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infotek 2023-04-27 08:29

Arizona眼睛模型

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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。 Jb~nu  
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模型 `=]I -5#.W  
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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。 ?\HXYCi0r  
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. IT`r&;5  
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光源 BjT0m k"P  
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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。 wYf9&}k\4  
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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。 W^c> (d</  
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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。 94=aVM\>>  
图2. 字母F光源的设定方法光 ;2m<#~@0  
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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 ]M"l-A  
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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。 ; rSpM  
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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。 htn"rY(  
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图5. 视网膜重点采样规格设定
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脚本 1|za>N6[yu  
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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: I_Q*uH.Y5  
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。 9zj^\-FA_l  
余下的脚本计算与屈光度有关的所有参数。 @v1f)(N  
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分析 {+V1>6  
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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。 2 {lo  
图7. 字母F在视网膜上颜色分析
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脚本代码 WJG&`PP  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 83*"58  
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Dim entity As T_ENTITY Kt,ENbF  
Dim op As T_OPERATION q? x.P2  
Dim mat As T_MODELMATERIAL P^-tGo!  
Dim A As Double } k[gR I]  
Dim pupilDiam As Double b"+ J8W  
Dim eID As Long GS^U6Xef  
Dim parID As Long $u"t/_%  
Dim count As Integer gxpGi@5  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double c&Pgz~iP  
Dim tlens As Double, nlens As Double ,+0>p  
Dim curv As Double, conic As Double N?d4Pu1m  
Dim ok As Long < PoRnx  
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Sub Main tqY)  
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    '用户输入对话框 W s!N%%g  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 hJ0)"OA5  
        TextBox 220,21,40,21,.TextBox1 'default: 0 kcd~`+C  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 X@u-n_  
        OKButton 40,91,90,21 |V2+4b,  
        CancelButton 190,91,90,21 I|=$.i  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 sa%2,e'  
        TextBox 220,49,40,21,.TextBox2 'default: 4 ;Ry )^5Q  
    End Dialog ~ #Gu:  
    Dim dlg As UserDialog h' OLj#H  
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    ok = Dialog (dlg) jI$}\*g  
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    If ok=0 Then    'cancel button was pressed oWVlHAPj  
        Print "Execution cancelled." pIh%5Z U  
        End j|f$:j  
    End If 28L3"c  
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    'Assign accommodation and pupil diameter & use defaults if field left empty c43" o  
    If dlg.TextBox1 = "" Then ~%9ofXy  
        A = 0           'Default accommodation :%Dw3IrOM  
    Else Ws[[Me, =  
        A = CDbl(dlg.TextBox1) NJb5HoYZ  
    End If DXAA[hUjF  
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    If dlg.TextBox2 = "" Then `F:PWG`  
        pupilDiam = 4   'Default pupil diameter {q2H_H  
    Else ;b:Ct<  
        pupilDiam = CDbl(dlg.TextBox2) v>TI.;{y  
    End If 3Q^@ !hu  
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    Print " " ?U]/4]  
    Print "Accommodation = " & A & " Diopters" dq?q(_9  
    Print "Pupil Diameter = " & pupilDiam & " mm" 7kM_Ijd$  
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    ' Calculate new parameters with accommodation X]q,A5g  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ~:."BA  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens MT" 2^&R  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 5fS89?/?  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens TL(L[  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens jcF/5u5e  
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    tlens = 3.767 + 0.04*A                  'Lens thickness Zg%SE'kK  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction ANh5-8y  
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    'Adjust parameters to account for accommodation EAq/Yw2$  
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    '************************************************************************* %k#Q) zWJ  
    'Aqueous thickness (Position of Lens) Y7)YJI  
    '************************************************************************* >G<AyS&z*  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6C>x,kU  
    GetCustomElement eID, entity ;pdW7  
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    parID = FindFullName( "Geometry.Arizona Eye" ) krm&.J  
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    ' Delete any shift(s) in z +0;n t  
    count = 0 +O:Qw[BL/Z  
    While GetOperationCount(eID)>count P-ma~g>I  
        GetOperation eID, count, op 4RsV\Y{FN  
        If op.Type="ShiftZ" Then u79.`,Ad&  
            DeleteOperation eID,count NG@9 }O  
            count=count-1 r7sPFM  
        End If Kd CPt!  
        count=count+1 N4"%!.Y  
    Wend d; \x 'h2  
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    'Set new shift in 4O[T:9mn0  
    op.Type = "ShiftZ" RLr;]j8cm  
    op.val1 = taq \}t(g}7T  
    op.parent = parID z7F~;IB*u  
    AddOperation eID, op [Fe`}F}Co8  
    Print "Set aqueous humor thickness = " & taq-0.55 0Z#&!xTb  
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    '************************************************************************* 2#5SI  
    'Radius and conic constant of anterior lens ~q#UH'=%  
    '************************************************************************* |_HH[s*U  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) l"!.aIY"e  
    GetConic eID, entity, curv, conic pm O}m>  
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    SetConic eID, entity, 1/Rant, CCant YVZm^@ZVV  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ?G+v#?A  
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    '************************************************************************* E N%cjvE  
    'Radius and conic constant of posterior lens T<~NB5&f  
    '************************************************************************* I(ds]E ;_E  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) XX~~SvSM  
    GetConic eID, entity, curv, conic erYpeq.  
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    SetConic eID, entity, 1/Rpost, CCpost ]~CG zV  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost /og2+!  
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    '************************************************************************* '~%1p_0dq  
    'Lens thickness (Position of posterior lens surface) RvvK`}/6  
    '************************************************************************* tlu-zUsi  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) \MQ|(  
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    ' Delete any z-shift(s) ZffK];D  
    count = 0 uG&xtN8  
    While GetOperationCount(eID)>count eiI}:5~ /g  
        GetOperation eID, count, op \kZxys!4  
        If op.Type="ShiftZ" Then Y<%$;fx$Sx  
            DeleteOperation eID,count rgdDkWLXC  
            count=count-1 2Q,e1' =  
        End If Ki{&,:@  
        count=count+1 aGx`ec*t  
    Wend `gfh]7T  
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    'Set new z-shift !.H< dQS  
    op.Type = "ShiftZ" `omZ'n)  
    op.val1 = tlens C^XJE1D.  
    op.parent = parID tM <6c+  
    AddOperation eID, op ^aN;M\  
    Print "Set lens thickness = " & tlens EKhwrBjS  
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    '************************************************************************* y[oc^Zuo  
    'Lens index of refraction /=A^@&:_#  
    '************************************************************************* [>Z~& cm  
    eID = FindMaterial( "Lens" ) )t{?7wy  
    GetModelMaterial eID, mat BV"7Wp;  
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    mat.Nd = nlens fB|rW~!v  
    SetModelMaterial eID, mat '@i/?rNi%N  
    Print "Set lens index of refraction = " & nlens 3|8\,fO?  
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    '************************************************************************* AK%`EsI^  
    'Pupil diameter c#|!^gjf  
    '************************************************************************* "detDB   
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 9^QiFgJy  
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    'Adjust pupil diameter (trimming volume inner hole) n.n;'p9t@  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" [U.3rcT"N  
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    ' Adjust pupil location to just in front of the lens !E8y!|7$  
    parID = FindFullName( "Geometry.Arizona Eye" ) kL\ FY  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) pZUckQ  
    count = 0 :{bvCos<)  
    While GetOperationCount(eID)>count Xd@  -  
        GetOperation eID, count, op c+,F)i^`  
        If op.Type="ShiftZ" Then RT HD2  
            DeleteOperation eID,count !f[LFQD  
            count=count-1 "bZ%1)+  
        End If F=!p7msRB  
        count=count+1 q@8Jc[\d  
    Wend pyYm<dn  
    op.Type = "ShiftZ" {z> fe }  
    op.val1 = taq-0.01 k#X~+}N^  
    op.parent = parID EKo!vie G  
    AddOperation eID, op _rt+OzZ*L  
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    Print "Set pupil diameter = " & pupilDiam 6RV42r^pf  
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    'Update AZ Eye subassembly Description o~<Xc  
    eID = FindFullName( "Geometry.Arizona Eye" ) Z> Jm  
    GetEntity eID, entity 5IE3[a%X  
    entity.Description = "Accommodation = " & A & "D" Ey96XJV  
    SetEntity eID, entity j}O~6A>|  
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    Update @i2"+_}*  
    Print "DONE!" +9Q,[)e r  
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End Sub v6=pV4k9  
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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: GPV=(}z  
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Accommodation = 4 Diopters *g7BR`Bt]z  
Pupil Diameter = 4 mm mbT4K8<^  
Set aqueous humor thickness = 2.81 `R[cM; c2  
Set anterior lens radius = 10.4 and conic constant = -2.375869 v2eLH:6  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 1.Kun !w  
Set lens thickness = 3.927 =D-u".{  
Set lens index of refraction = 1.42672 R(p`H}^  
Set pupil diameter = 4 {<ms;Oi'  
DONE!
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