Vision Shaping Treatment (VST) Process

The Bausch + Lomb Vision Shaping Treatment (VST) process produces a temporary reduction of myopia by changing the shape (flattening) of the cornea, which is elastic in nature. Regular contact lenses are designed to cause 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 all or most of one’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

How it works



Indications: myopia, astigmatism
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 0.20mm to 0.32mm, for plus lenses 0.20mm to 0.32mm
Reverse Curve: 5.0 to 9.0 mm. Steeper than the base curve in proportion to the amount of correction
Alignment Curve 1: 7.0 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 to 9.25 mm. Steeper than the base curve but flatter than AC1 and Reverse curve
Peripheral Curves: 9.00mm to 15.00mm
Back Vertex Power: +1.50 to –5.00 Diopters
Specific Gravity: 1.24
Refractive Index: 1.423
Light Absorbance: Blue (640nm) 10.0, Green (640nm) 4.8, Yellow (420nm) 10.3, Red (525nm) 2.5
Wetting Angle: 30° by captive bubble
Water Content: <1%
Oxygen Permeability: 127 (gas to gas method), 85 (polarographic methodISO/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.

Disinfection Methods

Boston Care Systems

Bausch + Lomb Vision Shaping Treatment (VST): Additional information

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