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简介 rb"J{^ ,".1![b 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。 3`%]3qd} 4=BIYC"Lu 模型 PV[Bq t fV b~j ; 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。 _6y#?8RMB 8dgi"/[3 Table 1. AZ眼睛模型的定义 0Nvk|uI
V[ 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. Ol%KXq[ uq.!{3)8 光源 K{]9Yo !
MTmG/^ 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。 [&Yrnkgr Y@jO#6R ~Ox !7Lp 图1. 光源和提示信息使用 .paKV"LJ 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。 n(#| 3FD6.X>x 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。 r |H 1Yy <$" 图2. 字母F光源的设定方法光 y'$Re -a=RCzX] 图3. 字母F在视网膜上位置点列图 wFe?0u 视网膜的散射 8@$`'h^6 z CS.P.$ 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。 #N?VbDK9_ E.Vlz^B jpGZ&L7i& 图4. 视网膜朗伯散射设定 *n"{] tj^> 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。 -nHt6AbqP >8v4fk
IK yH9(ru 图5. 视网膜重点采样规格设定 3xhGmD\SKO 脚本 jTeHI|b O`M6=\ 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: rEoMj)~\4& // k`X 图6. 用户对话框的创建与编辑 5YZh e4R 图7. 用户对话框编辑器 l;~b:[r 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。 xWiR7~E 余下的脚本计算与屈光度有关的所有参数。 NFsCq_f L?Fb} 分析 eBZ94rA] io[>`@= 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 !l(O$T9T _HAtTW 图7. 字母F在视网膜上颜色分析 -eQ>3x&3r 脚本代码 ^uV=|1<% }wIF$v?M Option Explicit 'Remove this to enable non-dimensioned variables to be used. hy]8t1894 "hbCP4 Dim entity As T_ENTITY X21k7 Ls Dim op As T_OPERATION "9^OT Dim mat As T_MODELMATERIAL ~LfFLC Dim A As Double G`oY(2U Dim pupilDiam As Double ZL7#44 Dim eID As Long +$;#bw)yH Dim parID As Long Q2)CbHSz Dim count As Integer 6)h~9iK Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double qlNB\~HCe Dim tlens As Double, nlens As Double >7$h Dim curv As Double, conic As Double "n, %Hh Dim ok As Long W6A-/;S\ 1_B;r9x Sub Main _kZ&t_] a
!yBEpMo '用户输入对话框 EJid@ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 !^x;4@Ejm TextBox 220,21,40,21,.TextBox1 'default: 0 1)BIh~1{p Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 INRP@Cp1 OKButton 40,91,90,21 J?$`Tnx^ CancelButton 190,91,90,21 J5zKwt Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ev[!:*6P TextBox 220,49,40,21,.TextBox2 'default: 4 ml1My1 End Dialog
B;A< pNT Dim dlg As UserDialog u$Wv*;TT% dsG:DS`q ok = Dialog (dlg) +Y_]< uE ^uP@d If ok=0 Then 'cancel button was pressed *v:o`{vM[ Print "Execution cancelled." f{w[H S,z End @#>YU End If peZ'sZ 6 *JA0Vs5 'Assign accommodation and pupil diameter & use defaults if field left empty G@4n]c_ If dlg.TextBox1 = "" Then )~{8C: A = 0 'Default accommodation er0y~ Else vWZ?*0^ A = CDbl(dlg.TextBox1) (v0i]1ly[ End If y;VmA#k` w?JM;'<AYQ If dlg.TextBox2 = "" Then y6P-:f/&* pupilDiam = 4 'Default pupil diameter WxJV
zHtR Else U}<' [o
V pupilDiam = CDbl(dlg.TextBox2) [l*;+N+ End If (r-8*)Qh8 vVFT0_ Print " " IWT
-)+ Print "Accommodation = " & A & " Diopters"
D}/nE>* Print "Pupil Diameter = " & pupilDiam & " mm" n%d7`?tm4 S^7u`- ' Calculate new parameters with accommodation THcX.%ToT taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 1UN$eb7 >f:OU," Rant = 12.0 - 0.4*A 'Radius of anterior lens .F]"%RK[ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens qpX`ZY^ l}XnCOIT, Rpost = -5.224557 + 0.2*A 'Radius of posterior lens eEX* \1Gg CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens IQyw>_~] ;0nL1R]w( tlens = 3.767 + 0.04*A 'Lens thickness o(@^V!}V =p \eh?^ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction t $u. `##^@N<P 'Adjust parameters to account for accommodation uX8G<7O^ )E}eK-Yu '************************************************************************* ,h},jkY4 'Aqueous thickness (Position of Lens) roNs~]6 '************************************************************************* @ 5V3I^ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) wF)g@cw GetCustomElement eID, entity 7xfN}iHG ?Vc/mO2X parID = FindFullName( "Geometry.Arizona Eye" ) J8@7
5p9 Wo,fHY ' Delete any shift(s) in z -f=4\3y3p count = 0 6G;t:[H G While GetOperationCount(eID)>count 4=ZN4=(_[ GetOperation eID, count, op N3&n"w _d If op.Type="ShiftZ" Then Z#flu Q%V DeleteOperation eID,count 8RJa;JsH count=count-1 _MzdbUb5, End If wQrD(Dv(yA count=count+1 f=Kt[|%'e Wend 43/!pW DX<xkS[P 'Set new shift in vve[.Lud' op.Type = "ShiftZ" 1zIrU6H2;_ op.val1 = taq ke5_lr( op.parent = parID vf
h*`G$ AddOperation eID, op Z]k+dJ[- Print "Set aqueous humor thickness = " & taq-0.55 Dlx-mm_ r95$( N '************************************************************************* 3NlG,e'T2 'Radius and conic constant of anterior lens G~19Vv*; '************************************************************************* y9-}LET3j
eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ~.<}/GP] _ GetConic eID, entity, curv, conic b)+;@wa~ l1D"*J 2` SetConic eID, entity, 1/Rant, CCant {>zQW{! Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 3R[,,WAj$ Ku;8Mx{ '************************************************************************* y*5$B.u`. 'Radius and conic constant of posterior lens ka[%p, H '************************************************************************* ZN-5W|' O eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) y3NMt6 GetConic eID, entity, curv, conic hG>3y\!# %^<A`Q_ SetConic eID, entity, 1/Rpost, CCpost uz@WW!+o Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost GFO(O U?yKwH^{ '************************************************************************* "(^1Dm$( 'Lens thickness (Position of posterior lens surface) =f-.aq(G/ '************************************************************************* mx")cGGQ KI8Q
=* parID = FindFullName( "Geometry.Arizona Eye.Lens" ) uJ>_
2 f*GdHUZ* ' Delete any z-shift(s) q@&.)sLPgO count = 0 ,?>:Cdz4 While GetOperationCount(eID)>count *Q:EICDE7 GetOperation eID, count, op GeCyq%dN If op.Type="ShiftZ" Then A]mXV4RmI DeleteOperation eID,count 2a[_^v $v count=count-1 p/%B>Y> End If pk:2>sx/ count=count+1 o _DZ Wend xN]88L}Tn zFGZ;?i 'Set new z-shift 6$"0!fl> op.Type = "ShiftZ" 09C[B+>h op.val1 = tlens ]Qb85;0) op.parent = parID yct^AN|% AddOperation eID, op .~fAcc{Qj Print "Set lens thickness = " & tlens @(Y+W2Iyy+ kpt0spp '************************************************************************* SSG}'W!z 'Lens index of refraction c=A)_ZFg '************************************************************************* VLfE3i4Vwl eID = FindMaterial( "Lens" ) 6=xbi{m$ GetModelMaterial eID, mat }Qo:;&"3 iv]*HE mat.Nd = nlens *Mr?}_,X* SetModelMaterial eID, mat ,6FmU$
Kn Print "Set lens index of refraction = " & nlens 8I*WVa$l ??.9`3CYo '************************************************************************* Ib665H7w 'Pupil diameter `VxfAV?} '************************************************************************* h(VF eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) FtL{f=
%T:7I[f 'Adjust pupil diameter (trimming volume inner hole) |6}:n,KA. $Q!J.}P@ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" fooQqWC) zIjUfgO/M ' Adjust pupil location to just in front of the lens 235wl parID = FindFullName( "Geometry.Arizona Eye" ) V`MV_zA2 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) #aV2+ `d count = 0 a;$'A[hq While GetOperationCount(eID)>count MGzuQrl{H GetOperation eID, count, op [$b\#{shtP If op.Type="ShiftZ" Then y8.(filNB DeleteOperation eID,count BXf.^s{H count=count-1 >9v?p= End If (ON_(MN
count=count+1 ,wvzY7% Wend LVj62&,- op.Type = "ShiftZ" jS,zdJs= op.val1 = taq-0.01 .g6DKjy> op.parent = parID k TLA["<m AddOperation eID, op 6s"Erq5q 'F665 Print "Set pupil diameter = " & pupilDiam ADa'(#+6 O]Mz1 ev| 'Update AZ Eye subassembly Description 5c~OG6COx eID = FindFullName( "Geometry.Arizona Eye" ) v9[[T6t/' GetEntity eID, entity bl)iji`] entity.Description = "Accommodation = " & A & "D" !MiH^wP SetEntity eID, entity K&WNtk3hT J0hY~B~X Update H8}}R~ZO Print "DONE!" ,^_aqH )!!xvyc End Sub z!={d1u#T *qLOr6 如果屈光度是4,光瞳直径是4,则会输出如下数据: %7$oig\wE 'e(`2 Accommodation = 4 Diopters Tmo+I4qoL Pupil Diameter = 4 mm mne=9/sE" Set aqueous humor thickness = 2.81 2_4m}T3 Set anterior lens radius = 10.4 and conic constant = -2.375869 cQaEh1n Set posterior lens radius = -4.424557 and conic constant = -3.081019 DfCo= Set lens thickness = 3.927 sH>Z{xjr Set lens index of refraction = 1.42672 H...!c1M@ Set pupil diameter = 4 +=y ktf DONE! T&2aNkuG Wkk=x& U 6y
;V QQ:2987619807 B(GcPDj(K
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