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简介 ANhtz1Fl <,]:jgX 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。 MgJ6{xzz Js,! G 模型 NfgXOLthM
r6m^~Wq!} 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。 F(G..XJQ &uNec(c Table 1. AZ眼睛模型的定义 O sgPNy0 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. ?*fa5=ql <&5z0rDKWw 光源 }T?X6LA$I8 G$<(>"Yr~$ 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。 mk>; 3m* fq7#rZCxX 7> Z| K 图1. 光源和提示信息使用 E=s h^Q(A 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。 %6m/ve Mg2+H+C~: 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。 !m@cTB7i
8 1,N92T5 图2. 字母F光源的设定方法光 G]K1X"W? iiPVqU% 图3. 字母F在视网膜上位置点列图 9z7_D_yN2 视网膜的散射 jRK}H*uem E'AR.! 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。 Q
dj(D\. #"gt&t9Q ewMVUq*: 图4. 视网膜朗伯散射设定 *[Hp&6f 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。 VeA@HC`?" @ st>#]i4 S,&LH-ps 图5. 视网膜重点采样规格设定 c#OxI*,+/ 脚本 42Z:J 0 ZbFD |~[ V 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: :@L7RZ`_ +IdM|4$\1 图6. 用户对话框的创建与编辑 }a]`"_i;[ 图7. 用户对话框编辑器 N1 t4o~ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 tr0b#4 余下的脚本计算与屈光度有关的所有参数。 !nmZ"n|}p V._-iw]v 分析 Xb_
V\b0 S<mZs; 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 14,)JZN [OC(~b 图7. 字母F在视网膜上颜色分析 q\fbrv%I4 脚本代码 ]iV]7g8: Hv/C40uM- Option Explicit 'Remove this to enable non-dimensioned variables to be used. r:QLU]
N*IroT3 Dim entity As T_ENTITY 1c$pz:$vX Dim op As T_OPERATION V.~kG ,Ht Dim mat As T_MODELMATERIAL \8{SQ% Dim A As Double ?JuJu1 Dim pupilDiam As Double 1$*8F Dim eID As Long A c_P^ Dim parID As Long 579Q&|L. Dim count As Integer x\yM|WGL Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double > X~\(|EM Dim tlens As Double, nlens As Double _}{KS, f]0 Dim curv As Double, conic As Double ZU\$x<, Dim ok As Long WIWo4[( ]3,'U(!+ Sub Main !r/i<~'Bx [@K'}\U^+ '用户输入对话框 Y>$5j}K Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 rZI63S TextBox 220,21,40,21,.TextBox1 'default: 0 %`Ce#b()' Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 (B#FLoK OKButton 40,91,90,21 lxn/97rA CancelButton 190,91,90,21 htB2?%S=T Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ]OpGD5jZ TextBox 220,49,40,21,.TextBox2 'default: 4 HNZ$CaJh End Dialog E~y8X9HZ) Dim dlg As UserDialog XDK Me} qnP4wRpr ok = Dialog (dlg) IADSWzQ@ Ana[>wSZO@ If ok=0 Then 'cancel button was pressed ?V`-z#y7 Print "Execution cancelled." i4YskhT End ra~=i|s End If uQdeKp4( AD 'Assign accommodation and pupil diameter & use defaults if field left empty p\zqZ=s If dlg.TextBox1 = "" Then c&;" Y{ A = 0 'Default accommodation )CXlPbhY? Else ".jO2GO^ A = CDbl(dlg.TextBox1) /KH85/s End If lBP?7`U ww|fqx? If dlg.TextBox2 = "" Then p5]W2i., pupilDiam = 4 'Default pupil diameter dV$[O`F*b Else *)[fGxz
\ pupilDiam = CDbl(dlg.TextBox2) 3]S*p ErY End If EWJB/iED QMMpB{FZ`o Print " " +[}y`
-t Print "Accommodation = " & A & " Diopters" GW
{tZaB Print "Pupil Diameter = " & pupilDiam & " mm" cc${[yj) #X]*kxQ< ' Calculate new parameters with accommodation
]Zb9F[ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness u?>},M/ } W]A`-Jv Rant = 12.0 - 0.4*A 'Radius of anterior lens z,;XWv? CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 'e:4 GUL~k@:_k Rpost = -5.224557 + 0.2*A 'Radius of posterior lens aPJTH0u CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Xau%v5r YusmMsN? tlens = 3.767 + 0.04*A 'Lens thickness D[^K0<-Z 9>{ml&$ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction )d[n-Si Jk{SlH3' 'Adjust parameters to account for accommodation /yU#UZ4; 9#[,{2pJr '************************************************************************* $`OyGeq"T 'Aqueous thickness (Position of Lens) e# Y{YtE '************************************************************************* 7
\xCNOKh eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Z6B$\Q5Od GetCustomElement eID, entity [(
xPX cvw17j parID = FindFullName( "Geometry.Arizona Eye" ) pI f6RwH}% i:Y5aZc/Ds ' Delete any shift(s) in z >~d'i count = 0 !ak760*A While GetOperationCount(eID)>count 7 @\i5 GetOperation eID, count, op / 8O=3 If op.Type="ShiftZ" Then 8XV RRk DeleteOperation eID,count NvzPZ9=@- count=count-1 5XT^K)' End If 7j|CWurvq count=count+1 2KO`+ Wend x7B;\D#`i/ jhRr! 'Set new shift in ['>ZC3?"h op.Type = "ShiftZ" ^coCsV^CW" op.val1 = taq NJJ=ch op.parent = parID zw'%n+5m AddOperation eID, op = y^5PjN Print "Set aqueous humor thickness = " & taq-0.55 3LyNi$`f Z|KDi
`S '************************************************************************* XFTqt] 'Radius and conic constant of anterior lens DhxS@/ '************************************************************************* RKzO$T eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) z}}P+P/ GetConic eID, entity, curv, conic {KDN|o+% I[rR-4.F] SetConic eID, entity, 1/Rant, CCant /7#MJH5b6 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 6RIbsy N, u]2,E '************************************************************************* z3[J
sE% 'Radius and conic constant of posterior lens 7Wv.-LD6 '************************************************************************* ?!m\|'s- eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) %J'/ cmR& GetConic eID, entity, curv, conic qu#xc0? >r X$E<B\ SetConic eID, entity, 1/Rpost, CCpost =x?WZMO Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost .[eC w S/*\j7cj '************************************************************************* bGB$a0 'Lens thickness (Position of posterior lens surface) @=z.^I30 '************************************************************************* h+Lpj^<2a ^?]-Q*w3Qs parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 7L:Eg QiA}0q3]0 ' Delete any z-shift(s) 5'DY)s-K count = 0 Uufig)6 While GetOperationCount(eID)>count 2\&3x}@ GetOperation eID, count, op 0N)DHD?U If op.Type="ShiftZ" Then vaQsG6q[ DeleteOperation eID,count 3 ;" [WOv count=count-1 izcjI.3e, End If mc`Z;D/mt count=count+1 ;`xCfOY( Wend =!DX,S7 0datzEns` 'Set new z-shift #?\(l% op.Type = "ShiftZ" ml|FdQ op.val1 = tlens t@R n#(~" op.parent = parID Q3hSWXq' AddOperation eID, op fp(zd;BSQ Print "Set lens thickness = " & tlens 2::YR? I*N v|HST '************************************************************************* K@:omT 'Lens index of refraction gREk,4DAv '************************************************************************* YH+(N eID = FindMaterial( "Lens" ) H}_R `S GetModelMaterial eID, mat cGm?F,/` V=&M\58 mat.Nd = nlens 569p/? SetModelMaterial eID, mat sMVk]Mb Print "Set lens index of refraction = " & nlens x'?p?u~[ B R '************************************************************************* UpD4'!<buV 'Pupil diameter S8kzAT '************************************************************************* H)S!%(x4 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) {A< 9 61 a_0I)'
? 'Adjust pupil diameter (trimming volume inner hole) 7vRp<
w\D
!e SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 7f
k)a PRUl-v ' Adjust pupil location to just in front of the lens \}4*}Lr parID = FindFullName( "Geometry.Arizona Eye" ) XUVj<U eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) KX;JX*)J count = 0 2[(~_VJ While GetOperationCount(eID)>count IUEpE9_ GetOperation eID, count, op zjow % If op.Type="ShiftZ" Then x'\C'zeF DeleteOperation eID,count du~V=%9 count=count-1 S[7^#O.) End If ig YYkt count=count+1 NZZy^p&O Wend |,=^P`#% op.Type = "ShiftZ" :
qK-Rku op.val1 = taq-0.01 |/xx**? op.parent = parID N2HD=[*cr AddOperation eID, op iFI+W<QR _x""-X~OL Print "Set pupil diameter = " & pupilDiam &L+.5i W 2[]m>; 'Update AZ Eye subassembly Description KIv_
AMr eID = FindFullName( "Geometry.Arizona Eye" ) (y6}xOa( GetEntity eID, entity sCt)Yp+8}B entity.Description = "Accommodation = " & A & "D" /W*Z. SetEntity eID, entity ORF:~5[YS` *U%3[6hm Update OE0G*`m Print "DONE!" :] U\{;q2 0,m]W) End Sub +'5I8FE- 8kdJtEW3 如果屈光度是4,光瞳直径是4,则会输出如下数据: vK+reXE EZjtZMnj Accommodation = 4 Diopters Bf#cBI Pupil Diameter = 4 mm >w7KOVbN3
Set aqueous humor thickness = 2.81 ZQfPDH= Set anterior lens radius = 10.4 and conic constant = -2.375869 eBxm Set posterior lens radius = -4.424557 and conic constant = -3.081019 l"}_+5 Set lens thickness = 3.927 T_D] rMl Set lens index of refraction = 1.42672 _ {wP:dI " Set pupil diameter = 4 |BZrV3;H DONE! N%Ta.`r
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