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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 [HI&>dm=$  
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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。 vo )pT  
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模型 D M(WYL{  
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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。 |:$D[=  
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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. TU&6\]yF_  
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光源 W7>4-gk  
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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。 &sR=N60n  
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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。 aDFu!PLB{)  
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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。 'bGL@H  
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图2. 字母F光源的设定方法光 L@2%a'  
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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 &o{I9MD  
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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。 ztf VXmi'  
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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。 1{4d)z UB  
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图5. 视网膜重点采样规格设定
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脚本 S>O fUrt  
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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: h^^zR)EVb  
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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。 \s?OvqI:  
余下的脚本计算与屈光度有关的所有参数。 : Q X~bq  
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分析 _=E))Kp{z  
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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。 m6^Ua  
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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 D5fJuT-bp  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 26JP<&%L  
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Dim entity As T_ENTITY B!GpD@U  
Dim op As T_OPERATION )hm U/E@  
Dim mat As T_MODELMATERIAL <HM\ZDo@P  
Dim A As Double &?>h#H222  
Dim pupilDiam As Double W)JUMW2|  
Dim eID As Long pw{3I 2Ix  
Dim parID As Long T:o!H Xdj^  
Dim count As Integer <q hNX$t  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double H .)}|  
Dim tlens As Double, nlens As Double ]#R'hL%f  
Dim curv As Double, conic As Double a(Ka2;M4J  
Dim ok As Long IK5FSN]s/  
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Sub Main :kh l}|  
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    '用户输入对话框 <_@ K4zV  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 I7TdBe-  
        TextBox 220,21,40,21,.TextBox1 'default: 0 kRs[H xI3  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 *zeY<6  
        OKButton 40,91,90,21 jC+>^=J(  
        CancelButton 190,91,90,21 }MP2)6  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 (1JZuR<?c  
        TextBox 220,49,40,21,.TextBox2 'default: 4 j[NA3Vj1P  
    End Dialog xal,j*  
    Dim dlg As UserDialog  v'i"Q  
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    ok = Dialog (dlg) =o;QvOS;  
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    If ok=0 Then    'cancel button was pressed uW%7X2K  
        Print "Execution cancelled." ^4(CO[|c~  
        End pcXY6[#N  
    End If u^a\02aV[  
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    'Assign accommodation and pupil diameter & use defaults if field left empty $_ub.g|  
    If dlg.TextBox1 = "" Then .B*Yg<j  
        A = 0           'Default accommodation F48:mfj1r  
    Else z"o;|T:  
        A = CDbl(dlg.TextBox1) `%AFKmc^;  
    End If vLR)B@O,2  
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    If dlg.TextBox2 = "" Then YM{Q)115  
        pupilDiam = 4   'Default pupil diameter >C"cv^%c  
    Else 2!>phE  
        pupilDiam = CDbl(dlg.TextBox2) C0/s/p'  
    End If vW]Frb  
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    Print " " $de_>  
    Print "Accommodation = " & A & " Diopters" *E0+!  
    Print "Pupil Diameter = " & pupilDiam & " mm" Fp4?/-]  
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    ' Calculate new parameters with accommodation I=D{(%+^d  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 1~8F&  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 5FqUFzVqsl  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens "F>-W \%  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens g3n^ <[E  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens {l{p  
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    tlens = 3.767 + 0.04*A                  'Lens thickness qM3^)U2  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Uo(\1&?  
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    'Adjust parameters to account for accommodation j)Kk:BFFY  
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    '************************************************************************* C yC<{D+  
    'Aqueous thickness (Position of Lens) j^KM   
    '************************************************************************* @ :Q];rc  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) !Y=s_)X  
    GetCustomElement eID, entity 9UOx~Ty  
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    parID = FindFullName( "Geometry.Arizona Eye" ) n-,~Bp [  
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    ' Delete any shift(s) in z &k\7fvF  
    count = 0 NF0IF#;a  
    While GetOperationCount(eID)>count xp/u, q  
        GetOperation eID, count, op 0LoA-c<Ay  
        If op.Type="ShiftZ" Then Mp75L5  
            DeleteOperation eID,count YV-2es+Bd  
            count=count-1 aFo%B; 8m  
        End If yHQ.EZ~%  
        count=count+1 IaE};8a8  
    Wend b9EJLD  
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    'Set new shift in 9^0 'VRG  
    op.Type = "ShiftZ" ( NjX?^  
    op.val1 = taq v7O{8K+  
    op.parent = parID [KWF7GQi  
    AddOperation eID, op [lS'GszA  
    Print "Set aqueous humor thickness = " & taq-0.55 M(Jf&h4b  
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    '*************************************************************************  .^@+$}   
    'Radius and conic constant of anterior lens s`C#=l4  
    '*************************************************************************  i2)SSQ  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) rZGbU&ZM8  
    GetConic eID, entity, curv, conic 9<7Q{  
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    SetConic eID, entity, 1/Rant, CCant Iay7Fkv  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 1{o CMq/v  
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    '*************************************************************************  Ea\a:  
    'Radius and conic constant of posterior lens kGc)Un?'{U  
    '************************************************************************* TM!R[-\  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Y141Twjvd  
    GetConic eID, entity, curv, conic $ }B"u;:SU  
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    SetConic eID, entity, 1/Rpost, CCpost 68I4MZK>4  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost dUb(C1h  
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    '************************************************************************* uO[4 WZ  
    'Lens thickness (Position of posterior lens surface) k% In   
    '************************************************************************* % Pa-fee  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) -2 tZ  
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    ' Delete any z-shift(s) 9\Xl 3j!  
    count = 0 NLz$jk%=g  
    While GetOperationCount(eID)>count  k[vn:  
        GetOperation eID, count, op -v jjcyTt  
        If op.Type="ShiftZ" Then KOF!a  
            DeleteOperation eID,count y]?$zbB  
            count=count-1 9s*Lzi[}  
        End If <wE2ly&x  
        count=count+1 Wc,8<Y'   
    Wend *D<sk7  
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    'Set new z-shift L~mL9[(,  
    op.Type = "ShiftZ" Z@ I%ppd  
    op.val1 = tlens >F-J}P  
    op.parent = parID IZ2#jSDn  
    AddOperation eID, op ?: meix  
    Print "Set lens thickness = " & tlens ZgXh[UHQy  
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    '************************************************************************* ;m`I}h<  
    'Lens index of refraction ]iz5VI@  
    '************************************************************************* |23 }~c,  
    eID = FindMaterial( "Lens" ) (nE$};c<b2  
    GetModelMaterial eID, mat uO^{+=;A =  
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    mat.Nd = nlens o9~qJnB/O  
    SetModelMaterial eID, mat 6@I7UL >  
    Print "Set lens index of refraction = " & nlens eQ9x l  
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    '************************************************************************* Hb]7>[L  
    'Pupil diameter n[iil$VKh  
    '************************************************************************* S [u <vHy  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) VX>_Sp s  
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    'Adjust pupil diameter (trimming volume inner hole) 5cfzpOqr0  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" b _u&%  
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    ' Adjust pupil location to just in front of the lens uY;/3 ?k&  
    parID = FindFullName( "Geometry.Arizona Eye" ) NA3yd^sr  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ?%LD1 <ya  
    count = 0 T\WNT#My  
    While GetOperationCount(eID)>count @DUdgPA  
        GetOperation eID, count, op qq?>ulu*W  
        If op.Type="ShiftZ" Then ,\qo   
            DeleteOperation eID,count S"eKiS,z  
            count=count-1 i#-Jl7V[a  
        End If w"BTu-I  
        count=count+1 %(kq Hxc  
    Wend w_{z"VeD  
    op.Type = "ShiftZ" -p;o e}|  
    op.val1 = taq-0.01 BF_k~  
    op.parent = parID /f6]XP\'`+  
    AddOperation eID, op We4 FR4`  
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    Print "Set pupil diameter = " & pupilDiam TY#1Z )%  
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    'Update AZ Eye subassembly Description z44uhRh  
    eID = FindFullName( "Geometry.Arizona Eye" ) txgGL'  
    GetEntity eID, entity L;f=\q"g  
    entity.Description = "Accommodation = " & A & "D" Q72wg~%w  
    SetEntity eID, entity ^y3\e  
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    Update P! 3$RO  
    Print "DONE!" Pw7'6W1  
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End Sub fwnpmuJ  
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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: vV'^HD^v  
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Accommodation = 4 Diopters 7]^ }  
Pupil Diameter = 4 mm 6X jUb  
Set aqueous humor thickness = 2.81 +Va?wAnr  
Set anterior lens radius = 10.4 and conic constant = -2.375869 feopO j6~+  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 QbNv+Eu5  
Set lens thickness = 3.927 e7?W VV,  
Set lens index of refraction = 1.42672 M!hby31  
Set pupil diameter = 4 ljis3{kn""  
DONE! Nb8<8O ^  
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