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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。 Y5~_y?BX  
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模型 21$YZlhJ  
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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。 /-wAy-W  
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. j*m7&wOE  
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光源 :XK.A   
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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。 D7b<&D@  
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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。 e9;<9uX  
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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。 6,sZo!G  
图2. 字母F光源的设定方法光 wRL=9/5(8  
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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 |->{NU Z{  
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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。 K.?~@5%  
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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。 d/G`w{H}y  
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图5. 视网膜重点采样规格设定
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脚本 *ktM<N58  
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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: .%7#o  
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。 HDU tLU d  
余下的脚本计算与屈光度有关的所有参数。 s7 IaU|m  
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分析 L;=:OX 0  
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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。 c#M 'Mye  
图7. 字母F在视网膜上颜色分析
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脚本代码 h4x*C=?A  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. F23/|q{{  
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Dim entity As T_ENTITY 2Q`@lTUv  
Dim op As T_OPERATION 1\:puC\)  
Dim mat As T_MODELMATERIAL ;hi+.ng_  
Dim A As Double :SilQm*Pl  
Dim pupilDiam As Double _Z'j%/-4@D  
Dim eID As Long 7q*L-Xe]k  
Dim parID As Long mHjds77e  
Dim count As Integer 0UeDM*  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double @EH:4~  
Dim tlens As Double, nlens As Double Kl<qp7o0  
Dim curv As Double, conic As Double s0"S;{_#  
Dim ok As Long u1a5Vtel  
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Sub Main `T2RaWR4=  
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    '用户输入对话框 2bBTd@m4  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 R,CFU l7Q  
        TextBox 220,21,40,21,.TextBox1 'default: 0 WmTSxneo  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 dxbP'2~  
        OKButton 40,91,90,21 es@_6ol.@  
        CancelButton 190,91,90,21 u"r~5  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 hko0 ?z  
        TextBox 220,49,40,21,.TextBox2 'default: 4 Uj&2'>MJ$  
    End Dialog 4`5jq)  
    Dim dlg As UserDialog /v"u4Ipj  
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    ok = Dialog (dlg) I`kaAOe  
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    If ok=0 Then    'cancel button was pressed +h^>?U,  
        Print "Execution cancelled." #y13(u,dN  
        End Q':xi;?Kt  
    End If mh;<lW\K/Z  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 4VINu9\V  
    If dlg.TextBox1 = "" Then mw%do&e  
        A = 0           'Default accommodation YKq,`7"%  
    Else v 0mc1g+9  
        A = CDbl(dlg.TextBox1) P.mz$M  
    End If ,-^Grmr4M  
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    If dlg.TextBox2 = "" Then 1P(rgn:8e  
        pupilDiam = 4   'Default pupil diameter ;Ut0tm  
    Else |SC^H56+  
        pupilDiam = CDbl(dlg.TextBox2) r# MJ  
    End If S05+G}[$  
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    Print " " ScU?T<u:i  
    Print "Accommodation = " & A & " Diopters" 0FmYM@Wc  
    Print "Pupil Diameter = " & pupilDiam & " mm" T!e ]=  
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    ' Calculate new parameters with accommodation hI*gw3V  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness braHWC'VYg  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 5BnO-[3  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens i:W.,w%8  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens xayo{l=uGv  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens )*@n G$i99  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 8px@sXI*`  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction @qk$ 6X  
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    'Adjust parameters to account for accommodation 8o43J;mA  
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    '************************************************************************* Ag=>F5  
    'Aqueous thickness (Position of Lens) _<pSCR0  
    '************************************************************************* Qa@b-v'by  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" )  (c;F%m|  
    GetCustomElement eID, entity (UWWULV  
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    parID = FindFullName( "Geometry.Arizona Eye" ) |}N -5U  
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    ' Delete any shift(s) in z QcJ?1GwA"  
    count = 0 %suSZw`  
    While GetOperationCount(eID)>count Oz(0$c  
        GetOperation eID, count, op  SyFw  
        If op.Type="ShiftZ" Then m  "'  
            DeleteOperation eID,count ("-Co,4ey  
            count=count-1 [.Vy  
        End If =Hplg>h)  
        count=count+1 ^\=<geEj  
    Wend :YaEMQJ^  
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    'Set new shift in dbM~41C6  
    op.Type = "ShiftZ" J'c]':U  
    op.val1 = taq x`n$4a'7b  
    op.parent = parID B1)gudP`  
    AddOperation eID, op ?'ID7mL  
    Print "Set aqueous humor thickness = " & taq-0.55  *R1 m=  
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    '************************************************************************* |Iei!jm  
    'Radius and conic constant of anterior lens MH@=Qqx#=t  
    '************************************************************************* 8,iBG! RF  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) B].V|8h  
    GetConic eID, entity, curv, conic Q@]~O-  
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    SetConic eID, entity, 1/Rant, CCant T DOOq;+  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant kT6h}d^/^  
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    '************************************************************************* fA"N5qQI(  
    'Radius and conic constant of posterior lens BfZAK0+*$  
    '************************************************************************* }e$^v*16  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) tt5t(+5j  
    GetConic eID, entity, curv, conic ipzv]c&  
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    SetConic eID, entity, 1/Rpost, CCpost 6S]K@C=r  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost SOE 5`  
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    '************************************************************************* .. jc^'L  
    'Lens thickness (Position of posterior lens surface) )F _vWbg  
    '************************************************************************* We%HdTKT  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 8<V6W F`e  
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    ' Delete any z-shift(s) {A!1s;  
    count = 0 h r@c7/L  
    While GetOperationCount(eID)>count [+ ,%T;d;  
        GetOperation eID, count, op - Q3jK)1  
        If op.Type="ShiftZ" Then xvo""R/g8  
            DeleteOperation eID,count %f[0&)1!.v  
            count=count-1 581Jp'cje  
        End If z[Sq7bbYO  
        count=count+1 Cj{+DXT  
    Wend sVXIR  
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    'Set new z-shift {Hc [H-  
    op.Type = "ShiftZ" =VA5!-6<Uq  
    op.val1 = tlens pO]{Y?X:  
    op.parent = parID {#?$ p i[  
    AddOperation eID, op Iv,Ub_Ll9  
    Print "Set lens thickness = " & tlens *xHj*  
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    '************************************************************************* O*qSc^9q  
    'Lens index of refraction m@(8-_  
    '************************************************************************* $MW-c*5a  
    eID = FindMaterial( "Lens" ) jLc"1+  
    GetModelMaterial eID, mat 0 0JH*I  
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    mat.Nd = nlens }jL_/gvgy  
    SetModelMaterial eID, mat `Uz2(zqS  
    Print "Set lens index of refraction = " & nlens -@*[   
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    '************************************************************************* .kbo]P  
    'Pupil diameter 1#nR$  
    '************************************************************************* ]IF QD  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Q4~/Tl;  
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    'Adjust pupil diameter (trimming volume inner hole) :eHD{=  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" #:q$sKQ_$  
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    ' Adjust pupil location to just in front of the lens v3zd>fDnRp  
    parID = FindFullName( "Geometry.Arizona Eye" ) *U<l$gajq  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) [nSlkl   
    count = 0 .$o0$`}  
    While GetOperationCount(eID)>count L>trLD1pt  
        GetOperation eID, count, op R=7,F6.  
        If op.Type="ShiftZ" Then adCTo  
            DeleteOperation eID,count , ZisJksk  
            count=count-1 b\Wlpb=QZ  
        End If N*^iOm]Y  
        count=count+1 [quT&E  
    Wend !sTOo  
    op.Type = "ShiftZ" aLo^f= S  
    op.val1 = taq-0.01 CIt%7 \c  
    op.parent = parID wSV}{9}wr%  
    AddOperation eID, op $Gy&  
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    Print "Set pupil diameter = " & pupilDiam OuZPgN  
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    'Update AZ Eye subassembly Description {4C/ZA{|l  
    eID = FindFullName( "Geometry.Arizona Eye" ) k vu SE  
    GetEntity eID, entity ^i"~6QYE  
    entity.Description = "Accommodation = " & A & "D" :m&cm%W]ts  
    SetEntity eID, entity xr*%:TwCta  
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    Update |>'.(  
    Print "DONE!" KfPYH\ 0  
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End Sub 8*bEsc|  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: e=H,|)P  
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Accommodation = 4 Diopters -%G}T}"_  
Pupil Diameter = 4 mm dvc=<!"'S  
Set aqueous humor thickness = 2.81 Hxr)`i46  
Set anterior lens radius = 10.4 and conic constant = -2.375869 )%zOq:{\5  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 ZFxa2J~;  
Set lens thickness = 3.927 t@#l0lu$  
Set lens index of refraction = 1.42672 m)1+D"z  
Set pupil diameter = 4 j@o \d%.'!  
DONE!
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