FRED运用:Arizona眼睛模型
简介 %H,s~IU 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。 4z9lk^#"X kRBO] 模型 =Vazxt@[ ~1 31|e`C 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。 c"pOi&
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Table 1. AZ眼睛模型的定义 [attachment=67931] 3eXIo= 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. 4RYH^9;>K 4l68+ 光源 n;Q8Gg2U QG2 Zh9R 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。 T#*H Au}l^&,zN `|nCnT'
[attachment=67932] 图1. 光源和提示信息使用 QCE7VV1Rw 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。 eF9GhwE= <c:H u{D 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。 0\X<vrW -B&(&R
[attachment=67933] 图2. 字母F光源的设定方法光 /F(n%8)Yq wJCw6&D,/
[attachment=67934] 图3. 字母F在视网膜上位置点列图 '[%#70* 视网膜的散射 7v)p\#- Jww#zEK 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。 Y?3tf0t/ J p+'"a +A)>
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[attachment=67935] 图4. 视网膜朗伯散射设定 o ]z#~^w 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。 GZNN2
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[attachment=67936] 图5. 视网膜重点采样规格设定 !4'F z[RK 脚本 V
K 7 H"6x/&s.=k 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: WKlyOK=} b \ln XN
[attachment=67937] 图6. 用户对话框的创建与编辑 zqXF`MAB=
[attachment=67938] 图7. 用户对话框编辑器 FiUwy/,ZV 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。 "wTCO1 余下的脚本计算与屈光度有关的所有参数。 `Hlf.>b1 dS4z Oz" 分析 J ~3m7 Y%;X7VxU* 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 L\:m)g,F. Ui`{U
[attachment=67939] 图7. 字母F在视网膜上颜色分析 ?X@[ibH6 脚本代码 '5De1K.\` P=jsOuW Option Explicit 'Remove this to enable non-dimensioned variables to be used. F}ATY! 7Y(Dg`8G Dim entity As T_ENTITY $["HC-n?.k Dim op As T_OPERATION \\#D!q* Dim mat As T_MODELMATERIAL *qy \%A Dim A As Double KGg
S"d Dim pupilDiam As Double C9sU^]#F Dim eID As Long _#:7S
sJ Dim parID As Long 4^l 9d Dim count As Integer $S|+U}]C Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double a'?;;ZC- Dim tlens As Double, nlens As Double t~/:St Dim curv As Double, conic As Double !ZH "$m| Dim ok As Long 4A6Y
\Z XI t:fz%IOe Sub Main *YvtT(Gt w.(W G+ '用户输入对话框 uH%b rbrU Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 LkS tU) TextBox 220,21,40,21,.TextBox1 'default: 0 v7wyQx+Q Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Sl,DZ! OKButton 40,91,90,21 @Xl(A]w%! CancelButton 190,91,90,21 K6p\ >J Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 nLz;L r! TextBox 220,49,40,21,.TextBox2 'default: 4 [,AFtg[ End Dialog \EVT*v=}/ Dim dlg As UserDialog /-[vC$B" }_zN%Tf~ ok = Dialog (dlg) SefhOh^,V >B**fZ~L If ok=0 Then 'cancel button was pressed E4892B:` Print "Execution cancelled." }
u;{38~ End 3Z9Yzv)A End If C?gqX0[ q 9S@x 'Assign accommodation and pupil diameter & use defaults if field left empty M1-tRF If dlg.TextBox1 = "" Then DPxx9lN_rx A = 0 'Default accommodation ~
O#\$u Else e72Fz#<q A = CDbl(dlg.TextBox1) >ceC8"}J5M End If zl:by? Z%3CmKdeF If dlg.TextBox2 = "" Then @u9L+*F
pupilDiam = 4 'Default pupil diameter )Y)_T&O Else 6)uBUM;i pupilDiam = CDbl(dlg.TextBox2) L?N&kzA End If `D[O\ VE =M;F&;\8 Print " " B.5+!z&7 Print "Accommodation = " & A & " Diopters" N)g _LL>^ Print "Pupil Diameter = " & pupilDiam & " mm" B1 }-
q@bye4Ry%W ' Calculate new parameters with accommodation uE')<fVX( taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness NgyEy n
\ ;O`f+rG~ Rant = 12.0 - 0.4*A 'Radius of anterior lens Q/]~`S CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens (yP1}? OXrm!' Rpost = -5.224557 + 0.2*A 'Radius of posterior lens u>lt}0 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Eu(QeST\ $lT8M-yK\ tlens = 3.767 + 0.04*A 'Lens thickness )mm0PJF~q y7F
|v8bq nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction q1:dcxR[ vK)'3% 'Adjust parameters to account for accommodation M@{?#MkS% 1(BLdP3& '************************************************************************* =|E
" 'Aqueous thickness (Position of Lens) 5eff3qrH{ '************************************************************************* ZEI)U,
I. eID = FindFullName( "Geometry.Arizona Eye.Lens" ) cgrSd99. GetCustomElement eID, entity .S54:vs rt*x[5< parID = FindFullName( "Geometry.Arizona Eye" ) 0(-4"u>? b=lJ`| ' Delete any shift(s) in z xS1n,gTA count = 0 &B(z**+9 While GetOperationCount(eID)>count NRtH?&7 GetOperation eID, count, op `YqtI/-w If op.Type="ShiftZ" Then $f3 IO#N DeleteOperation eID,count 3XQa%|N( count=count-1 V>QyiB End If ?P0b/g count=count+1 e1W9"&4>G{ Wend 3!p`5hJd $}WT"K 'Set new shift in B.G6vx4yp op.Type = "ShiftZ" -yqgs>R(d op.val1 = taq aNu.4c/5 op.parent = parID gEk;Tj AddOperation eID, op Bz } nP9 Print "Set aqueous humor thickness = " & taq-0.55 7!AyL w TbD '************************************************************************* phu,&DS! 'Radius and conic constant of anterior lens O`y3H lc '************************************************************************* j_g(6uZhz3 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) k)I4m.0a5 GetConic eID, entity, curv, conic e}?Q&Lci _"
9 q(1 SetConic eID, entity, 1/Rant, CCant b+qd'
,.Z Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant y5eEEG6 o+.L@3RT4 '************************************************************************* KuJ9bn{u!C 'Radius and conic constant of posterior lens {BJ>x:2 '************************************************************************* eX#.Zt] eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) `r SOt*< GetConic eID, entity, curv, conic f9K7^qwkiz Q O =5Q SetConic eID, entity, 1/Rpost, CCpost ?:$
q~[LY Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost o~XK*f=( ~o_JZ: '************************************************************************* phH@{mI 'Lens thickness (Position of posterior lens surface) aC}\`.Kb '************************************************************************* -6DRX q~9-A+n parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 'EIe5Op '/xynk%)xw ' Delete any z-shift(s) q~> +x?30 count = 0 ]#G s6CsT| While GetOperationCount(eID)>count qj~=qV0p GetOperation eID, count, op op`9(=DJ] If op.Type="ShiftZ" Then :8@)W<>% DeleteOperation eID,count t)W=0iEd9 count=count-1 D@&xj_#\} End If
gra6&&^" count=count+1 *xxk70Cb Wend ~NIhS! !+3&%vQ) 'Set new z-shift EmT_T3v op.Type = "ShiftZ" K/*R}X op.val1 = tlens -&
(iU#W op.parent = parID %/I:r7UR{ AddOperation eID, op EY"of[p Print "Set lens thickness = " & tlens WOj}+?/3 R CsZm8oL$ '************************************************************************* [j/|)cj 'Lens index of refraction hiVa\s '************************************************************************* %mss{p!d6 eID = FindMaterial( "Lens" ) @H`jDaB9 GetModelMaterial eID, mat K*5gb^Ul zlEI_th:~ mat.Nd = nlens a&JY x SetModelMaterial eID, mat 8gNTW7W/ Print "Set lens index of refraction = " & nlens _0$>LWO~ h.R46 : '************************************************************************* gN<7(F 'Pupil diameter `WH$rx! '************************************************************************* pv0|6X?J" eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) RTlC]`IGT b|AjB: G 'Adjust pupil diameter (trimming volume inner hole) # l9VTzi % WDTnEm SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ?n{m2.H M <JX ' Adjust pupil location to just in front of the lens Ut2T:%m{ parID = FindFullName( "Geometry.Arizona Eye" ) 7HW:;2dL eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) (.=Y_g. count = 0 v CsE|eMP While GetOperationCount(eID)>count y2+f)Xp_.C GetOperation eID, count, op 2fkyz If op.Type="ShiftZ" Then i45.2, DeleteOperation eID,count ngZq]8=o count=count-1 f4pIF"U9> End If s/@uGC0> count=count+1 ~/A2:}Cp= Wend %' WC7s op.Type = "ShiftZ" 95IP_1}? op.val1 = taq-0.01 1/mBp+D op.parent = parID w!<e#Z]3b AddOperation eID, op E8av/O
VUd Q0"?TSY Print "Set pupil diameter = " & pupilDiam @$kO7k0{g [?N,3 'Update AZ Eye subassembly Description TI8\qIW eID = FindFullName( "Geometry.Arizona Eye" ) ;5;>f)diS GetEntity eID, entity &i3SB[| entity.Description = "Accommodation = " & A & "D" |e!Y
C iU SetEntity eID, entity x7e0& ^`#7(S)a/ Update &iu]M=Yb Print "DONE!" '2Zs15)V ;/V])4= End Sub 7l-MVn_8 Kh4rl)L*+% 如果屈光度是4,光瞳直径是4,则会输出如下数据: ,? <;zq &;?+ ^L> Accommodation = 4 Diopters #QsJr_= Pupil Diameter = 4 mm 7R[7M%H Set aqueous humor thickness = 2.81 `vzMuL; Set anterior lens radius = 10.4 and conic constant = -2.375869 J#H,QYnf(L Set posterior lens radius = -4.424557 and conic constant = -3.081019 bn|HvLQ"1 Set lens thickness = 3.927 f%n ;Z}= Set lens index of refraction = 1.42672 f9UDH8X Set pupil diameter = 4 -}4CY\d6' DONE! Cm8h
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(文章来源:讯技光电)
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