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简介 <*JFY%y" %,T=|5 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。 GuK3EM*_ Kb X&E0 模型 1lo.X_ P:D;w2'Q 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。 &Va="HNKt I3gl+)Q Table 1. AZ眼睛模型的定义 <fHJ9(5$V 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. }NjZfBQW` Ft
E5H 光源 ;w/@_!~ "C0?s7Y 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。 -pmb-#`M 5{/uHscwLa )]}G8A 图1. 光源和提示信息使用 r>: ~!o* 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。 . ;rE4B |d$4Fu(M~ 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 :FT x#cZ (+yH 图2. 字母F光源的设定方法光 mT:NC'b<9 GY>G}bfh 图3. 字母F在视网膜上位置点列图 *+OS;R1< 视网膜的散射 M*!WXQlud `j1oxJm 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 }y%c. BLN|QaZ rJZR8bo 图4. 视网膜朗伯散射设定 *b'4>U 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 cY5w,.Q/! ]p8zT|bv 7s0\`eXo/ 图5. 视网膜重点采样规格设定 3
,zW6 -} 脚本 lihIPMU +GJPj(S 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: w73?E#8 _tUh*"e& 图6. 用户对话框的创建与编辑 [#=IKsO'R6 图7. 用户对话框编辑器 xa.tH)R 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 O8OAXRt/Y 余下的脚本计算与屈光度有关的所有参数。 7nm'v'\u+V &szYa-K* 分析 KomMzG: 6hMKAk 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 2E8G5?qe) ^T:L6: 图7. 字母F在视网膜上颜色分析 }DQTy.d;P 脚本代码 Ngj&1Ta&[ fy]c=:EmD Option Explicit 'Remove this to enable non-dimensioned variables to be used. *`}
!{
Mb FDFwx| Dim entity As T_ENTITY -woFKAy` Dim op As T_OPERATION zYrJHn#vB Dim mat As T_MODELMATERIAL [^Bjmw[7 Dim A As Double M^*\$K% Dim pupilDiam As Double d~AL4~} Dim eID As Long p}3` "L= Dim parID As Long Uks%Mo9on Dim count As Integer [YP{%1*RM Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 55' Dim tlens As Double, nlens As Double HKr}"`I. Dim curv As Double, conic As Double -)Bvx>8fq- Dim ok As Long T/A2Y+@N; _p>F43%p Sub Main r<'DS9m )Gavjj&uJ '用户输入对话框 :hT.L3n, Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 J/fnSy TextBox 220,21,40,21,.TextBox1 'default: 0 c7~R0nP Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 F^$;hMh% OKButton 40,91,90,21 IITUM) CancelButton 190,91,90,21 a2Nxpxho Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 |_+#&x TextBox 220,49,40,21,.TextBox2 'default: 4 T60pw End Dialog Q-<Qm ? Dim dlg As UserDialog F~i ~%f, "w$,`M?2 ok = Dialog (dlg) e
pp04~ ~+j2a3rv-{ If ok=0 Then 'cancel button was pressed #CPLvg# Print "Execution cancelled." >s 6ye End &e6UEG End If rf-yUH]&S r<vy6 'Assign accommodation and pupil diameter & use defaults if field left empty Xp_m=QQsm If dlg.TextBox1 = "" Then i(pHJP:a: A = 0 'Default accommodation [al$sCD]+ Else {aN pk,n A = CDbl(dlg.TextBox1) S
:8 End If I ^m 0Dna+V/jI If dlg.TextBox2 = "" Then yhYF "~CM pupilDiam = 4 'Default pupil diameter ,%
QhS5e Else Nf^<pT[* pupilDiam = CDbl(dlg.TextBox2) [nZIV End If (w#t V* BGBHA"5fz Print " " =qc+sMo Print "Accommodation = " & A & " Diopters" BO#tn{(# Print "Pupil Diameter = " & pupilDiam & " mm" y/y~<-|<@ :^WF%X ' Calculate new parameters with accommodation 4")`}T taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness h Fik>B#! cLl~4jL Rant = 12.0 - 0.4*A 'Radius of anterior lens &n
)MGg1% CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens Go)g}#.& *s*Y uY%y Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ,bXZ<RY$ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens F^'$%XK V chKK9SC+| tlens = 3.767 + 0.04*A 'Lens thickness y7M{L8{0 +x=)Kp> nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction iW^J>aKy T"[]'|' 'Adjust parameters to account for accommodation xsB0LUt UPU$SZAIx '************************************************************************* itP`{[ 'Aqueous thickness (Position of Lens) ;o3gR4u_L '************************************************************************* .a]#AFX eID = FindFullName( "Geometry.Arizona Eye.Lens" ) q9_$&9 GetCustomElement eID, entity 1*9.K' ?}Z t&(# parID = FindFullName( "Geometry.Arizona Eye" ) \O;2^ R
,qQC< ' Delete any shift(s) in z 8 s$6R|ti count = 0 +q}t%K5 While GetOperationCount(eID)>count @wgd
3BU GetOperation eID, count, op PQkw)D<n]_ If op.Type="ShiftZ" Then )Q'E^[Ua DeleteOperation eID,count \~ChbPnc count=count-1 Fs( PVN End If Sy|GM~ count=count+1 WJOoDS!i Wend QM F GYx0U8MJ[e 'Set new shift in +T$Olz op.Type = "ShiftZ" _ \6v@ op.val1 = taq b$7]cE
op.parent = parID gHLI>ew*QR AddOperation eID, op <ToBVGX Print "Set aqueous humor thickness = " & taq-0.55 FKTF?4+\U ZOqS"3j! j '************************************************************************* 3T)rJEN A 'Radius and conic constant of anterior lens .how@>:P+ '************************************************************************* 8u+kA
mI eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) x 3=1/#9 GetConic eID, entity, curv, conic L'e^D| YpDJ(61+ SetConic eID, entity, 1/Rant, CCant '\I(n|\ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant {h@\C|nF cjEqN8 '************************************************************************* yV!4Im.> 'Radius and conic constant of posterior lens [34N/;5 '************************************************************************* #[#evlr= eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) dtC@cK/,D GetConic eID, entity, curv, conic HU $"o6ap ^-_*@e*JE SetConic eID, entity, 1/Rpost, CCpost sgp.;h' Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ?8-!hU@QC `N *:,8j '************************************************************************* Plp.\N%f3 'Lens thickness (Position of posterior lens surface) J,yKO(}<C '************************************************************************* = {O ~ [s>3xWZ+a parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ( 2HM"Pd {Yj5Mj|# ' Delete any z-shift(s) 2!^=G=H/ count = 0 b_31 \ While GetOperationCount(eID)>count x%}D+2ro-t GetOperation eID, count, op *p}mn#ru- If op.Type="ShiftZ" Then fHup&|. DeleteOperation eID,count zeHF-_{ count=count-1 lGd'_~'= End If 7AV{
h[J count=count+1 <k:I2LF_ Wend +
Q-b} ;5 j|B|v 'Set new z-shift *,\"}x* op.Type = "ShiftZ" !g|O.mt op.val1 = tlens VL9wRu; op.parent = parID ^c\O,*: AddOperation eID, op }%_|k^t Print "Set lens thickness = " & tlens NKO"'
5*YoK)2J '************************************************************************* ?F"o+]i+^ 'Lens index of refraction ,9P-<P '************************************************************************* SyvoN,;Q eID = FindMaterial( "Lens" ) Bu{Kjv GetModelMaterial eID, mat M~:_^B mTE(JZt mat.Nd = nlens 9F/I",EA SetModelMaterial eID, mat b(*\4n Print "Set lens index of refraction = " & nlens J2=4%#R! lMFR_g?r '************************************************************************* \;{ ]YX 'Pupil diameter b>07t!; '************************************************************************* 3B1\-ry1M eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) / FcRp ," Mn0.!J
" 'Adjust pupil diameter (trimming volume inner hole) yLa@27T\A 9M96$i`P SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ,;g%/6X k~>(XG[x& ' Adjust pupil location to just in front of the lens fkxkf^g) parID = FindFullName( "Geometry.Arizona Eye" ) LZykc
c9g eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) hFIh<m=C?Y count = 0 Lw>B:3e While GetOperationCount(eID)>count {iD/0q GetOperation eID, count, op V?{d<Ng~J If op.Type="ShiftZ" Then #1<m\z 7l DeleteOperation eID,count 7V"?o count=count-1 gu
k,GF9p] End If fs!dI count=count+1 V[tebv! Wend $BwWQ?lp op.Type = "ShiftZ" %N8I'*u op.val1 = taq-0.01 P#O"{+` op.parent = parID )4g_S?l= AddOperation eID, op 6FB0g8 FZ-Wgh
0z Print "Set pupil diameter = " & pupilDiam qezWfR` a~_9BM41T 'Update AZ Eye subassembly Description 7'\.QJ!< eID = FindFullName( "Geometry.Arizona Eye" ) t!?`2Z5 GetEntity eID, entity kF|$oBQ entity.Description = "Accommodation = " & A & "D" Px_8lB/; SetEntity eID, entity n`5Nf IK -vcG Update Ic/hVKYG5 Print "DONE!" j\uZo.Ot+ F-;J N End Sub ?@"@9na 6N@=*0kh- 如果屈光度是4,光瞳直径是4,则会输出如下数据: V;SfW2`) b<u\THy# Accommodation = 4 Diopters gfL :SP8 Pupil Diameter = 4 mm P
y'BMk Set aqueous humor thickness = 2.81 j7P49{ Set anterior lens radius = 10.4 and conic constant = -2.375869 uX7L1~s- Set posterior lens radius = -4.424557 and conic constant = -3.081019 <-`bWz=+ Set lens thickness = 3.927 a
,mgM&yD Set lens index of refraction = 1.42672 ~?/7:S Set pupil diameter = 4 7F"ljkN1S DONE! ().C Ab$E@H# c&D+=
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