Spherical / aspheric corneal GP
Multiple labs
Manufacturer / labMultiple labs
Product / familySpherical corneal GP
DesignSingle-vision rigid corneal lens; spherical or aspheric back surface, tricurve/tetracurve periphery
Corrects / indicated forMyopia, hyperopia, regular astigmatism up to ~2.50 D, patients wanting sharpest optics or GP durability
MaterialBoston XO, Optimum Comfort, Paragon HDS 100, Menicon Z (lab choice)
Dk100 ×10⁻¹¹ (material)
Overall diameter8.8-10.2 mm
Optic zone7.0-8.5 mm
Centre thickness~0.12-0.18 mm (minus)
Power range±30.00 (lab range)
Wear scheduledaily wear (some materials FDA-approved for extended/overnight)
ReplacementEvery 1-2 years
Fitting approachDiagnostic fitting set; target an apical-clearance to light-touch alignment pattern on fluorescein, lens lag 1-2 mm on blink.
The optical benchmark, masks anterior corneal astigmatism with the tear lens. Boston XO / Optimum Comfort are the common mid-Dk choices; Menicon Z (Dk 163) for extended wear.
Verify parameters against current manufacturer documentation before fitting.