Arizona眼睛模型

?w+ V: D   人眼光学模型可用来设计眼科用设备，光学系统注定了要与人眼一起使用。本文演示了这样一个模型：Arizona眼睛模型，在Jim Schwiegerling教授的书中有详细描述：《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源，并包括一个基于想要的屈光度来调整模型的内嵌脚本。 hGkJ$QT   5'c#pm\Q   模型 }opw_h+/F   le]~Cy0   模型的定义如表1种所示，由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度（A）来决定。 SiUu**zC   Table 1. AZ眼睛模型的定义 P#7=h:.522   - Z`RKR8C   在FRED中使用0屈光度来创建的，光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. ypyKRsx   #=={h?UDT   光源 pQKSPr   "i\#L`TkzX   多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 MM_:2 ^P)   _bi)d201   图1. 光源和提示信息使用 0~z\WSo   @0 /qP<E   除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处，并增加了pre-propagation distance= -8。尽管光线在光瞳处创建，规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射，而不是在光瞳处入射。 |/vJ+aKq   E^zfI9R   在往下看是内置的脚本用来修改屈光度，使其为4（250mm），光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 c(e>Rmh   图2. 字母F光源的设定方法光 U2A 82;Z   y ;uR@{   图3. 字母F在视网膜上位置点列图 8'HS$J;C   F,{mF2U*$   视网膜的散射 [IQ|c?DxpL   0'fswa)   在散射文件中，有一个名为“Retina surface”的72%的反射型朗伯散射，它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射，改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 f+Sb>$   2Jio_Hk   图4. 视网膜朗伯散射设定 Cf3!Ud   o]Rlivahm   注意在视网膜的表面有散射重点采样规格定义，在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳，半角度10度。 "GZieI D   2h'Wu qO   图5. 视网膜重点采样规格设定 Iz5NA0[=2   > :IWRc2   脚本 p.SipQ.P   o[T+/Ej&   内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框，如下图所示： n+Kv^Y`qxO   图6. 用户对话框的创建与编辑 {PcJuRTHB   图7. 用户对话框编辑器 8&)v%TX   +ti ?7|bK<   如果“OK”按钮按下，将会核对对话框下面的代码行，如果点击取消则脚本终止。然后输入的参数赋予变量，如果此处是保留为空白，则使用默认值。因此，如果没有值输入并点击“OK”按钮，则脚本是以屈光度为0，光瞳直径为4mm来运行的。 7l=;I%   余下的脚本计算与屈光度有关的所有参数。 <aJQV)]\   wOl?(w=|   分析 +t+<?M B   q.VYPkEib   屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 u]};QR   图7. 字母F在视网膜上颜色分析 AO$AT_s   K"H\gmV_g   脚本代码 6t6Z&0$h~   by X!,   Option Explicit     'Remove this to enable non-dimensioned variables to be used. FT@uZWgQ=   ^taN?5   Dim entity As T_ENTITY ~lys   Dim op As T_OPERATION S3E,0%yo+)   Dim mat As T_MODELMATERIAL "y,YC M`   Dim A As Double 3}0\W.jH   Dim pupilDiam As Double G @..?>   Dim eID As Long Ki\.w~Qs   Dim parID As Long ,erf{"Nh   Dim count As Integer (~=.[Y   Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double #]kjyT0   Dim tlens As Double, nlens As Double HYmC3   Dim curv As Double, conic As Double h_vT A   Dim ok As Long a>'ez0C   ?m |}}a   Sub Main :"\,iH   l@4_D;b3o"       '用户输入对话框 sUZA!sv       Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 I6W`y h`I)           TextBox 220,21,40,21,.TextBox1 'default: 0 _\ToA9m           Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 9CY{}g           OKButton 40,91,90,21 V&M*,#(?           CancelButton 190,91,90,21 &9p!J(C           Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 /o9T [^\           TextBox 220,49,40,21,.TextBox2 'default: 4 .$qa?$@       End Dialog |h>PUt@LL       Dim dlg As UserDialog 4wl1hp>,   5ilGWkb`'X       ok = Dialog (dlg) &AQqI   z)qYW6o%       If ok=0 Then    'cancel button was pressed 1F^Q*t{           Print "Execution cancelled." q@|+`>h           End Fb5U@X/vE       End If I&;>(@K   ,,'jyqD       'Assign accommodation and pupil diameter & use defaults if field left empty I0Pw~Jj{       If dlg.TextBox1 = "" Then ~s!Q0G^G           A = 0           'Default accommodation SS=<\q#MS       Else .+9hm|           A = CDbl(dlg.TextBox1) Dqx#i-L23       End If SB_Tzp   tIsWPt]Y       If dlg.TextBox2 = "" Then `8:)? 0Ez           pupilDiam = 4   'Default pupil diameter LKIMT       Else liKlc]oM           pupilDiam = CDbl(dlg.TextBox2) :C~Ar]       End If PsY![CPrW   9u B?-.       Print " " pP. _%5       Print "Accommodation = " & A & " Diopters" Z'z)Oo       Print "Pupil Diameter = " & pupilDiam & " mm" QU"WpkO   ~MC|       ' Calculate new parameters with accommodation Kc/1LeAi k       taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness )dXa:h0RZ   RZOK+!H:       Rant = 12.0 - 0.4*A                     'Radius of anterior lens ;[v!#+yml       CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens {VgE07r   ALF0d|>=uj       Rpost = -5.224557 + 0.2*A               'Radius of posterior lens YG "Ta|@5       CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 51#*8u+L   jjs/6sSRk       tlens = 3.767 + 0.04*A                  'Lens thickness *c0H_8e   bz4Gzp'6k       nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 1^~&"s U   lSj gN~:z       'Adjust parameters to account for accommodation F^i3e31*t   "[bkdL<       '************************************************************************* ;FPx        'Aqueous thickness (Position of Lens) = tv70d'       '************************************************************************* i]JTKL{\q       eID = FindFullName( "Geometry.Arizona Eye.Lens" ) zTz}H*U       GetCustomElement eID, entity ewZ?+G+m   wu41Mz7       parID = FindFullName( "Geometry.Arizona Eye" ) 7 +O)AU{   p~pD`'%       ' Delete any shift(s) in z [);oj<       count = 0 D31X {dJ       While GetOperationCount(eID)>count H|9t5            GetOperation eID, count, op #8$?# dT           If op.Type="ShiftZ" Then ;Rrh$Ag               DeleteOperation eID,count IkrB}               count=count-1 eV;r /4           End If \Z-th,t           count=count+1 KkvcZs'4m       Wend ^_7|b[Bt   }K{1Bm@S       'Set new shift in O[@!1SKT0       op.Type = "ShiftZ" 9:j?Jvw$       op.val1 = taq ~#-?V[       op.parent = parID H4$qM_N       AddOperation eID, op })g<I+]Hf9       Print "Set aqueous humor thickness = " & taq-0.55 3Cf9'C   5cSiV7#Y:       '************************************************************************* X Xque-       'Radius and conic constant of anterior lens -IPo/?}       '************************************************************************* j-<]OOD       eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) y Zafq"o       GetConic eID, entity, curv, conic VtBC~?2U)B   ' \JE>#       SetConic eID, entity, 1/Rant, CCant )M0YX?5AR       Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant s :vNr@TS   p|>*M\LE#       '************************************************************************* p{f R$-d       'Radius and conic constant of posterior lens z7K{ ,y       '************************************************************************* 2d)Dhxzxk       eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) |'^s3i&w       GetConic eID, entity, curv, conic  Nx}nOm   _NDQ2O       SetConic eID, entity, 1/Rpost, CCpost A*JOp8\)       Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost J_Lmy7~xbD   q_MN       '************************************************************************* iw@rW5%'~       'Lens thickness (Position of posterior lens surface) %(CC       '************************************************************************* KVi6vdgD   rrD 6x>       parID = FindFullName( "Geometry.Arizona Eye.Lens" ) p`tz*ewC   1d^~KBfv       ' Delete any z-shift(s) "1O_h6C       count = 0 B#K gU&Loo       While GetOperationCount(eID)>count -hd           GetOperation eID, count, op m#"_x{oa           If op.Type="ShiftZ" Then Z@~gN5@,M               DeleteOperation eID,count FP@_V-               count=count-1 `3TR`,=           End If !:{Qbv&T           count=count+1 ak(s@@k       Wend eG=d)`.JaV   tUu' gs|       'Set new z-shift L&\W+k       op.Type = "ShiftZ" Yuv(4a<M%       op.val1 = tlens +a,SP        op.parent = parID pPReo)       AddOperation eID, op l`v5e"V       Print "Set lens thickness = " & tlens I?T !   inu.U[.       '************************************************************************* /s?%ft#-9o       'Lens index of refraction x39tnf/F       '*************************************************************************  ~OD6K`s3       eID = FindMaterial( "Lens" ) 7nt(Rtbsu       GetModelMaterial eID, mat 0h-NT\m   z)R kd0/X       mat.Nd = nlens Kz'GAm\       SetModelMaterial eID, mat ZCCCuB       Print "Set lens index of refraction = " & nlens c <TEA   R|?n       '************************************************************************* 5ibr1zs       'Pupil diameter ;>,B(Xz4i       '************************************************************************* +y| B"}x       eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 8mX!mYO3c   ko%mZ0Y       'Adjust pupil diameter (trimming volume inner hole) 01(U)F\   <bcf"0A       SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" *|&Y ,H?   fTxd8an{       ' Adjust pupil location to just in front of the lens [Rj4=qq=       parID = FindFullName( "Geometry.Arizona Eye" ) bTs2$81[       eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) c |0p'EQ       count = 0 &A: &2sP8       While GetOperationCount(eID)>count It*U"4 lgi           GetOperation eID, count, op ju2H0AQ           If op.Type="ShiftZ" Then rCJ$Pl9R               DeleteOperation eID,count yY]x''K               count=count-1 r^k+D<k[7           End If f2.=1)u.           count=count+1 FM]clC;X?       Wend b+Q{Z*       op.Type = "ShiftZ" 73q E!(       op.val1 = taq-0.01 %[XP}L$       op.parent = parID [3dGHf;miw       AddOperation eID, op m2SJ\1 J=   <?41-p-;       Print "Set pupil diameter = " & pupilDiam 1 |z4]R,<   4KH'S'eR       'Update AZ Eye subassembly Description ^"Bhp:o2       eID = FindFullName( "Geometry.Arizona Eye" ) r'noB<|e       GetEntity eID, entity O%%Q./oh       entity.Description = "Accommodation = " & A & "D"  65Z}Hf       SetEntity eID, entity QRQ{Bq}#   &D<6Go/)_*       Update &5}YTKe}|       Print "DONE!" >4g!ic~O        2K4Xu9-i:b   End Sub kB+$Kt<]L   {? Slo5X|   如果屈光度是4，光瞳直径是4，则会输出如下数据： SY95s   _J*l,]}S   Accommodation = 4 Diopters Aa-5k3:x]=   Pupil Diameter = 4 mm WOPIF~1v   Set aqueous humor thickness = 2.81 i59}6u_f   Set anterior lens radius = 10.4 and conic constant = -2.375869 F=5+JjrX   Set posterior lens radius = -4.424557 and conic constant = -3.081019 E2|M#Y   Set lens thickness = 3.927 =LGM[Z3$s   Set lens index of refraction = 1.42672 Vc0j)3   Set pupil diameter = 4 G/ si( LK   DONE!

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