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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 <cU%yA710  
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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。 FzNj':D  
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模型  TD%&9$F  
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模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 [>t;P ,  
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Table 1. AZ眼睛模型的定义
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在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. ka6E s~  
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光源 V0BT./ B\<  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 i I`vu  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 R:$E'PSx  
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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。 r8?p6E  
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图2. 字母F光源的设定方法光 dr c-5{M  
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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 3n)$\aBE  
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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。 ^RO<r}B u  
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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。 FzcXSKHV %  
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图5. 视网膜重点采样规格设定
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脚本 }79O[&  
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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: $}{[_2  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 ti (Hx  
余下的脚本计算与屈光度有关的所有参数。 >$TvCw  
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分析 dW%t ph  
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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。 R~T}  
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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 i%[gNh  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 0&j90J$`  
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Dim entity As T_ENTITY a#"orc j  
Dim op As T_OPERATION /AAD Fa  
Dim mat As T_MODELMATERIAL n@xQ-v  
Dim A As Double v@tEHRadz  
Dim pupilDiam As Double U 7.kYu  
Dim eID As Long @fYVlHT%E  
Dim parID As Long 51b%uz  
Dim count As Integer bj}Lxc],  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ij;NM:|Sd  
Dim tlens As Double, nlens As Double vQyY %  
Dim curv As Double, conic As Double bsDA&~)s  
Dim ok As Long S4`X^a}pY  
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Sub Main tp}/>gU!  
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    '用户输入对话框 # :k=  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 9D+k71"+  
        TextBox 220,21,40,21,.TextBox1 'default: 0 Qy0w'L/@  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 `DF49YP"~  
        OKButton 40,91,90,21 8 5X}CCQ  
        CancelButton 190,91,90,21 #55:qc>m  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ofV0L  
        TextBox 220,49,40,21,.TextBox2 'default: 4 84.L1|k  
    End Dialog oG1zPspL  
    Dim dlg As UserDialog '"E!av>  
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    ok = Dialog (dlg) F0p=|W  
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    If ok=0 Then    'cancel button was pressed U,#x\[3!Jt  
        Print "Execution cancelled." 4h@,hY1#  
        End dh7`eAMY   
    End If (O4oI U  
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    'Assign accommodation and pupil diameter & use defaults if field left empty mdEJ'];AH  
    If dlg.TextBox1 = "" Then e' o2PW  
        A = 0           'Default accommodation =yZq]g6Q  
    Else Bh2l3J4X  
        A = CDbl(dlg.TextBox1)  x)Bbo9J  
    End If #4O4,F>e  
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    If dlg.TextBox2 = "" Then '~&W'='b;  
        pupilDiam = 4   'Default pupil diameter &L$9Ii  
    Else m%`YAD@2z  
        pupilDiam = CDbl(dlg.TextBox2) Pgr2 S I  
    End If qIQ=OY=6  
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    Print " " @!fUp b  
    Print "Accommodation = " & A & " Diopters" JE-*o"&  
    Print "Pupil Diameter = " & pupilDiam & " mm" mG\QF0h  
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    ' Calculate new parameters with accommodation MSQ^ovph  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness |qn 2b=  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens F]yB=  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens "jum*<QZz  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens #j~FlY5  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ZQE1]ht  
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    tlens = 3.767 + 0.04*A                  'Lens thickness T<pG$4_  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction /ovVS6Ai  
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    'Adjust parameters to account for accommodation y(Gn+  
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    '************************************************************************* h5'hP>b#  
    'Aqueous thickness (Position of Lens) >n09K8 A  
    '************************************************************************* B>L7UQ6_[  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) -_ I)5*N  
    GetCustomElement eID, entity />S^`KSTM  
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    parID = FindFullName( "Geometry.Arizona Eye" ) a ~v$ bNu  
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    ' Delete any shift(s) in z 6h>#;M  
    count = 0 B[@q.n  
    While GetOperationCount(eID)>count ;n Bf  
        GetOperation eID, count, op :Ph>\aG  
        If op.Type="ShiftZ" Then }(t`s  
            DeleteOperation eID,count t<##0#xS.  
            count=count-1 T ?[28|  
        End If rQimQ|+  
        count=count+1 cpjwc@UMe  
    Wend ,~d0R4)  
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    'Set new shift in F<I*?${[  
    op.Type = "ShiftZ" e3; &  
    op.val1 = taq GJ*IH9YR  
    op.parent = parID " !EnQB=  
    AddOperation eID, op eK:?~BI!  
    Print "Set aqueous humor thickness = " & taq-0.55 >)ekb7  
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    '************************************************************************* $IE}fgA@5  
    'Radius and conic constant of anterior lens \l:R]:w;ZI  
    '************************************************************************* ;-Yvi,sS+  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ,- AF8BP  
    GetConic eID, entity, curv, conic dxs5woP  
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    SetConic eID, entity, 1/Rant, CCant <!sLf z?  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant N55F5  
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    '************************************************************************* Hx gC*-A$/  
    'Radius and conic constant of posterior lens rC-E+%y  
    '************************************************************************* $NVVurXa  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) fY00  
    GetConic eID, entity, curv, conic +\T8`iCFB  
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    SetConic eID, entity, 1/Rpost, CCpost A2 + %  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost {1SsH ir>  
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    '************************************************************************* H d|p@$I  
    'Lens thickness (Position of posterior lens surface) g5nJ0=9  
    '************************************************************************* Ku ,wI86  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) yI: ;+K  
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    ' Delete any z-shift(s) DJ"PP 5d  
    count = 0 OeqKKVuQ  
    While GetOperationCount(eID)>count \V$qAfP)  
        GetOperation eID, count, op ;g!rc#z2g  
        If op.Type="ShiftZ" Then u}nSdZC  
            DeleteOperation eID,count ^N/d`IAjv  
            count=count-1 L(;$(k-/(  
        End If \\dUp>1=  
        count=count+1 =>;&M)+q  
    Wend 9w=7A>.U  
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    'Set new z-shift ./F:]/Mt  
    op.Type = "ShiftZ" PMytk`<`zw  
    op.val1 = tlens Xq;|l?,O  
    op.parent = parID h <4`|Bg+  
    AddOperation eID, op YCDH0M  
    Print "Set lens thickness = " & tlens F LWVI4*  
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    '************************************************************************* v.(dOIrX  
    'Lens index of refraction \\k=N(n  
    '************************************************************************* LaQ7A,]  
    eID = FindMaterial( "Lens" ) G<7M;vRvP  
    GetModelMaterial eID, mat G`FYEmD  
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    mat.Nd = nlens ~, }|~  
    SetModelMaterial eID, mat Z^|N]Ej  
    Print "Set lens index of refraction = " & nlens N9!L8BBaK  
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    '************************************************************************* Jc#D4e1#  
    'Pupil diameter $Lp [i <O]  
    '************************************************************************* 4Fft[S(  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) to?!qxn  
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    'Adjust pupil diameter (trimming volume inner hole) 5GM-*Ak@  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" @5^&&4>N  
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    ' Adjust pupil location to just in front of the lens '{ _ X1  
    parID = FindFullName( "Geometry.Arizona Eye" ) {32m&a  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) / dJz?0  
    count = 0 qnp}#BZ  
    While GetOperationCount(eID)>count I!L J&>  
        GetOperation eID, count, op  |,$&jSe  
        If op.Type="ShiftZ" Then TaRPMKk  
            DeleteOperation eID,count {'M<dI$  
            count=count-1 EIRDH'[L  
        End If /wLBmh1"  
        count=count+1 7W)W9=&BT  
    Wend TLsF c^X  
    op.Type = "ShiftZ" q}t]lD %C  
    op.val1 = taq-0.01 OInl?_,,T#  
    op.parent = parID 2K9X (th1  
    AddOperation eID, op 86{>X5+  
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    Print "Set pupil diameter = " & pupilDiam k ;^$Pd?t  
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    'Update AZ Eye subassembly Description P*6m~`"5  
    eID = FindFullName( "Geometry.Arizona Eye" ) h^ Cm\V  
    GetEntity eID, entity wY<s  
    entity.Description = "Accommodation = " & A & "D" [h'u@%N|/  
    SetEntity eID, entity ?>B?*IK!  
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    Update 6bPxEILm  
    Print "DONE!" vW &G\L  
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End Sub #%[;v K  
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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: $BdwKk !k  
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Accommodation = 4 Diopters gk|>E[.  
Pupil Diameter = 4 mm M[`[+5v  
Set aqueous humor thickness = 2.81 `0qjaC  
Set anterior lens radius = 10.4 and conic constant = -2.375869 &\ 9%;k  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 RxqNgun@  
Set lens thickness = 3.927 56)!&MF  
Set lens index of refraction = 1.42672 _[R(9KyF0f  
Set pupil diameter = 4 Ca'BE#q  
DONE! 9I/l+IS"X  
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