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简介 l$!NEOK zCwb>v 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 X)[QEq^ W`wT0kP?*] 模型 1EV0Y]T1 ?0s&Kz4B 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 /h&>tYVio yAel4b/} Table 1. AZ眼睛模型的定义 XT==N-5, 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. aO\@5i_r Xd~li fF 光源 )[t3-' wLQM]$O 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。 zfml^N Qcs0w( ! -gOqo 图1. 光源和提示信息使用 *K=me/
3 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。 Y:'c<k :Sk<0VVd7 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。 % o0.8qVJi B"RZpx 图2. 字母F光源的设定方法光 cC,gd\}M gD6BPW~0 图3. 字母F在视网膜上位置点列图 D4GXZX8K 视网膜的散射 cXOb= )#cGePA 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。 ou&7v<)x4 !un_JZD w{ x=e 图4. 视网膜朗伯散射设定 hN:2(x 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。 RAEiIf!3 04z2gAo qjvIp- 图5. 视网膜重点采样规格设定 oX1{~lDJl 脚本 S#7.y~e\ }KrZ6cG9# 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: RK=YFE 0 |<7nf7 5c} 图6. 用户对话框的创建与编辑 LZ~$=< 图7. 用户对话框编辑器 1FC1*7A[ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 C
F< 余下的脚本计算与屈光度有关的所有参数。 TqMy">> nr{}yQu 分析 "{(4 !O8vr4= 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 iW<B1'dp We#O'm 图7. 字母F在视网膜上颜色分析 BhJ~ jV" 脚本代码 *,__\/U98 )c<5:c Option Explicit 'Remove this to enable non-dimensioned variables to be used. <?iwi[S T\Q)"GB Dim entity As T_ENTITY -{fbZk&A Dim op As T_OPERATION 4;d9bd)A Dim mat As T_MODELMATERIAL CpICb9w Dim A As Double u7<s_M3%N Dim pupilDiam As Double E>?T<!r~j Dim eID As Long N;\by<snN Dim parID As Long wXsA-H/` Dim count As Integer n.Q?@\}2 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 4E& 3{hnp Dim tlens As Double, nlens As Double 7uRXu>h Dim curv As Double, conic As Double -xf=dzm) Dim ok As Long ~3 z10IG 7nHlDPps) Sub Main l2!4}zI2 vrIM!~*W '用户输入对话框 eESJk14 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 X"{s"Mc0G TextBox 220,21,40,21,.TextBox1 'default: 0 T=2 91)@ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 R3$eq
) OKButton 40,91,90,21 =X2EF CancelButton 190,91,90,21 ]7^YPFc+ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 8ESBui3; TextBox 220,49,40,21,.TextBox2 'default: 4 a8%/Xwr~ End Dialog `7|v Dim dlg As UserDialog w_I}FPT<(: _>*$%R ok = Dialog (dlg) A:ef}OCL p]#%e0 If ok=0 Then 'cancel button was pressed @&2bLJJ+ Print "Execution cancelled." T;}pMRd% End }45&s9m= End If u<\/T&S W$P)fPU' 'Assign accommodation and pupil diameter & use defaults if field left empty Jh[fFg] If dlg.TextBox1 = "" Then avk0pY(n A = 0 'Default accommodation $3%EKi Else 6kKIDEX A = CDbl(dlg.TextBox1) BaTE59W End If A=|&N%lP' e ?H`p"l If dlg.TextBox2 = "" Then V4Ql6vg_f pupilDiam = 4 'Default pupil diameter y:Qo:Z~ Else z.pP~he pupilDiam = CDbl(dlg.TextBox2) \?)<==^ End If [HK[{M=v= ;e_n7>'#% Print " " xq.,7#3 Print "Accommodation = " & A & " Diopters" )}7rM6hv Print "Pupil Diameter = " & pupilDiam & " mm" p}}o#a~V), kL,AY-Iu{@ ' Calculate new parameters with accommodation 6`{Y#2T taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness zrG&p Z a!P?RbW Rant = 12.0 - 0.4*A 'Radius of anterior lens
!5Kv9P79 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 4 ?,N;Q hIC$4lR~ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens RpR;1ktF> CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ' Ky5|4 ~(%nnG6x tlens = 3.767 + 0.04*A 'Lens thickness 7
rOziKZ" Y:/z)"u,C nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction &aaXw?/zr J(VJMS;_ 'Adjust parameters to account for accommodation Y+syc dq Sim\+SL{# '************************************************************************* x\GCsVy 'Aqueous thickness (Position of Lens) Qhsh{muw( '************************************************************************* ?x"<0k1g eID = FindFullName( "Geometry.Arizona Eye.Lens" ) *obBo6!zM GetCustomElement eID, entity diGPTV-?$ 6fQNF22E parID = FindFullName( "Geometry.Arizona Eye" ) \;}F6g 7g cr$&+e ' Delete any shift(s) in z try'%0}> count = 0 a8FC#kfq While GetOperationCount(eID)>count egxh GetOperation eID, count, op [ K;3Qf) If op.Type="ShiftZ" Then B_anO{3$4 DeleteOperation eID,count (qnzz!s count=count-1 r'uD|T H End If 1j
"/}0fx count=count+1 kcVEE)zb Wend 1RZhy_$\. m@R!o 'Set new shift in {A2(a7vV op.Type = "ShiftZ" Dx/BxqG6}_ op.val1 = taq PW x9CT op.parent = parID htj:Z:C` AddOperation eID, op #TM+Vd$ Print "Set aqueous humor thickness = " & taq-0.55 HP^<2?K oQ1>*[e<u '************************************************************************* >fJY 'Radius and conic constant of anterior lens |TatRB3> '************************************************************************* x4Mq{MrWp eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) x}$SB%9/ GetConic eID, entity, curv, conic 9`81br+~ UR44
iA] SetConic eID, entity, 1/Rant, CCant Va"Q1 *" Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant fwK5p?Xhm YD_hg#=n '************************************************************************* [QEV6S] 'Radius and conic constant of posterior lens `+[Ct08 '************************************************************************* s4/4o_[W eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) _8Cw_ GetConic eID, entity, curv, conic FCnOvF65 lk]q\yO_% SetConic eID, entity, 1/Rpost, CCpost W+d=BnOa8 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ]KdSwIbi j\iE3:94$ '************************************************************************* :sAb'6u1EU 'Lens thickness (Position of posterior lens surface) awkPFA*c' '*************************************************************************
v% 6uU SEa'>UG parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Ybo:2e hkB/
OJ ' Delete any z-shift(s) v1h\
6r' count = 0 )voJq\Y)% While GetOperationCount(eID)>count Hd]o?q\ GetOperation eID, count, op d$qivct If op.Type="ShiftZ" Then m/@ ;N,K DeleteOperation eID,count Wu3or"lcw* count=count-1 m:&go2Y End If uF,F<%d count=count+1 X5@+M!` Wend Cw6\'p%l-\ @oE^( 'Set new z-shift @h7)M:l op.Type = "ShiftZ" E><$sN6 op.val1 = tlens nSY3=Edx= op.parent = parID 3L}eFg,d AddOperation eID, op C.qNBl* Print "Set lens thickness = " & tlens 'KvSI=$ K#Ia19au5 '************************************************************************* .n$c+{ 'Lens index of refraction ymH>]
cUm '************************************************************************* )Fk*'6 eID = FindMaterial( "Lens" ) #gW"k;7P GetModelMaterial eID, mat s0r::yO CjR!dh1w_ mat.Nd = nlens M3q%(!2 SetModelMaterial eID, mat Uh[MBwK Print "Set lens index of refraction = " & nlens wwh1aV * 3(&k4 '************************************************************************* Wo)$*? 'Pupil diameter 2<$pai"yl '************************************************************************* p>#sR4d> eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) N+lhztYQ? Fnqj^5 'Adjust pupil diameter (trimming volume inner hole) To/6=$wto qwhDv+o SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" gXJtk; O>R@Xj)M ' Adjust pupil location to just in front of the lens y{>T['"@ parID = FindFullName( "Geometry.Arizona Eye" ) }H#C<:A eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 8'WoG]E_ count = 0 Z
FIy While GetOperationCount(eID)>count fQm3D% GetOperation eID, count, op [0bp1S~ If op.Type="ShiftZ" Then DpCe_Vb%M DeleteOperation eID,count ,FIG5-e,} count=count-1 u@]rR&h` End If GG&J count=count+1 W3+;1S$k Wend )7c/i+FsC op.Type = "ShiftZ" mzO5&h7 op.val1 = taq-0.01 q$7w?(Lk op.parent = parID 953GmNZ7 AddOperation eID, op !LR9}Xon >O]u4G! Print "Set pupil diameter = " & pupilDiam *""iXi[ mX2X.ww(4 'Update AZ Eye subassembly Description Vp$<@Y eID = FindFullName( "Geometry.Arizona Eye" ) }A}cq!I^ GetEntity eID, entity ^O.` P entity.Description = "Accommodation = " & A & "D" V~#8lu7; SetEntity eID, entity U|
T}0 "]T1DG" Update Z-j?N{3& Print "DONE!" -e\OF3Td 'QSj- End Sub ~@#s<a,%; GX+Gqj. 如果屈光度是4,光瞳直径是4,则会输出如下数据: \J(kevX 8\F|{vt# Accommodation = 4 Diopters h[bC#( Pupil Diameter = 4 mm g-pEt# Set aqueous humor thickness = 2.81 }wB!Bx2 Set anterior lens radius = 10.4 and conic constant = -2.375869 {3T&6 LA Set posterior lens radius = -4.424557 and conic constant = -3.081019 }0[<xo>K Set lens thickness = 3.927 vs^)= Set lens index of refraction = 1.42672 lFp : F5 Set pupil diameter = 4 q*K[? DONE! zr ~4@JTS :x,dYJm ug_c}Nv=Y QQ:2987619807 B='(0Uxy-
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