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简介 6s,2NeVWa Lh 9S8EU 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。 ek[kq[U9 }
gkP 模型 @\~tHJ?hQd (/fT]6( 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。 bag&BHw y~p4">] Table 1. AZ眼睛模型的定义 vOgLEN&] 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. 1D$::{h GEtbs+ [ 光源 g+9v$[! >h[(w 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。 /Ri,>}n ?f@ 9n ph |yAK@Hl' 图1. 光源和提示信息使用 4zzlazU 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。 d +xA: k2OM="Ei} 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。 ja75c~RUw 3G&0Ciet 图2. 字母F光源的设定方法光 m %Y(O K_##-6> 图3. 字母F在视网膜上位置点列图 \ 522,n` 视网膜的散射 6+Jry@ L *{QjH 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。 "!a`ygqpT ?{j@6, *')Q {8` 图4. 视网膜朗伯散射设定 iIB9j8 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。 hBoP=X.~ ,|iy1yg( L"^.0*X/d 图5. 视网膜重点采样规格设定 H`?*
bG 脚本 |1i]L @& cdN/Qy 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:
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iKR{P6 图6. 用户对话框的创建与编辑 GY7s 图7. 用户对话框编辑器 >3+FZ@.iT 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。 U,38qKE 余下的脚本计算与屈光度有关的所有参数。 bHJoEYY^ FbBX}n 分析 08O7F W[GQ[h 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 u&tFb]1@) ~BtKd* ~* 图7. 字母F在视网膜上颜色分析 pEkOSG 脚本代码 a!?.F_T9A WT?b Bf Option Explicit 'Remove this to enable non-dimensioned variables to be used. )+*{Y$/U EFwL.'Fh Dim entity As T_ENTITY $kIo4$.Y$ Dim op As T_OPERATION T|!D>l' Dim mat As T_MODELMATERIAL [='p!7z Dim A As Double bz$Qk;m=H Dim pupilDiam As Double h*G#<M Dim eID As Long hMz&JJ&B Dim parID As Long =tNzGaWJ Dim count As Integer joY1(Y Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double K Ka c6Zj Dim tlens As Double, nlens As Double E;xMPK$ Dim curv As Double, conic As Double u2\+?`Ox Dim ok As Long KCl &H PK_Fx';ke^ Sub Main VkWO} l`G(O$ct '用户输入对话框 X:R%1+&* Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 u\:rY)V TextBox 220,21,40,21,.TextBox1 'default: 0 y%2%^wF Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 |GuKU! OKButton 40,91,90,21 2|$lk8 /, CancelButton 190,91,90,21 D>ojW|@} Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Z6NJ)XQy6F TextBox 220,49,40,21,.TextBox2 'default: 4 `(!W s\: End Dialog >/8ru*Oc Dim dlg As UserDialog u>81dO]H .|U4N/XN%q ok = Dialog (dlg) XynU/Go, ~Vwk:+): If ok=0 Then 'cancel button was pressed Gee~>:_Q{J Print "Execution cancelled." "$]ls9-%n End HgYc@P*b End If &K+ *&(2`#C; 'Assign accommodation and pupil diameter & use defaults if field left empty Q^[e/U, If dlg.TextBox1 = "" Then p
"/(>8 A = 0 'Default accommodation KlY,NSlQ Else 2]2{&b u A = CDbl(dlg.TextBox1) LjSLg[ i End If qo)Q}0 _yiRh: If dlg.TextBox2 = "" Then V+peO pupilDiam = 4 'Default pupil diameter z~BD(FDI Else |
A3U@>6 pupilDiam = CDbl(dlg.TextBox2) ? 7/W> End If t8t}7XD
gW'P`Oxw Print " " &t~zD4u B Print "Accommodation = " & A & " Diopters" Sjw2 j#Q Print "Pupil Diameter = " & pupilDiam & " mm" wTB)v ! *^X#Eb ' Calculate new parameters with accommodation C usVW taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness lTxY6vi 5ze`IY Rant = 12.0 - 0.4*A 'Radius of anterior lens kw6cFz CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens r hiS .=>\Qq% Rpost = -5.224557 + 0.2*A 'Radius of posterior lens j|&{e91,? CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens l#X=]xQf FYp|oD2=1 tlens = 3.767 + 0.04*A 'Lens thickness XC*uz NS7@8 #C nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction +R2^*
*< M4zX*&w.T 'Adjust parameters to account for accommodation BO?mQu~ mGt\7&` '************************************************************************* [B}1z 'Aqueous thickness (Position of Lens) !S~,>,yd '************************************************************************* }5fU7&jA;3 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) hZp=BM"bJ GetCustomElement eID, entity <^CYxy mY$nI -P parID = FindFullName( "Geometry.Arizona Eye" ) }%-UL{3% @PT`CK} ' Delete any shift(s) in z V<7R_}^_7 count = 0 fKPiRlLS While GetOperationCount(eID)>count ZmEG<T05 GetOperation eID, count, op x?%rx}h If op.Type="ShiftZ" Then \?bwm&6+r DeleteOperation eID,count R2Twm!1 count=count-1 g,00'z_D End If }s`jl``PM count=count+1 Ul'~opf Wend S1D9AcK 9
eSN+q 'Set new shift in 4(` 2# op.Type = "ShiftZ" w^ixMn~nLF op.val1 = taq ArNur~ op.parent = parID iifc;6 2 AddOperation eID, op :'5G_4y)h Print "Set aqueous humor thickness = " & taq-0.55 ?D RFsA 4?9soc '************************************************************************* *4(/t$)pEl 'Radius and conic constant of anterior lens ^/_\etV '************************************************************************* r!{w93rPX eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) y+K7WUwhq GetConic eID, entity, curv, conic )z]q"s5 Y OSSd;ueur$ SetConic eID, entity, 1/Rant, CCant "wT~$I" Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Ov$N" (t]lP/
'************************************************************************* uvu**s 'Radius and conic constant of posterior lens o~i]W.SI( '************************************************************************* o7_MMeQ4 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ?RgU6/2 GetConic eID, entity, curv, conic +zFV~]b /E`l:&89) SetConic eID, entity, 1/Rpost, CCpost
K^!e-Xi6 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost "|.+L AJ;u&&c4C\ '************************************************************************* OmT Z-*N 'Lens thickness (Position of posterior lens surface) pm'@2dT '************************************************************************* TEaD-mY3 es.\e.HK parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ,Az`6PW :GwSs'$O ' Delete any z-shift(s) -V;0_Nx7p count = 0 88 tFB While GetOperationCount(eID)>count ,xtKPA GetOperation eID, count, op U /1[~429 If op.Type="ShiftZ" Then %nDPM? aO DeleteOperation eID,count H6%!v1 u count=count-1 O?C-nw6kP End If z:ru68 count=count+1 D,}'E0 Wend ps!5HZ2: rZ8Y=) e 'Set new z-shift 3<zTkI op.Type = "ShiftZ" b*'=W"%\ op.val1 = tlens _V_8p)% op.parent = parID 5UrXVdP AddOperation eID, op H0D>A<Ue Print "Set lens thickness = " & tlens W%cj39$ .T#y N\S1 '************************************************************************* g:.,}L 'Lens index of refraction c:?#zX '************************************************************************* \J,- <wF eID = FindMaterial( "Lens" ) |"Xi%CQ2 GetModelMaterial eID, mat |l6<GWG+ NgE&KPj\ mat.Nd = nlens 5I8FD".i SetModelMaterial eID, mat s%L"
c Print "Set lens index of refraction = " & nlens xu%!
b0 )5GdvqA '************************************************************************* >?G|Yz*kEJ 'Pupil diameter }Ll3AR7\ '************************************************************************* lry&)G=5 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ? !oVf> ga{25q}" 'Adjust pupil diameter (trimming volume inner hole) A/$KA'jX |7S4; SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ~q8V<@? I9*BENkR ' Adjust pupil location to just in front of the lens MuFU?3ovG* parID = FindFullName( "Geometry.Arizona Eye" ) ~*' 8=D?) eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) c5=v`hv count = 0 P[#WHbn While GetOperationCount(eID)>count h-2E9Z GetOperation eID, count, op PBAz`y2 If op.Type="ShiftZ" Then j?f,~Y<k DeleteOperation eID,count *&hXJJ[+ count=count-1 ^EuyvftZ End If /8$1[[[ count=count+1 r_g\_y7ua Wend WB=<W#?w7% op.Type = "ShiftZ" _ntW}})K op.val1 = taq-0.01 *xv/b= op.parent = parID p+`*~6Jj/ AddOperation eID, op px
[1# * (1elF) Print "Set pupil diameter = " & pupilDiam t5X^(@q4N ^+-L;XkeY 'Update AZ Eye subassembly Description S,"ChR eID = FindFullName( "Geometry.Arizona Eye" ) }<\65 B$1 GetEntity eID, entity ,s yA() entity.Description = "Accommodation = " & A & "D" /ie3H,2 SetEntity eID, entity Iu1Sj`A }lNufu Update ,8J*S Print "DONE!" ,3@15j Yyo9{4v+p{ End Sub Z z;<P )Py+jc. 如果屈光度是4,光瞳直径是4,则会输出如下数据: E9Xk8w'+ K&D}!.~/ Accommodation = 4 Diopters !(ux.T0 Pupil Diameter = 4 mm ]!tYrSM! Set aqueous humor thickness = 2.81 Za:BJ: Set anterior lens radius = 10.4 and conic constant = -2.375869 }%>$}4 , Set posterior lens radius = -4.424557 and conic constant = -3.081019 )(ZPSg$/F Set lens thickness = 3.927 >nIcFm Set lens index of refraction = 1.42672 8v)~J}[ Bz Set pupil diameter = 4 ^pQ;0[9Y0 DONE! "PX3%II 2GD mZl tFST.yT>zg QQ:2987619807 /<?X-IDz.{
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