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简介 ph%/;?wY Bz9!a k~4 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。 hUB_[#8# MBXumc_g 模型 yXR$MT+ ~ :s$ rD 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>7`D3 "ln(EvW Table 1. AZ眼睛模型的定义 2m[z4V@` 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. a0CmCv2# 5Ee%!Pk 光源 e6QUe.S t_x\&+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。 4mQ:i7~ g"hm"m}i _CciU.1k&, 图1. 光源和提示信息使用 _rY,=h{+ 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。 M7fw/i M{3He)& 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。 "S_t%m&R ;6U=fBp7< 图2. 字母F光源的设定方法光 +/-#yfn!TR O9dIobu4 图3. 字母F在视网膜上位置点列图 V[5-A $ft 视网膜的散射 j0Kj> f,k'gM{K 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 y5RcJM L#M9 ! +(` 图4. 视网膜朗伯散射设定 4!XB?-. 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 !WR(H&uBr\ iLws;3UX;x 506B= 图5. 视网膜重点采样规格设定 k*w]a 脚本 #78p#E jY('?3 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: 1*Yf[;L B<I%:SkF@ 图6. 用户对话框的创建与编辑 }'b3'/MJ 图7. 用户对话框编辑器 wbyY?tH 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 +5JCbT@y 余下的脚本计算与屈光度有关的所有参数。 S>/p6}3] h*Rh:yCR> 分析 G{pfyfF )~rfx 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 _rR+u56y- X2}\i5{ 图7. 字母F在视网膜上颜色分析 <IC=x(T 脚本代码 \j+O |#`|) lQ<2Vw#Yl Option Explicit 'Remove this to enable non-dimensioned variables to be used. cuO(*%Is1 ^&03D5@LoY Dim entity As T_ENTITY N /p9Ws Dim op As T_OPERATION Vl%AN;o Dim mat As T_MODELMATERIAL m$ )yd~ Dim A As Double d(3F:dbk Dim pupilDiam As Double r`qMif' Dim eID As Long =!w5%|r. Dim parID As Long ,^pM]+NF| Dim count As Integer @{iws@. Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double zH0%;
o} Dim tlens As Double, nlens As Double ug'I:#@2 Dim curv As Double, conic As Double A[
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@:z Dim ok As Long n#uH^@#0 n (7m Sub Main J;W(}"cFq gbsRf&4h '用户输入对话框 #=V%S
2~ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ZR.1SA0x?O TextBox 220,21,40,21,.TextBox1 'default: 0 Sf);j0G,D Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 m2E$[g OKButton 40,91,90,21 |NJe4lw+? CancelButton 190,91,90,21 SpPG Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 orVsMT[A TextBox 220,49,40,21,.TextBox2 'default: 4 *Z>Yv37P End Dialog ]( V+ qj Dim dlg As UserDialog M#LQz~E 3~z4#8= ok = Dialog (dlg) A{iI,IFe hb9e6Cc If ok=0 Then 'cancel button was pressed &$?e D{ Print "Execution cancelled." h!5^d!2, End %C\Q{_ AS End If '%_1eaH $#2ik~]> 'Assign accommodation and pupil diameter & use defaults if field left empty ?VrZM If dlg.TextBox1 = "" Then bj\v0NKN4 A = 0 'Default accommodation '(mJ*Eb Else 8Y *SZTzV A = CDbl(dlg.TextBox1) a% |[m,FvP End If [HI&>dm=$ .=~beTS'Vo If dlg.TextBox2 = "" Then 9_h3<3e pupilDiam = 4 'Default pupil diameter nF~</> Else `au('
xi< pupilDiam = CDbl(dlg.TextBox2) z~Ph=1O>p End If @[#U_T- I _P
0,UgZz Print " " fzO4S^mTo8 Print "Accommodation = " & A & " Diopters" b#bdz1@s Print "Pupil Diameter = " & pupilDiam & " mm" [_hHZMTH .281;] = ' Calculate new parameters with accommodation >8_#L2@ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness py`RH) -CfGWO#Gbx Rant = 12.0 - 0.4*A 'Radius of anterior lens s\i=-` CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens eZ5UR014 aehGT| Rpost = -5.224557 + 0.2*A 'Radius of posterior lens A"x1MjuqLM CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Vo}3E] lE:X~RO"~ tlens = 3.767 + 0.04*A 'Lens thickness nv1'iSEeOl 'bGL@H nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction g
<^Y^~+E L@2%a' 'Adjust parameters to account for accommodation FL% GW: >8Wvz.Nq/ '************************************************************************* }$!bD
'Aqueous thickness (Position of Lens) Oe4 l`
=2 '************************************************************************* p.^mOkpt eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Zs<}{`- GetCustomElement eID, entity g66=3c9</6 2|@@xF parID = FindFullName( "Geometry.Arizona Eye" ) ,oX48Wg_+ 9 P_`IsVK ' Delete any shift(s) in z c|3%0=,` count = 0 ot]eaad While GetOperationCount(eID)>count ]2(vO0~ GetOperation eID, count, op S>OfUrt If op.Type="ShiftZ" Then K]' 84!l DeleteOperation eID,count h^^zR)EVb count=count-1 v39`ct= e End If jIJVl \i] count=count+1 r7Bv?M^! Wend 9;2PoW8 V2sWcV? 'Set new shift in `fh^[Q|4n0 op.Type = "ShiftZ" J_YbeZ] op.val1 = taq }[}u5T`w> op.parent = parID 0#4_vg . AddOperation eID, op GdG1e%y]z Print "Set aqueous humor thickness = " & taq-0.55 *F* c (rO_Vfaa '************************************************************************* 1}#v<b$ 'Radius and conic constant of anterior lens Be}e%Rk '************************************************************************* /:v+:-lU eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) GY<ErS)2 GetConic eID, entity, curv, conic ~ ui/Qf2| C-d|;R}Ww SetConic eID, entity, 1/Rant, CCant &?>h#H222 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant {PgB~|W pw{3I 2Ix '************************************************************************* eO;i1 > 'Radius and conic constant of posterior lens BM=`zGh" '************************************************************************* ,\!4A eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) DLcfOOn1I GetConic eID, entity, curv, conic ,!t1( H
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4< SetConic eID, entity, 1/Rpost, CCpost L,!?'.*/] Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost -q' n p0H UfjLNe}wA '************************************************************************* :0IxnK(r& 'Lens thickness (Position of posterior lens surface) %F-/|x1#Q '************************************************************************* I7TdBe- 6la# 0U23 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) L>+g;GJ /tRzb8` ' Delete any z-shift(s) _?>!Bz
m count = 0 mN+~fuh While GetOperationCount(eID)>count 9+@"DuYc6 GetOperation eID, count, op #S2LQ5U If op.Type="ShiftZ" Then kwNXKn/ DeleteOperation eID,count /*p4(D_A count=count-1 Ntr5Q
IPd End If b9ysxuUdS count=count+1 W!q'wrIx( Wend ^4(CO[|c~ pcXY6[#N 'Set new z-shift 3S1V^C-eBx op.Type = "ShiftZ" S_LY>k? op.val1 = tlens 0h!2--Aur op.parent = parID h`+Gs{1qw AddOperation eID, op HRIf)n&~f Print "Set lens thickness = " & tlens MK9?81xd b7R#tT '************************************************************************* |57KTiiNLI 'Lens index of refraction r5Ej '************************************************************************* WS9n.opl} eID = FindMaterial( "Lens" ) w8:F^{ GetModelMaterial eID, mat K+2bNKZ0 S`2M QL mat.Nd = nlens Gp9>R~$ SetModelMaterial eID, mat 5&7)hMppI Print "Set lens index of refraction = " & nlens }<7Dyn, ac>}$Uw) '************************************************************************* 8=gr F 'Pupil diameter
r4t|T^{sl '************************************************************************* P]!$MOt eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) $D5[12X qyl~*r* 'Adjust pupil diameter (trimming volume inner hole) ?15k~1nA y$s}-O]/- SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" n>>hfxv(O! &<@{ d ' Adjust pupil location to just in front of the lens jjBcoQU$o parID = FindFullName( "Geometry.Arizona Eye" ) hor ok:{ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) &=fBqod count = 0 R<LW*8 While GetOperationCount(eID)>count U#G
uB&V GetOperation eID, count, op I@cKiB If op.Type="ShiftZ" Then G+4a%?JH DeleteOperation eID,count I'"*#QOX count=count-1 RL~|Kr<7J End If QI~s~j count=count+1 WzgzI/ Wend As@~%0 S op.Type = "ShiftZ" X^% I 3 op.val1 = taq-0.01 ]]o7ej op.parent = parID %s$_KG !& AddOperation eID, op Xn.zN>mB e;x`C Print "Set pupil diameter = " & pupilDiam L6BHh_*E kr8NKZ/ 'Update AZ Eye subassembly Description Xfx(X4$ 9 eID = FindFullName( "Geometry.Arizona Eye" ) ERL(>) GetEntity eID, entity mDipP entity.Description = "Accommodation = " & A & "D" SynxMUlA SetEntity eID, entity 598xV|TON #:T5_9p Update WP32t@ Print "DONE!" L"zOa90ig ;5my(J*b End Sub /.'1i4Xa1P 9^0 'VRG 如果屈光度是4,光瞳直径是4,则会输出如下数据: ( NjX?^ yN{Ybp Accommodation = 4 Diopters <S
$Z Pupil Diameter = 4 mm fouy?? Set aqueous humor thickness = 2.81 S7aS Ut! Set anterior lens radius = 10.4 and conic constant = -2.375869 wX#\\Jgi Set posterior lens radius = -4.424557 and conic constant = -3.081019 1|/2%IDUI Set lens thickness = 3.927 Y+upZ@Ga Set lens index of refraction = 1.42672 dp)lHBV Set pupil diameter = 4 XT>e/x9' DONE! BOL_kp"
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