The Process
The VST® process temporarily reduces myopia by changing the shape (flattening) of the cornea, which is elastic in nature.
The Product
Regular contact lenses are designed to have little or no effect on the cornea—but Boston® Orthokeratology (oprifocon A) shaping lenses are designed to purposely flatten the shape of the cornea by applying slight pressure to the center of the cornea when the patient is asleep.
After the lens is removed, the cornea retains its altered shape for most or all of the wearer’s waking hours. The lenses are designed to be worn overnight, with removal during the following day.
Key Features & Benefits
- Works for a wide range of patients, including low to moderate myopes (-1.00D to -5.00D) and low astigmats (up to -1.50D cylinder)
- Delivers device-free visual acuity
Disinfection Methods
Boston® Care Systems
How It Works
Interested in fitting a Vision Shaping Treatment VST(R) lens design? Watch this training video.
Design
| Indications | Myopia |
| Modality | Overnight wear |
| Lens Material | Boston® Equalens® II |
| Chord Diameter | 9.6 mm to 11.6 mm |
| Base Curve Range | 7.30 mm to 10.15 mm |
| Center Thickness | For low minus lens 0.20 mm to 0.32 mm, for plus lenses 0.20 mm to 0.32 mm |
| Reverse Curve | 5.0 mm to 9.0 mm. Steeper than the base curve in proportion to the amount of correction |
| Alignment Curve 1 | 7.0 mm to 9.0 mm. Steeper than the base curve, but flatter than the Reverse curve. Generally equal to the Flat K of the cornea being fit |
| Alignment Curve 2 | 7.25 mm to 9.25 mm. Steeper than the base curve, but flatter than AC1 and reverse curve |
| Peripheral Curves | 9.00 mm to 15.00 mm |
| Back Vertex Power | +1.50 to –5.00 Diopters |
| Specific Gravity | 1.24 |
| Refractive Index | 1.423 |
| Light Absorbance | Blue (640 nm) 10.0, Green (640 nm) 4.8, Yellow (420 nm) 10.3, Red (525 nm) 2.5 |
| Wetting Angle | 30° by captive bubble |
| Water Content | <1% |
| Oxygen Permeability | 127 (gas to gas method), 85 (polarographic method ISO/Fatt) |
| Tint | Blue, green, red, or yellow |
| UV Absorber* | Yes |
*UV-absorbing contact lenses are NOT substitutes for protective UV-absorbing eyewear such as UV-absorbing goggles or sunglasses. Persons should continue to use their protective UV-absorbing eyewear as directed.
Discover more about available VST® designs
BE Retainer®, Contex® OK®, DreamLens®, Forge Ortho-K, MesaGrande, MiracLens, MoonLens®, Orthofocus™, REMLens®, Vipok® and WAVE NightLens® are brand names of the respective owners, used by permission.