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简介 j8M}*1 {{ R/:-6?@ 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。 t2BkQ8vr k
<A>J-| 模型 p
W:[Q\rSj Rde#=>@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。 R5X<8(4p ;s3"j~5m) Table 1. AZ眼睛模型的定义 I/|)? 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. 58mzh82+ x7L$x=8s 光源 F04`MY" # h/- 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 -qs.'o
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1mJBxg}( 图1. 光源和提示信息使用 ZJP.-` U 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 D(~6h,=m CmJI" 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 ?T$i \$VtwVQ,b 图2. 字母F光源的设定方法光 AQbbIngo jzI\Q{[m' 图3. 字母F在视网膜上位置点列图 }Da8S|)H 视网膜的散射 {tu* ="d= [LL"86D 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。 6.EfM^[ 2(5wFc 0"#tK4 图4. 视网膜朗伯散射设定 mf,mKgfG 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。 G+m|A*[> uTbI\iq 17$JBQ,[ 图5. 视网膜重点采样规格设定 k1$|vzMh 脚本 C(}9 @2CYv> 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: WT'P[RU2 MZ=U}
&F 图6. 用户对话框的创建与编辑 <rRmbFH# 图7. 用户对话框编辑器 >kz5azV0 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。 .oaW#f}0P 余下的脚本计算与屈光度有关的所有参数。 -66|Y v^[tK2&v 分析 Ea!}r|~]0 _f|Au`7m 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 xb8fV*RO8A *vJ1~SRV 图7. 字母F在视网膜上颜色分析 L@CN0ezQs 脚本代码 fa\<![8LAU %lv2 ;- Option Explicit 'Remove this to enable non-dimensioned variables to be used. 6x*ImhQ.J e>nRJH8pK Dim entity As T_ENTITY 7Ar4:iNvX Dim op As T_OPERATION 87~. |nu Dim mat As T_MODELMATERIAL *3S,XMS{O Dim A As Double e<~uU9
lg1 Dim pupilDiam As Double (LL4V
3) Dim eID As Long `9a%}PVQ- Dim parID As Long mEz&:A Dim count As Integer fU>"d>6!S Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double PS`)6yn{_ Dim tlens As Double, nlens As Double #4%,09+ Dim curv As Double, conic As Double A[htG\A` 0 Dim ok As Long Y_Ej-u+>{ E^A9u
|x Sub Main 4xtbP\= Pk~P '用户输入对话框 uO,90g[C/R Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 NZ7a^xT_) TextBox 220,21,40,21,.TextBox1 'default: 0 @L{HT8utK3 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 1ReO.Dd`R OKButton 40,91,90,21 &IXr*I CancelButton 190,91,90,21 p*#SSR9< Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 c{|soc[# TextBox 220,49,40,21,.TextBox2 'default: 4 2NIK0%6 End Dialog ~u,g5 Dim dlg As UserDialog Xw9,O8}C7 kl3#&>e ok = Dialog (dlg) 6M+~{9(S I4qzdD If ok=0 Then 'cancel button was pressed ;[gv-H Print "Execution cancelled." Gxm+5q End N7+K$)3 End If h-lMrI)U?h
pfZn<n5p 'Assign accommodation and pupil diameter & use defaults if field left empty 'qQDM_+ If dlg.TextBox1 = "" Then C(e!cOG A = 0 'Default accommodation ;)"r^M)): Else '~liDz*O A = CDbl(dlg.TextBox1) 7D9R^\K End If (t<i?>p k(%RX_]C If dlg.TextBox2 = "" Then PJO;[:
.I pupilDiam = 4 'Default pupil diameter >4LX!^V" Else =E4nNL? pupilDiam = CDbl(dlg.TextBox2) ^h^j:!76j End If ,1^)JshZ~ -lb}}z+/ Print " " PcDPRX!@ Print "Accommodation = " & A & " Diopters" 7@+0E2' Print "Pupil Diameter = " & pupilDiam & " mm" w<\N-J|m w$61+KH K ' Calculate new parameters with accommodation "TN}=^A\F taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness A{&Etu(K ag|d_; Rant = 12.0 - 0.4*A 'Radius of anterior lens [}P|OCW CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens Y*w<~m =YLt?5|e Rpost = -5.224557 + 0.2*A 'Radius of posterior lens "GZhr[AW CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ~a/yLI"'g 2Q1* Xq{ tlens = 3.767 + 0.04*A 'Lens thickness MzJ5_} [0)iY%^ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Hej0l^ f"k/j?e* 'Adjust parameters to account for accommodation |6_<4lmTxF ;9u6]%hQTX '************************************************************************* __3Cjo^6& 'Aqueous thickness (Position of Lens) 5%tIAbGW '************************************************************************* BMFpkK9| eID = FindFullName( "Geometry.Arizona Eye.Lens" ) V4VTP]'n GetCustomElement eID, entity @X1>Wv|[ ?*}V>h 8m) parID = FindFullName( "Geometry.Arizona Eye" ) 0 B3*\ H}5 wW!*"z ' Delete any shift(s) in z kw=+"U count = 0 3fM While GetOperationCount(eID)>count \Sm.]=br GetOperation eID, count, op 3R4-MK If op.Type="ShiftZ" Then !^`ZHJ-3>; DeleteOperation eID,count b?HW6Kfc count=count-1 /i^b;?/1 End If aEX+M57k~ count=count+1 xx9qi^
Wend x#Hq74H, 6S`eN\s 'Set new shift in )(75dUl op.Type = "ShiftZ" v?d~H`L op.val1 = taq
D&N5) op.parent = parID Is?0q@ AddOperation eID, op <VgnrqF6: Print "Set aqueous humor thickness = " & taq-0.55 `wk#5[Y_ 2/>AmVM '************************************************************************* 7,Z%rqf\) 'Radius and conic constant of anterior lens *,pG4kh! '************************************************************************* CS6,mX eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) HjV83S; GetConic eID, entity, curv, conic *qKwu?]?> mC J/gWDY SetConic eID, entity, 1/Rant, CCant j.ANBE96> Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant LFg<j1Gk` bO^%#<7 '************************************************************************* N:gS]OI* 'Radius and conic constant of posterior lens JJ7-$h'0q '************************************************************************* ("H:T?4Qs eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) d \0K3=h GetConic eID, entity, curv, conic @c7 On)sy m,*t}j0 7 SetConic eID, entity, 1/Rpost, CCpost jC;XY !d6 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost m,)Re8W- |{ *ce<ip5 '************************************************************************* W&Fa8 'Lens thickness (Position of posterior lens surface) y .
AN0 '************************************************************************* =EV8~hMyqh e|Lh~sVq parID = FindFullName( "Geometry.Arizona Eye.Lens" ) b/
~&M+) i-tX5Md| ' Delete any z-shift(s) 6,cyi|s count = 0 kiqq_`66 While GetOperationCount(eID)>count @R`OAdy GetOperation eID, count, op G0a UZCw If op.Type="ShiftZ" Then Z$6W)~;, DeleteOperation eID,count p/SJt0 count=count-1 V{c
n1Af End If NV*t count=count+1 W;Fcp Wend =Z%&jul l|5ss{llR 'Set new z-shift FDpNM\SR1l op.Type = "ShiftZ" :c<C;. op.val1 = tlens vgsu~(L; op.parent = parID ~TurYvf AddOperation eID, op \s+<w3 Print "Set lens thickness = " & tlens d]w*fn s)&"ga '************************************************************************* /5zzzaj{ 'Lens index of refraction S(/@.gI:f '************************************************************************* uw;s](~E eID = FindMaterial( "Lens" ) /AW6XyMD_ GetModelMaterial eID, mat %qN8uQx sveFxI mat.Nd = nlens .RoO6:T6 SetModelMaterial eID, mat [o>/2 Print "Set lens index of refraction = " & nlens 5.5dB2w v)rN]b] '************************************************************************* 574b] 'Pupil diameter {s_0[> '************************************************************************* Yo(8mtYU eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) <}.)kg${O (7-K4j` 'Adjust pupil diameter (trimming volume inner hole) /`2VJw ;?%2dv2d SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" zgVplp T73saeN ' Adjust pupil location to just in front of the lens cCWOGd parID = FindFullName( "Geometry.Arizona Eye" ) H$\?D+xlf eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) t_P1a0Zu count = 0 5F&i/8Ib While GetOperationCount(eID)>count 0#<_:E GetOperation eID, count, op h_y<A@[P} If op.Type="ShiftZ" Then 'KyT]OObS DeleteOperation eID,count ~x>IN1Vci count=count-1 /A##Yv!biR End If :UFf6T? count=count+1 7+=j]+O Wend l\MiG Na op.Type = "ShiftZ" Ig$5Ui op.val1 = taq-0.01 zA-?x1th& op.parent = parID 7_q"%xH AddOperation eID, op
@A$%baH0 eb.`Q+Gb Print "Set pupil diameter = " & pupilDiam G++kUo< ]l+2Ca:-[j 'Update AZ Eye subassembly Description [iL2c=_ eID = FindFullName( "Geometry.Arizona Eye" ) +R#*eo;o7 GetEntity eID, entity S7N54X2JwL entity.Description = "Accommodation = " & A & "D" FcfN]! SetEntity eID, entity /[{?zS{ 5z El`h Update F!a YK2 Print "DONE!" e(!a~{(kq% `{tykYwCLc End Sub wl(}F^:/` \6C"bQ 如果屈光度是4,光瞳直径是4,则会输出如下数据: '7_'s1 -4GSGR'L&y Accommodation = 4 Diopters XV+BSW7} Pupil Diameter = 4 mm fI"`[cA"] Set aqueous humor thickness = 2.81 TR
]lP<m Set anterior lens radius = 10.4 and conic constant = -2.375869 W>1\f0' Set posterior lens radius = -4.424557 and conic constant = -3.081019 5|H?L@_9 Set lens thickness = 3.927 t'[vN~I' Set lens index of refraction = 1.42672 =YPWt>\a} Set pupil diameter = 4 -U;s,>\) DONE! M5P63=1+
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