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简介 @An "ClDa q|EE
em 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。 ruf*-&Kr7
)ld !(d= 模型 $%%K9Y
wv6rjg:7 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 ~A X@o-WU doj$chy Table 1. AZ眼睛模型的定义 s/"l ?d 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. k`u:Cz#aB 3WTNWz#h 光源 n>5/y
c"/q *pOdM0AE 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。 en1NFP MU-T>S4
7^3a296 图1. 光源和提示信息使用 SFaG`T= 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。 ;`(l)X+7 :RqTbE4B 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。 InCJ4D ^rP`
.Z 图2. 字母F光源的设定方法光 b5Sgf'B^ AfV
a[{E 图3. 字母F在视网膜上位置点列图 "y5LojdCs 视网膜的散射 $
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AD=qB5: 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。 P%nN#Qm yH:gFEJ:x `1Cg)\&[e0 图4. 视网膜朗伯散射设定 jH4'jB 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。 }5I+VY7a iFi6,V*PRt %~$P.Zh 图5. 视网膜重点采样规格设定 6(9S'~*'R 脚本 o;#9$j7QP! B>!OW2q0D 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: Oosr`e@S bL)7/E 图6. 用户对话框的创建与编辑 -76l*=| 图7. 用户对话框编辑器 p3N/"t&> 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。 bV~z}V& 余下的脚本计算与屈光度有关的所有参数。 `RriVYc< b_p/ 1W: 分析 gFx2\QV (C=.&',P 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 r*gQGvc ~%8T_R /3 图7. 字母F在视网膜上颜色分析 x_yQoae
脚本代码 tzKIi_2 .ZzxW Option Explicit 'Remove this to enable non-dimensioned variables to be used. , '_y@9?I Ns*&;x9 Dim entity As T_ENTITY /&`sB| Dim op As T_OPERATION lebwGW,! Dim mat As T_MODELMATERIAL x)h|!T=B~ Dim A As Double .0 [
zZ Dim pupilDiam As Double eMDO;q Dim eID As Long 63EwV p/| Dim parID As Long n*Q~<`T Dim count As Integer Qel2OI `b Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double LZ?z5U: Dim tlens As Double, nlens As Double .h0@Vs Dim curv As Double, conic As Double :7&-<ae2 Dim ok As Long Wvg+5Q vfn _Nq; Sub Main \N[Z58R !z afOix" '用户输入对话框 M$O*@]) Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _(R1En1 TextBox 220,21,40,21,.TextBox1 'default: 0 pel{ ;r Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 \bc ob8u OKButton 40,91,90,21 ]rpU3 3 CancelButton 190,91,90,21 )U?O4| \P Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ry2ZVIFa TextBox 220,49,40,21,.TextBox2 'default: 4 6hW ~Q End Dialog Xqz\%&G Dim dlg As UserDialog fH#*r|~ ,?OWwm&J ok = Dialog (dlg) H2p lT 9Ez>srH( If ok=0 Then 'cancel button was pressed &N`s@Ka Print "Execution cancelled." </.9QV End 3t*e|Ih&j5 End If ;AjY-w )yOdRRP 'Assign accommodation and pupil diameter & use defaults if field left empty (pU@$H If dlg.TextBox1 = "" Then
x+=Ko A = 0 'Default accommodation t,f)!D$ Else `[&) X A = CDbl(dlg.TextBox1) ]WO0v`xh End If }u>F}mUa -_p +4tV If dlg.TextBox2 = "" Then npj_i /&g pupilDiam = 4 'Default pupil diameter doERBg`Jh Else gq'}LcV pupilDiam = CDbl(dlg.TextBox2) *i=+["A End If U)PNY p H5iv>H Print " " c6;326aDq Print "Accommodation = " & A & " Diopters" %/K'VE6pb Print "Pupil Diameter = " & pupilDiam & " mm" &{x%"Aq/ m,u5S=3A{! ' Calculate new parameters with accommodation 5Dhpcgq<< taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness /F(wb_! #TXN\YNP Rant = 12.0 - 0.4*A 'Radius of anterior lens (F<VcB CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens kPt] [1jo sp2"c"_+ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens :nt 7jm, CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens _>6xUt \L-K}U>J tlens = 3.767 + 0.04*A 'Lens thickness @AvDV$F tm"9` nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction BotGPk><c cIm_~HH 'Adjust parameters to account for accommodation TSl:a & -$@$ '************************************************************************* 4)cQU.(*k 'Aqueous thickness (Position of Lens) &EELq"5K '************************************************************************* t7t?xk!2 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) WRq:xDRn0 GetCustomElement eID, entity uA'S8b%C ,vxxp]#5 parID = FindFullName( "Geometry.Arizona Eye" ) :75$e%'A ir72fSe ' Delete any shift(s) in z pBd_BaN count = 0 'V*ixK8R0 While GetOperationCount(eID)>count C9,|G7~*q GetOperation eID, count, op c Nhy.Z~D If op.Type="ShiftZ" Then M_:_(y>l DeleteOperation eID,count 4P>[]~S count=count-1 z
?3G` End If MR) *Xh count=count+1 FnoE\2}9 Wend sQ)D.9\~ i42M.M6D $ 'Set new shift in n]15 ~GO. op.Type = "ShiftZ" _RT JEG op.val1 = taq oCCTRLb02 op.parent = parID g!#M0 AddOperation eID, op CQ4MQ<BJ. Print "Set aqueous humor thickness = " & taq-0.55 (}1:]D{)@V ]uikE2nn '************************************************************************* }!&Vc f 'Radius and conic constant of anterior lens )&nfV5@" '************************************************************************* k\ 2.\Lwb eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) q&:UP GetConic eID, entity, curv, conic z'W8t|m}Pb l/wdu( SetConic eID, entity, 1/Rant, CCant \V1geSoE Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant tK|jh
@hb K '************************************************************************* 8zOoVO 'Radius and conic constant of posterior lens ! H^,p$`[i '************************************************************************* rt_k } eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Q^B !^_M GetConic eID, entity, curv, conic d,hKy2 ;$VQRXq SetConic eID, entity, 1/Rpost, CCpost L/YEW7M Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost k3 YDnMRA9 +K@wh '************************************************************************* /"f4aF[ 'Lens thickness (Position of posterior lens surface) <{z*6FM!' '************************************************************************* vFz#A/1 &e-MOM2& parID = FindFullName( "Geometry.Arizona Eye.Lens" ) dr54D y{?wxg9 ' Delete any z-shift(s) 6]Vf`i count = 0 =vpXYj While GetOperationCount(eID)>count N084k}io GetOperation eID, count, op daX$=n If op.Type="ShiftZ" Then (]Pr[xB DeleteOperation eID,count [?=Vqd count=count-1 zL%ruWNG End If HW@r1[Y count=count+1 ik;S!S\v Wend u>K(m))5W3 # },4m 'Set new z-shift |e]2 >NjQa op.Type = "ShiftZ" "u H VX|` op.val1 = tlens &nRbI:R op.parent = parID zFFip/z\ AddOperation eID, op 4GL-3e Print "Set lens thickness = " & tlens ri]"a?Rm ~vL`[JiK '************************************************************************* CY4ntd4M 'Lens index of refraction fx"~WeVcO '************************************************************************* GY3g`M
eID = FindMaterial( "Lens" ) A_ftf7, GetModelMaterial eID, mat ){sn!5= |)4aIa mat.Nd = nlens Gy3t SetModelMaterial eID, mat #guq/g$ Print "Set lens index of refraction = " & nlens N!TC}#}l Mq#sSBE<K '************************************************************************* b.4H4LV 'Pupil diameter Q|CLis- '************************************************************************* $3BH82 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" )
g%.;ZlK 0C,2gcq 'Adjust pupil diameter (trimming volume inner hole) `yvH0B - Mqk[+n SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" NCKhrDd& n{@^ne4m ' Adjust pupil location to just in front of the lens n6 VX0R parID = FindFullName( "Geometry.Arizona Eye" ) p_Yx"nO7 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) MIn6p count = 0 ^(:Z*+X~> While GetOperationCount(eID)>count ($vaj; GetOperation eID, count, op 6z-&Zu7@ If op.Type="ShiftZ" Then T 8.
to DeleteOperation eID,count .Jvy0B} B count=count-1 5TB==Fj ? End If -!s?d5k") count=count+1 pAY[XN Wend UD+r{s/% op.Type = "ShiftZ" $.g)%#h: op.val1 = taq-0.01 sT;:V
op.parent = parID Tl%n|pc AddOperation eID, op h=7eOK] H*H=a Print "Set pupil diameter = " & pupilDiam ;Q}pmBkqB KsG>,#
Q 'Update AZ Eye subassembly Description E979qKl eID = FindFullName( "Geometry.Arizona Eye" ) {<k}U;uiO GetEntity eID, entity %ylpn7I\6 entity.Description = "Accommodation = " & A & "D" G#f(oGn : SetEntity eID, entity M6MtE_E )yyS59s Update o<f#Zi Print "DONE!" h{BO\^6x F,NS:mE End Sub #R#o/@| .o"FT~}z 如果屈光度是4,光瞳直径是4,则会输出如下数据: 1^HUu"Kt Qk_Mx" Accommodation = 4 Diopters Kd%>:E* Pupil Diameter = 4 mm &58TX[# Set aqueous humor thickness = 2.81 giNyD4uO Set anterior lens radius = 10.4 and conic constant = -2.375869 &l| :1 Set posterior lens radius = -4.424557 and conic constant = -3.081019 J nzI-
y Set lens thickness = 3.927 jaOt"iU.B Set lens index of refraction = 1.42672 :{tj5P!S
Set pupil diameter = 4 L(ni6- DONE! 3L5o8?[ B;6N.X(K (+=TKI<= QQ:2987619807 f[;l7
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