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简介 oe1$;K>.7 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 /80RO:'7 S4>1 d- 模型 D"s
]dQ$r ;LFs.Jc< 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。 "xMnD(p 8(GJz ~y Table 1. AZ眼睛模型的定义 5uvFCY./c 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. iFB {a?BE 5m a(~5 光源 IaYy5Rw I(0 *cWO 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。 OR-fC FP h1 }qS 9d >AnTf&H 图1. 光源和提示信息使用 >}!})]Xw9 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。 r=^? +m1y#|08 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。 \9jvQV/y %b3s|o3An 图2. 字母F光源的设定方法光 5|bc*iqU 6nHyd<o 图3. 字母F在视网膜上位置点列图 eQ eucmQd{ 视网膜的散射
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<sC. 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。 8al%F_r] ~_hn{Ous L[.RV*sL 图4. 视网膜朗伯散射设定 4A~1Z,"%v( 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。 \6c8Lqa 3Ay<2v |$.`4h? 图5. 视网膜重点采样规格设定 )2y#
cM* 脚本 85]3y%f9 `@Tl7I\ 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: )i*- j= s&~i S[ 图6. 用户对话框的创建与编辑 rIZ^ix-N 图7. 用户对话框编辑器 <gbm
1iEe 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。 3!0~/8!f@ 余下的脚本计算与屈光度有关的所有参数。 pv ;ZR T9O3$1eqfo 分析 o[E|xw &Uu8wFbIJ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ubQZTA x 1;N5@0%p 图7. 字母F在视网膜上颜色分析 %cFqD
& 6 脚本代码 q[MZSg qA5PIEvdq Option Explicit 'Remove this to enable non-dimensioned variables to be used. sAfNu~d uQ'Izdm Dim entity As T_ENTITY 4-veO3&.h Dim op As T_OPERATION MY"8! Dim mat As T_MODELMATERIAL <WRrB
`nO Dim A As Double }D\i1/Y Dim pupilDiam As Double Bi$nYV)-l Dim eID As Long 55#s/`gd)^ Dim parID As Long Z@{e\sZ) Dim count As Integer Rx%SeM2 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double &'d3Yt Dim tlens As Double, nlens As Double :B"Y3~I Dim curv As Double, conic As Double Fl0 :Z Dim ok As Long <maYS2 6y+}=)J Sub Main R8![
$mkU +_ZXzzcO< '用户输入对话框 {;| >Qn Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 RDWUy(iX TextBox 220,21,40,21,.TextBox1 'default: 0 pGdo:L? Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 rf]'VJg#3 OKButton 40,91,90,21 TZYz`l+v CancelButton 190,91,90,21 $PE{}`#g Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 sxFkpf_h TextBox 220,49,40,21,.TextBox2 'default: 4 2{fPQQ;# End Dialog ~s4o1^6L Dim dlg As UserDialog yTwtGo& {Jn*{5tZ> ok = Dialog (dlg) HHcWyu mcqLN5 If ok=0 Then 'cancel button was pressed IMtfi(Y%F Print "Execution cancelled." 4J${gcju End /<-@8CC< End If qGrUS_~q* $=GnoS 'Assign accommodation and pupil diameter & use defaults if field left empty [OK( If dlg.TextBox1 = "" Then _q<Ke/ A = 0 'Default accommodation E[kf%\
Else l11+sqg A = CDbl(dlg.TextBox1) g:]X '%Ub End If 0JS#{EDh+ Q@w=Jt< If dlg.TextBox2 = "" Then {]V+C=` pupilDiam = 4 'Default pupil diameter hX&Jq%{oa Else Z/~7N9?m( pupilDiam = CDbl(dlg.TextBox2) FvVR \a End If Xah-*]ET }G53" Print " " LZF%bJv Print "Accommodation = " & A & " Diopters" O|I)HpG; Print "Pupil Diameter = " & pupilDiam & " mm" !aQQq[ q@0g KC&U ' Calculate new parameters with accommodation \PJpy^i taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness Zm+QhnY| M'-Z" Rant = 12.0 - 0.4*A 'Radius of anterior lens d:SLyFD$q CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 5nSi29C q9iHJ'lMD* Rpost = -5.224557 + 0.2*A 'Radius of posterior lens z(g6$Y{ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens CS|al(?~ -}$mv tlens = 3.767 + 0.04*A 'Lens thickness V~!lY\ pf[m"t6G~ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction (N
0kTi]b A4 'Adjust parameters to account for accommodation rS&"UH?c7 *iwVB^^$ '************************************************************************* v|
Yh]y 'Aqueous thickness (Position of Lens) SL ) ope '************************************************************************* Z0#&D&2sV eID = FindFullName( "Geometry.Arizona Eye.Lens" ) :N>n1tHL;A GetCustomElement eID, entity 8LH\a.> Cyu= c1D ; parID = FindFullName( "Geometry.Arizona Eye" ) lNs;-`I~ %]1.)j ' Delete any shift(s) in z 0LD$"0v/C3 count = 0 %(YU*Tf~ While GetOperationCount(eID)>count }{y(&Oy3Y GetOperation eID, count, op CD:$22*] If op.Type="ShiftZ" Then YQ$EN>.eO DeleteOperation eID,count K);)$8K count=count-1 G%FLt[ End If i2&I<: count=count+1 lV
M)'m Wend Yx3ivjX.> 2PTAIm Rq 'Set new shift in KMll8X op.Type = "ShiftZ" VV$4NV&`Q op.val1 = taq Q@0Zh,l op.parent = parID PL|zm5923 AddOperation eID, op Sk7sxy<F' Print "Set aqueous humor thickness = " & taq-0.55 gUWW}*\ U "OWW -m '************************************************************************* %yPjPUHy 'Radius and conic constant of anterior lens G5,g$yNs '************************************************************************* qac8zt#2
C eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) M7gb3gw6 GetConic eID, entity, curv, conic K'\Jnn 'dvi@Jx SetConic eID, entity, 1/Rant, CCant ?mn&b G Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Bk2j|7
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NJMC '************************************************************************* U~I
y),5 'Radius and conic constant of posterior lens aExt TE '************************************************************************* 4H*M^?h\# eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ?"-1QG GetConic eID, entity, curv, conic B]#^&89wG) E]dc4US SetConic eID, entity, 1/Rpost, CCpost 1uco{JX<S Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ifI0s)Pn !%Bhg? '************************************************************************* /1 h ${mo~ 'Lens thickness (Position of posterior lens surface) & N.]8x5A '************************************************************************* h$l`)AH^ vww>] Z} parID = FindFullName( "Geometry.Arizona Eye.Lens" ) \N[2-;[3 6lob&+ ' Delete any z-shift(s) BT^HlW< count = 0 ":!1gC While GetOperationCount(eID)>count u9u'!hAGH GetOperation eID, count, op noZ!j>f{@l If op.Type="ShiftZ" Then Mb:> DeleteOperation eID,count }uiD8b{I count=count-1 LZ}m; End If %;,4q B
count=count+1 "@YtxYTW- Wend zK>}x= %:N;+1 'Set new z-shift $[0\Th op.Type = "ShiftZ" Jp"[` m op.val1 = tlens 6 Z<|L^ op.parent = parID oer3DD( AddOperation eID, op FBeo@ Print "Set lens thickness = " & tlens 6%Pvh- ~_ !CUM*<iV '************************************************************************* sL],@z8<k 'Lens index of refraction 3?Fe(!@ '************************************************************************* uaqV)H eID = FindMaterial( "Lens" ) O`Y@U?^N GetModelMaterial eID, mat M'nzoRk wGgeK,*_ mat.Nd = nlens WDJ rN SetModelMaterial eID, mat q{l %k Print "Set lens index of refraction = " & nlens #'4Psz sspGB>h8l '************************************************************************* MDCwgNPiQW 'Pupil diameter K"cV7U rE '************************************************************************* nT9Hw~f<j eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) n(#[[k9&Ic E&dxM{` 'Adjust pupil diameter (trimming volume inner hole) vLpIVNA]]Y ',!>9Dj SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" kTA4!654 0[p"8+x ' Adjust pupil location to just in front of the lens Ctbc!<@o parID = FindFullName( "Geometry.Arizona Eye" ) rP IAu[],g eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) !b?cY{ count = 0 9B/iQCFtj$ While GetOperationCount(eID)>count C8%MKNPd GetOperation eID, count, op w\a6ga!xt" If op.Type="ShiftZ" Then =w7+Yt DeleteOperation eID,count |3BxNFe`% count=count-1
0:$pJtx" End If e4FR)d0x count=count+1 <B!DwMk;. Wend X/h|;C*9 op.Type = "ShiftZ" ;Irn{O op.val1 = taq-0.01 U+[h^M$U op.parent = parID <vt}+uMzXv AddOperation eID, op Ro=dgQ0:t '4}8WYKQ Print "Set pupil diameter = " & pupilDiam q4g)/x%nc AWg'J 'Update AZ Eye subassembly Description 4'"WD0 eID = FindFullName( "Geometry.Arizona Eye" ) ~-UO^$M- GetEntity eID, entity .:O($9^Ho entity.Description = "Accommodation = " & A & "D" 84coi SetEntity eID, entity 4m6/ba T1%}H3 Update yp)D"w4@ Print "DONE!" K{:[0oIHc 6?a z End Sub S
R s !6hV|2aJy 如果屈光度是4,光瞳直径是4,则会输出如下数据: 3R%yKa# na@Go@q Accommodation = 4 Diopters v8zO Y#? Pupil Diameter = 4 mm :3{n(~ Set aqueous humor thickness = 2.81 yd[4l%G(zS Set anterior lens radius = 10.4 and conic constant = -2.375869 }*S`1IWMj Set posterior lens radius = -4.424557 and conic constant = -3.081019 In8{7&iVO Set lens thickness = 3.927 \Nk578+AA Set lens index of refraction = 1.42672 <o/l K\> Set pupil diameter = 4 -/Zy{2 <u DONE! R ^ZOcONd- Mkr
&30il[ (文章来源:讯技光电)
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