg. 2014;doi:10.3928/1081597X-20140711-06.
- For more information:
- Cristos Ifantides, MD, MBA, of Tyson Eye in Cape Coral, Florida, can be reached at cristosmd@gmail.com.
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