Calculator
Prism calculator
Say where the optical centre sits relative to the pupil. The exam method uses Prentice's rule in the 180 and 90 meridians; exact optics uses the full power matrix.
Lens and optical centre
Prism at the pupil
- Horizontal
- 1.20Δ BO
- Vertical
- None
- Resultant
- 1.20Δ at 180.0°
- 180 meridian: +4.00 D × 3 mm ÷ 10 = 1.20Δ BO
- 90 meridian: +4.00 D × 0 mm ÷ 10 = None
- Horizontal
- 1.20Δ BO
- Vertical
- None
- Resultant
- 1.20Δ at 180.0°
Power matrix P = −F·r.