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简介 iHBetkAu 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。 _3~/Z{z8 e ?sMOBPlv 模型 K2|2Ks_CS _Wg?H:\ 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。 1cq"H/N UTwXN |'| Table 1. AZ眼睛模型的定义 w`KqB(36 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. 3b{ 7Z 2 +-2o b90_m 光源 ,Pi!%an w }:+SA 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。 &rs 71b0MHNkvv KTtB!4by
图1. 光源和提示信息使用 GBeWF-`B 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。 O2{~Q{p (w[#h9j 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。 03pD< Y=83r]% 图2. 字母F光源的设定方法光 R5Pk>-KF 9[2qgw\D 图3. 字母F在视网膜上位置点列图 f4 k 视网膜的散射 +}VaQ8ti4 \rj>T6 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。 JkShtLEr %cO^: \qf0=CPw8 图4. 视网膜朗伯散射设定 Xfc+0$U@ 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 ^/~ZP?%] \+)aYP2Hu jFDVd;#CS 图5. 视网膜重点采样规格设定 %?`O
.W 脚本 @>fsg-| {=%,NwPs 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: I1pnF61U S;0z%$y 图6. 用户对话框的创建与编辑 v!`:{)2C 图7. 用户对话框编辑器 5,\-; 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。 jj&mRF0gCb 余下的脚本计算与屈光度有关的所有参数。 %*zV&H q4ttmL8 分析 J@o_-\@ 1Q_Q-Z 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 a<0q%Ax =2t=Zyp0Y 图7. 字母F在视网膜上颜色分析 '7Mz]@ 脚本代码 (%c&Km7K KE.O>M,I. Option Explicit 'Remove this to enable non-dimensioned variables to be used. 3$?nzKTW\ ;Fo7 -kK Dim entity As T_ENTITY 4.Q[Tu Dim op As T_OPERATION 2TG2<wqvE Dim mat As T_MODELMATERIAL Q<NQ9lX Dim A As Double 2D(sA Dim pupilDiam As Double \2!. Dim eID As Long rK3KxG Dim parID As Long &.(iS Dim count As Integer ^q_wtuQ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double $EHFf$M Dim tlens As Double, nlens As Double k.7!)jL7 Dim curv As Double, conic As Double ,RDWx Dim ok As Long
:f:&B8 xQ';$& Sub Main kL8E# amq,^ '用户输入对话框 fN@ZJ~F%j Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 %y\5L#T!> TextBox 220,21,40,21,.TextBox1 'default: 0 Tay$::V Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 !vSq?!y6*P OKButton 40,91,90,21 </Y(4Xwf= CancelButton 190,91,90,21 dGj0;3FI% Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 N
p*T[J TextBox 220,49,40,21,.TextBox2 'default: 4 7x77s End Dialog oOc-1C
y Dim dlg As UserDialog S(U9Dlyarg J+Fev.9> ok = Dialog (dlg) u Fw1% z R'EQ If ok=0 Then 'cancel button was pressed `#w#!@s#@ Print "Execution cancelled."
qou\4YZ End r7].48D End If {chZ&8)f oH&@F@r:+ 'Assign accommodation and pupil diameter & use defaults if field left empty -9.lFuI If dlg.TextBox1 = "" Then [3qH?2& A = 0 'Default accommodation w &T\8k= Else fVgN8b|&' A = CDbl(dlg.TextBox1) 4X*U~} End If _&\'Va$ XkkzY5rxOc If dlg.TextBox2 = "" Then %o4v} mzV pupilDiam = 4 'Default pupil diameter -
AgD Else lwgwdB pupilDiam = CDbl(dlg.TextBox2) &*'^uCna End If GDC@s<[k t_xK?`` Print " " &4 KUXn[F Print "Accommodation = " & A & " Diopters" 5@r6'Z Print "Pupil Diameter = " & pupilDiam & " mm" %*!6R:gAp kppi>!6 ' Calculate new parameters with accommodation mjg@c|rTG taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 7gV9m9 # 2Sa{=x
N) Rant = 12.0 - 0.4*A 'Radius of anterior lens ~GX
]K H CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 0Fon`3(^\ VpYD/Oj4; Rpost = -5.224557 + 0.2*A 'Radius of posterior lens sRZ<c CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens p&V64L:V j!!s>7IZ tlens = 3.767 + 0.04*A 'Lens thickness l3ogMRq@ u6?9#L( nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction QtG6v<A J^7M0A4K 'Adjust parameters to account for accommodation $V`1<>4 UCmy$aW '************************************************************************* 'Ca;gi !U 'Aqueous thickness (Position of Lens) \ +sa[jK '************************************************************************* XC~"T6F eID = FindFullName( "Geometry.Arizona Eye.Lens" ) KWjhkRK4] GetCustomElement eID, entity ^yc8is'` k
Qr parID = FindFullName( "Geometry.Arizona Eye" ) !',%kvJI QgYt(/S ' Delete any shift(s) in z D6?h
6`J count = 0 Q<D_QJ While GetOperationCount(eID)>count gt.F[q3
GetOperation eID, count, op tF-l=ph}` If op.Type="ShiftZ" Then f1'X<VA DeleteOperation eID,count Yl'8"
\HF count=count-1 |:#Ug End If KFO
K%vbM count=count+1 +2eri_p Wend #prYZcHv:_ x`C"Z7t 'Set new shift in /Ta-3Eh! op.Type = "ShiftZ" r_Ou\|jU op.val1 = taq u1UCe op.parent = parID `p* 43nV AddOperation eID, op (2Lmu[ Print "Set aqueous humor thickness = " & taq-0.55 2BF455e 3J
5,V '************************************************************************* g)$KN,gGuO 'Radius and conic constant of anterior lens | Z7j
s" '************************************************************************* V0
Z8VqV eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) <+
[N* GetConic eID, entity, curv, conic (gVN<Es )hQ]>o@i{ SetConic eID, entity, 1/Rant, CCant d*6/1vyjT Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant _e>N3fT @uV]7d"z( '*************************************************************************
[tt{wl"E 'Radius and conic constant of posterior lens DHeZi3&i '************************************************************************* 3`{
vx eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Gukvd6-g9b GetConic eID, entity, curv, conic Hu6Qr XMZ$AeF@ SetConic eID, entity, 1/Rpost, CCpost pnp8`\cIH Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost
jwLZC Ev3'EA~` '************************************************************************* svxjad@l/
'Lens thickness (Position of posterior lens surface) z<fd!g+^ '************************************************************************* I;wxgWOP (b[=~Nh' parID = FindFullName( "Geometry.Arizona Eye.Lens" ) E.Th}+ p8-$MF]]6 ' Delete any z-shift(s) `5Z'8^ count = 0 *3={s"a.( While GetOperationCount(eID)>count EJ<L,QH3 GetOperation eID, count, op "m6G;cv If op.Type="ShiftZ" Then wVI_SQ<8V DeleteOperation eID,count
F{Yr8(UHA count=count-1 <Dgf'GrJ End If ZQ`4'|" count=count+1 z(.,BB[ Wend : 4-pnn HRbv% 'Set new z-shift toD!RE op.Type = "ShiftZ" ~}ifwm'7 a op.val1 = tlens PcZ<JJ16F$ op.parent = parID {%k[Z9*tO AddOperation eID, op \/SOpC Print "Set lens thickness = " & tlens Yuf+d-% }Ptv[{q]GE '************************************************************************* $>_`.*I/ 'Lens index of refraction _ Dz*% '************************************************************************* CXz9bhn<4 eID = FindMaterial( "Lens" ) seAEv0YWz GetModelMaterial eID, mat )
d'H&c3 FxK!h.C. mat.Nd = nlens />:$"+gKo SetModelMaterial eID, mat 4)}>dxv Print "Set lens index of refraction = " & nlens Z]2z*XD $K\e
Pfk '************************************************************************* G[>CBh5 'Pupil diameter L$!2<eK '************************************************************************* Jc5YGj 7 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) =2rdbq6R !U2<\!_ 'Adjust pupil diameter (trimming volume inner hole) e~># M$ >Q"3dw SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" _^RN$4.R> Uh1UZ
r ' Adjust pupil location to just in front of the lens x@O)QaBN! parID = FindFullName( "Geometry.Arizona Eye" ) !~7lY]_U eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) #7:ah
count = 0 z$g__q- While GetOperationCount(eID)>count k+i0@G'C( GetOperation eID, count, op A4d3hF~ l` If op.Type="ShiftZ" Then Dh#5-Kf% DeleteOperation eID,count ei1;@k/ count=count-1 4~oRcO8!Y End If %Rr_fSoV count=count+1 TL$w~dY Wend YFj#{C. op.Type = "ShiftZ" N(J#<;!yb op.val1 = taq-0.01 [;-;{
*{G op.parent = parID '@.Lg0` AddOperation eID, op I`g&> i~<.@&vt Print "Set pupil diameter = " & pupilDiam Abmi=]\bx ^aJ]|*m 'Update AZ Eye subassembly Description -<T>paE9 eID = FindFullName( "Geometry.Arizona Eye" ) #\xy,C'Y GetEntity eID, entity %g>k0~TRf# entity.Description = "Accommodation = " & A & "D" |KPNl\%ID SetEntity eID, entity #-"C_~-MH l;aO"_E1m Update aDLlL?r3 Print "DONE!" ,PKUgL}w i"DyXIrk2 End Sub 6y?uH;SL D^];6\=.i 如果屈光度是4,光瞳直径是4,则会输出如下数据: E2.!|u2 H#nJWe_9A Accommodation = 4 Diopters &g*1 If Pupil Diameter = 4 mm mB
bGj3u; Set aqueous humor thickness = 2.81 J=O_nup6C Set anterior lens radius = 10.4 and conic constant = -2.375869 G$/Qcr6W< Set posterior lens radius = -4.424557 and conic constant = -3.081019 mmNn,>AO! Set lens thickness = 3.927 I>-1kFma; Set lens index of refraction = 1.42672 Pum& |