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    [技术]Arizona眼睛模型 [复制链接]

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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 j\.\ePmk]  
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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。 D!CuE7}  
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    模型 JLH,:2  
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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。 ZMI vzQYI  
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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. hz~jyH.h_  
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    光源 bjYaJtn  
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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。 =Frbhh57  
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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。 6`l7saHXE  
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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。 Yl$Cj>FG  
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    图2. 字母F光源的设定方法光 &i%1\ o  
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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 mtn+bV R%  
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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。 aR~Od Ys  
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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。 j1{\nP/  
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    图5. 视网膜重点采样规格设定
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    脚本 5zBayJh#  
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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: Lc:DJA  
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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。 r06M.r   
    余下的脚本计算与屈光度有关的所有参数。 }lzN)e  
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    分析 8 K/o/  
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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。 tSvklI  
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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 7berkU0P  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. 6b8@6;&LI  
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    Dim entity As T_ENTITY P_w\d/3  
    Dim op As T_OPERATION 0u"/7OU  
    Dim mat As T_MODELMATERIAL r 7mg>3  
    Dim A As Double 2iM8V  
    Dim pupilDiam As Double |_P-  
    Dim eID As Long ]$vJK  
    Dim parID As Long GK/Q]}Q8pZ  
    Dim count As Integer i;Y@>-[e<  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double +L$,jZqS  
    Dim tlens As Double, nlens As Double ", :Ta|  
    Dim curv As Double, conic As Double X}5aE4K/  
    Dim ok As Long (cj3[qq  
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    Sub Main 9A4h?/  
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        '用户输入对话框 dWI.t1`i  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 r_kw "9  
            TextBox 220,21,40,21,.TextBox1 'default: 0 ;Q]j"1c  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 B !(t<W8cu  
            OKButton 40,91,90,21 '%m0@5|hCD  
            CancelButton 190,91,90,21 Y)@PGxjz  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 .2b) rKo~  
            TextBox 220,49,40,21,.TextBox2 'default: 4 ,ZYj8^gF  
        End Dialog {xC CUU  
        Dim dlg As UserDialog elgCPX&:W  
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        ok = Dialog (dlg) Iy}r'#N  
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        If ok=0 Then    'cancel button was pressed wnE c   
            Print "Execution cancelled." P'Fy,fNg  
            End e<> Lr  
        End If >t"]gQHtx  
    S%ri/}qI[{  
        'Assign accommodation and pupil diameter & use defaults if field left empty 5g- apod  
        If dlg.TextBox1 = "" Then axY-Vj  
            A = 0           'Default accommodation {tE/Jv $  
        Else bw7!MAXd  
            A = CDbl(dlg.TextBox1) bmAgB}Ior  
        End If [hg|bpEG  
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        If dlg.TextBox2 = "" Then ndm19M8Y|  
            pupilDiam = 4   'Default pupil diameter fJ Ch  
        Else JXlFo3<  
            pupilDiam = CDbl(dlg.TextBox2) dv0TJ 0%  
        End If eh'mSf^=p  
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        Print " " QD:0iD?  
        Print "Accommodation = " & A & " Diopters" 8-5a*vV,>  
        Print "Pupil Diameter = " & pupilDiam & " mm" x~GV#c  
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        ' Calculate new parameters with accommodation T^a {#B  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness LIH>IpamN  
    Xl6)&   
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens Z"gllpDr$  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens -aNTFt~|[  
    Et'C4od s  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens c 3@SgfKmk  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens  ZW2#'$b  
    b,a\`%m}  
        tlens = 3.767 + 0.04*A                  'Lens thickness !9"R4~4  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction .bl0w"c^qq  
    {NK>9phoB  
        'Adjust parameters to account for accommodation fC3IxlG  
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        '************************************************************************* =] 5;=>(  
        'Aqueous thickness (Position of Lens) V8Q#%#)FHe  
        '************************************************************************* (?\ZN+V)  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 9L#B"lh  
        GetCustomElement eID, entity pOI+  
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        parID = FindFullName( "Geometry.Arizona Eye" ) -R'p^cMA  
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        ' Delete any shift(s) in z g}^ /8rW  
        count = 0 e( ^9fg_SG  
        While GetOperationCount(eID)>count ,:\2Lf  
            GetOperation eID, count, op &up/`8   
            If op.Type="ShiftZ" Then * Kzs(O  
                DeleteOperation eID,count ga^<_;5<  
                count=count-1 0]oQ08  
            End If :=L[kzX  
            count=count+1 pjj 5  
        Wend p>eD{#2  
    SbnV U[  
        'Set new shift in P'9aZd  
        op.Type = "ShiftZ" J#V `W&\,6  
        op.val1 = taq IVNNiNN*5  
        op.parent = parID CJKH"'u3^  
        AddOperation eID, op j|G-9E  
        Print "Set aqueous humor thickness = " & taq-0.55 , D1[}Lr=K  
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        '************************************************************************* .`'SL''c  
        'Radius and conic constant of anterior lens M<$l&%<`G  
        '************************************************************************* 4\OELU  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 3X!~*_i C  
        GetConic eID, entity, curv, conic F[=m|MZb  
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        SetConic eID, entity, 1/Rant, CCant 3+|6])Hi1  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant jATU b-  
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        '************************************************************************* `u>BtAx8  
        'Radius and conic constant of posterior lens rFy9K4D  
        '************************************************************************* <dYk|5AdLF  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) BWPYHWW}E  
        GetConic eID, entity, curv, conic c&Zm>Qo[  
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        SetConic eID, entity, 1/Rpost, CCpost Lv^j l  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 17i^|&J6}:  
    ; %Da {  
        '************************************************************************* ?*s!&-KI  
        'Lens thickness (Position of posterior lens surface) GO)rpk9  
        '************************************************************************* W"-nzdAJ5  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) kx=AX*I  
    tJu<#h X  
        ' Delete any z-shift(s) Y+jKP*ri  
        count = 0 kTk?[BK  
        While GetOperationCount(eID)>count Np-D:G  
            GetOperation eID, count, op Ksp;bfe  
            If op.Type="ShiftZ" Then iE Oyc59  
                DeleteOperation eID,count *tO<wp&  
                count=count-1 ~Op1NE  
            End If ]Cz16e&=2  
            count=count+1 hrL<jcv|  
        Wend ; p_X7N  
    ^]DWrmy  
        'Set new z-shift OX`n`+^D  
        op.Type = "ShiftZ" Km nr }Lp9  
        op.val1 = tlens ^`!Daqk  
        op.parent = parID "QF083$  
        AddOperation eID, op }6bLukv  
        Print "Set lens thickness = " & tlens YiCDV(prT  
    \fz j fZ1n  
        '************************************************************************* lX4p'R-h  
        'Lens index of refraction `SwnKg  
        '************************************************************************* <di_2hN  
        eID = FindMaterial( "Lens" ) 'AAY!{>  
        GetModelMaterial eID, mat 0/ Ht;(  
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        mat.Nd = nlens 7xc<vl#:q7  
        SetModelMaterial eID, mat ,![=_d  
        Print "Set lens index of refraction = " & nlens ;9PM?Iy[  
    :z\f.+MI  
        '************************************************************************* O$H150,Q  
        'Pupil diameter 1;P\mff3Y  
        '************************************************************************* Ax0,7,8y  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) (6BCFl:/Q<  
    EDo@J2A  
        'Adjust pupil diameter (trimming volume inner hole) |u{QI3#'  
    0uz"}v)  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" <n\.S  
    eC$v0Gtq  
        ' Adjust pupil location to just in front of the lens mvgm o  
        parID = FindFullName( "Geometry.Arizona Eye" ) I5L7BTe  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) C' ._}\nX  
        count = 0 i-?zwVmn  
        While GetOperationCount(eID)>count +I<Sq_-  
            GetOperation eID, count, op ]K7  64}  
            If op.Type="ShiftZ" Then |&Pl4P  
                DeleteOperation eID,count A,{D9-%  
                count=count-1 vy@Lu cB  
            End If 5 DB>zou   
            count=count+1 9>R|k$`  
        Wend q&E5[/VK:  
        op.Type = "ShiftZ" >t2b?(h/x  
        op.val1 = taq-0.01 Y/0O9}hf  
        op.parent = parID Fw9``{4w  
        AddOperation eID, op &%X Jf~IQ  
    u mlZ(??.  
        Print "Set pupil diameter = " & pupilDiam 9@Sb! 9h  
    3~</lAm;  
        'Update AZ Eye subassembly Description V@:=}*E  
        eID = FindFullName( "Geometry.Arizona Eye" ) ;n!X% S<z*  
        GetEntity eID, entity i8Y gG0[)  
        entity.Description = "Accommodation = " & A & "D" -mJ&N  
        SetEntity eID, entity g&T Cff  
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        Update p^rX.?X  
        Print "DONE!" z[%v _S  
         6\Vu#r  
    End Sub _-\s[p5  
    #L.}CzAz  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: p qN[G=0  
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    Accommodation = 4 Diopters 0juIkN#  
    Pupil Diameter = 4 mm t!SQLgA  
    Set aqueous humor thickness = 2.81 TDIOK  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 R0mT/h2  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 -Y=c g;  
    Set lens thickness = 3.927 Zk#i9[g9*  
    Set lens index of refraction = 1.42672 .eNwC.8i  
    Set pupil diameter = 4 8.Ef5-m  
    DONE! W4*BR_H&*  
     
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