(113 days)
The LenSx 550 Laser System is indicated for anterior capsulotomy and laser phacofragmentation during cataract surgery. The anterior capsulotomy and phacofragmentation procedures may be performed either individually or consecutively during the same surgery.
The LenSx 550 Laser is an ophthalmic surgical laser that has previously been cleared for use in anterior capsulotomy during cataract surgery (K082947). The LenSx 550 generates femtosecond laser pulses that are scanned in a three-dimensional pattern in the eye. Localization of these laser pulses is accomplished by an aiming beam that identifies the surfaces of the lens, and an off-the-shelf, disposable contact lens and suction ring assembly that fixates the eye relative to the delivery system. As described in K082947, anterior capsulotomy is performed by delivering a cylindrical pattern of laser pulses to intersect the anterior lens capsule.
The same surgical device, with only minor software changes, is now also being proposed for use in phacofragmentation during cataract surgery. As described in this premarket notification, laser phacofragmentation divides the lens into quadrants, in the same way that division of the lens into quadrants is performed with standard ultrasound phacofragmentation in the initial step of phacoemulsification.
To perform phacofragmentation, the LenSx system delivers a series of laser pulses to form two intersecting ellipsoidal planes. Photodisruption of the lens tissue in this pattern, which appears as a cross from a surgical (top) view, segments the nucleus into four sections before the eye is physically entered by any instruments or devices.
Following entry into the eye and then into lens, the fragmented nuclear quadrants created by the LenSx 550 are further fragmented and removed using a standard phacoemulsification probe.
Here's a breakdown of the acceptance criteria and study information for the LenSx 550 Laser System, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state quantitative acceptance criteria (e.g., a specific percentage reduction in ultrasound power, or a target accuracy for laser pulse placement). Instead, the performance is described in comparative and qualitative terms.
| Performance Metric | Acceptance Criteria (Implicit from study design) | Reported Device Performance |
|---|---|---|
| Phacofragmentation Accuracy & Reproducibility | High degree of accuracy and reproducibility for laser pulse placement in plastic substrates. Confirmed accuracy and reproducibility of localized laser tissue effects in ex vivo porcine eyes. | Demonstrated a high degree of accuracy and reproducibility for laser pulse placement in plastic substrates. Further confirmed the accuracy and reproducibility of the localized laser tissue effects in ex vivo porcine eyes. |
| Reduction in Ultrasound Power | Significantly reduced ultrasound power required to complete phacofragmentation compared to standard methods with a predicate device (Alcon Series 20000 Legacy). | The study group (using laser phacofragmentation) required significantly less manual manipulation and ultrasound power to achieve the desired phacofragmentation effect compared to the control group (standard ultrasonic phacoemulsification). |
| Clinical Outcomes | Excellent clinical results with no significant adverse events, comparable to advanced phacoemulsification techniques reported in previous studies. | Clinical results were excellent in both the laser phacofragmentation and control groups, with no significant adverse events. Results in both groups were consistent with those of advanced phacoemulsification techniques reported in previous studies. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size (Clinical Study - Test Set): A total of 92 subjects, divided into two groups of 46 eyes each.
- Study Group: 46 eyes
- Control Group: 46 eyes
- Data Provenance: Prospective clinical study performed outside the U.S. (specific country not mentioned).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number of experts or their qualifications for establishing the ground truth of the clinical outcomes or the success of phacofragmentation. The clinical study evaluated performance, and "clinical results were excellent in both groups, with no significant adverse events," implying expert assessment by the surgical team or researchers involved, but details are not provided.
4. Adjudication Method for the Test Set
The document does not describe any explicit adjudication method (e.g., 2+1, 3+1). The "clinical results were excellent" implies a direct observation and assessment by the surgical team or lead investigators, rather than a formal adjudication process post-facto by a separate panel.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A multi-reader multi-case (MRMC) comparative effectiveness study was not conducted in the traditional sense of evaluating multiple human readers' diagnostic performance. This was a clinical comparative effectiveness study comparing a new surgical technique (LenSx laser phacofragmentation) with a standard technique (ultrasonic phacoemulsification).
- Effect Size: The study found that the laser phacofragmentation group required "significantly less manual manipulation and ultrasound power." The document states "significantly reduced" but does not provide a specific quantitative effect size (e.g., a percentage reduction or a statistical measure like Cohen's d) for the improvement in ultrasound power or manual manipulation.
6. Standalone (Algorithm Only) Performance Study
Yes, aspects of standalone performance were evaluated through pre-clinical studies:
- Plastic substrates: Demonstrated "a high degree of accuracy and reproducibility for laser pulse placement."
- Ex vivo porcine eyes: Further confirmed "the accuracy and reproducibility of the localized laser tissue effects."
These pre-clinical studies assessed the device's inherent capability to perform the intended physical action (laser phacofragmentation) without human intervention in the fragmentation process itself (though a human would operate the device).
7. Type of Ground Truth Used
- Pre-clinical studies (plastic substrates, ex vivo porcine eyes): The ground truth was based on physical observation and measurement of laser pulse placement accuracy, reproducibility, and localized tissue effects.
- Clinical study:
- Effectiveness of phacofragmentation: Ground truth implicitly based on surgical observation of the extent of fragmentation, and measured reduction in ultrasound power needed for subsequent phacoemulsification.
- Safety: Ground truth based on clinical observation of adverse events.
- Clinical outcomes: Ground truth based on overall clinical assessment by the medical professionals involved, and comparison to "advanced phacoemulsification techniques reported in previous studies."
8. Sample Size for the Training Set
The document does not specify a separate training set in the context of machine learning. The studies described are performance evaluations of the device's hardware and software logic. The device itself (LenSx 550 Laser System) was previously cleared (K082947) for anterior capsulotomy, implying its core technology was already established. The current submission focuses on a new indication (phacofragmentation) with "only minor software changes." The pre-clinical studies and clinical studies described are for validation of the new indication, not for training a specific AI model.
9. How the Ground Truth for the Training Set Was Established
As no specific AI training set or process is described, this information is not applicable based on the provided text. The device's operation appears to be based on pre-programmed patterns and optical localization rather than a continuously learning AI model that requires a ground-truthed training set for its development.
§ 886.4390 Ophthalmic laser.
(a)
Identification. An ophthalmic laser is an AC-powered device intended to coagulate or cut tissue of the eye, orbit, or surrounding skin by a laser beam.(b)
Classification. Class II.