Optical characteristics of contact lens 1. Thick Lens Optics F = F1 + F2-(t / n) F1F2 The key refractive power of a contact lens depends on FOZR(front optical zone radius of curvature). 2. Vertex distance effect F = Fs / (1-dFs) s = spectacle diopter 3. Tear lens LL = BC-K LL = tear lens BC = Base Curve K = corneal front surface curvature 4. ORv + CLP + LL = SRv 5. Magnification vs. spectacle Think magnification change of myopia and hyperopia with contact lens? 6. Accommodation and convergence Minus lens more than spectacle Positive lens less than spectacle A=1/s(1-2dP) 7. Others More >