1. BLOC 5: ASTIGMATIC LENSES Subject 11.- Sphero-cylindrical Formula. Subject 12.- Sphero-cylindrical formula and the lens- meter. Subject 13.- Transposition Rule. Subject 14.- Astigmatic lens parameters. Subject 15.- Relation of parameters in astigmatic lenses.

2. Subject 11: Spherocylindrical Formula. Sphero-cylindrical Combination Astigmatic Lens and optical crosses (power diagram). Optical Cross and relation with the surfaces of the spherical-toric lens. Optical Cross and relation with the surfaces of the spherical-cylindrical lens. Spherical-Cylindrical Formula.

3. Sphere Cylinder Combination.

4. Astigmatic Lens and optical cross diagram Indicates the power for each meridian of the lens.

5. Relation of the Optical Cross and the surfaces of a spherotoric lens

6. *Relation of the Optical Cross and the surfaces of a spherocylindrical lens.

7. Optical Cross (examples)

8. REPRESENTATION OF THE SPHEROCYLINDRICAL FORMULA Spherocylindrical Formula SPHERE CYLINDER AXIS e c x  o CYLINDER AXIS SPHERE  o x c e

9. Spherocylinder Formula Pe=+5D Pb=-2D Pc=-4D e=+5+(-2)=+3D c=-2-0=-2D AXIS CYLINDER SPHERE 90º -2 +3