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    [技术]Arizona眼睛模型 [复制链接]

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    离线infotek
     
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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 -{A64gfFxT  
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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。 |jH Yf42Q  
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    模型 t#f-3zd9  
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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。 wmbG$T%k  
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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. 6L~5qbQ  
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    光源 LCIe1P2  
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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。 asvM/ 9  
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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。 66W J=? JV  
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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。 tG"EbWi  
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    图2. 字母F光源的设定方法光 ?` ebi|6  
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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 [BKTZQ@G@  
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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。 Ly`.~t(~l  
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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。 Ql}#mC.>/  
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    图5. 视网膜重点采样规格设定
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    脚本 W-1Ub |8C  
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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: p7Yb8#XfU  
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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。 u]3VK  
    余下的脚本计算与屈光度有关的所有参数。 )Y1+F,C  
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    分析 w*Ze5j4@ \  
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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。 S U P  
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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 LwI4 2  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. Pf<BQ*n  
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    Dim entity As T_ENTITY ;ejtP #$  
    Dim op As T_OPERATION c<)O#i@3/  
    Dim mat As T_MODELMATERIAL 2+\@0j[q  
    Dim A As Double \xk8+=/A  
    Dim pupilDiam As Double =\jPnov!  
    Dim eID As Long g3'yqIjQL  
    Dim parID As Long w4uY/!~k  
    Dim count As Integer _cc9+o  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double g.Kyfs4`  
    Dim tlens As Double, nlens As Double #|cr\\2*  
    Dim curv As Double, conic As Double N?%FVF  
    Dim ok As Long 4':U rJ+  
    1 u~.^O}J  
    Sub Main Y]}>he1/5  
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        '用户输入对话框 W^9=z~-h  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Z#_VxA>]v  
            TextBox 220,21,40,21,.TextBox1 'default: 0 R8u9tTW  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 .|J-(J<>[.  
            OKButton 40,91,90,21 -hO[^^i9  
            CancelButton 190,91,90,21 <:0d%YB)  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 B}ASZYpW>  
            TextBox 220,49,40,21,.TextBox2 'default: 4 NK(; -~{P  
        End Dialog u*!/J R  
        Dim dlg As UserDialog * p,2>[e  
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        ok = Dialog (dlg) 9Or  
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        If ok=0 Then    'cancel button was pressed [JX=<a)U  
            Print "Execution cancelled." l`<u\],  
            End fK9wr@1  
        End If ( |Xc_nC  
    vM /D7YS:  
        'Assign accommodation and pupil diameter & use defaults if field left empty R)5zHCwOw  
        If dlg.TextBox1 = "" Then ~_yz\;#  
            A = 0           'Default accommodation .:+&2#b  
        Else Iqm QQ_KH  
            A = CDbl(dlg.TextBox1) GH6ozWA  
        End If C'//(gjQ-G  
    ! ^U!T\qDi  
        If dlg.TextBox2 = "" Then bp(X\:zAy  
            pupilDiam = 4   'Default pupil diameter 5Og=`T  
        Else dI9u: -  
            pupilDiam = CDbl(dlg.TextBox2) ;1woTAuD  
        End If P<gr=&  
    J*'#! xIa  
        Print " " YumHECej  
        Print "Accommodation = " & A & " Diopters" g:>Mooxzi  
        Print "Pupil Diameter = " & pupilDiam & " mm" N[dv  
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        ' Calculate new parameters with accommodation }c0EGoU}?  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness >c 5V VA8  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens x3?:"D2  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens  D^JuL6U  
    .6nNqGua1  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens FrBJv<  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens mg7Q~SLL{  
    #i~2C@]  
        tlens = 3.767 + 0.04*A                  'Lens thickness SPK% ' s  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction nd1%txIsr  
    a8!/V@a  
        'Adjust parameters to account for accommodation Yv[j5\:x  
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        '************************************************************************* %o9;jX  
        'Aqueous thickness (Position of Lens) Yhkn(k2  
        '************************************************************************* ,k5b,}tN  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ir*T ,O 2J  
        GetCustomElement eID, entity atO/Tp  
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        parID = FindFullName( "Geometry.Arizona Eye" ) .TTXg,8#D  
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        ' Delete any shift(s) in z g` QbJ61a  
        count = 0 =W~K_jE5lo  
        While GetOperationCount(eID)>count w$5#jJX\  
            GetOperation eID, count, op SecZ5(+=  
            If op.Type="ShiftZ" Then ?u]%T]W  
                DeleteOperation eID,count ?YO$NYwE  
                count=count-1 D.\s mk  
            End If X3j<HQcK  
            count=count+1 g[~"c}  
        Wend 3Vj,O?(Z  
    $'2yPoR  
        'Set new shift in ,TAzJ  
        op.Type = "ShiftZ" AK*F,H9  
        op.val1 = taq O1_dA%m  
        op.parent = parID i; 3^vhbQ  
        AddOperation eID, op aN5w  
        Print "Set aqueous humor thickness = " & taq-0.55 5-ju5z?=  
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        '************************************************************************* C4jq T  
        'Radius and conic constant of anterior lens &_EjP hZ  
        '************************************************************************* okO^ /"  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) i YJzSVO  
        GetConic eID, entity, curv, conic .l->O-=  
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        SetConic eID, entity, 1/Rant, CCant IW.~I,!x  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant aBO%qmtt  
    ;*Cu >f7  
        '************************************************************************* q{W@J0U  
        'Radius and conic constant of posterior lens +h$) l/>:  
        '************************************************************************* zl W 5$cC[  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) iS{8cN3R  
        GetConic eID, entity, curv, conic ]~SOGAFW  
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        SetConic eID, entity, 1/Rpost, CCpost 9*+%Qt,{B  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost :Q\{LBc  
    $Y!$I.+  
        '************************************************************************* CmNd0S4v  
        'Lens thickness (Position of posterior lens surface) 8yH*  
        '************************************************************************* vElVw. P  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6Y|jK< n?H  
    .I@jt?6X  
        ' Delete any z-shift(s) fBptjt_  
        count = 0 < xm>_~,w  
        While GetOperationCount(eID)>count j zaC  
            GetOperation eID, count, op szY=N7\S*  
            If op.Type="ShiftZ" Then $~|#Rz%v  
                DeleteOperation eID,count "YUyM5X  
                count=count-1 /=zzym~<>  
            End If 4wZ{Z 2w  
            count=count+1 0{/P1  
        Wend e>Vr#a4  
    ==[a7|q  
        'Set new z-shift 2\xv Yf-  
        op.Type = "ShiftZ" G &'eP  
        op.val1 = tlens 5Mfs)a4j.  
        op.parent = parID ,haCZH {  
        AddOperation eID, op ?G[<~J3-E  
        Print "Set lens thickness = " & tlens rRN7H L+b  
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        '************************************************************************* Mt@P}4   
        'Lens index of refraction u; xl}  
        '************************************************************************* Kp +Lk  
        eID = FindMaterial( "Lens" ) ?qeBgkL(B^  
        GetModelMaterial eID, mat kMGK 8y  
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        mat.Nd = nlens ?NZKu6  
        SetModelMaterial eID, mat /qW5M4.w  
        Print "Set lens index of refraction = " & nlens tdTD!'  
    8KioL{h  
        '************************************************************************* %rpJZ t  
        'Pupil diameter fX,L;Se"  
        '************************************************************************* @_tQ:U,v  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) #Y3:~dmJ-  
    J`T1 88  
        'Adjust pupil diameter (trimming volume inner hole) ,O@x v  
    /YbyMj*  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" qW57h8M  
    ;- D1n  
        ' Adjust pupil location to just in front of the lens +?[ ,y  
        parID = FindFullName( "Geometry.Arizona Eye" ) uaMf3HeYV  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) -_bHLoI  
        count = 0 (vCMff/ Y1  
        While GetOperationCount(eID)>count c?qg i"kS  
            GetOperation eID, count, op v$R+5_@[l  
            If op.Type="ShiftZ" Then D"WqJcDt  
                DeleteOperation eID,count [E_eaez7#  
                count=count-1 C3n_'O  
            End If $2uZdl8Rvj  
            count=count+1 }QszOi\fV1  
        Wend K-&&%Id6R  
        op.Type = "ShiftZ" HH>"J /;c,  
        op.val1 = taq-0.01 L lmdydC%  
        op.parent = parID sh []OSM  
        AddOperation eID, op vc.:du  
    tZS-e6*S  
        Print "Set pupil diameter = " & pupilDiam ;P9P2&c8c  
    gC81ICM  
        'Update AZ Eye subassembly Description SF.4["$  
        eID = FindFullName( "Geometry.Arizona Eye" ) &Q>)3]|p  
        GetEntity eID, entity X<\y%2B|l  
        entity.Description = "Accommodation = " & A & "D" bi:m;R  
        SetEntity eID, entity E5d?toZ,8"  
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        Update R;9H`L/>  
        Print "DONE!" ?@U7tNI  
         xjHOrr OQ  
    End Sub 8r^~`rL  
    $vNz^!zgV  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: =VMV^[&>  
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    Accommodation = 4 Diopters 3V]B|^S  
    Pupil Diameter = 4 mm 49%qBO$R  
    Set aqueous humor thickness = 2.81 >hcA:\UPk  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 GzJLG=M  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 zGrUl|j  
    Set lens thickness = 3.927 ze!S4&B  
    Set lens index of refraction = 1.42672 t.sbfLu  
    Set pupil diameter = 4 2c>eMfa  
    DONE! E DuLgg@  
     
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