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简介 |P|2E~[r mdrqX<x'~ 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。 i(.PkYkaq /`aPV"$M 模型 AU%Yr6 ( )ldn?v 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。 =X[?d/[ =B;qy7? Table 1. AZ眼睛模型的定义 UCj+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.
u0oTqD? `}sFT:1& 光源 b.[9Adi > >rP[Xox' 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^K;+& T xnWezO_ eUCBQK 图1. 光源和提示信息使用 .:Wp9M 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。 `H*mQERb BU>R<A5h 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。 "o u{bKe 5-({z%:P 图2. 字母F光源的设定方法光 T9r6,yY
j^U"GprA 图3. 字母F在视网膜上位置点列图 hmuhq:<f 视网膜的散射 !~'D;Jh $w-@Oa*h9U 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 b{-|q6 J
n2QvUAZ& X#h a*u~U 图4. 视网膜朗伯散射设定 S-Vxlku] 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 Qu8=zI>t 7!Im|7Ty })uyq_nz 图5. 视网膜重点采样规格设定 FrLv%tK| 脚本 'BgR01w J ""N~##)8 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: KXcRm) bi@'m?XwJ 图6. 用户对话框的创建与编辑 ObreDv^, 图7. 用户对话框编辑器 yn(bW\ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 g@/}SJh/> 余下的脚本计算与屈光度有关的所有参数。 PGYx]r v6L]3O1 分析 PX/^* {o*$|4q4 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ^vxNS[C`; Uy)pEEu 图7. 字母F在视网膜上颜色分析 +eLL)uk 脚本代码 j*f\Z!EeZ r[7*1'.p Option Explicit 'Remove this to enable non-dimensioned variables to be used. THK^u+~LM D97 vfC Dim entity As T_ENTITY &l_}yf"v Dim op As T_OPERATION 0blbf@XA Dim mat As T_MODELMATERIAL ?pd/cj^ Dim A As Double {:n1|_r4Z Dim pupilDiam As Double N$:-q'hX Dim eID As Long Vl<7> Dim parID As Long {KEmGHC4R Dim count As Integer =kK%,Mr Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double .We{W{ Dim tlens As Double, nlens As Double ]8Xip/uE Dim curv As Double, conic As Double 10m|? Dim ok As Long $ZB`4!JxG (q}LirR Sub Main {9XNh[NbP \,v+ejhw '用户输入对话框 d:_; Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 g\IwV+iDf TextBox 220,21,40,21,.TextBox1 'default: 0 ,69547#o Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 U.$Th_ OKButton 40,91,90,21 ^/x\HGrw CancelButton 190,91,90,21 x1E;dbOZ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 m] -cRf)9 TextBox 220,49,40,21,.TextBox2 'default: 4 %yl17:h# End Dialog M&Ln'BC Dim dlg As UserDialog <viC~=k; ]-SJ";aU ok = Dialog (dlg) X2:23j< _bgv +/ If ok=0 Then 'cancel button was pressed Ra
H1aS( Print "Execution cancelled." [U"/A1p End 0plX"NU End If tL<.B 7~k=t!gTY 'Assign accommodation and pupil diameter & use defaults if field left empty Y
ZuA"l Y If dlg.TextBox1 = "" Then \.Op6ECV9 A = 0 'Default accommodation ^kz(/c/ ? Else )t\aB_ = A = CDbl(dlg.TextBox1) p7r/`_'| End If .`v%9-5v
=]"I0G-s! If dlg.TextBox2 = "" Then m_`%#$s} pupilDiam = 4 'Default pupil diameter b&LAk-}[ Else ?0+g.,9 pupilDiam = CDbl(dlg.TextBox2) {I?)ODx7qC End If u3tT=5.D \ a(ce?C Print " " ?k;htJcGv Print "Accommodation = " & A & " Diopters" (vchZn# Print "Pupil Diameter = " & pupilDiam & " mm" hv\Dz*XTs0 x.] tGS ' Calculate new parameters with accommodation #5'&
|< taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness Z;RUxe|<k wQ@:0GJH Rant = 12.0 - 0.4*A 'Radius of anterior lens 6f
?,v5 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens |')PQ X:g#&e_ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens zZ<* CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens (hQi { 4udj"-V tlens = 3.767 + 0.04*A 'Lens thickness rzLW@k
j|!t3}(( nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction LNHi}P~ 8?YeaMIBB 'Adjust parameters to account for accommodation _5x]BH6f :g^
mg-8 '************************************************************************* BHZhdm@), 'Aqueous thickness (Position of Lens) <1<xSr '************************************************************************* S9r+Nsn eID = FindFullName( "Geometry.Arizona Eye.Lens" ) .q[}e);) GetCustomElement eID, entity ylQj2B,CB `<M>"~W parID = FindFullName( "Geometry.Arizona Eye" )
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P +OS ' Delete any shift(s) in z s;*
UP count = 0 ;DR5?N/a While GetOperationCount(eID)>count Pt/]Z<VL GetOperation eID, count, op 0(:SEiz6s If op.Type="ShiftZ" Then FoH1O+e DeleteOperation eID,count j0a=v}j3 count=count-1 d%-/U!z? End If w-LENdw count=count+1 gTU5r4xm~ Wend z0SF2L H uZ\+{j= 'Set new shift in e3~{l~Rb op.Type = "ShiftZ" 32%Fdz1S op.val1 = taq tpO'<b op.parent = parID G'PZ=+!XO/ AddOperation eID, op &vn2u bauS Print "Set aqueous humor thickness = " & taq-0.55 ~ A=Gra nhjT2Sl '************************************************************************* 0.w7S6v|& 'Radius and conic constant of anterior lens 1;V_E2?V '************************************************************************* " r o'? eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) A~<!@`NjB GetConic eID, entity, curv, conic m_@XoS
yxI 0H_uxkB~ SetConic eID, entity, 1/Rant, CCant 0`-b57lF& Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 9!W$S[ABRB |('o g *$ '************************************************************************* IM/xBP 'Radius and conic constant of posterior lens PoPR34]^J '************************************************************************* 3,6f}:CG eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) =|ODa/2p GetConic eID, entity, curv, conic .SER,],P rVl 8?uy SetConic eID, entity, 1/Rpost, CCpost hd~#I<8;2 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost <r t$~} 7*KUM6z '************************************************************************* L~Peerby 'Lens thickness (Position of posterior lens surface) Bdb}4X rL '************************************************************************* f(~N+2} %<(d%&~ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) }l[e@6r F R]&Csr#~ ' Delete any z-shift(s) %]DA4W count = 0 G:tY1'5 While GetOperationCount(eID)>count %N fpEo GetOperation eID, count, op %'2.9dB If op.Type="ShiftZ" Then W.jXO"pN DeleteOperation eID,count Y_+#|]=$B count=count-1 "V26\ End If UF#!6"C@ count=count+1 2tpu v(H; Wend T>rmm7F /r"<:+ 'Set new z-shift TPk?MeVy%W op.Type = "ShiftZ" ~o"=4q`> op.val1 = tlens ~U"m"zpLP op.parent = parID TaBya0- AddOperation eID, op 'kcR:5B Print "Set lens thickness = " & tlens "YgpgW ?<C(ga '************************************************************************* oYZ
4F 'Lens index of refraction 0
h!Du|? '************************************************************************* dVEs^ZtI eID = FindMaterial( "Lens" ) $">j~! ' GetModelMaterial eID, mat A`f"<W-m Fw\Z[nh mat.Nd = nlens cVL|kYVWT SetModelMaterial eID, mat QDQ"Sc06 Print "Set lens index of refraction = " & nlens {eaR,d~X f/#Id]B '*************************************************************************
\\KjiT' 'Pupil diameter ?8"*B^*Sh '************************************************************************* bN zb#P#hP eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) bkDVW v4"Ukv 'Adjust pupil diameter (trimming volume inner hole) m]>zdP+ h'
!C SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" TsK!36cg ',0:/jSz ' Adjust pupil location to just in front of the lens <Q9l'u]3$c parID = FindFullName( "Geometry.Arizona Eye" ) rtJER?A eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) dnoF)(d&Cm count = 0 018SFle While GetOperationCount(eID)>count [StnKQ?"wz GetOperation eID, count, op oR2?$KF If op.Type="ShiftZ" Then xyk%\&"7 DeleteOperation eID,count W4^zKnH count=count-1 hFi gY\$m End If @9HRGxJ=} count=count+1 zY_J7,0g Wend 9efey? z op.Type = "ShiftZ" jL\j$'KC op.val1 = taq-0.01 Qq`S=:}~x op.parent = parID <}{<FXk[ AddOperation eID, op iv~R4;;) j*?8w(! Print "Set pupil diameter = " & pupilDiam T:@6(_Z >^jBE'' 'Update AZ Eye subassembly Description 1Z< ^8L< eID = FindFullName( "Geometry.Arizona Eye" ) lfHN_fE>Mq GetEntity eID, entity \DQu!l@1U entity.Description = "Accommodation = " & A & "D" {fACfSW6 SetEntity eID, entity 2j%=o?me^p o{,IO!q Update hi!A9T3%}M Print "DONE!" Lxp}o7>K u>fMO9X}2 End Sub HRyFjAR\? 6^LXctW. 如果屈光度是4,光瞳直径是4,则会输出如下数据: LVB wWlJ q8d](MaX Accommodation = 4 Diopters kJ5z['4? Pupil Diameter = 4 mm .8|wc Set aqueous humor thickness = 2.81 }g/u.@E Set anterior lens radius = 10.4 and conic constant = -2.375869 $WIVCp Set posterior lens radius = -4.424557 and conic constant = -3.081019 ?0/$RpFEM# Set lens thickness = 3.927 YQN:&Cls Set lens index of refraction = 1.42672 hAf/&yA@ Set pupil diameter = 4 *0>`XK$mWo DONE! nKm#
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8sB QQ:2987619807 aG
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