CATARACT SURGERY
More Physiologic IOP Matters
5 minute read
Updated June 17, 2024
Board-certified cataract and refractive surgeon Alison Early, MD and her colleagues share the impact that performing cataract surgery at a more physiologic IOP has had on their patients, offering valuable insight as to why the movement is picking up steam.
Advancements in surgical techniques can impact the way cataract surgery is performed, but only if surgeons are willing to adopt them. One such early adopter of the latest surgical technique—performing cataract surgery at a more physiologic intraocular pressure (IOP)—is Alison Early, MD, a board-certified cataract and refractive surgeon.
“I remember right out of residency keeping the settings of my phaco machine exactly the same as I learned during training, with the IOP around 50mmHg,” said Dr. Early. “My patients’ comfort during surgery and outcomes were ‘normal,’ and I didn’t think there was room for it to get better than that.”
At the time, Dr. Early was using a passive irrigation system that did not adjust for changes in IOP in real time caused by pressure and flow 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 and lower vacuum levels to protect against the shallowing of the anterior chamber.1
Why Performing Cataract Surgery at More Physiologic IOP Matters
Multiple studies conducted between 2009 and 2017 revealed that the tried and true method of operating at a higher IOP was impacting corneal tissue and the anterior chamber, resulting in post-operative outcomes that included higher instance of corneal edema as shown by an increase in corneal volume at one month, an increase in central corneal thickness at day one and seven, a reduction of corneal clarity at day one, and a higher presence of Descemet’s folds at day one.2-4 These studies also demonstrated that surgery performed at higher IOP levels experienced greater anterior segment inflammation as shown by the presence of flare and cells at day one.3,4
CENTURION® with ACTIVE SENTRY® surgeons can operate at significantly higher vacuum levels without compromising anterior chamber stability.4-9 How? By operating at a more physiologic IOP with the CENTURION® with ACTIVE SENTRY®.
In fact, another study conducted in 2022 revealed that a more physiologic IOP (~20 mmHg) supported a higher protection rate of endothelial cell density at day four and month three following surgery compared to cases that were performed at a higher physiologic IOP.5,10 Dr. Early describes this discovery, which is now becoming more well-known among savvy ophthalmic surgeons, as monumental in optimizing her patients’ comfort and outcomes.
“My goal for patients isn’t optimized vision eventually, but the best possible vision as soon as possible after surgery. I find that patients who heal faster tend to be more satisfied overall,” said Dr. Early. “The science supports that operating at a more physiologic IOP Supports faster healing, as does my own real-world experience.”
Other Surgeons Joining the Movement
It’s not just Dr. Early who is finding that her patients are more satisfied after transitioning to a more physiologic IOP. Some of the most accomplished experts in the industry, including Dagny Zhu, MD, of NVISION Eye Center near Los Angeles and Cristos Ifantides, MD, MBA, of Tyson Eye in southwest Florida, also feel that operating at a more physiologic IOP with ACTIVE SENTRY has helped to improve their patients’ outcomes and satisfaction.
“Data show that intraoperative patient-pain tends to peak during the phacoemulsification stage,” said Dr. Zhu.5,10,11 “Operating at a lower IOP, especially for my myopic patients who tend to be more sensitive to IOP fluctuations, has done wonders for their intra-procedure comfort and helping to support their overall satisfaction as a result.”10,11
For Dr. Ifantides, the intraoperative effect on chamber stability is paramount.
“We’ve been using the CENTURION with ACTIVE SENTRY for a while now which has been great for keeping our patient’s anterior chambers stable,” shared Dr. Ifantides. “In the few instances where we’ve turned ACTIVE SENTRY® off, you can actually see the difference in the stability of the chamber almost instantaneously.”
Operating at a More Physiologic IOP Can Improve Patient Outcomes12
As emphasized by leading experts, patients' satisfaction is key following cataract surgery as they want clear vision sooner rather than later. Lowering the amount of pressure on the eye during surgery can reduce the vasculature change in the retina and reduces the negative impact on the anterior vitreous face barrier that performing at a higher irrigation pressure tends to cause.12
While modern cataract surgery uses topical anesthesia as well as phacoemulsification techniques, operating at a higher IOP can impact the retinal tissue that surgeons are now trying to avoid by performing at a more physiologic level.5,12
For surgeons who already have CENTURION with ACTIVE SENTRY and want to join the movement, Dr. Early suggests using the ACTIVE SENTRY to lower your IOP settings incrementally, rather than taking the plunge all at once.
“A new surgical technique should improve, not shake, your confidence,” added Dr. Early. “By lowering your IOP settings little by little, you won’t be able to notice a difference in the ‘feel’ that you’re used to—but I can assure you that your patients will.”
CENTURION® VISION SYSTEM IMPORTANT PRODUCT INFORMATION
Caution: Federal (USA) law restricts this device to sale by, or on the order of, a physician.
As part of a properly maintained surgical environment, it is recommended that a backup IOL Injector be made available in the event the AutoSert® IOL Injector Handpiece does not perform as expected.
Indication: The Centurion® Vision System is indicated for emulsification, separation, irrigation, and aspiration of cataracts, residual cortical material and lens epithelial cells, vitreous aspiration and cutting associated with anterior vitrectomy, bipolar coagulation, and intraocular lens injection. The AutoSert® IOL Injector Handpiece is intended to deliver qualified AcrySof® intraocular lenses into the eye following cataract removal. The AutoSert® IOL Injector Handpiece achieves the functionality of injection of intraocular lenses. The AutoSert® IOL Injector Handpiece is indicated for use with the AcrySof® lenses SN6OWF, SN6AD1, SN6AT3 through SN6AT9, as well as approved AcrySof® lenses that are specifically indicated for use with this inserter, as indicated in the approved labeling of those lenses.
Warnings: Appropriate use of Centurion® Vision System parameters and accessories is important for successful procedures. Use of low vacuum limits, low flow rates, low bottle heights, high power settings, extended power usage, power usage during occlusion conditions (beeping tones), failure to sufficiently aspirate viscoelastic prior to using power, excessively tight incisions, and combinations of the above actions may result in significant temperature increases at incision site and inside the eye, and lead to severe thermal eye tissue damage. Good clinical practice dictates the testing for adequate irrigation and aspiration flow prior to entering the eye. Ensure that tubings are not occluded or pinched during any phase of operation. The consumables used in conjunction with ALCON® instrument products constitute a complete surgical system. Use of consumables and handpieces other than those manufactured by Alcon may affect system performance and create potential hazards.
AEs/Complications: Inadvertent actuation of Prime or Tune while a handpiece is in the eye can create a hazardous condition that may result in patient injury. During any ultrasonic procedure, metal particles may result from inadvertent touching of the ultrasonic tip with a second instrument. Another potential source of metal particles resulting from any ultrasonic handpiece may be the result of ultrasonic energy causing micro abrasion of the ultrasonic tip.
ATTENTION: Refer to the Directions for Use and Operator’s Manual for a complete listing of indications, warnings, cautions and notes.
References
- Nicoli CM, Dimalanta R, Miller KM. Experimental anterior chamber maintenance in active versus passive phacoemulsification fluidics systems. J Cataract Refract Surg. 2016;42(1):157-162. doi:10.1016/j.jcrs.2015.08.017
- Suzuki, H., Oki, K., Shiwa, T., Oharazawa, H. & Takahashi, H. Effect of bottle height on the corneal endothelium during phacoemulsification. J Cataract Refract Surg 35, 2014-2017, doi:10.1016/j.crs.2009.05.057(2009).
- Vasavada, A. R. et al. Impact of high and low aspiration parameters on postoperative outcomes of phacoemulsification: randomized clinical trial. J Cataract Refract Surg 36, 588-593, doi:10.1016/j.jcrs.2009.11.009 (2010).
- Vasavada, V. et al. Real-time dynamic intraocular pressure fluctuations during microcoaxial phacoemulsification using different aspiration flow rates and their impact on early postoperative outcomes: a randomized clinical trial. J Refract Surg 30, 534-540, doi:10.3928/1081597X-20140711-06 (2014).
- Kokubun, T. et al. The protective effect of normal-IOP cataract surgery on the corneal endothelium, The 25th Annual Meeting of the Japanese Ophthalmological Society.
- Thorne, A., Dyk, D. W., Fanney, D. & Miller, K. M. Phacoemulsifier occlusion break surge volume reduction. J Cataract Refract Surg 44, 1491-1496, doi:10.1016/j.jcrs.2018.01.032 (2018).
- CENTURION® with ACTIVE SENTRY® Directions for Use
- CENTURION® with ACTIVE SENTRY® Operations Manual
- Active Sentry® Handpiece Directions for Use
- Scarfone HA, et al. Vitreous-lens interface changes after cataract surgery using active fluidics and active sentry with high and low infusion pressure settings. J Cataract Refract Surg. 2024 Apr 1;50(4):333-338. doi: 10.1097/j.jcrs.0000000000001359. PMID: 37938025; PMCID: PMC10959530.
- Liu Y, Hong J, Chen X. Comparisons of the clinical outcomes of Centurion® active fluidics system with a low IOP setting and gravity fluidics system with a normal IOP setting for cataract patients with low corneal endothelial cell density. Front Med (Lausanne). 2023 Nov 23;10:1294808. doi: 10.3389/fmed.2023.1294808. PMID: 38076276; PMCID: PMC10704024.
- Kokubun T, et al. Verification for the usefulness of normal tension cataract surgery. Presented at: The 126th Annual Meeting of the Japanese Ophthalmological Society (JOS); Apr 14-17, 2022; Osaka, Japan.
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