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简介 B2G5hbaA 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。 -[=AlqL 3W-NS~y 模型 h76NR Xh0wWU* 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。 YR|(;B t}XB|h Table 1. AZ眼睛模型的定义 ]~\SR0 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. -?aw^du ci,o8 [Y 光源 ^%oG8z,L p&OJa$N$[ 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。 ) _9e@~, :!I)r$ xMSNrOc 图1. 光源和提示信息使用 YMj7 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。 g<2lPH
I(^jOgYU 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。 ti{H(;;@ 5mna7BCEb 图2. 字母F光源的设定方法光 Ufaqhh {
OxAY_ 图3. 字母F在视网膜上位置点列图 m]0^ 视网膜的散射 Ez/\bE foFg((tS 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。 O^X[9vrW V#gF*]q lPRdwg- 图4. 视网膜朗伯散射设定 vbRrk($` 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。 Sv~YFS :oy (o x4K{ $Yx6#m}[M 图5. 视网膜重点采样规格设定 'R4>CZ%jV 脚本 <\1}@?NGC QJM-`( 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: \3H<z@; #1QX!dK+ 图6. 用户对话框的创建与编辑 A*7Io4e! 图7. 用户对话框编辑器 +CnyK(V 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 f
MY; 余下的脚本计算与屈光度有关的所有参数。 8!u/
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{ppn gdoJ4b 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Y!++CMzU !lQ#sL` 图7. 字母F在视网膜上颜色分析 My]+?.Ru 脚本代码 [2GXAvXsT IWjR0 Option Explicit 'Remove this to enable non-dimensioned variables to be used. ";wyNpb( xa87xX=a Dim entity As T_ENTITY Tjnt(5 g Dim op As T_OPERATION 8- dRdQu] Dim mat As T_MODELMATERIAL [c&2i`C Dim A As Double ]j& FbP)3 Dim pupilDiam As Double 5TXg;v#Z Dim eID As Long //\ds71h Dim parID As Long cT/3yf Dim count As Integer Z|2Eb* Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 0s860Kn Dim tlens As Double, nlens As Double _:wZmZU} Dim curv As Double, conic As Double 3C277nx Dim ok As Long 9 '2= (bg}an Sub Main "DVt3E 7<h.KZPc '用户输入对话框 kx|me~I
Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 yB-.sGu TextBox 220,21,40,21,.TextBox1 'default: 0 84iJ[Fq{ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 [X;>*- OKButton 40,91,90,21 X3P&"}a CancelButton 190,91,90,21 R<Z^L~) Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 |if'_x1V TextBox 220,49,40,21,.TextBox2 'default: 4 jmkRP"ZnA End Dialog 3H1Pp*PH Dim dlg As UserDialog y7CWBTH0> 8ou e-:/a ok = Dialog (dlg) HDyQzCG, OZG0AX+=# If ok=0 Then 'cancel button was pressed e &d3SQ% Print "Execution cancelled." Kn']n91m End <e'P%tG' End If :FnOS<_B h]qT1(I 'Assign accommodation and pupil diameter & use defaults if field left empty 'KSa8;:=C If dlg.TextBox1 = "" Then ]} '^` A = 0 'Default accommodation ,,S9$@R Else }.'Z=yy A = CDbl(dlg.TextBox1) Zotz?jVVr End If ?p(kh^ z d& hD[v If dlg.TextBox2 = "" Then 0[.3Es:_ pupilDiam = 4 'Default pupil diameter ?RDO] I> Else ~u!gUJ: pupilDiam = CDbl(dlg.TextBox2) )B81i!
q End If QW2?n`Fa9- k,T_e6( Print " " RYt6=R+f Print "Accommodation = " & A & " Diopters" [KMS<4t' Print "Pupil Diameter = " & pupilDiam & " mm" 9X3yp:>V q'.;W@m ' Calculate new parameters with accommodation jA,|JgN|n taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness h77IWo6% Lj iI+NJ Rant = 12.0 - 0.4*A 'Radius of anterior lens 9/G!0uE CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ^+M><jE9 7ZQ'h3K Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Hr6wgYPi CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens }hCaNQ&jH y5_XHi@u~o tlens = 3.767 + 0.04*A 'Lens thickness r
^MiRa xo(k?+P>. nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Q3,=~}ZNK qC..\{z 'Adjust parameters to account for accommodation ".E5t@ }?m ?gN9kd) '************************************************************************* Mb/L~gd" 'Aqueous thickness (Position of Lens) gH'_ymT=
3 '************************************************************************* /1[gn8V691 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) UQ~4c, GetCustomElement eID, entity s@s/'^` =-qf ;5[| parID = FindFullName( "Geometry.Arizona Eye" ) gD6tHg>_ /VO^5Dnb ' Delete any shift(s) in z ]H+{eJB7O count = 0 5z~\5x While GetOperationCount(eID)>count Px#$uU GetOperation eID, count, op qOi5WX6F/ If op.Type="ShiftZ" Then U*qNix DeleteOperation eID,count -;>#3O- count=count-1 ib]vX- End If (z2Z)_6L*L count=count+1 {i>Jfl]G} Wend thptm 5oJ Dux } 'Set new shift in z,x"a op.Type = "ShiftZ" ,1
P[ op.val1 = taq ~ezCu_ op.parent = parID sT`^ljp4 AddOperation eID, op AK *N Print "Set aqueous humor thickness = " & taq-0.55 4\6:\ 9 mPIykAj8 '************************************************************************* ~{M@?8wi 'Radius and conic constant of anterior lens j o_
sAb '************************************************************************* )* TF" eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Sl>>SP GetConic eID, entity, curv, conic jV^C19 Hbk&6kS SetConic eID, entity, 1/Rant, CCant ?'sXgo.} Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant !5UfWk\G x2k*|=$ '************************************************************************* +j[`,5oS 'Radius and conic constant of posterior lens HabzCH '************************************************************************* Go <' eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" )
HE;V zR GetConic eID, entity, curv, conic 6^E`Sa!s sx5r(0Z SetConic eID, entity, 1/Rpost, CCpost %!y89x=E Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost j[XYj6*d >vujZw_0> '************************************************************************* qS.)UaA 'Lens thickness (Position of posterior lens surface) n3ZAF' '************************************************************************* xmr|'}Pt[ :wipE]~4t parID = FindFullName( "Geometry.Arizona Eye.Lens" ) `f)(Y1%. ArzDI{1 ' Delete any z-shift(s) h/<=u9J count = 0 (A{NF( While GetOperationCount(eID)>count Nfw YDY GetOperation eID, count, op i2PZ'.sL If op.Type="ShiftZ" Then zZ=$O-&% DeleteOperation eID,count _ 08];M| count=count-1 3.vgukkk5 End If aFY u}kl count=count+1 _]|Qec) Wend =_PvrB 2' &?+WXL> 'Set new z-shift EGS%C%>l/o op.Type = "ShiftZ" hz\WZ^ op.val1 = tlens <o0~H op.parent = parID z[9UQU~x? AddOperation eID, op /IR#A%U Print "Set lens thickness = " & tlens 6OB" , Mw^*yW '************************************************************************* <>=mCZ2 'Lens index of refraction jN/ j\x' '************************************************************************* ssl&5AS eID = FindMaterial( "Lens" ) #3MKH8k&~ GetModelMaterial eID, mat qn"K9k % fhNxR mat.Nd = nlens HZZDv+ SetModelMaterial eID, mat 2o5;Uz1{ Print "Set lens index of refraction = " & nlens `;F2n2@ 6RK\}@^=K '************************************************************************* u7=T(4a 'Pupil diameter &5Y_>{, '************************************************************************* - k`.j eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) it1/3y
=] `.^ |]|u 'Adjust pupil diameter (trimming volume inner hole) z%:1) [uR/M SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ?CY1]d 'fY9a(Xt. ' Adjust pupil location to just in front of the lens 8&E}n(XE parID = FindFullName( "Geometry.Arizona Eye" ) CMl~=[foW eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) -MfQ&U count = 0 *Km7U-BG While GetOperationCount(eID)>count &erm`Ho GetOperation eID, count, op T20VX 8gX If op.Type="ShiftZ" Then )`?%]D DeleteOperation eID,count ?+`xe{k count=count-1 #jS[ End If %Kto.Xq count=count+1 DWf$X1M Wend 5 DFZ^~ op.Type = "ShiftZ" <z) E(J\ op.val1 = taq-0.01 g}Qx`65: op.parent = parID \=nrt? AddOperation eID, op ,rO[mNk9@ 44-r\> Print "Set pupil diameter = " & pupilDiam |4C^$ I>"Ci(N 'Update AZ Eye subassembly Description =2 jhII eID = FindFullName( "Geometry.Arizona Eye" ) &]iKriG GetEntity eID, entity g>0vm2| entity.Description = "Accommodation = " & A & "D" }5b M1h#z SetEntity eID, entity qnIew?-* +)/Uu3"= Update LP<<'(l` Print "DONE!" )bDnbO$s_ rFu ez$ End Sub C}"@RHEu ZkWL_ H) 如果屈光度是4,光瞳直径是4,则会输出如下数据: j_Nm87i] c`kQvXx Accommodation = 4 Diopters h-XY4gq/ Pupil Diameter = 4 mm hh"-w3+ Set aqueous humor thickness = 2.81 rt!r2dq" Set anterior lens radius = 10.4 and conic constant = -2.375869 !% S4n Set posterior lens radius = -4.424557 and conic constant = -3.081019 2\@Z5m3B Set lens thickness = 3.927 D>kD1B1 Set lens index of refraction = 1.42672 {o|k.zy Set pupil diameter = 4 "H+,E_&( DONE! e7k%6'@ *g$i5!yM' (文章来源:讯技光电)
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