1. PROGRESSIVE ADDITION LENS: OPTICS AND DESIGN SHRESTHA GS, M.Optom

3. RANGE OF CLEAR VISION Single vision Bifocal Progressive 0.33 0.50 1.00 2.00 5.00 NEAR INTERMEDIATE DISTANCE NEAR INTERMEDIATE DISTANCE NEAR INTERMEDIATE DISTANCE

5. What are progressive addition lens ?

6. Physiological Considerations Distance Intermediate Near Typical dioptric power (D) for clear viewing of objects

8. Binocular Vision Binocular vision: As the patient’s gaze is lowered for near objects, the eyes converge to maintain a single binocular image. The progressive lenses should ensure that this is maintained for different object distances from the eyes, as illustrated by the lines.

9. Peripheral (Extra-Foveal) Vision Peripheral vision: The PAL design should ensure that *objects in the periphery of the visual field are easily fused. **The distribution of prism in each lens should also be balanced for binocular viewing. ***Corresponding areas in the two lenses should provide a similar level of vision.

12. Why Use Progressive Lenses? Bifocal lens Progressive lens The bifocal lens (left) can disrupt the patient’s view with visual disturbances (arrows) when the eye crosses the boundary of the near seg. The progressive lens (right) has no such problem and enables a smooth transition between different reading distances.

13. PAL references

16. Progressive Lens Design - Optics Distance Zone Near Zone Umbilical line Intermediate Zone Lens Radius Changes Along Umbilical Line

19. Progressive Lens Design 2. Hard Vs Soft Lens Design Hard Soft

23. Width of Far V ision (+4mm): 0.5 [D]- 16.2 mm 1.0 [D]- Unlimited Max Cylinder [D]- Nasal: 1.5[D] Max Cylinder [D]- Temporal: 1.5 [D] Width of Corridor (-6mm): 1.0[D]- 9 mm Length of corridor: 14.2 mm Minimum fitting: 19 mm Width of near Vision (-18 mm): 1.0[D]- 21.63 mm Soft Design

29. Progressive Lens Design 3. Symmetrical Vs Asymmetrical Symmetrical PAL - same lens design is rotated to fit the other eye Asymmetrical PAL - each eye has a different lens

48. Computer lens 12 mm power transition zone Access uses a unique aspheric surface: Upper portion for mid-range distances Lower portion has reading Rx Power varies smoothly from top to bottom Mid-range Near

50. mc compared to Adult Progressive Lenses Addition Power Plot mc Myopia Control Standard Adult Progressive Short Corridor Adult Progressive

51. Eye tracking

52. R1 Far Zone Rn Progressive Zone R2 Near Zone Controlling the distortion is the key to the ultimate progressive lens Topographic Map Minimizing Distortions

53. The technology that enables us to design progressive lenses through an exact simulation of the natural human eye view. Eye Point Technology

54. The optical power is created by 3 parameters: thickness, index and curvatures The surface of the lens is scanned by a 3D measuring system, mapping the curvatures of the lens. Eye Point Technology

56. Visual Simulator

57. Panamic Panamic Rodenstock Life 2 Hoya GP Wide Zeiss Gradal Top Sola Max Analyzed by Rotlex Class I on a random lens Panorama Gold Comparison

58. Rodenstaik life II Sola Max Sola Max Panamic Rodenstock Life 2 Hoya GP Wide Zeiss Gradal Top Comparison

59. Comparison

60. Hoya GP Wide Hoya GP Wide Panamic Rodenstock Life 2 Zeiss Gradal Top Sola Max Zeiss gradal top Comparison

61. Thank you