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简介 P".rm0@R 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。 ?/Z5%?6 _MUSXB' 模型 Br"K{g? Bet?]4\_ 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。 _(:bGI'.m lf2(h4[1R Table 1. AZ眼睛模型的定义 2Xp?O+b#"O 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. qjLFgsd h7>`:~ 光源 l~GcD ((]Sy,rdk 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。 ')j@OO3 );ZxKGjc4 b'G!)n 图1. 光源和提示信息使用 g}*F"k4j 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。 rs:a^W5t YRJw,xl 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。 v,,Dz8!Ty 7bx!A+, t 图2. 字母F光源的设定方法光 IHNl`\Le
$oH?7sj 图3. 字母F在视网膜上位置点列图 psE&Rx3) 视网膜的散射 Vw b6QIs NEX{vZkgw 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。 hdx"/.s mdukl!_x w:o,mzuXK 图4. 视网膜朗伯散射设定 @ykM98K 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。 ]"4\]_?r @ (LEuYq} ^Euqy,8} 图5. 视网膜重点采样规格设定 yX|0R
H 脚本 :LBRyBV 5<L+T 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: `'M}.q,k~ |fg{Fpc 图6. 用户对话框的创建与编辑 $${9 %qPzb 图7. 用户对话框编辑器 8yn}|Y9Fu 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。 jsnk*>j 余下的脚本计算与屈光度有关的所有参数。 W\J wEb9Y m8<l2O=m 分析 8iwqy0< A>W8^|l6+- 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 tu0agSpU ,xsFBNCC 图7. 字母F在视网膜上颜色分析 z\?cazQ 脚本代码 qx<h rC0Z& b)Dzau Option Explicit 'Remove this to enable non-dimensioned variables to be used. UFY_.N~ b6A]/290x Dim entity As T_ENTITY \1b! I)T9 Dim op As T_OPERATION tgB\;nbB Dim mat As T_MODELMATERIAL ;33LuD<h. Dim A As Double \w\{x0u Dim pupilDiam As Double o&b1-=MC2 Dim eID As Long x7l3&;yDv Dim parID As Long 1Ydym2 Dim count As Integer Y1Qg|U o Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double h#!u"'JW Dim tlens As Double, nlens As Double O+Q t8, Dim curv As Double, conic As Double LU4k/ Dim ok As Long Auz.wes XF 8$D Sub Main KZ;Q7 1 yDW$v/j.| '用户输入对话框 7BDRA},o Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 jLu`DKB TextBox 220,21,40,21,.TextBox1 'default: 0 4tv}V:EO Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ME%W,B.|"s OKButton 40,91,90,21 `$odxo+ CancelButton 190,91,90,21 uNSbAw3 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ,3tcti~sZ TextBox 220,49,40,21,.TextBox2 'default: 4 DHlCus=ic End Dialog 9dFSppM Dim dlg As UserDialog qFD#D_O6 PA(XdT{ ok = Dialog (dlg) *.]M1 5VG[FY6Pl If ok=0 Then 'cancel button was pressed 1JI\e6]I Print "Execution cancelled." g:sn/Zug] End tuF
hPqe { End If -0/5! 8I`t`C/4 'Assign accommodation and pupil diameter & use defaults if field left empty v9qgfdBS5 If dlg.TextBox1 = "" Then r-];@ A = 0 'Default accommodation TsB"<6@!AA Else |_^A$Hv A = CDbl(dlg.TextBox1) 6eNo}Tos9 End If ,@1.&!F4it ~;*SW[4 If dlg.TextBox2 = "" Then 0*F{=X~L pupilDiam = 4 'Default pupil diameter SCZ6:P"$qX Else t<|S7EqIL pupilDiam = CDbl(dlg.TextBox2) 23AMrDF=N End If [o0Z;}fU P~5[.6gW Print " " ,r-l^I3< Print "Accommodation = " & A & " Diopters" }
:@s Print "Pupil Diameter = " & pupilDiam & " mm" 5 B lptC DKG%z~R* ' Calculate new parameters with accommodation ^/<0r]= taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness c3>#.NP_ $YX\&%N Rant = 12.0 - 0.4*A 'Radius of anterior lens `T
gwa CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ^" EsBt zIyMq3 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens mrzrQ@sN CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens .9< i b`=\<u8 tlens = 3.767 + 0.04*A 'Lens thickness 8d90B9 FM)Es&p& nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction wap@q6fz< /"Bm1 'Adjust parameters to account for accommodation B|~tW21 B4yC"55 '************************************************************************* }CiB+ 'Aqueous thickness (Position of Lens) /WlpRf% '************************************************************************* UUf-G0/P eID = FindFullName( "Geometry.Arizona Eye.Lens" ) V?a+u7*U& GetCustomElement eID, entity l.#iMi(@p~ ~qG`~/7 parID = FindFullName( "Geometry.Arizona Eye" ) xMAfa>]{n Q!%4Iq%jr ' Delete any shift(s) in z hpxqL%r count = 0 f#s
/Ycp+ While GetOperationCount(eID)>count
$rAHtr GetOperation eID, count, op #sn2Vmi If op.Type="ShiftZ" Then x2|YrkGv DeleteOperation eID,count '8Q:}{ count=count-1 f
xWW"B*A End If 1mLd_]F'F count=count+1 Kd?TIeF E Wend dU7+rc2,CU ],lrT0_cT 'Set new shift in ;^q@w op.Type = "ShiftZ" fgs){Ng` op.val1 = taq TV~<1vj op.parent = parID 1e 8J-Nkj AddOperation eID, op g:l5,j.K Print "Set aqueous humor thickness = " & taq-0.55 /B$9B -R^OYgF '************************************************************************* #}/YnVk 'Radius and conic constant of anterior lens Xndgs}zz '************************************************************************* p[Pa(a,B7 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ionFPc]. GetConic eID, entity, curv, conic wj-=#gyAoo e/pZLj]M SetConic eID, entity, 1/Rant, CCant He#5d!cf:M Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 7QXA*.'
F Zc_%hQf2A '************************************************************************* Y:GSjq 'Radius and conic constant of posterior lens )ZU)$dJ>V '************************************************************************* "|{3V:e>a eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ~FnB!Mh}? GetConic eID, entity, curv, conic {s=n "*Qp) o5!"dxR SetConic eID, entity, 1/Rpost, CCpost 5Ocd2T' Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 4NY00d/R Y<~Nx~w{ '************************************************************************* mN5`Fct*A> 'Lens thickness (Position of posterior lens surface) Who7{|M\' '************************************************************************* OQ[E-%v1 R +~gqPk parID = FindFullName( "Geometry.Arizona Eye.Lens" ) .~)[> 1ga-8&! ' Delete any z-shift(s) v35wlt^} count = 0 0FA
N9u2 While GetOperationCount(eID)>count ']nB_x7 GetOperation eID, count, op G#V}9l8Q If op.Type="ShiftZ" Then -JL DeleteOperation eID,count ]_cBd)3P} count=count-1 'ZyHp=RN) End If JfJUOaL count=count+1 4)'8fi Wend 0((3q'[ < 6XVr-ef 'Set new z-shift 1!u}~E_ op.Type = "ShiftZ" r"yA=d'c op.val1 = tlens )_*<uSl op.parent = parID k=t\ AddOperation eID, op ' 0iXx Print "Set lens thickness = " & tlens #St=% ! s%tPGjMq '************************************************************************* $=>(7 =l_ 'Lens index of refraction Y{].%xM5 '************************************************************************* ]= 2wQ8 eID = FindMaterial( "Lens" ) E,6(/`0H* GetModelMaterial eID, mat UQGOCP_ "CYh"4]@rD mat.Nd = nlens 19 h7 M SetModelMaterial eID, mat X#l]%IrW! Print "Set lens index of refraction = " & nlens 8no_xFA .#"O VI]# '************************************************************************* t;P%&:"@M 'Pupil diameter m'Jk!eo '************************************************************************* Yjv[rH5v eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) }-3|
v<d %9z N U 'Adjust pupil diameter (trimming volume inner hole) &!I^m Evd>s SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Da#|}m0> 1}#(4tw) ' Adjust pupil location to just in front of the lens *9"L?S(X# parID = FindFullName( "Geometry.Arizona Eye" ) 7aH E:Dnwp eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) eySV -f{ count = 0 0qXkWGB While GetOperationCount(eID)>count L8<Yk`jx GetOperation eID, count, op TNs0^h) If op.Type="ShiftZ" Then az7<@vSXi DeleteOperation eID,count EjsAV F
[@ count=count-1 b6Jv|1w' End If pWo`iM& F count=count+1 jr@u Wend ]=A=VH& op.Type = "ShiftZ" JTcK\t8 op.val1 = taq-0.01 >G`=8Ku op.parent = parID 6d~[M y AddOperation eID, op S>~QuCMY 7
4rmxjiN Print "Set pupil diameter = " & pupilDiam 8Z;wF vkmTd4g 'Update AZ Eye subassembly Description %G9:M;|' eID = FindFullName( "Geometry.Arizona Eye" ) q2VQS1R`8 GetEntity eID, entity ien >Ou entity.Description = "Accommodation = " & A & "D" n7~!klF- SetEntity eID, entity <UJgl{- 6l|pTyb1 Update (5@9j Print "DONE!" sY?pp
'}a -#]?3*NO End Sub WeGT} 'U<-w$!f+^ 如果屈光度是4,光瞳直径是4,则会输出如下数据: C3fSSa%b s&S8P;K| Accommodation = 4 Diopters 9wLV\>i[k Pupil Diameter = 4 mm bK `'zi Set aqueous humor thickness = 2.81 HjTK/x'_'L Set anterior lens radius = 10.4 and conic constant = -2.375869 9 F~U%
>GX Set posterior lens radius = -4.424557 and conic constant = -3.081019 ~ei\~;n\@ Set lens thickness = 3.927 t?^C9(;6 Set lens index of refraction = 1.42672 >j1\]uo Set pupil diameter = 4 }?B=R#5 DONE! kzCD>m gvYib`# (文章来源:讯技光电)
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