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简介 a{{g<<H i hh/sPi 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。 rj6#1kt oh$Q6G 模型 ew"v{=X =m5SK5vLKT 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。 IpP~Uz ^h{)Gf,+\ Table 1. AZ眼睛模型的定义 1KjU ]
r2 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. rk)##) ,=l7:n 光源 Z!U)I-x&
>3c@x 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。 @:KJYm[ B/`
!K ;A#`]-i C 图1. 光源和提示信息使用 uL[.ND2._& 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。 4C FB"?n0 lkBdl#]9 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。 :]J Ye* }N*_KzPIa 图2. 字母F光源的设定方法光 Y[L-7^o@y N 5 $c]E 图3. 字母F在视网膜上位置点列图 |Pg@M 视网膜的散射 Offu9`DiZ g55`A`5%C 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 _cu:aktf2 jAud {m*T /{|fyKo\? 图4. 视网膜朗伯散射设定 A]XZnQ 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 QcgfBsv96 .w]GWL q`pP$i: 图5. 视网膜重点采样规格设定 )KP5WudX 脚本 F+@5C:<? '3?\K3S4i 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: :H c0b= ;X?mmv' 图6. 用户对话框的创建与编辑 h(5P(` M 图7. 用户对话框编辑器 3\Xbmq8} 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。 \|K;-pL 余下的脚本计算与屈光度有关的所有参数。 !H ~<
]8T!qS(UJd 分析 G#?Sfn O0 / 4lvP 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 s&NX@ kcQ'$<Mz< 图7. 字母F在视网膜上颜色分析 435;Vns\n 脚本代码 &9Xhl'' 0@EwM Option Explicit 'Remove this to enable non-dimensioned variables to be used. Z.M,NR #y%!\1M/:A Dim entity As T_ENTITY ~j<+k4I~ Dim op As T_OPERATION ezMI\r6 Dim mat As T_MODELMATERIAL IV)<5'v Dim A As Double P><o,s"v Dim pupilDiam As Double PTEHP Dim eID As Long _vZ"4L+Iw+ Dim parID As Long W16,Alf: Dim count As Integer LU9A# Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 'z$Q rFW Dim tlens As Double, nlens As Double !=N"vD* Dim curv As Double, conic As Double 39=1f6I1 Dim ok As Long 65Cg]Dt71 YJo["Q Sub Main phgm0D7 VP6ZiQ| '用户输入对话框 ,%)6jYHR w Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 yfm^?G|sW TextBox 220,21,40,21,.TextBox1 'default: 0 $5*WLG&AK Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 a|?4) OKButton 40,91,90,21 h}xeChw] CancelButton 190,91,90,21 m o:D9 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 lgb?)= TextBox 220,49,40,21,.TextBox2 'default: 4 d.P\fPSD End Dialog Rb{U+/gq Dim dlg As UserDialog O/<K!;(@? *q1% IJ ok = Dialog (dlg) V#`fs|e;y _-#'j2 If ok=0 Then 'cancel button was pressed #cCL.p"] Print "Execution cancelled." Q_Gi]M9 End dX)GPC-D7 End If /;utcc AqV7\gdOC 'Assign accommodation and pupil diameter & use defaults if field left empty uxzze~_+C If dlg.TextBox1 = "" Then E~_]Lfs) A = 0 'Default accommodation 8f3vjK' Else J52
o
g4l A = CDbl(dlg.TextBox1) sUU{fNC6| End If lHhUC16> ]~E0gsq If dlg.TextBox2 = "" Then k0Uyf~p~ pupilDiam = 4 'Default pupil diameter )kkhJI*v Else afb+GA! pupilDiam = CDbl(dlg.TextBox2) Qu]z)";7 End If ,Bal q@xBJ[IM Print " " F
3'9u# Print "Accommodation = " & A & " Diopters" wV^V]c ?U Print "Pupil Diameter = " & pupilDiam & " mm" zBe8,, e QJ7L7S ' Calculate new parameters with accommodation G3{=@Z1 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness |K|h+fgG6* 7%{ | Rant = 12.0 - 0.4*A 'Radius of anterior lens T9879[ZU\ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens [mPjP%{=@ 14"J d\M8 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ?|ZTaX6A CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens as>L[jyG/ :G<E^<M\)^ tlens = 3.767 + 0.04*A 'Lens thickness b/Xbs0q BouTcC nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction PfZ+PqS 91xB9k1zO 'Adjust parameters to account for accommodation xQp|;oW;z h`H,a7 '************************************************************************* C|o`k9I# 'Aqueous thickness (Position of Lens) QQV~?iW{~ '************************************************************************* {4-[r#R<M eID = FindFullName( "Geometry.Arizona Eye.Lens" ) b@2J]Ay E* GetCustomElement eID, entity A4]s~Ur e@ \p0( parID = FindFullName( "Geometry.Arizona Eye" ) {je-I9%OK g{P%s'%* ' Delete any shift(s) in z &zuG81F6 count = 0 Kk{<@v) While GetOperationCount(eID)>count V}zEK0n(6 GetOperation eID, count, op D2,z)O%VK If op.Type="ShiftZ" Then I'@Ydt2 DeleteOperation eID,count jr`Es s count=count-1 6HlePTf8 End If Usta0Ag count=count+1 b? j< BvQ Wend %bdjBa} ?Sb8@S&J 'Set new shift in ? mhs$g> op.Type = "ShiftZ" tu5*Qp\ op.val1 = taq m{7(PHpw op.parent = parID bl'z<S,
' AddOperation eID, op 5A4&+rdU Print "Set aqueous humor thickness = " & taq-0.55 Y9`5G% "kA*Vc# '************************************************************************* UDL
RCS8i 'Radius and conic constant of anterior lens :Pv*,qHE '************************************************************************* c-Pw]Ju eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) \{EpduwZ GetConic eID, entity, curv, conic "XT"|KF|D R+7oRXsu SetConic eID, entity, 1/Rant, CCant 5j-]EJb Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant >B>CB3U 1NcCy!+ '************************************************************************* U.@*`Fg 'Radius and conic constant of posterior lens IO/4.m-aN# '************************************************************************* @e'5E^ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) E(i[o? GetConic eID, entity, curv, conic 0V!l,pg yA3wtm/? SetConic eID, entity, 1/Rpost, CCpost R9!Uo Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost hbcuK& E!O\87[ '************************************************************************* yu;SH[{Wi 'Lens thickness (Position of posterior lens surface) G\a8B#hg '************************************************************************* 2mq$H_ h?$T!D> parID = FindFullName( "Geometry.Arizona Eye.Lens" ) XB[<;*Iz E{2Eoj;gq ' Delete any z-shift(s) 1U,1)<z~u count = 0 RO3oP1@B While GetOperationCount(eID)>count (4%YHS8 GetOperation eID, count, op /o2P+Xr8" If op.Type="ShiftZ" Then q}FVzahv DeleteOperation eID,count OK{xuX8u count=count-1 =GXu 5 8 End If +L=*:e\j count=count+1 0W%@gs5d& Wend u@3y&b dCFlM&(i 'Set new z-shift $ F S_E op.Type = "ShiftZ" Gx
72 op.val1 = tlens e9E\% p op.parent = parID _aPh(qprc AddOperation eID, op wI5Yn
h Print "Set lens thickness = " & tlens uZi.HG{<) ;2m<CSv!D '************************************************************************* 1+7GUSIb 'Lens index of refraction I_q~*/<h '*************************************************************************
$@i"un; eID = FindMaterial( "Lens" ) 2:LHy[{5 GetModelMaterial eID, mat emW:C-/h/@ +B|7p9qy mat.Nd = nlens _|''{kj( SetModelMaterial eID, mat |D.O6?v@ Print "Set lens index of refraction = " & nlens Oi} T2I 7_# 1Ec|; '************************************************************************* BtY%r7^o 'Pupil diameter tW;:- '************************************************************************* **>/}.%?K eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) #pHs@uvO D.%B$Y;G 'Adjust pupil diameter (trimming volume inner hole) vEG'HOP IooNb:( SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" )RsM!} c
'\SfW< ' Adjust pupil location to just in front of the lens 3u33a"nL8 parID = FindFullName( "Geometry.Arizona Eye" ) LG]3hz9^9 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) z* <y5 count = 0 ?tg
y| While GetOperationCount(eID)>count *{o UWt GetOperation eID, count, op -]:GL>b If op.Type="ShiftZ" Then 6/ `.(fL1 DeleteOperation eID,count KL'zXkS count=count-1 ]h9!ei
[ End If X_$a,"'~) count=count+1 eb|i3. Wend w-$[>R[hw op.Type = "ShiftZ" #;#3%? op.val1 = taq-0.01 \/|)HElKR op.parent = parID +!0eu>~_& AddOperation eID, op s4H2/EC j6ut}Uq Print "Set pupil diameter = " & pupilDiam l =IeJh )$Z(|M4 'Update AZ Eye subassembly Description rbqo"g` eID = FindFullName( "Geometry.Arizona Eye" ) 4l8BQz}sb GetEntity eID, entity Vc3mp;6" entity.Description = "Accommodation = " & A & "D" y/c%+Ca/ SetEntity eID, entity F&;
;o<m}bGaT Update W
>(vYU Print "DONE!" ->lu#;A5 fYrGpW(` End Sub vf~`eT
Wd(86idnc 如果屈光度是4,光瞳直径是4,则会输出如下数据: SNT5Am z! 4O{Avt7C Accommodation = 4 Diopters YH:8<O,{- Pupil Diameter = 4 mm k6\^p;!Y Set aqueous humor thickness = 2.81 ]|:uU Set anterior lens radius = 10.4 and conic constant = -2.375869 =sOo:s Set posterior lens radius = -4.424557 and conic constant = -3.081019 @o e\"vz Set lens thickness = 3.927 f*xpE`& Set lens index of refraction = 1.42672 (!?K7<Jv Set pupil diameter = 4 >P. 'CU DONE! dv
N<5~ 5c-N0@\ Ps R>V)L QQ:2987619807 sP$Ks#/
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