(194 days)
The CONTEX OK™ (siflufocon A) Rigid Gas Permeable Contact Lens for Orthokeratology is indicated for use in the reduction of myopic refractive error in non-diseased eyes. The lens is indicated for daily wear in an orthokeratology fitting program for the temporary reduction of myopia of up to 3.00 diopters. The lens may be disinfected using a chemical disinfection system only. Note: To maintain the orthokeratology effect of myopia reduction lens wear must be continued on a prescribed wearing schedule.
The CONTEX OK™ (orthokeratology) contact lens is a rigid gas permeable contact lens in a reverse geometry design. The lens material siflufocon A, is a fluoro silicone acrylate polymer which contains D & C Green #6 as a color additive. The CONTEX OK™ (orthokeratology) contact lens has the following dimensions: Chord Diameter................Approximately 6.5 to 13.0 mm Center Thickness for Low Minus Lens..................................0.10 to 0.30 mm for Plus Lens:........................................0.20 to 0.70 mm Base Curve........................................6.50 to 11.00 mm Secondary Curves........................ 0.1 to 2 mm. Flatter or Steeper than Base Curve Peripheral Curves........................ 0.1 to 2 mm. Flatter or Steeper than Base Curve Powers........................................-10.00 to +5.00 Diopters Aspheric Lens Eccentricity ................................................................................................................................................... (Oblate, Prolate or Tangent Conic) The physical properties of the lens are: Refractive Index...... 1.43 (Nd at 25°) Light Transmittance... > 92.5% (370-760 nm) Wetting Angle ... 24.0 (Contact Receding Angle) Specific Gravity.... 1.25 Hardness.... 82 Water Content...
This document describes an orthokeratology contact lens (CONTEX OK™) intended for the temporary reduction of myopia. Below is an analysis of its acceptance criteria and the study performed.
1. Table of Acceptance Criteria (Implied) and Reported Device Performance
The acceptance criteria are implied through the intended use and the clinical study results, as no explicit numerical acceptance targets are stated. The device is shown to be effective if it can achieve a temporary reduction in myopic refractive error.
| Acceptance Criteria (Implied from Intended Use) | Reported Device Performance |
|---|---|
| Safety: Minimal adverse reactions and slit-lamp findings. | Adverse Reactions: No eyes experienced adverse reactions, slit-lamp findings requiring treatment, or symptoms/problems/complaints requiring treatment. |
| Slit-Lamp Findings: 188 reports of Grade 1 findings (6 edema, 108 staining, 24 injection, 50 tarsal abnormality). No Grade 2 or higher findings. Findings reduced in incidence over time. | |
| Symptoms/Complaints: 425 reports, largest being blur following lens wear (20.2%) and variable vision (17.2%) due to corneal changes; other complaints consistent with RGP lenses. | |
| Effectiveness: Temporary reduction of myopic refractive error up to 3.00 diopters. | Refractive Power Reduction: |
- Average reduction: 1.69 diopters (range 0.25 to 4.25 D).
- 32% of eyes had 0.25-1.00 D reduction.
- 32% of eyes had 1.25-2.00 D reduction.
- 23% of eyes had 2.25-3.00 D reduction.
- 9% of eyes had 3.25-4.00 D reduction.
- 1% of eyes had 4.25 D reduction.
- 106 out of 110 eyes showed some reduction.
- Limit for full reduction to emmetropia: -3.50 diopters.
- For initial myopia >3.75D, average reduction was 2.75D. |
| Visual Acuity Improvement: | Uncorrected Visual Acuity (Final Visit): - 39% of eyes achieved 20/20 or better.
- 71% of eyes achieved 20/40 or better.
Visual Acuity with contact lenses (Final Visit): - 99 eyes (90%) 20/20 or better
- 109 eyes (99%) 20/40 or better
- 1 eye 20/70.
- Some eyes experienced 1-3 line drops in visual acuity, attributed to residual astigmatism. |
| Corneal Flattening (Keratometry): | Keratometry: - 89% of eye meridians flattened.
- Average flattening: 1.17 diopters.
- Greatest flattening: 4.13 diopters.
- Corneal astigmatism change: 8% no change, 32% decrease 1D. |
2. Sample Size Used for the Test Set and the Data Provenance
- Sample Size (Test Set): 138 eyes were initially enrolled, with 136 eyes dispensed contact lenses. 110 eyes completed a minimum of three months of contact lens wear. The performance data is generally reported on these 110 eyes that completed the study.
- Data Provenance: The document does not explicitly state the country of origin. It describes a "Preclinical Studies: Described in the original 510 (k) submission K941883" and "Clinical Studies" for the K9736097 submission, suggesting the data is part of the regulatory submission for the United States. The study appears to be prospective clinical trial, observing patients over a three-month period.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
The document does not provide information on the number or qualifications of experts used to establish a ground truth for the test set. Clinical studies concerning contact lenses typically rely on measurements taken by trained optometrists or ophthalmologists, but this information is not detailed here.
4. Adjudication Method for the Test Set
The document does not describe any specific adjudication method (e.g., 2+1, 3+1, none) for the test set data. Clinical measurements were likely taken by the participating clinicians.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This study is a clinical trial evaluating the safety and effectiveness of a medical device (contact lens) in patients, rather than an AI-assisted diagnostic tool.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done
No, a standalone (algorithm only) performance study was not done. This product is a physical medical device (contact lens), not an algorithm or AI system.
7. The Type of Ground Truth Used
The "ground truth" for evaluating the contact lens's performance was based on direct clinical measurements and observations of the patients using the device, including:
- Refractive Power: Measured reduction in myopic refractive error (diopters).
- Visual Acuity: Measured visual acuity (e.g., 20/20, 20/40).
- Keratometry: Measured changes in corneal flattening (diopters).
- Slit-Lamp Findings: Direct observation of ocular health.
- Adverse Events/Symptoms/Complaints: Patient reported and clinically observed adverse effects.
8. The Sample Size for the Training Set
This product is a physical medical device (contact lens), not an AI algorithm. Therefore, there is no "training set" in the context of machine learning. The clinical study enrolled 138 eyes, with 110 eyes completing three months of wear. This would be considered the sample for evaluating the device's performance.
9. How the Ground Truth for the Training Set Was Established
As this is not an AI algorithm, there is no "training set" or "ground truth" for a training set in the machine learning sense. The clinical data collected from the 110 eyes that completed the study served as the evidence for safety and effectiveness.
§ 886.5916 Rigid gas permeable contact lens.
(a)
Identification. A rigid gas permeable contact lens is a device intended to be worn directly against the cornea of the eye to correct vision conditions. The device is made of various materials, such as cellulose acetate butyrate, polyacrylate-silicone, or silicone elastomers, whose main polymer molecules generally do not absorb or attract water.(b)
Classification. (1) Class II if the device is intended for daily wear only.(2) Class III if the device is intended for extended wear.
(c)
Date PMA or notice of completion of a PDP is required. As of May 28, 1976, an approval under section 515 of the act is required before a device described in paragraph (b)(2) of this section may be commercially distributed. See § 886.3.