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简介 ;`#R9\C=h 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。 7v%c. V,_m>$Mo 模型 tsc`u> p?Azn>qBa 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 VQla.Y EpAgKzVpJ Table 1. AZ眼睛模型的定义 d>hv-nD 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. 2DCQ5XewYe .}!.4J%q2 光源 Gc|)4c *z0d~j*W; 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 g Y~r{ uMg\s\Z GkJcd; 图1. 光源和提示信息使用 Ax=HDW} 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 %rptI$^*X 0ae8Xm3J@R 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。 (P)G|2= . ImaM 图2. 字母F光源的设定方法光 i
6G40!G=) Tzex\]fw 图3. 字母F在视网膜上位置点列图 B`}um;T#~, 视网膜的散射 ~w>h#{RB 2 kDsIEA 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。 J3 _aHI @yuiNj.T y>a?<*Y+e 图4. 视网膜朗伯散射设定 _B^zm-}8|B 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。 n"EKVw7Y $6"(t= %{ F^O83[S 图5. 视网膜重点采样规格设定 jfuHZ^ YA 脚本 aas.-NT .Fn|Okn^gr 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: +Y%6y]8 glMHT, 图6. 用户对话框的创建与编辑 OldOc5D 图7. 用户对话框编辑器
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D*l 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。
;/K2h_=3z 余下的脚本计算与屈光度有关的所有参数。 Z4] n<~o P3_.U8g$r 分析 <sH}X$/ w"^h<]b 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ^LMgOA(7 cl~Yx4 图7. 字母F在视网膜上颜色分析 XNJ4T]>< 脚本代码 1^\w7Rew2 $m 4-^= Option Explicit 'Remove this to enable non-dimensioned variables to be used. \/NF??k,jk T D_@0Rd Dim entity As T_ENTITY Q7s@,c!m_ Dim op As T_OPERATION js_`L#t Dim mat As T_MODELMATERIAL [oLV,O|s|j Dim A As Double MYAt4cHc2 Dim pupilDiam As Double WTvUz.Et Dim eID As Long
qyH-Z@ Dim parID As Long YFO{i-*q Dim count As Integer `geHSx_ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double }E
'r?N Dim tlens As Double, nlens As Double B
71/nt9 Dim curv As Double, conic As Double 3A#Tn7 Dim ok As Long `%C -7D'? <S@jf4 Sub Main Wc3z7xK1@ H9cPtP~a) '用户输入对话框 P$)g=/td1 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ^ Bx[% TextBox 220,21,40,21,.TextBox1 'default: 0 jJ,_-ui Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 fO*jCl OKButton 40,91,90,21 QZ a.c CancelButton 190,91,90,21 '/W$9jm Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 PMzPj, TextBox 220,49,40,21,.TextBox2 'default: 4
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DL End Dialog c3vb~l) Dim dlg As UserDialog % MHb Y=Vbs x ok = Dialog (dlg) ~^mUu`@r /)P}[Q4 If ok=0 Then 'cancel button was pressed y~SVD@ Print "Execution cancelled." COrk (V End ~3&{`9Y End If :KLXrr }#XFa# 'Assign accommodation and pupil diameter & use defaults if field left empty Jup)m/ If dlg.TextBox1 = "" Then 4QL>LK A = 0 'Default accommodation d1j9{ Else E[H A = CDbl(dlg.TextBox1) x$Dq0FX!%_ End If =&HLz
7| ,^(]zZh If dlg.TextBox2 = "" Then mDB pupilDiam = 4 'Default pupil diameter 'Uok<; Else LFp "Waiv pupilDiam = CDbl(dlg.TextBox2) M^FY6TT4O End If #+I'V\[ IrLGAQ0 Print " " rwm^{Qa Print "Accommodation = " & A & " Diopters" C-'hXh;hQ Print "Pupil Diameter = " & pupilDiam & " mm" }lJ;|kx$
bzgC+yT ' Calculate new parameters with accommodation zG!nqSDG taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness }U_
'7_JT "t@p9> Rant = 12.0 - 0.4*A 'Radius of anterior lens 8%?y)K^
D CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens {@Mr7*u [Kgb#L'{ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens uV/5f#) CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens &p0e)o~Ux UO/sv2CN tlens = 3.767 + 0.04*A 'Lens thickness VtreOJ+ je4l3Hl nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction .g*j]!_] @f!X%)\;x 'Adjust parameters to account for accommodation okNo-\Dh! sp9gz~Kq '************************************************************************* -N *L1Zj 'Aqueous thickness (Position of Lens) eI
#Gx_mg '************************************************************************* P]E-Wp'p eID = FindFullName( "Geometry.Arizona Eye.Lens" )
QrZ#<{,J5 GetCustomElement eID, entity C0rf ny={OhP- parID = FindFullName( "Geometry.Arizona Eye" ) ~Bd=]a$mj
H}@:Bri ' Delete any shift(s) in z 2G8pDvBr count = 0 eim +oms While GetOperationCount(eID)>count C@rGa7 GetOperation eID, count, op .R9Z$Kbq If op.Type="ShiftZ" Then U,
6iT DeleteOperation eID,count niVR!l count=count-1 I`>U#x* End If '`];=QY9pg count=count+1 B@,9Cx564 Wend y4V:)@P v*;d 'Set new shift in /r}L_wI op.Type = "ShiftZ" :Mf" op.val1 = taq 6Rd4waj_,U op.parent = parID 9
_d2u# AddOperation eID, op iyskADS Print "Set aqueous humor thickness = " & taq-0.55 EeIDlm0o IRdt:B|@ '************************************************************************* ~MpikBf 'Radius and conic constant of anterior lens J
3!~e+wn '************************************************************************* *[Hrbln eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) XQ}Zr/f6 GetConic eID, entity, curv, conic S{YzHK )Q)qz$h@ SetConic eID, entity, 1/Rant, CCant ~j0rORy] Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant *bkb-nKw IThd\#= '************************************************************************* @KG0QHyiU 'Radius and conic constant of posterior lens t6+m` Kq '************************************************************************* _IH" SVub eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) yPyu) GetConic eID, entity, curv, conic ?J[3_!"t xO$P
C, SetConic eID, entity, 1/Rpost, CCpost >r.]a ` Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 0.aXg " 'CLZ7pV '************************************************************************* L`NIYH<^ 'Lens thickness (Position of posterior lens surface) _ k-_&PR '************************************************************************* xNz(LZ.c W,q @ww u parID = FindFullName( "Geometry.Arizona Eye.Lens" ) M5xJ_yjG 8:cbr/F< ' Delete any z-shift(s) #6sz@X fV count = 0 !Sq<_TO While GetOperationCount(eID)>count Hl*vS GetOperation eID, count, op 6&3,fSP If op.Type="ShiftZ" Then =:W2NN' DeleteOperation eID,count DA=!AK> count=count-1 $KHm5*;nd End If xn8KOwX% count=count+1 Obdn#Wm= Wend \1EuHQ? <,d550GSm 'Set new z-shift Bous d op.Type = "ShiftZ" SnCwoxK op.val1 = tlens nhI+xqfn op.parent = parID U'jt'( AddOperation eID, op _=v#"l Print "Set lens thickness = " & tlens t0)1;aBZ H`EhsYYK '************************************************************************* QV4|f[Ki% 'Lens index of refraction ?vXgHDs^T '************************************************************************* Lp`.fn8Ln eID = FindMaterial( "Lens" ) lH-VqkR\ GetModelMaterial eID, mat s.3"2waZ=T !oLn= mat.Nd = nlens {I#_0Q,i SetModelMaterial eID, mat ]TV_p[L0B Print "Set lens index of refraction = " & nlens O&%'j 16NHzAQ '************************************************************************* V>6klA}o 'Pupil diameter p8Vqy-: '************************************************************************* fv+]iK<{ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) -Cf)`/ .35(MFvq! 'Adjust pupil diameter (trimming volume inner hole) ~uQ*u.wi =~^b
SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" -YoL.`s1 % "RJi? ' Adjust pupil location to just in front of the lens )ycI.[C parID = FindFullName( "Geometry.Arizona Eye" ) N['DqS = eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) L G}{ibB count = 0 k
%I83,+ While GetOperationCount(eID)>count bWPsfUn# GetOperation eID, count, op N:j7J If op.Type="ShiftZ" Then &AiAd6 DeleteOperation eID,count {QG.> lB count=count-1 F>;Wbk&[| End If osV6= count=count+1
A l[ZU Wend A#U! KX op.Type = "ShiftZ" #~0Nk6*u op.val1 = taq-0.01 *PmZqe op.parent = parID wMa8HeBE\ AddOperation eID, op |r9<aVlK .Rr^AGA4 Print "Set pupil diameter = " & pupilDiam TrI+F+; #UGSn:D<i 'Update AZ Eye subassembly Description mc{z eID = FindFullName( "Geometry.Arizona Eye" ) c3]t"TA, GetEntity eID, entity '%$Vmf)= entity.Description = "Accommodation = " & A & "D" )f?I{ SetEntity eID, entity +p u[JHF >%/x~UFc5 Update E@VQxB7+ Print "DONE!" ?m7:@GOE1 )~2\4t4|g End Sub S-t#d7'B YQ0#j'}/ 如果屈光度是4,光瞳直径是4,则会输出如下数据: 5es t Ek+R Accommodation = 4 Diopters y)kxR Pupil Diameter = 4 mm 6w.E Sm Set aqueous humor thickness = 2.81 R hWQ:l] Set anterior lens radius = 10.4 and conic constant = -2.375869 {}$9
70y Set posterior lens radius = -4.424557 and conic constant = -3.081019 4uF.kz-cg Set lens thickness = 3.927 :saP
:& Set lens index of refraction = 1.42672 W>3S%2d Set pupil diameter = 4 ch
i=]*9 DONE! @SfQbM##% 7q0_lEh (文章来源:讯技光电)
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