1. Reporter: 曾千芳 Date:2011/12/15 Optical Models of Eye 1

2. 大綱 Introduction Method(cornea/lens)  aspheric surface  Index of refraction Schematic eye models Model the human eye in ZEMAX 2

3. Introduction Develop a model eye that 1.Represent the ocular anatomy as closely as possible. 2.Presdicts spherical and chromatic aberrations as close to empirical as possible. 3

4. Method Schematic drawing of the new schematic eye Surface1:air-cornea. Surface2:cornea-anterior chamber. Surface3:anterior chamber-lens. (pupil aperture decentered 0.5mm) Surface 4:imaginary plane dividing the lens into anterior and posterior sections. Surface5:lens-viterous 小窩 : 感知視覺 4

5. Cornea/Lens To describing an aspheric surface. A common method is to use a conicoid in the form: R: the radius at the apex ; Q:asphericity parameter(specifies the type of conicoid); Cornea: 5

6. Index of refraction -lens 6

7. Schematic eye models 7

8. Model the human eye in ZEMAX 8 Setup the surface EX: Surface1(cornea) Surf:Type = Standard Comment = Cornea Radius = 7.77 Thickness = 0.55 Glass = Model; 1.376 Semi-Diameter = 5.00 Conic = -0.18 Surfance3 (lens front) Surf:Type = Gradient 3 Comment = Lens-front Radius = 12.4 Thickness = 1.59 Semi-Diameter = 5.00 n0 = 1.368 Nr2 = -1.978E-003 Nz1 = 0.049057 Nz2 = -0.015427

9. Discussion The anatomical accuracy of a schematic eye is very important for the purpose of modeling vision in refractive procedures. A lens with a gradient-index (GRIN) structure was introduced in this new model to represent the anatomical structure of the human crystalline lens. Most previous finite schematic eyes either had aspheric refracting surfaces and a homogeneous lens or a GRIN lens structure with spherical surfaces but not both. Effect to Aberration: posterior corneal aspheric surface, modification of the parameters of GRIN lens…etc. 9

10. Future work 10 The present model does not yet account for changes with age or individual variability. Further research on the changes of ocular biometry with age is required for incorporation of this factor into the eye model.