A recent study sponsored by Centricity Vision and published in Clinical Ophthalmology compared the use of ZEPTO’s precision pulse capsulotomy (PPC) to continuous curvilinear capsulorhexis (CCC) in cataract surgery.
Let’s start with ZEPTO.
Developed by Centricity Vision, the ZEPTOLink intraocular lens (IOL) Positioning System is the first and only automated anterior capsulotomy device that creates an instantaneous capsulotomy for a precise, 360° IOL overlap on a patient’s visual axis.
To note, the system received 510(k) clearance from the FDA in May 2023.
Exactly how does it work?
The platform integrates with any phacoemulsification (phaco) system (taking up minimal space and potentially saving time) to use its suction and irrigation to give surgeons complete control during the step-by-step process:
- Insertion of the hand tip via a 2.2+ mm incision.
- Suction delivery of the centered handpiece tip close to the lens capsule.
- Application of energy micropulses (forming the capsulotomy) and removal of the device through the main incision.
See here for additional details, including the recommended chamber depth and a visual step-by-step walkthrough.
Editor's note: The following interview was published on September 6, 2023, as a supplement to this article.
Below, Visionary Medical Education Director Michael Cooper, OD, FAAO, speaks with Mark Vital, MD, of Houston Eye Associates in Houston, Texas—and a specialist of cornea and external disease as well as anterior segment surgery—on the ZEPTOLink IOL Positioning System.
Gotcha … now refresh me on CCC.
Continuous curvilinear capsulorhexis (CCC) has long been considered the standard surgical technique for removing the central part of the anterior lens capsule during cataract surgery— either manual sutureless extracapsular cataract extraction or phaco.
And how do endothelial cells play into this?
Cataract surgery with phaco is associated with a 5% to 20% loss of corneal endothelial cells anywhere from 1 to 3 months post-surgery.
This has been attributed to “the ultrasound energy delivered during lens [phaco] and to fluidic turbulence during surgery.”
While not typically a reason for concern for a patient, extensive endothelial cell loss could potentially lead to corneal decomposition and edema, or potentially require penetrating or endothelial keratoplasty.
Okay. I’m ready for the study details.
The prospective, randomized, multisite clinical trial included 67 patients (ages 50+) who (randomly) received lens cataract surgery for cataract removal via either PPC (n = 33) or CCC (n = 34) arms.
The hypothesis: that corneal endothelial cell loss—plus the percentage of hexagonal cells [%Hex] and coefficient of variation [CV] in cell size—at 3 months post-PPC cataract surgery was not greater than that of post-CCC cataract surgery.
Below, Dr. Vital, one of the study's authors, offers a summary of the trial.
What was measured?
The endothelial cell density (ECD) of the corneas (for treated eyes) were measured via specular microscopy images of the central corneal endothelium.
Primary endpoint was ECD loss at 3 months post-surgery, while secondary endpoints were ECD loss at 1 month post-surgery as well as %Hex and CV at baseline (pre-surgery), 1 month, and 3 months.
And the actual surgical procedures?
Per the study, all surgeries were conducted using a 2.4 mm primary corneal incision coupled with the Centurion Vision System (Alcon), while the ophthalmic viscosurgical device used was DuoVisc (Alcon).
Now the findings.
Overall, there was no significant differences noted among both PPC- and CCC-treated patients at 1 or 3 months post-surgery for ECD, #Hex, or CV.
Further, PPC use during cataract surgery did not result in any increased loss of endothelial cells beyond normal expectations.
Give me some numbers.
At 1-month post-surgery, an 11.5% mean ECD loss was noted in the CCC group, compared to a 12.3% loss in the PPC group (P = 0.818, t-test).
At 3 months post-surgery, an 11.7% mean ECD loss was noted in the CCC group, compared to a 12.4% loss in the PPC group (P = 0.815, t-test)
Dr. Vital shares his conclusions below.
The study authors noted that, based on the data, “PPC as an automated capsulotomy method has demonstrated [an endothelial cell] safety profile equivalent to CCC during cataract surgery.
Below, Dr. Vital shares a few final details on the ZEPTOLink.