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简介 f4mQDRlD :l;SG=scx 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。 cFV)zFu Q>%{Dn\? 模型 G`D~OI T4c]VWtD 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。 ;ndwVZ~, q{c/TRp7 Table 1. AZ眼睛模型的定义 j#f7-nHyz8 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. u)hr mw!EDJ;' 光源 rL KwuZ a,/wqX 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。 2[V9`r8* dlf nhf pm4'2B|)g 图1. 光源和提示信息使用 *"HA=-Z; 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。 [_X.Equ 9w:F_gr 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。 g[%iVZ o4U[;.?c 图2. 字母F光源的设定方法光 s?9$o
Qq1 32S5Ai@Cd" 图3. 字母F在视网膜上位置点列图 K^yZfpa8 视网膜的散射 9 aacW Py!
F 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 "J=A(w5 ExW3LM9(
%&81xAt 图4. 视网膜朗伯散射设定 FSNzBN 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 e.n*IJ_fz !uxma~ZH- xULcS :Q 图5. 视网膜重点采样规格设定 y88lkV4a 脚本 0kiV-yc <uf,@N5m 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: R)Y*<Na F8*zG 4/& 图6. 用户对话框的创建与编辑 kKHGcm^r 图7. 用户对话框编辑器 G?e\w+}Pj@ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 Y2oN.{IH 余下的脚本计算与屈光度有关的所有参数。 |EpL~G_ `9vCl@"IV 分析 BIn7<.& km=d'VvnI 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 #^zUaPV 7r L>X39R~ 图7. 字母F在视网膜上颜色分析 b'mp$lt! 脚本代码 q)F@f / lD]/Kx Option Explicit 'Remove this to enable non-dimensioned variables to be used. [7+dZL[ s6HfN' Dim entity As T_ENTITY :L&d>Ii|' Dim op As T_OPERATION \*r]v;NcP Dim mat As T_MODELMATERIAL ?c0@A*:o Dim A As Double QP={b+8 Dim pupilDiam As Double i4g99Kvl Dim eID As Long ,Srj38p Dim parID As Long t)n}S;iD Dim count As Integer 7zWr5U. Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Ed ,O>( Dim tlens As Double, nlens As Double rD*CLqK Dim curv As Double, conic As Double =e!o Dim ok As Long dl; qs
0'}> Sub Main !Bqmw ;qwNM~ '用户输入对话框 <`Q*I
Y Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 >6\rhx> TextBox 220,21,40,21,.TextBox1 'default: 0 cfrvx^,2& Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 -A3>+G3[ OKButton 40,91,90,21 *0!IHr"fn CancelButton 190,91,90,21 >}|Vmy[/ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 #>[5NQ;$' TextBox 220,49,40,21,.TextBox2 'default: 4 #CcWsI>+w> End Dialog W4V
!7_ Dim dlg As UserDialog n+94./Mh f !D~aJ ok = Dialog (dlg) ]$xN`O4W{ pU)g93 If ok=0 Then 'cancel button was pressed (Tbw@BFk Print "Execution cancelled." x J[Xmre End ztG!NZL End If se, 0Rvkt r-]Hm Y x 'Assign accommodation and pupil diameter & use defaults if field left empty *E1 v If dlg.TextBox1 = "" Then rZSX fgfr A = 0 'Default accommodation ye^l~ Else mO~A}/je A = CDbl(dlg.TextBox1) 25-5X3(>j= End If LI/;`Y= +i1\],7 If dlg.TextBox2 = "" Then dLnu\bSF pupilDiam = 4 'Default pupil diameter 1}>u Y Else I6B4S"Q5< pupilDiam = CDbl(dlg.TextBox2) " +n\0j; End If !5escR!\D mok%TK Print " " ;+W9EbY2 Print "Accommodation = " & A & " Diopters" @ApX43U( Print "Pupil Diameter = " & pupilDiam & " mm" @b,&b6V r@9qjva ' Calculate new parameters with accommodation :!nBTw taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness KfkE'_F %J%ZoptY: Rant = 12.0 - 0.4*A 'Radius of anterior lens X1GpLy)p CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens FY(C<fDRo{ F>!gwmn~ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens BMlu>, CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Y#[>j4<T xO nW~Z tlens = 3.767 + 0.04*A 'Lens thickness klqN9d9k
<z+b88D nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction z')zVoW, C6P(86? 'Adjust parameters to account for accommodation v@KP~kp SF#Rc>v '************************************************************************* {6uh Ub
'Aqueous thickness (Position of Lens) XnCrxj '************************************************************************* :lGH31GG eID = FindFullName( "Geometry.Arizona Eye.Lens" ) #FL\9RXy GetCustomElement eID, entity k=o>DaEh( qV`JZ\n parID = FindFullName( "Geometry.Arizona Eye" ) MaX:oGF, sHwn,4|iY ' Delete any shift(s) in z {#Vck\& count = 0 o"5[~$O While GetOperationCount(eID)>count Q[U_
0O,A9 GetOperation eID, count, op ['l.]k-b} If op.Type="ShiftZ" Then *[MK{m DeleteOperation eID,count /Wqx@# count=count-1 qp6*v& End If Bt\z0*t=s count=count+1 eJm7}\/6` Wend XA%a7Xtni y?1<7>L5~ 'Set new shift in y_Tc$g~ op.Type = "ShiftZ" 7KzMa%= op.val1 = taq \h&ui]V op.parent = parID %j*i= AddOperation eID, op ,*w Print "Set aqueous humor thickness = " & taq-0.55 V&>\U?q: h)746T ) '************************************************************************* ZX
Sl+k. 'Radius and conic constant of anterior lens #ErIot '************************************************************************* OSsxO(;g eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) nfV32D|3 GetConic eID, entity, curv, conic d'yA"b] az=(6PX SetConic eID, entity, 1/Rant, CCant I
)LO@ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ?(!<m'jEy 0B;cQSH!q '************************************************************************* H"g$qSx 'Radius and conic constant of posterior lens q:9#Vcw '************************************************************************* clwJ+kku@ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) YsHZFF GetConic eID, entity, curv, conic i(k]}Di: c T!L+zg SetConic eID, entity, 1/Rpost, CCpost RRBokj)] Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost vFL\O i{$h]D_fD '************************************************************************* Po:)b 'Lens thickness (Position of posterior lens surface) # XD-a '************************************************************************* bxS+ R\ 3N] parID = FindFullName( "Geometry.Arizona Eye.Lens" ) /W6r{Et 71h?t`N ' Delete any z-shift(s) u*<G20~A count = 0 0H6^2T< While GetOperationCount(eID)>count ~
}<!ON; GetOperation eID, count, op v.ftfL! If op.Type="ShiftZ" Then +cw;a]o^> DeleteOperation eID,count 4ZZ/R?AiK count=count-1 g`skmHS89 End If zgdOugmmt_ count=count+1 :.+?v*%;n Wend &$vW <u"h'e/oW_ 'Set new z-shift ~$zodrS9 op.Type = "ShiftZ" w;;.bz m op.val1 = tlens t1)~J op.parent = parID JERWz~n} AddOperation eID, op :PrQ]ss@C5 Print "Set lens thickness = " & tlens J)w58/`?t 5 E%dF9q '************************************************************************* 3KF[ v{ 'Lens index of refraction f&\v+'[p '************************************************************************* -n-rKN.T eID = FindMaterial( "Lens" ) m,~
@1 GetModelMaterial eID, mat -'tgr6=|w" QDRgVP mat.Nd = nlens (]Z$mv! SetModelMaterial eID, mat 0$n0fu Print "Set lens index of refraction = " & nlens (L)tC*Qjc
@+v;B: '************************************************************************* P|[i{h 'Pupil diameter ]Y3|*t(\ '************************************************************************* rsp?N{e eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 1,p[4k~Ww 0@9.h{s@ 'Adjust pupil diameter (trimming volume inner hole) ;)^eDJ<
a;a2x
.< SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 8q6b3q:c ~$0Qvyb> ' Adjust pupil location to just in front of the lens ys5b34JN parID = FindFullName( "Geometry.Arizona Eye" ) K#=)]qIk eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) QOECpk- count = 0 Tm8c:S^uq) While GetOperationCount(eID)>count MSmvQ GetOperation eID, count, op %5=XszS If op.Type="ShiftZ" Then \(lt [= DeleteOperation eID,count $lj1924?^ count=count-1 2EubMG End If 4s<*rKm~ count=count+1 vG'JMzAm Wend ndkV(#wQS op.Type = "ShiftZ" t(4%l4i;X op.val1 = taq-0.01 U!"+~d) op.parent = parID 2WjQ-mM# AddOperation eID, op N/A.1W qY24Y Print "Set pupil diameter = " & pupilDiam -Bqn^ E
lc%2Pi[X 'Update AZ Eye subassembly Description -f.<s!a eID = FindFullName( "Geometry.Arizona Eye" ) U@<>2 GetEntity eID, entity 0u4:=Z}W entity.Description = "Accommodation = " & A & "D" =kq!e SetEntity eID, entity ':71;^zXf Q"UQv< Update ; 4E0%@R Print "DONE!" w0x%7mg@ iPMI$ End Sub mbBd3y #c5 NFU}9 如果屈光度是4,光瞳直径是4,则会输出如下数据: A f@IsCOJ X[:&p|g] Accommodation = 4 Diopters .c'EXuI7), Pupil Diameter = 4 mm W@w#A] Set aqueous humor thickness = 2.81 +_gPZFpbx Set anterior lens radius = 10.4 and conic constant = -2.375869 J9^RP~>bs Set posterior lens radius = -4.424557 and conic constant = -3.081019 b$P=rIB Set lens thickness = 3.927 )o'&f"/ Set lens index of refraction = 1.42672 *yqEl
O Set pupil diameter = 4 xp%,@]p DONE! r%hnl9 B
Mh949; #/ 1 QQ:2987619807 xBhfC!AK}
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