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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 `uusUw-Gf  
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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。 `#`C.:/n  
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    模型 3&M0@/  
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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。 L5KcI  
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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. UMD\n<+cG,  
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    光源 7!Im|7Ty  
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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。 ?/sn"~"  
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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。 -T+'3</T  
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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。 +N2ILE8[<  
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    图2. 字母F光源的设定方法光 ?GLCd7TP  
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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 L %ifl:K  
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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。 aAn p7\7  
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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。 hV) `e"r\s  
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    图5. 视网膜重点采样规格设定
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    脚本 #a tL2(wJ  
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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: /"~UGn]R  
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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。 \GioSg  
    余下的脚本计算与屈光度有关的所有参数。 a gL@A  
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    分析 EaL>~: j  
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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。 01RW|rN  
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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 ^1_[UG  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. u'DpZ  
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    Dim entity As T_ENTITY ;$4&Qp:#  
    Dim op As T_OPERATION a=9QwEZ  
    Dim mat As T_MODELMATERIAL %S$$*|_G  
    Dim A As Double N:+d=G`x  
    Dim pupilDiam As Double A McZm0c`  
    Dim eID As Long ?FR-a Xx  
    Dim parID As Long H(M{hfa|  
    Dim count As Integer j}(m$j'  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double .EH1;/  
    Dim tlens As Double, nlens As Double YGc:84S  
    Dim curv As Double, conic As Double :l iDoGDi  
    Dim ok As Long JB.U&  
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    Sub Main w $`w  
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        '用户输入对话框 \W= qqE]  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 :IfwhI)  
            TextBox 220,21,40,21,.TextBox1 'default: 0 P46Q3EE  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 rQU6*f  
            OKButton 40,91,90,21 tp&|*M3  
            CancelButton 190,91,90,21 AR$SQ_4  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 "QiLu=Rq  
            TextBox 220,49,40,21,.TextBox2 'default: 4 >&7^yXS  
        End Dialog l5KO_"hy  
        Dim dlg As UserDialog G\V*j$}!  
    'ShK7j$  
        ok = Dialog (dlg) :rjfAe=s  
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        If ok=0 Then    'cancel button was pressed R*S:/s  
            Print "Execution cancelled." h@(+(fVHrp  
            End x)eoz2E1  
        End If ,j.bdlI#  
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        'Assign accommodation and pupil diameter & use defaults if field left empty %k )H7nj  
        If dlg.TextBox1 = "" Then D&~%w!  
            A = 0           'Default accommodation ?N!kYTR%}  
        Else !7MRHI/0C  
            A = CDbl(dlg.TextBox1) @>V;guJC%  
        End If -%^'x&e  
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        If dlg.TextBox2 = "" Then S'hUh'PZ  
            pupilDiam = 4   'Default pupil diameter zEukEA^9`  
        Else MOnTp8   
            pupilDiam = CDbl(dlg.TextBox2) >s0![coz  
        End If q(~|roKA(  
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        Print " " WY!4^<|w"  
        Print "Accommodation = " & A & " Diopters" t*)mX2R,  
        Print "Pupil Diameter = " & pupilDiam & " mm" 6DgdS5GhT_  
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        ' Calculate new parameters with accommodation n+YUG  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness fBv: TC%  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens mdEl CC0  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ^w<aS w  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens R<{Vgy  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens cF8X  
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        tlens = 3.767 + 0.04*A                  'Lens thickness aW{5m@p{"  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction >!a- "  
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        'Adjust parameters to account for accommodation '\xE56v)F  
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        '************************************************************************* \x]\W#C  
        'Aqueous thickness (Position of Lens) 5s`r&2 w  
        '************************************************************************* =+ >>l0=_v  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) c%gL3kOT  
        GetCustomElement eID, entity ;+6><O!G  
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        parID = FindFullName( "Geometry.Arizona Eye" ) 6o(IL-0]c  
    GdVF;  
        ' Delete any shift(s) in z 7Zd g314  
        count = 0 P R3Arfle  
        While GetOperationCount(eID)>count AovBKB $  
            GetOperation eID, count, op ugE!EEy[^  
            If op.Type="ShiftZ" Then QHf&Z*Xtl  
                DeleteOperation eID,count gkA_<,38  
                count=count-1 "*F`,I3  
            End If -GHd]7n  
            count=count+1 ih^FH>@  
        Wend ,$> l[G;Bm  
    Vd  d  
        'Set new shift in W ulyM cJ  
        op.Type = "ShiftZ" 3,6f}:CG  
        op.val1 = taq 9q_{_%G%  
        op.parent = parID q` IY;"~  
        AddOperation eID, op gD4vV'|  
        Print "Set aqueous humor thickness = " & taq-0.55 hd~#I<8;2  
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        '************************************************************************* 7*K UM6z  
        'Radius and conic constant of anterior lens L~Peerby  
        '************************************************************************* Bdb}4X rL  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) f(~N+2}  
        GetConic eID, entity, curv, conic %<(d %&~  
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        SetConic eID, entity, 1/Rant, CCant M\{\WyeX  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant !|H,g wqU  
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        '************************************************************************* @*Ry`)T  
        'Radius and conic constant of posterior lens f5Gn!xF  
        '************************************************************************* Q!V:=d  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Mh5> hD  
        GetConic eID, entity, curv, conic :=ek~s.UV  
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        SetConic eID, entity, 1/Rpost, CCpost 2tpuv(H;  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost T>rmm7F  
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        '************************************************************************* rlY0UA,  
        'Lens thickness (Position of posterior lens surface) vB_3lAJt@  
        '************************************************************************* K3[+L`pz  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 2J&~b8:  
    x0(bM g>7  
        ' Delete any z-shift(s) n-" (~  
        count = 0 *?HGi>]\ |  
        While GetOperationCount(eID)>count  ,S=[#  
            GetOperation eID, count, op L#byYB;E{  
            If op.Type="ShiftZ" Then _r{H)}9  
                DeleteOperation eID,count \+O.vRc"M  
                count=count-1 <;PKec  
            End If ckA\{v  
            count=count+1 |zpy!X3  
        Wend *kFd#b+xB  
    2WFZ6  
        'Set new z-shift 9AX}V6\+  
        op.Type = "ShiftZ" @GQfBV|3  
        op.val1 = tlens :1j8!R5  
        op.parent = parID Jp]?tlT  
        AddOperation eID, op `M6"=)twu  
        Print "Set lens thickness = " & tlens P7XZ|Td4*  
    ra T9  
        '************************************************************************* yT@Aj;X0v  
        'Lens index of refraction JpC=ACF  
        '************************************************************************* d ,98W=7  
        eID = FindMaterial( "Lens" ) cE 'LE1DK  
        GetModelMaterial eID, mat b3E1S+\=~  
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        mat.Nd = nlens |du%c`wl  
        SetModelMaterial eID, mat 3u/JcU-<  
        Print "Set lens index of refraction = " & nlens 'lA}E  
    1~L;S  
        '************************************************************************* :&vX0 Ce:  
        'Pupil diameter VRQ`-#  
        '************************************************************************* /x ?@M n>  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 6-_g1vq  
    I$t8Ko._"  
        'Adjust pupil diameter (trimming volume inner hole) h{^v756L  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" `z(o01y  
    W<X3!zuKSg  
        ' Adjust pupil location to just in front of the lens =eU=\td^  
        parID = FindFullName( "Geometry.Arizona Eye" ) u_^mN9h  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ^:{8z;w!(  
        count = 0 nD BWm`kN  
        While GetOperationCount(eID)>count //2O#Fg{/  
            GetOperation eID, count, op cj>UxU][eS  
            If op.Type="ShiftZ" Then QX<n^W  
                DeleteOperation eID,count BJux5Nh  
                count=count-1 . f ja;aG  
            End If Z&Ob,Ru  
            count=count+1 A r]*?:4y[  
        Wend Lxp}o7>K  
        op.Type = "ShiftZ" u>fMO9X} 2  
        op.val1 = taq-0.01 HRyFjAR\?  
        op.parent = parID 6^LXctW.  
        AddOperation eID, op &>Ve4!i q  
    UXBWCo;-  
        Print "Set pupil diameter = " & pupilDiam kJ5z['4?  
    .8|wc  
        'Update AZ Eye subassembly Description :lB`K>)iB}  
        eID = FindFullName( "Geometry.Arizona Eye" ) #("M4}~  
        GetEntity eID, entity x*vD^1"'P  
        entity.Description = "Accommodation = " & A & "D" prj(  
        SetEntity eID, entity F}u'A,Hc  
    &6vaLx  
        Update 9Y.(xp &vw  
        Print "DONE!" !y b06Z\f  
         #]jl{K\f#X  
    End Sub "Wg,]$IvU  
    /(JG\Ut  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: 'Eur[~k  
    ) 1AAL0F\B  
    Accommodation = 4 Diopters #!F>cez  
    Pupil Diameter = 4 mm v@%4i~N  
    Set aqueous humor thickness = 2.81 NF8<9  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 >g{&Qx`&  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 {OEjITm  
    Set lens thickness = 3.927 N4+Cg t(  
    Set lens index of refraction = 1.42672 gvR]"h  
    Set pupil diameter = 4 ~ZVz sNrx  
    DONE! F9o7=5WAb  
     
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