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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 vHPp$lql  
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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。 bytAdS$3  
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模型 /"$;3n~  
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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。 fWywegh  
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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. Ul@yXtj  
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光源 _fu?,  
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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。 /}\EMP  
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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。 -Fe) )Y'=  
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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。  cf#2Wg)  
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图2. 字母F光源的设定方法光 p#UrZKR  
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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 FDA``H~  
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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。 qJb9JL$s  
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 9H9 P'lx9  
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图5. 视网膜重点采样规格设定
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脚本 Qx-/t9`!Z  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: x roo_  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 X\:;A{  
余下的脚本计算与屈光度有关的所有参数。 )_eEM1  
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分析 cRm+?/  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 AM4lAq_  
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图7. 字母F在视网膜上颜色分析
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脚本代码 t'e1r&^:r~  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. tA2Py  
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Dim entity As T_ENTITY +ML4.$lc^  
Dim op As T_OPERATION \wR $_X&  
Dim mat As T_MODELMATERIAL (7l'e=J0  
Dim A As Double cI~uI '  
Dim pupilDiam As Double s9R#rwIc  
Dim eID As Long "]1 !<M6\i  
Dim parID As Long -? _#Yttu  
Dim count As Integer 'aYUF&GG  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double CatbEXO  
Dim tlens As Double, nlens As Double {t<E*5N]a  
Dim curv As Double, conic As Double >yr:L{{D}G  
Dim ok As Long F xek#  
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Sub Main <$6r1y*G  
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    '用户输入对话框 Ass :  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 gEghDO_G  
        TextBox 220,21,40,21,.TextBox1 'default: 0 kiYHJ\a  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ?VUU[h8"v5  
        OKButton 40,91,90,21 %b 8ig1  
        CancelButton 190,91,90,21 _{Q)5ooP  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 -BQoNEh  
        TextBox 220,49,40,21,.TextBox2 'default: 4 uDhe )  
    End Dialog _yH{LUIj  
    Dim dlg As UserDialog oT7 6)O  
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    ok = Dialog (dlg) c`S`.WID  
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    If ok=0 Then    'cancel button was pressed Qt-7jmZw1  
        Print "Execution cancelled." ``X1xiB  
        End 3K;V3pJ].  
    End If #`Af  
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    'Assign accommodation and pupil diameter & use defaults if field left empty tx` Z?K[  
    If dlg.TextBox1 = "" Then /b&ka&|t  
        A = 0           'Default accommodation {KQ-QKxxS  
    Else {5 V@O_*{  
        A = CDbl(dlg.TextBox1) |ry![\  
    End If 55Pe&V1=  
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    If dlg.TextBox2 = "" Then E?v9c>c  
        pupilDiam = 4   'Default pupil diameter h^QLvOuR  
    Else `!,"">5  
        pupilDiam = CDbl(dlg.TextBox2) v11Uw?CM  
    End If 0tz7^:|D  
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    Print " " + d?p? v  
    Print "Accommodation = " & A & " Diopters" v2Ft=_*G|  
    Print "Pupil Diameter = " & pupilDiam & " mm" .1{:Q1"S  
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    ' Calculate new parameters with accommodation V;pR w`  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness WswM5RN  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens B4 k5IS  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens g5& ZXA  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ahh&h1q7|  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens oV/:T\Qn=  
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    tlens = 3.767 + 0.04*A                  'Lens thickness eoj(zY3  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction tZXq<k9  
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    'Adjust parameters to account for accommodation *P01 yW0  
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    '************************************************************************* "cZ){w  
    'Aqueous thickness (Position of Lens) 9kzJ5}  
    '************************************************************************* G1 K@Ir<  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) g+j\wvx0  
    GetCustomElement eID, entity =L\&} kzB  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ~0@ uR  
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    ' Delete any shift(s) in z mI,a2wqi  
    count = 0 l5 T0x=y9!  
    While GetOperationCount(eID)>count " k0gZb  
        GetOperation eID, count, op Gh5 3 Pne  
        If op.Type="ShiftZ" Then NwcRH9};i  
            DeleteOperation eID,count +;Pkpuu  
            count=count-1 [-0=ZKH?  
        End If lyS`X  
        count=count+1 1rIL[(r4  
    Wend ^/ff)'.J  
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    'Set new shift in 6Z@?W  
    op.Type = "ShiftZ" tjLG$M1z`  
    op.val1 = taq ^\oMsU5(  
    op.parent = parID **CGkL  
    AddOperation eID, op A I v  
    Print "Set aqueous humor thickness = " & taq-0.55 kmg/hNtN  
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    '************************************************************************* hg7_ZjO  
    'Radius and conic constant of anterior lens yJ:rry  
    '************************************************************************* $ghlrV;:ct  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) (kVxa8 0  
    GetConic eID, entity, curv, conic yRivf.wH  
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    SetConic eID, entity, 1/Rant, CCant yR% l[/ X  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant |fB/hs \  
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    '************************************************************************* v'Pbx  
    'Radius and conic constant of posterior lens Doe:m#aNj  
    '************************************************************************* 65vsQ|Zw  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) \Ez&?yb/  
    GetConic eID, entity, curv, conic uO((Mg  
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    SetConic eID, entity, 1/Rpost, CCpost U]&/F{3 im  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost pwv mb\  
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    '************************************************************************* ^)o#/"JA  
    'Lens thickness (Position of posterior lens surface) <Zo{D |hW  
    '************************************************************************* !ir%Pz ^)  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) gSHN,8. `  
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    ' Delete any z-shift(s) `k7X|  
    count = 0 OD~yIV  
    While GetOperationCount(eID)>count DH"_.j  
        GetOperation eID, count, op OGcW]i  
        If op.Type="ShiftZ" Then JkEITuTth  
            DeleteOperation eID,count DFb hy  
            count=count-1 :<H4hYt2  
        End If fRwr}n'  
        count=count+1 RS|*3 $1  
    Wend pI1g<pe  
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    'Set new z-shift wkY$J\J  
    op.Type = "ShiftZ" ba)hWtenH  
    op.val1 = tlens /vPr^Wv  
    op.parent = parID y,6KU$G  
    AddOperation eID, op NOFH  
    Print "Set lens thickness = " & tlens %NcBq3  
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    '************************************************************************* ]l"9B'XR  
    'Lens index of refraction ";upu  
    '************************************************************************* lm*C:e)4A  
    eID = FindMaterial( "Lens" ) %"ehZ d0r  
    GetModelMaterial eID, mat }%c0EY'  
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    mat.Nd = nlens 4m%Yck{R  
    SetModelMaterial eID, mat Lie= DD  
    Print "Set lens index of refraction = " & nlens @cQ |`  
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    '************************************************************************* 6A4{6B  
    'Pupil diameter YXg^t$  
    '************************************************************************* EL6<%~,V"I  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ([A%>u>h  
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    'Adjust pupil diameter (trimming volume inner hole)  `ghNS  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ?[.g~DK,  
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    ' Adjust pupil location to just in front of the lens v?o("I[ C  
    parID = FindFullName( "Geometry.Arizona Eye" ) M8VsU*aU  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) g@m__   
    count = 0 Pa{bkr  
    While GetOperationCount(eID)>count FX+^S?x.  
        GetOperation eID, count, op {~V_6wY g  
        If op.Type="ShiftZ" Then PI)uBA;  
            DeleteOperation eID,count C9j5Pd5q1L  
            count=count-1 \,G19o}`Es  
        End If Pu}PE-b  
        count=count+1 UdFYG^i  
    Wend 3 =_to7]  
    op.Type = "ShiftZ" m@yx6[E#  
    op.val1 = taq-0.01 .VkLF6  
    op.parent = parID h: zi8;(  
    AddOperation eID, op mFyYn,Mu|  
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    Print "Set pupil diameter = " & pupilDiam _<jccQ  
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    'Update AZ Eye subassembly Description <7oZV^nd *  
    eID = FindFullName( "Geometry.Arizona Eye" ) %sS7o3RW\  
    GetEntity eID, entity 'D?sRbJ=  
    entity.Description = "Accommodation = " & A & "D" o2^?D`Jr  
    SetEntity eID, entity !< ^`Sx/+  
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    Update [jF\"#A  
    Print "DONE!" X6oY-4O  
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End Sub Rp.FG   
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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: kN* \yH|  
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Accommodation = 4 Diopters "HbrYYRb'  
Pupil Diameter = 4 mm :yAvo4 )  
Set aqueous humor thickness = 2.81 nHB`<B  
Set anterior lens radius = 10.4 and conic constant = -2.375869 N-GQ\&   
Set posterior lens radius = -4.424557 and conic constant = -3.081019 mWU*}-M  
Set lens thickness = 3.927 MM Nz2DEy[  
Set lens index of refraction = 1.42672 !n5s/"'H  
Set pupil diameter = 4 Jm}zit:o  
DONE! +isaqfy/  
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