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简介 \fX0&l;T9\ {..6{~L 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。 %Aqt0e
c@eQSy 模型 8C,}nh mP!=&u fcU 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。 l(irNKutgo 8iv0&91Z Table 1. AZ眼睛模型的定义 }u3Q*oAGl 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. 35q4](o9" 6]%SSq& 光源 S*aVcyDEP bcM65pt_C 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。 v&7yqEm}B "3&bh>#qY L=7Y~aL= 图1. 光源和提示信息使用 p`+=)
n 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。 aXv[~ ";kwh8wB 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。 teQ<v[W. 1
N{unS 图2. 字母F光源的设定方法光 Z=[qaJ{] QL].)Vgf 图3. 字母F在视网膜上位置点列图 i1c
z+} 视网膜的散射 D+nKQ4 4](jV}Hg 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-^,r
t4 /v <FH} iBqxz:PHN( 图4. 视网膜朗伯散射设定 bjL8Wpk 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。 eNHSfq &c AFKYt bZ5cKQ\6 图5. 视网膜重点采样规格设定 ]QJN` ;b0 脚本 [-5l=j
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m 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: T)Uhp _c z$w5` 图6. 用户对话框的创建与编辑 G7qB 图7. 用户对话框编辑器 >D\jyd$wh& 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。 .or1*-B K 余下的脚本计算与屈光度有关的所有参数。 FQlYCb >;sz(F3) 分析 /bSAVSKR hZw bYvu 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 \yE*nZ LBIsj}e 图7. 字母F在视网膜上颜色分析 >)j`Q1Qc\ 脚本代码 srGF=1_ %ij,xN Option Explicit 'Remove this to enable non-dimensioned variables to be used. {W' 9k i-YSt5iq Dim entity As T_ENTITY *SmR|Qy Dim op As T_OPERATION ,hVDGif Dim mat As T_MODELMATERIAL _O$7*k Dim A As Double Hob n{E Dim pupilDiam As Double d69synEw>k Dim eID As Long I1)t1%6"vJ Dim parID As Long Lz/{
q6> Dim count As Integer nB9(y4 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double SZVAf|]Yg Dim tlens As Double, nlens As Double L;
o$vI~U, Dim curv As Double, conic As Double -+HD5Hc Dim ok As Long lJJ`aYDp xt zjFfq Sub Main VkD}gJY x4N*P '用户输入对话框 K})w Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Zsto8wuf# TextBox 220,21,40,21,.TextBox1 'default: 0 dcH@$D@~S Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 QFg{.F?3q> OKButton 40,91,90,21 /=@V5) CancelButton 190,91,90,21 cna/?V Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 \LYNrL~?J TextBox 220,49,40,21,.TextBox2 'default: 4 L;i(@tp|v End Dialog PLueH/gC . Dim dlg As UserDialog uwc@~=; Zq" ok = Dialog (dlg) MWI7u7{ yfZYGhPN( If ok=0 Then 'cancel button was pressed y4N2gBTKu Print "Execution cancelled." nU,~*Us End !-~sxa280r End If y1bo28 l\_81oZ 'Assign accommodation and pupil diameter & use defaults if field left empty B'hN3. If dlg.TextBox1 = "" Then Zo#c[9IaC A = 0 'Default accommodation zI$'D|A Else s-Qq#T A = CDbl(dlg.TextBox1) c@x6<S%* End If X@\ 9}*9 * zc[t If dlg.TextBox2 = "" Then OjurfVw pupilDiam = 4 'Default pupil diameter @;7Ht Z` Else _BI[F
m pupilDiam = CDbl(dlg.TextBox2) IqCh4y3 End If Ns$,.D l9z{pZ\KM Print " " Wrf+5 ;,, Print "Accommodation = " & A & " Diopters" U"535<mR Print "Pupil Diameter = " & pupilDiam & " mm" 5Bp>*MR/". |&_(I ' Calculate new parameters with accommodation ~Z}DN*S taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness R,`3 SW() IweNe`Z Rant = 12.0 - 0.4*A 'Radius of anterior lens qHu\3@px CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens >">grDX 4k)0OQeW6 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens =}%Q}aPp CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens N=j$~,yG H`nd | tlens = 3.767 + 0.04*A 'Lens thickness rih@(;)1 dZ x nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction M;sT+Z{ lmYyaui 'Adjust parameters to account for accommodation %']`t-N8 dMK\ y4#i '************************************************************************* W?gelu] 'Aqueous thickness (Position of Lens) "DSRy D0M '************************************************************************* ^L-; S eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ]3d5kf GetCustomElement eID, entity NdB:2P #]J"j]L parID = FindFullName( "Geometry.Arizona Eye" ) ?ajVf./Ja x\!vr. ' Delete any shift(s) in z p/gf count = 0 w01u~"E While GetOperationCount(eID)>count n 9Ktn} GetOperation eID, count, op #kp+e)F If op.Type="ShiftZ" Then YJ>P+e\o9 DeleteOperation eID,count vk<4P;A(G count=count-1 KMXd End If FSb4RuD9 count=count+1 ~b})=7 n. Wend r#w.yg4EX yc0_7Im? 'Set new shift in kyL]4:@W` op.Type = "ShiftZ" B<jVo%og op.val1 = taq [fg-"-+:M op.parent = parID 2U) 0k* AddOperation eID, op ASa)xf9 Print "Set aqueous humor thickness = " & taq-0.55 |3Bmsd/3 aK--D2@}i '************************************************************************* q{pa _ 'Radius and conic constant of anterior lens i!+0''i{# '************************************************************************* [E0.4FLT! eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) cG5u$B GetConic eID, entity, curv, conic w\ddC DZ *#j_nNM4 SetConic eID, entity, 1/Rant, CCant #NWS)^&1b Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant |b+CXEzo TH*}Ja^/ '************************************************************************* n4 o}}tI 'Radius and conic constant of posterior lens {`V ^V_ '************************************************************************* >~})O&t eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) @cn8 m GetConic eID, entity, curv, conic 7Jn%c<s {tUxRX SetConic eID, entity, 1/Rpost, CCpost z7R2viR[ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ,=dc-%J Y,{pG]B$w '************************************************************************* 7,FhKTV1/ 'Lens thickness (Position of posterior lens surface) `(
_N9.>B '************************************************************************* =}2k+v-B 4oN*J +"=+ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) , nW)A/?} 9S8V`aC ' Delete any z-shift(s) yw*|
H T count = 0 af|x(:!H While GetOperationCount(eID)>count URj2 evYW GetOperation eID, count, op -GYJ)f If op.Type="ShiftZ" Then Z=s.`?Z DeleteOperation eID,count 7|(o=+Bt count=count-1 0D&-BAzi End If uVa`2]NV r count=count+1 JwdvY] Wend apWv+A f*Yr*yC 'Set new z-shift ~;0W
+ op.Type = "ShiftZ" @# GS4I op.val1 = tlens l{hO"fzy op.parent = parID 9]QHwa>_|2 AddOperation eID, op :\~YbA Print "Set lens thickness = " & tlens f s2}a EKNmXt1
lE '************************************************************************* <STE~ZmO 'Lens index of refraction /]9(InM9/ '************************************************************************* $j/#IzD1D eID = FindMaterial( "Lens" ) -AwkP GetModelMaterial eID, mat -?vVV@W-O^ _eUd
RL> mat.Nd = nlens a!\^O).pA SetModelMaterial eID, mat S>y}|MG Print "Set lens index of refraction = " & nlens z4JhLef % X-`PF '************************************************************************* t4+bRmS`_ 'Pupil diameter `+@r0:G&v '************************************************************************* b?k6-r$j eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) v;d3uunqv j9&x#U 'Adjust pupil diameter (trimming volume inner hole) u^( s0q JN3&(t SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" t!o=-k yHn8t]{ ' Adjust pupil location to just in front of the lens IgPU^?sp parID = FindFullName( "Geometry.Arizona Eye" ) jfpbD
/ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ~9c jc count = 0 |N:kf&]b While GetOperationCount(eID)>count C;oO=R3r GetOperation eID, count, op #2;8/"v If op.Type="ShiftZ" Then LrdX^_,nt DeleteOperation eID,count .J\i ! count=count-1 ]*<!|;q End If Dp^6|T* HU count=count+1 cpM]APF- Wend ~z7Fz"o< op.Type = "ShiftZ" Vw5Pgt x op.val1 = taq-0.01 OZ}o||/Rc op.parent = parID rS_pv=0S AddOperation eID, op QG5)mIJ QsyM[; \j: Print "Set pupil diameter = " & pupilDiam UH#S |o4 #=#bv` 'Update AZ Eye subassembly Description tD> qHR eID = FindFullName( "Geometry.Arizona Eye" ) 6NGQU%Hd GetEntity eID, entity g|5cO3m0' entity.Description = "Accommodation = " & A & "D" L 7l"*w( SetEntity eID, entity i7\MVI8 ja^ Update Xuj=V?5 Print "DONE!" sq+cF/jo6 U%KsD 4B End Sub O;m [ 9XX:_9|I 如果屈光度是4,光瞳直径是4,则会输出如下数据: 4v.i!U#
{ (} Y|^uM, Accommodation = 4 Diopters DiSU\?N2' Pupil Diameter = 4 mm j4$NQ]e^4 Set aqueous humor thickness = 2.81 7A{,)Y/w ^ Set anterior lens radius = 10.4 and conic constant = -2.375869 fT5vO.a
Set posterior lens radius = -4.424557 and conic constant = -3.081019 @Op7OFY% Set lens thickness = 3.927 T*](oA@ Set lens index of refraction = 1.42672 @-XMox/ Set pupil diameter = 4 Q'0:k{G
DONE! -"}nm!j /5 D9\ E kX Y
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2d QQ:2987619807 GW0e=Y=LR
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