Search Results

The Corvis ST is intended to measure the intra-ocular pressure of the eye in patients with less than 3 diopters of corneal astigmatism. In addition, the Corvis ST is designed to photograph the eye and take Scheimpflug images of the anterior segment of the eye to evaluate the thickness of the cornea.

The Corvis ST performs the following two functions: Tonometry and Pachymetry. The Corvis ST measures intraocular pressure without contact with the eye by applying an air puff to the eye. The eye is illuminated and during the air puff, a high-speed camera records the movement of the eye with more than 4000 images per second. The high-speed camera analyzes a sequence of 140 Scheimpflug images of the cornea to determine intra-ocular pressure. The Corvis ST measure corneal thickness and shape based on sectional images when the cornea is not influenced by the air puff. The pachymetry measurements of the Corvis ST and the cleared Oculus predicate use the same image processing routine for analysis to obtain corneal thickness measurements. Tonometry and pachymetry functions can be performed during the same evaluation or separately.

Here's a breakdown of the acceptance criteria and study details for the Corvis ST, based on the provided document:

Acceptance Criteria and Device Performance:

Study Details:

1. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

   • Pachymetry (Clinical):
     • Test Set Size: 51 subjects (102 eyes).
     • Data Provenance: Internal study (implies data was collected by the manufacturer, likely prospective). No specific country of origin is mentioned, but the manufacturer is based in Germany.
   • Tonometry (Clinical):
     • Test Set Size: 120 eyes (40 eyes per IOP group).
     • Data Provenance: Not explicitly stated if internal, but likely collected prospectively for the purpose of the study. No specific country of origin is mentioned.
   • Pachymetry (Bench):
     • Test Set Size: "Several glass plates with several known thicknesses." Not a human sample size.
     • Data Provenance: Internal study.
   • Tonometry (Bench):
     • Test Set Size: Manometric controlled test eye (phantom). Not a human sample size.
     • Data Provenance: Internal study.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

   • Pachymetry (Clinical): Ground truth was established by comparing to measurements from the FDA-cleared predicate device, Pachycam (K041841). No human experts were explicitly mentioned for ground truth.
   • Tonometry (Clinical): Ground truth was established using the Goldmann applanation tonometer (Haag-Streit), which is considered a clinical standard. No human experts were explicitly mentioned for ground truth.
   • Bench Testing (Pachymetry & Tonometry): Ground truth was established by known physical standards (calibrated glass plates for pachymetry, manometrically controlled pressure chamber for tonometry).

3. Adjudication method (e.g. 2+1, 3+1, none) for the test set

   • No adjudication method involving human readers for the test set was mentioned or implied for either pachymetry or tonometry. The comparison was directly against established reference devices or physical standards.

4. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

   • No MRMC comparative effectiveness study was mentioned.
   • The Corvis ST is a diagnostic measurement device (tonometer/pachymeter), not an AI-assisted diagnostic aid for human readers. Its performance is evaluated on the accuracy of its direct measurements against a reference, not on how it assists human interpretation.

5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

   • Yes, the performance studies described are for the standalone device. The device takes measurements directly, and its output (IOP, corneal thickness) is compared to a reference standard. There is no human-in-the-loop component for the measurement process itself in these evaluations.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

   • Pachymetry (Clinical): Ground truth based on measurements from an FDA-cleared predicate device (Pachycam).
   • Tonometry (Clinical): Ground truth based on measurements from a widely accepted clinical standard device (Goldmann applanation tonometer).
   • Bench Testing (Both): Ground truth based on known physical standards (calibrated glass plates, manometrically adjusted pressure chamber).

7. The sample size for the training set

   • The document describes performance studies, which are typically test sets. It does not provide information about a training set for the device's algorithms. The device's image processing routines are mentioned, and for pachymetry, it states they use the "same image processing routine" as the cleared predicate, implying established algorithms rather than ones newly trained for this submission.

8. How the ground truth for the training set was established

   • Not applicable as no training set information is provided in the document. The device's underlying technology seems to rely on established image processing techniques and comparison against predicate devices rather than a de novo AI model that requires a distinct training phase.

Ask a specific question about this device