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简介 jh)@3c cQyN@W 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。 KDq="=q ^]nLE]M 模型 !T][c~l 3@Mh* \;\b 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。 +h4W<YnW BZ?C k[E]Z Table 1. AZ眼睛模型的定义 =+Fb\HvX{ 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. o+A1-&qhN v}6iI}r 光源 MhD' oNAnJ+_ 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。 w3(|A> s3 hr
fF1
>A %- 540V{q 图1. 光源和提示信息使用 SQ_?4 s:: 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。 QDg5B6>$ !S':G 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。 #5@(^N5p` FOsd{Fw 图2. 字母F光源的设定方法光 II=`=H{ q()o|V 图3. 字母F在视网膜上位置点列图 hpF_@n
视网膜的散射 112WryS rMDvnF 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。 PN
l/}' K=[7<b,:3 9efDM 图4. 视网膜朗伯散射设定 ]`&_!T 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。 6(bN*. l#KcmOz 5qtk#FB 图5. 视网膜重点采样规格设定 rUb{iU;~m 脚本 _-_iw&F \%a0Lp{ I 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: c`!e#w d&FXndC4F 图6. 用户对话框的创建与编辑 .KA-=$~J1 图7. 用户对话框编辑器 3U@jw,K!{A 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 )[Tm[o?Y. 余下的脚本计算与屈光度有关的所有参数。 u?Ffqt9' F]
c\Qt 分析 'v6@5t19j dw"Es;^ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 t{]Ew4Y4%O VhUWws3E 图7. 字母F在视网膜上颜色分析 hu}$ \ 脚本代码 .uJ
J< mAW.p=; Option Explicit 'Remove this to enable non-dimensioned variables to be used. ccag8LC zr.\7\v Dim entity As T_ENTITY >a?Bk4w Dim op As T_OPERATION 'Cc~|gOgD Dim mat As T_MODELMATERIAL 0~qc,-)3 Dim A As Double |H?t+Dyn)q Dim pupilDiam As Double 7S a9 Dim eID As Long zEI+)|4?r Dim parID As Long .Fo#Dmq3 Dim count As Integer kW/G=_6 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 'Lrn< Dim tlens As Double, nlens As Double l)%PvLbL Dim curv As Double, conic As Double tAAMSb9[d Dim ok As Long EK';\} $l]:2!R Sub Main zZ=SAjT QP a2Ak?W1 '用户输入对话框 FCEy1^u Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 m)Plv+R} TextBox 220,21,40,21,.TextBox1 'default: 0 JsJP%'^/R Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 qbv\uYow3k OKButton 40,91,90,21 kUd]8Ff! CancelButton 190,91,90,21 FiUQ2w4 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ?\V#^q- TextBox 220,49,40,21,.TextBox2 'default: 4 X4V>qHV72 End Dialog @_+aX., Dim dlg As UserDialog iOk;o= ) E^S+ps ok = Dialog (dlg) PQ&*(G *S,~zOYN If ok=0 Then 'cancel button was pressed VQ9A/DH/ Print "Execution cancelled." 6'# 5Dqw"r End +{:uPY#1 End If 53i]Q;k [ }DhqzKl 'Assign accommodation and pupil diameter & use defaults if field left empty Z 1HH0{q-A If dlg.TextBox1 = "" Then "-Q+!byh A = 0 'Default accommodation AF'< Else
{MgRi7 A = CDbl(dlg.TextBox1) )2[)11J9t End If T8^9*]:@c! [dJ!JT/X{ If dlg.TextBox2 = "" Then 981-[ga`Y pupilDiam = 4 'Default pupil diameter X)b$CG Else hF2e-- pupilDiam = CDbl(dlg.TextBox2) S{=5nR9 j End If 1/}H
0\9' S/]\GG{ Print " " ,X@o@W+L Print "Accommodation = " & A & " Diopters" k\f
_\pj6 Print "Pupil Diameter = " & pupilDiam & " mm" pfN(Ae
Pt CHgip&(.F ' Calculate new parameters with accommodation "hk#pQ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness F1Z'tjj+ QOWGQl%! Rant = 12.0 - 0.4*A 'Radius of anterior lens *9'3 `^l CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens @]Cg5QW>T 0m_yW$w Rpost = -5.224557 + 0.2*A 'Radius of posterior lens :q9! CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ;(i6 X) :iE b^F} tlens = 3.767 + 0.04*A 'Lens thickness f[o~d`z UoT`/. nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction As,`($= Y1PR?c
Q 'Adjust parameters to account for accommodation y'2|E+*V '`jGr+K,wU '************************************************************************* \g}]u(zg% 'Aqueous thickness (Position of Lens) y7HFmGM '************************************************************************* f?5>V eID = FindFullName( "Geometry.Arizona Eye.Lens" ) (?4%Xtul1 GetCustomElement eID, entity 6GxLaI (`.# n3{ parID = FindFullName( "Geometry.Arizona Eye" ) noWF0+% _b&|0j:Ud ' Delete any shift(s) in z Wiis<^) count = 0 J M`w6} While GetOperationCount(eID)>count f}-'67*Y GetOperation eID, count, op aXe&c^AR If op.Type="ShiftZ" Then Dz }i-tw+ DeleteOperation eID,count 2`=jKt count=count-1 (|QJ[@?q End If si0}b~t count=count+1 tYjG8P# Wend u&zY>'}zm * 6}M.`.- 'Set new shift in @O#!W]6NT6 op.Type = "ShiftZ" u zZ|0 op.val1 = taq Ks.b).fH op.parent = parID j)J |'b| AddOperation eID, op _o~ pVBl/ Print "Set aqueous humor thickness = " & taq-0.55 Mq>
4! @\by`3*Q '************************************************************************* 7By7F:[ b 'Radius and conic constant of anterior lens r^
r+h[V '************************************************************************* +<bj}" eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) !gXxM,R GetConic eID, entity, curv, conic 7@c!4hmrU SEgw!2H SetConic eID, entity, 1/Rant, CCant RC_Pj) Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant i%i~qTN ^|/mn!7wD '************************************************************************* |
Y:`>2ev 'Radius and conic constant of posterior lens kz=ho~ @ '************************************************************************* pBqf+}g4 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) //@6w;P GetConic eID, entity, curv, conic o0r&w;! A]bb*a1 SetConic eID, entity, 1/Rpost, CCpost 'w:ugb9] Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost O=Su
E/q MIJuJ]U} '************************************************************************* =3(v4E':5 'Lens thickness (Position of posterior lens surface) /?81Ypt '************************************************************************* k0Vri$x v`4w=!4 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) fN2Sio: N'b GL% ' Delete any z-shift(s) hDXTC_^s count = 0 kff N0(MR While GetOperationCount(eID)>count 7C|AiSH GetOperation eID, count, op 6J;!p/C8E If op.Type="ShiftZ" Then Xqf\}p n DeleteOperation eID,count Yn?beu' count=count-1 n@pwOHQn<| End If _9BL7W $; count=count+1 y[McdlH m Wend SK}jhm"y Luao?;|U 'Set new z-shift aImzK/ op.Type = "ShiftZ" X;LYGJ{Xk op.val1 = tlens "ku[b\W op.parent = parID $:u*)&"t| AddOperation eID, op ykQb;ZP8jh Print "Set lens thickness = " & tlens bd/A0i?C aR2N,<Cp5 '************************************************************************* }8#olZ/(q 'Lens index of refraction x(c+~4:_M '************************************************************************* 99OZK eID = FindMaterial( "Lens" ) ~&~4{ GetModelMaterial eID, mat D5"5`w=C $#V'm{Hh mat.Nd = nlens &A
s>Y,y SetModelMaterial eID, mat (^yaAy#4 Print "Set lens index of refraction = " & nlens Y%i<~"k ]]p\1G '************************************************************************* vU%o5y: 'Pupil diameter M8H hjoo '************************************************************************* sm18u- eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 2*snMA H:~bWd'iz 'Adjust pupil diameter (trimming volume inner hole) kw59`z Es -UEi SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" {^oohW - Pz50etJ ' Adjust pupil location to just in front of the lens |0ZJ[[2 parID = FindFullName( "Geometry.Arizona Eye" ) ];5J eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) -O &>HA count = 0 >|S@twy While GetOperationCount(eID)>count =*fq5v GetOperation eID, count, op La6
9or If op.Type="ShiftZ" Then xR-;,=J DeleteOperation eID,count +VVn@=&? count=count-1 jA"}\^%3 End If A^}# count=count+1 k*_Gg Wend `N[@lV\xp! op.Type = "ShiftZ" Op0*tj2i), op.val1 = taq-0.01 o;c"-^> op.parent = parID <Ve0Ph K AddOperation eID, op DWtITO> 38sLyoG=i Print "Set pupil diameter = " & pupilDiam @Yt394gA%\ uWx<J3~q. 'Update AZ Eye subassembly Description qBF|' .$^ eID = FindFullName( "Geometry.Arizona Eye" ) 6!i`\>I] GetEntity eID, entity ((Av3{05H& entity.Description = "Accommodation = " & A & "D" e
oE)Mq SetEntity eID, entity ,~7~ S" VMABj\yG Update bB0/FiY7o Print "DONE!" 8$c) ]Bv S\ak(<X End Sub sm"Rp~[i A*BN
如果屈光度是4,光瞳直径是4,则会输出如下数据: %KF I~Qk
Wx}-H/t'2 Accommodation = 4 Diopters .hckZx / Pupil Diameter = 4 mm NEIF1(: Set aqueous humor thickness = 2.81 nt"\FZ*;3 Set anterior lens radius = 10.4 and conic constant = -2.375869 )z&C&Gqz
Set posterior lens radius = -4.424557 and conic constant = -3.081019 e
6wevK\ Set lens thickness = 3.927 O-.G(" Set lens index of refraction = 1.42672 sI6*.nR Set pupil diameter = 4 ?o)?N8U DONE! Q|[^dju
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