# K171404: BOSTON XO (hexafocon A), BOSTON XO2 (hexafocon B)

- Pathway: 510(k) (Traditional)
- Applicant: Bausch + Lomb, Incorporated
- Decided: Jul 17, 2017 after 66 days
- Product code: HQD (Lens, Contact (Other Material) - Daily)
- Device class: 2
- Regulation: 21 CFR 886.5916
- Recalls of this device: none
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 7 generations back to K943177 (1994). 19 ancestors in all.
14 later devices descend from it; 5 cite it directly.
0 of 34 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- P860022: Boston Equalens (Itaflurofocon a)/Equalens II (Oprifocon a) Rigid Gas Permeable Contact Lens, Bausch & Lomb (1987) Summary page 7.
- K161461: BostonSight PD Prosthetic Device, Bostonsight (2016) Summary page 7.

## Most influential descendants
- K180616: OPTIMUM GP (roflufocon D, roflurocon E) Daily Wear Contact Lens, HEXA100 (hexafocon A) Daily Wear Contact Lens (2018), 9 descendants of its own
- K212631: Optimum Infinite (tisilfocon A) Daily Wear Contact Lenses (2022), 7 descendants of its own
- K223394: Visionary Optics Scleral Contact Lens (roflufocon D, roflufocon E, hexafocon A, hexafocon B, tisilfocon A) (2022), 5 descendants of its own
- K183167: Boston ES (enflufocon A) Rigid Gas Permeable Contact Lens; Boston EO (enflufocon B) Rigid Gas Permeable Contact Lens; Boston XO (hexafocon A) Rigid Gas Permeable Contact Lens; Boston XO2 (hexafocon B) Rigid Gas Permeable Contact Lens (2019), 5 descendants of its own
- K233325: Visionary Optics Scleral Contact Lens (roflufocon D, roflufocon E, hexafocon A, hexafocon B, tisilfocon A, fluoroxyfocon A) (2024), 4 descendants of its own

## Indications for use
BOSTON XO® (hexafocon A) Contact Lenses are indicated for daily wear for the correction of refractive ametropia (myopia, hyperopia, astigmatism and presbyopia) in aphakic and non 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, 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. keratoconus, 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 simplex, 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 and non 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. keratoconus, 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, 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 simplex, 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.

Source page: https://510kreport.com/device/K171404
Methodology: https://510kreport.com/methodology