|
|
简介 Yo:>m*31 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。 zf2]|]*xz (MbI8B> 模型 WKmGw^ &a-:ZA@ 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。 Y_f6y9?ZE 13 Table 1. AZ眼睛模型的定义 b/ur!2yr 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. 6C) G 9-)oA+$ 光源 tS`fG; gxL5%:@ 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。 HtS:'~DYo ks'25tv}F 9<-AukK m 图1. 光源和提示信息使用 Q{mls 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。 rWSw1(sAA }&;0:hw% 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。 4JP01lq'\ xae}8E 图2. 字母F光源的设定方法光 tQ] R@i Z.VVY\ 图3. 字母F在视网膜上位置点列图 q6/ o.j 视网膜的散射 -zMXc"'C^k H}JH339 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。 "S)4Cjk /1Rm^s)2z y]M/oH 图4. 视网膜朗伯散射设定 q4(&.Al\@ 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。 E%jOJA vZ$uD,@;. USe"1(|E 图5. 视网膜重点采样规格设定 rN}{v}n 脚本 F]SexP4:A !^G+@~U 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: }q27M $eRxCX?b2 图6. 用户对话框的创建与编辑 * F~"4g 图7. 用户对话框编辑器 *1}9`$ 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。 7P!/jawxb 余下的脚本计算与屈光度有关的所有参数。 `h :&H,N N$?mula 分析 ]?mWnEi!z ZXHG2@E) 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 GVn7#0x nN/v7^^ 图7. 字母F在视网膜上颜色分析 <k}>eGn 脚本代码 L{'qZ#N[ XQ,IEj| Option Explicit 'Remove this to enable non-dimensioned variables to be used. 5K{(V^88F `;5UlkVZ5 Dim entity As T_ENTITY "t`r_Aw Dim op As T_OPERATION d*8 c,x Dim mat As T_MODELMATERIAL 1wqCoDgkp Dim A As Double 0O"GI33Mg Dim pupilDiam As Double LDr!d1A Dim eID As Long JL2IVENWc Dim parID As Long D-A#{e _ Dim count As Integer m7^a4 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Lm:O
vVVB Dim tlens As Double, nlens As Double 44RZk|U1J{ Dim curv As Double, conic As Double U-X Dim ok As Long m'oVqA& lb`P9mbr+ Sub Main 9j$
OU@N
8 (!DH'2I[ '用户输入对话框 CG$S? Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ?GB($D=Y'& TextBox 220,21,40,21,.TextBox1 'default: 0 _(J- MCY\ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 DTn=WGm) OKButton 40,91,90,21 +5?sYp\ CancelButton 190,91,90,21 [WX+/pm7> Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1
6bo,x TextBox 220,49,40,21,.TextBox2 'default: 4 \9@*Jgpd6* End Dialog 0%`\8 Dim dlg As UserDialog +J_A*B B2WPjhzD ok = Dialog (dlg) fcD$km 1}KNzMHk9 If ok=0 Then 'cancel button was pressed <74q]C Print "Execution cancelled." "{qhk{ End r"Pj,}$A End If 2~ Gcoda ~e, 'Assign accommodation and pupil diameter & use defaults if field left empty g4RkkoZ>) If dlg.TextBox1 = "" Then S)@R4{=e"V A = 0 'Default accommodation bN<c5 Else |@Q(~[It A = CDbl(dlg.TextBox1) cJj0`@0f End If Ai(M06P:h ZRD* ^9) If dlg.TextBox2 = "" Then PIB|&I|p pupilDiam = 4 'Default pupil diameter i
"62+ Else T1\Xz-1 pupilDiam = CDbl(dlg.TextBox2) Y@M=6G End If [UR+G8X21m 5#$E4k:YV Print " " [$8*(d"F' Print "Accommodation = " & A & " Diopters" %w/o#*j<; Print "Pupil Diameter = " & pupilDiam & " mm" W4|1wd}.t 8Tt2T}
Y ' Calculate new parameters with accommodation OA4NXl' taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness {BY`Wu:w q|=tt(}G Rant = 12.0 - 0.4*A 'Radius of anterior lens dH#S69> CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens yY[[) s3/->1#i Rpost = -5.224557 + 0.2*A 'Radius of posterior lens mrE^D| CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens H Y.,f_m onG,N1`+ tlens = 3.767 + 0.04*A 'Lens thickness ogip#$A}3 7&'^H8V nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ,Xo9gn _Dwn@{[(8 'Adjust parameters to account for accommodation Z9~~vf# *=~
9? '************************************************************************* 7s<v06Wo 'Aqueous thickness (Position of Lens) o
PR^Z
pt '************************************************************************* f.V0uBDN eID = FindFullName( "Geometry.Arizona Eye.Lens" ) W{1=O)w GetCustomElement eID, entity l
\xIGs >~>=[M0 parID = FindFullName( "Geometry.Arizona Eye" ) ?u'JhZ T7Lk4cU ' Delete any shift(s) in z .fUqsq count = 0 K )KE0/n While GetOperationCount(eID)>count s/`4]B;2U GetOperation eID, count, op O 4l[4,` If op.Type="ShiftZ" Then _GI [SzD DeleteOperation eID,count `@")R- count=count-1 1p+2*c End If czdNqk.kh count=count+1 8
6?D Wend PKwHq<vAsB frc>0\ 'Set new shift in csH1X/3ha\ op.Type = "ShiftZ" 2ZNTg@o op.val1 = taq ~Jp\'P7* op.parent = parID .F'Fk=N AddOperation eID, op n KDX=73 Print "Set aqueous humor thickness = " & taq-0.55 WTY{sq\'
o +]`MdOu '************************************************************************* 76zi)f1f 'Radius and conic constant of anterior lens OHp 121 '************************************************************************* 8l+\Qyj eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) @6h=O`X> GetConic eID, entity, curv, conic lJ R",_ <3Co/ .VQd SetConic eID, entity, 1/Rant, CCant vRRi"bo Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 6>Lr xJ^Gtq Um '************************************************************************* &P[eA u 'Radius and conic constant of posterior lens G)5%f\& '************************************************************************* kpxd+w eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) E-.M+[ GetConic eID, entity, curv, conic m`4Sp#m ~?[%uGI0h SetConic eID, entity, 1/Rpost, CCpost Q4CxtY Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost HQQc<7c", %$!}MxUM '************************************************************************* jP@H$$-=wH 'Lens thickness (Position of posterior lens surface) v(h
'************************************************************************* fo4j^,` !;zacw parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 5a5I+*
c %CD}A%~ ' Delete any z-shift(s) uDQ
d48> count = 0 H5^'J`0\ While GetOperationCount(eID)>count Co[ rhs GetOperation eID, count, op B=u@u([. If op.Type="ShiftZ" Then /NMd GKr DeleteOperation eID,count }yx'U 3 count=count-1 PZeVjL?E End If JV(|7Sk count=count+1 hgfCM Wend 5~aSkg,MD `|
L+a~~ 'Set new z-shift EG@*J*|S op.Type = "ShiftZ"
/DQoM@X op.val1 = tlens z"=#<C op.parent = parID "Z& { AddOperation eID, op hi`\3B Print "Set lens thickness = " & tlens -P(q<T2MV' )O#>ONm^ '************************************************************************* ! Hdg
$, 'Lens index of refraction HGh`O\f8 '************************************************************************* 2/E3~X7 eID = FindMaterial( "Lens" ) Z+(V'e; GetModelMaterial eID, mat O292JA q 1Rk'k4+ mat.Nd = nlens '7u#uL,pa1 SetModelMaterial eID, mat P7 H-Dw Print "Set lens index of refraction = " & nlens aVM@^n )0yY|E\ '************************************************************************* dfO@Yo-?*' 'Pupil diameter K e~a '************************************************************************* Ex&f}/F eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 7'J}|m{7 j42U|CuK 'Adjust pupil diameter (trimming volume inner hole) !3kyPoq+ =S|SQz5%w SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" V[HHP_ ]+
XgH#I ' Adjust pupil location to just in front of the lens Jc-0.^]E} parID = FindFullName( "Geometry.Arizona Eye" ) C-@@`EP eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) df&d+jY count = 0 IgG@v9' While GetOperationCount(eID)>count M})2y+ GetOperation eID, count, op {h7*a= If op.Type="ShiftZ" Then *jCXH<?R
DeleteOperation eID,count rgRh ySud count=count-1 4 "@BbVYR End If NMJ230? count=count+1 v,KH2 (N Wend vaxNF%^~yN op.Type = "ShiftZ" zq8z#FN op.val1 = taq-0.01 4IG'Tm op.parent = parID y9=/kFPRm AddOperation eID, op B&0-~o3WP uV#/Lgw{M Print "Set pupil diameter = " & pupilDiam ZgcA[P Yih^ZTf]O? 'Update AZ Eye subassembly Description : N> 5{ eID = FindFullName( "Geometry.Arizona Eye" ) ]mn(lK GetEntity eID, entity Fm#4;'x5E entity.Description = "Accommodation = " & A & "D" B=(m;A#G SetEntity eID, entity s~6?p%
2] \(cu<{=rU Update ujXC#r& Print "DONE!" sG%Q?&- ']Nw{}eS` End Sub /E2/3z Q6`oo/ 如果屈光度是4,光瞳直径是4,则会输出如下数据: S@k4k^Vg JY"<b6C^ Accommodation = 4 Diopters 2w $o;zz1 Pupil Diameter = 4 mm 9} :n Set aqueous humor thickness = 2.81 ;4z6="<Y Set anterior lens radius = 10.4 and conic constant = -2.375869 _Su?
VxU Set posterior lens radius = -4.424557 and conic constant = -3.081019 W=M]1hy Set lens thickness = 3.927 pfe9n[ Set lens index of refraction = 1.42672 $-|`#|CBd Set pupil diameter = 4 Zoh2m`6 DONE! xm6=l".%z J)6RXt*! (文章来源:讯技光电)
|