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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 Tl?jq]  
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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。 EYn9l n_]u  
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模型 DV*e.Y>  
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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。 wX!0KxR/Z  
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Table 1. AZ眼睛模型的定义
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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. >yLdrf  
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光源 lcfs 1].  
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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。 "K;""]#wg0  
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图1. 光源和提示信息使用
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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。 H5CL0#I  
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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。 gTd r  
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图2. 字母F光源的设定方法光 2cZgG^  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 :1v.Jk  
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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。 ZJ/K MW  
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图4. 视网膜朗伯散射设定
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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。 meGL T/   
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图5. 视网膜重点采样规格设定
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脚本 o,/wE  
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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: R^INl@(O  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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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。 CbOCL~ "  
余下的脚本计算与屈光度有关的所有参数。 N).'>  
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分析 l4U  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ~{pds  
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图7. 字母F在视网膜上颜色分析
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脚本代码 1R7tnR@[u  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used.  hV fANbs  
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Dim entity As T_ENTITY jVqpokWH  
Dim op As T_OPERATION Ml'lZ)  
Dim mat As T_MODELMATERIAL F!-%v5.y  
Dim A As Double thE9fr/  
Dim pupilDiam As Double d-z[=1m  
Dim eID As Long %8xKBL]J  
Dim parID As Long Q(x/&]7=V  
Dim count As Integer '1~;^rU  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double fm!\**Q1  
Dim tlens As Double, nlens As Double D&qJ@PR  
Dim curv As Double, conic As Double `]a0z|2'!  
Dim ok As Long vhDtjf/*  
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Sub Main ?P/73p  
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    '用户输入对话框 }T}xVd0  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 e\!Aoky  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ?%n"{k?#  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 5qFHy[I A  
        OKButton 40,91,90,21 Lyit`j~yH  
        CancelButton 190,91,90,21 ~ e a K]|  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 #aiI]'  
        TextBox 220,49,40,21,.TextBox2 'default: 4 l hST%3Ld  
    End Dialog ;s-@m<  
    Dim dlg As UserDialog +=sw&DH  
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    ok = Dialog (dlg) 9Q'[>P=1  
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    If ok=0 Then    'cancel button was pressed ZZi|0dG4;  
        Print "Execution cancelled." Qj$w7*U  
        End L~RFI&b  
    End If #)3 B  
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    'Assign accommodation and pupil diameter & use defaults if field left empty whm| "}x)u  
    If dlg.TextBox1 = "" Then fB]NEx|o~  
        A = 0           'Default accommodation rinTB|5  
    Else ae](=OQ  
        A = CDbl(dlg.TextBox1) /rky  
    End If |kTq &^$  
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    If dlg.TextBox2 = "" Then Sh?eb  
        pupilDiam = 4   'Default pupil diameter &9"Y:),  
    Else B{p74 >  
        pupilDiam = CDbl(dlg.TextBox2) dGz4`1(>  
    End If B#cN'1c  
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    Print " " 7 p1B"%  
    Print "Accommodation = " & A & " Diopters" 9ExI,  
    Print "Pupil Diameter = " & pupilDiam & " mm" 9%bErMHL  
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    ' Calculate new parameters with accommodation oB~V~c}8x  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Et0)6^-v  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens K\59vtga  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens rm-;Z<  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens <0qhc$M  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 29m$S7[  
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    tlens = 3.767 + 0.04*A                  'Lens thickness Z`U+ a  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction yqVoedN  
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    'Adjust parameters to account for accommodation c{KJNH%7  
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    '************************************************************************* /Ov1eQBNG  
    'Aqueous thickness (Position of Lens) pOh<I {r1  
    '************************************************************************* /J&ks>St  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) `j!_tE`  
    GetCustomElement eID, entity Tj{3#?]Ho  
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    parID = FindFullName( "Geometry.Arizona Eye" ) L]u^$=rI  
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    ' Delete any shift(s) in z 5jUy[w @  
    count = 0 =N8_S$nx(  
    While GetOperationCount(eID)>count cc:$$_'L  
        GetOperation eID, count, op ;r&Z?B$  
        If op.Type="ShiftZ" Then 29VX-45  
            DeleteOperation eID,count >/lB%<$/  
            count=count-1 >,h{`  
        End If IV1Y+Z )  
        count=count+1 %5DM ew  
    Wend cza_LO(  
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    'Set new shift in DHv86TvJt  
    op.Type = "ShiftZ" A*A/30o|R  
    op.val1 = taq !n P4S)A  
    op.parent = parID +8x_f0 <  
    AddOperation eID, op :Fu7T1  
    Print "Set aqueous humor thickness = " & taq-0.55 nc\2A>f`  
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    '************************************************************************* P=6d<no&<  
    'Radius and conic constant of anterior lens <VutwtA  
    '************************************************************************* L F} d  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) )tnbl"0  
    GetConic eID, entity, curv, conic YOj&1ymBZ  
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    SetConic eID, entity, 1/Rant, CCant jD}h`(bE  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant /BD'{tZ]Sl  
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    '************************************************************************* Uzc p  
    'Radius and conic constant of posterior lens G2?#MO  
    '************************************************************************* Yf~Kzv1]*  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 4Orq;8!BW  
    GetConic eID, entity, curv, conic P:N> #G~z  
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    SetConic eID, entity, 1/Rpost, CCpost B RskxyL&,  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost :z&kbG  
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    '************************************************************************* l U4 I*  
    'Lens thickness (Position of posterior lens surface) qNP)oU92  
    '************************************************************************* B{D4.!a  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) g,!.`[e'ex  
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    ' Delete any z-shift(s) M j6,VD9L  
    count = 0 bhIShk[  
    While GetOperationCount(eID)>count naH(lz|v  
        GetOperation eID, count, op DuR9L'  
        If op.Type="ShiftZ" Then 3Il._]#  
            DeleteOperation eID,count W;2J~V!c  
            count=count-1 EPH" 5$8  
        End If /j}Tv.'d  
        count=count+1 6w;`A9G[YI  
    Wend ~%g,Uypi  
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    'Set new z-shift %=9o'Y,4  
    op.Type = "ShiftZ" f$kbb 6juL  
    op.val1 = tlens -6s:D/t1'  
    op.parent = parID ~jzLw@"~$^  
    AddOperation eID, op l!Xj UnRF  
    Print "Set lens thickness = " & tlens -Yh(bS l  
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    '************************************************************************* KCw  
    'Lens index of refraction ]k^?=  
    '************************************************************************* SO(BkxV@  
    eID = FindMaterial( "Lens" ) IF|;;*Z8  
    GetModelMaterial eID, mat ?O#,{ZZf=  
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    mat.Nd = nlens OUF%DMl4  
    SetModelMaterial eID, mat Ys}^ hy  
    Print "Set lens index of refraction = " & nlens Fj~suZ`  
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    '************************************************************************* av|T|J/(  
    'Pupil diameter sL~4 ~178  
    '************************************************************************* ;<Hk Cd  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) @0 P4pt;(  
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    'Adjust pupil diameter (trimming volume inner hole) P658 XKE  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" yTg|L9  
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    ' Adjust pupil location to just in front of the lens abUO3 Y{  
    parID = FindFullName( "Geometry.Arizona Eye" ) I AwS39B  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ud5}jyJ  
    count = 0 `G\Gk|4; 2  
    While GetOperationCount(eID)>count saiXFM 7J  
        GetOperation eID, count, op MJ?t{=  
        If op.Type="ShiftZ" Then U!r8}@  
            DeleteOperation eID,count p{LbTjdNc  
            count=count-1 y.D+M$f  
        End If l+P!I{n  
        count=count+1 9GCK3  
    Wend UH%H9; ,$]  
    op.Type = "ShiftZ" ,m?V3xvq  
    op.val1 = taq-0.01 >\<eR]12  
    op.parent = parID 5Ex[}y9L`  
    AddOperation eID, op uuwJ-  
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    Print "Set pupil diameter = " & pupilDiam V.*M;T\i  
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    'Update AZ Eye subassembly Description 06%-tAq:  
    eID = FindFullName( "Geometry.Arizona Eye" ) Qe _{<E  
    GetEntity eID, entity /KOI%x  
    entity.Description = "Accommodation = " & A & "D" 5wx~QV=Hh  
    SetEntity eID, entity fb`x1Q  
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    Update 7afG4 (<k  
    Print "DONE!" 6}I X{nQI  
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End Sub AP,ZMpw  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: 0~RD@>]  
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Accommodation = 4 Diopters $%DoLpE>  
Pupil Diameter = 4 mm WFahb3kx  
Set aqueous humor thickness = 2.81 TaYl[I  
Set anterior lens radius = 10.4 and conic constant = -2.375869 iQ:eR]7X  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 \h#aPG<yo  
Set lens thickness = 3.927 >YWK"~|i~  
Set lens index of refraction = 1.42672 K<5yjG8&  
Set pupil diameter = 4 .W~XX  
DONE! `dV2\^*A  
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