(66 days)
BOSTON XO® (hexafocon A) Contact Lenses are indicated for daily wear for the correction of refractive ametropia (myopia, hyperopia, astigmatism and presbyopia) in aphakic persons with non-diseased eyes. Also, the lenses may be prescribed in otherwise non-diseased eyes that require a rigid contact lens for the management of irregular corneal conditions such as keratoconus, pellucid marginal degeneration, or following penetrating keratoplasty or refractive (e.g. LASIK surgery). Furthermore, eyes suffering from certain ocular surface disorders may benefit from the physical protection, aqueous hydrated environment and the saline bath provided by scleral lens designs. Boston XO Scleral Lens designs for daily wear are indicated for therapeutic use for the management of irregular and distorted corneal surfaces where the subject: 1. cannot be adequately corrected with spectacle lenses 2. requires a rigid gas permeable contact lens surface to improve vision 3. is unable to wear a corneal rigid gas permeable lens due to corneal distortion or surface irregularities Common causes of corneal distortion include but are not limited to corneal infections as a result of scar formation secondary to refractive surgery (e.g. LASIK or radial keratotomy) or corneal transplantation. Causes may also include corneal degeneration (e.g. keratoglobus, pellucid marginal degeneration, Salzmann's nodular degeneration) and corneal dystrophy (e.g., lattice dystrophy, granular corneal dystrophy, Reis-Bucklers dystrophy, Cogan's dystrophy). The Boston XO Scleral Lens designs for daily wear are also indicated for therapeutic use in eyes with ocular surface disease (e.g. ocular Graft-versus-Host disease, Sjögren's syndrome, dry eye syndrome and Filamentary Keratitis), limbal stem cell deficiency (e.g. Stevens-Johnson syndrome, chemical radiation and thermal burns), disorders of the skin (e.g. atopy, ectodermal dysplasia), neurotrophic keratitis (e.g. Herpes zoster, Familial Dysautonomia), and corneal exposure (e.g. anatomic, paralytic) that might benefit from the presence of an expanded tear reservoir and protection against an adverse environment. When prescribed for therapeutic use for a distorted cornea or ocular surface disease, the Boston Scleral Lenses may concurrently provide correction of refractive error. The lenses may be disinfected using a chemical disinfection (not heat) system only.
BOSTON XO2® (hexafocon B) Contact Lenses are indicated for daily wear for the correction of refractive ametropia (myopia, hyperopia, astigmatism and presbyopia) in aphakic persons with non-diseased eyes. Also, the lenses may be prescribed in otherwise non-diseased eyes that require a rigid contact lens for the management of irregular corneal conditions such as keratoconus, pellucid marginal degeneration, or following penetrating keratoplasty or refractive (e.g. LASIK surgery). BOSTON XO2 Contact Lenses are also indicated for daily wear in an orthokeratology fitting program for the temporary reduction of myopia of up to 5.00 diopters in non-diseased eyes. Note: To maintain the orthokeratology effect of myopia reduction, lens wear must be continued on a prescribed wearing schedule. Furthermore, eyes suffering from certain ocular surface disorders may benefit from the physical protection, aqueous hydrated environment and the saline bath provided by scleral lens designs. Boston XO2 Scleral Contact Lens designs for daily wear are indicated for therapeutic use for the management of irregular and distorted corneal surfaces where the subject: 1. cannot be adequately corrected with spectacle lenses 2. requires a rigid gas permeable contact lens surface to improve vision 3. is unable to wear a corneal rigid gas permeable lens due to corneal distortion or surface irregularities Common causes of corneal distortion include but are not limited to corneal infections, trauma, tractions as a result of scar formation secondary to refractive surgery (e.g. LASIK or radial keratotomy) or corneal transplantation. Causes may also include corneal degeneration (e.g. keratoglobus, pellucid marginal degeneration, Salzmann's nodular degeneration) and corneal dystrophy (e.g., lattice dystrophy, granular corneal dystrophy, Reis-Bucklers dystrophy, Cogan's dystrophy). The Boston XO2 Scleral Lens designs for daily wear are also indicated for therapeutic use in eyes with ocular surface disease (e.g. ocular Graft-versus-Host disease, Sjögren's syndrome and Filamentary Keratitis), limbal stem cell deficiency (e.g. Stevens-Johnson syndrome, chemical radiation and thermal burns), disorders of the skin (e.g. atopy, ectodermal dysplasia), neurotrophic keratitis (e.g. Herpes zoster, Familial Dysautonomia), and corneal exposure (e.g. anatomic, paralytic) that might benefit from the presence of an expanded tear reservoir and protection against an adverse environment. When prescribed for therapeutic use for a distorted cornea or ocular surface disease, the Boston Scleral Lenses may concurrently provide correction of refractive error. The lenses may be disinfected using a chemical disinfection (not heat) system only.
The Boston XO and Boston XO2 Rigid Gas Permeable (RGP) Contact Lenses are fluoro silicone acrylate copolymer rigid gas permeable contact lenses available in a variety of tints and may contain an ultraviolet light absorber. The hemispherical shells are available in several lens designs including spherical, aspherical, toric, scleral and irregular cornea designs.
The provided document is a 510(k) summary for the BOSTON XO®/XO2® Rigid Gas Permeable Contact Lenses. It outlines the indications for use and compares the device to predicate devices to demonstrate substantial equivalence, rather than detailing a study proving the device meets specific acceptance criteria with explicit performance metrics.
Therefore, many of the requested details about acceptance criteria, study design, sample sizes, ground truth establishment, and expert involvement are not present in this type of regulatory document.
However, based on the information provided, here's what can be extracted:
Acceptance Criteria and Device Performance
The document does not explicitly state numerical acceptance criteria for performance or a study proving those criteria are met. Instead, it relies on demonstrating substantial equivalence to already approved predicate devices. The "performance" in this context refers to the physical and chemical properties of the lens materials.
The table below summarizes the physical comparison of the subject device (Boston XO & XO2 Scleral Lens) to predicate devices (BostonSight PD Prosthetic Device and Boston Scleral Lens). The acceptance criteria implicitly are that these properties are comparable to legally marketed predicate devices, and that the expanded indications for use for scleral lenses do not introduce new questions of safety or effectiveness.
| Feature | Boston XO (hexafocon A) - Reported Performance | Boston XO2 (hexafocon B) - Reported Performance | Predicate Device (oprifocon A) - BostonSight PD Prosthetic Device | Predicate Device (oprifocon A) - Boston Scleral Lens |
|---|---|---|---|---|
| Refractive Index | 1.415 | 1.424 | 1.423 | 1.423 |
| Specific Gravity | 1.27 | 1.19 | 1.24 | 1.24 |
| Wetting Angle | 49° | 38° | 56° | 56° |
| Hardness | 81 | 78 | 81 | 81 |
| Modulus | 1500 Mpa | 1160 Mpa | 1300 Mpa | 1300 Mpa |
| Visible Light Transmittance | > 92% | > 95% | > 95% | > 95% |
| Water Content |
§ 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.