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简介 gR#lRA/ !8jr $ 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。 + 7~u_J q'9}Hz 模型 RX\l4H5; +CaA%u 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。 XLq%nVBM8\ t^')ST Table 1. AZ眼睛模型的定义 99/`23YL 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. ) 1PjI9M ,GVD.whUl 光源 n97pxD_74 %4#Q3YlyD 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。 OL0W'C9oA 77?D
~N[ =[ZuE0c 图1. 光源和提示信息使用 "I}]]?y 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。 |G(9mnZ1 >0c4C<_ 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。 A8jj]J+ jM07&o]D 图2. 字母F光源的设定方法光 Kh'7N! I}hY @ 图3. 字母F在视网膜上位置点列图 _VM()n; 视网膜的散射 40i]I@:JK ^|kqy<<X 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。 %V;B{?>9zB TDY2
M sc)}r_|g 图4. 视网膜朗伯散射设定 qh)10*FB 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。 N)0V6q" .W*" C y(92 Th$ 图5. 视网膜重点采样规格设定 YZ.?
k4> 脚本 '2=$pw x(r~<a[ 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: IMT]!j&Y, </B<=tc 图6. 用户对话框的创建与编辑 qy\Z2k 图7. 用户对话框编辑器 I|eYeJ3 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。 XhEJF ! 余下的脚本计算与屈光度有关的所有参数。 [!'fE#"a z-g"`w:Lj 分析 )&pcRFl /t=Fx94 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 D\CjR6DE G.l
~!; 图7. 字母F在视网膜上颜色分析 l'm\*=3 脚本代码 *^=zQ~ Z6\H4,k& Option Explicit 'Remove this to enable non-dimensioned variables to be used. q1_iV.G< appWq}db Dim entity As T_ENTITY M:/)|fk Dim op As T_OPERATION ih\=mB Dim mat As T_MODELMATERIAL A.wuB Dim A As Double M9ACaf@ Dim pupilDiam As Double s+a} _a: Dim eID As Long -:~"c@D Dim parID As Long v3I-i|L<) Dim count As Integer X :wfmb Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double |g1~- Dim tlens As Double, nlens As Double hgPzx@ Dim curv As Double, conic As Double *w,C5 f Dim ok As Long ww#]i&6 .sBwJZ Sub Main QXLHQ_V e4mAKB
s! '用户输入对话框 EZb_8<DH Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 yNDplm|9* TextBox 220,21,40,21,.TextBox1 'default: 0 L<H zPg Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 $z
\H* OKButton 40,91,90,21 B$D7}=|kc CancelButton 190,91,90,21 0T7c =5z4W Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 < ?{ic2j# TextBox 220,49,40,21,.TextBox2 'default: 4 al@Hr*' End Dialog `E:&a]ul Dim dlg As UserDialog J*nWCL JZ>E<U9& ok = Dialog (dlg) I:=rwnd pr.+r?la] If ok=0 Then 'cancel button was pressed /+JHnedK Print "Execution cancelled." 2|}`?bY]i` End 2uT"LW/(H End If mO8E-D*3 ~/l5ys 'Assign accommodation and pupil diameter & use defaults if field left empty p"tCMB If dlg.TextBox1 = "" Then 4Gor*{ A = 0 'Default accommodation )Rc Else z;Yo76P A = CDbl(dlg.TextBox1) ]9hXiY End If y*7{S{9 /{%p%Q[X If dlg.TextBox2 = "" Then -J]j= pupilDiam = 4 'Default pupil diameter }-N4D"d4o Else |y.^F3PE pupilDiam = CDbl(dlg.TextBox2) H{U(Rt]K End If kkU#0p? 7 5KgAY;| Print " " z{wZLqG Print "Accommodation = " & A & " Diopters" vp&N)t_ Print "Pupil Diameter = " & pupilDiam & " mm" _h^er+d!_ }CGA)yK~3 ' Calculate new parameters with accommodation cTa$t :K@ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness Lu5lpeSQ 34c+70x7 Rant = 12.0 - 0.4*A 'Radius of anterior lens =Ohro' CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens =HHtLW.|, -jWXE Rpost = -5.224557 + 0.2*A 'Radius of posterior lens )z!#8s CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens k<A|+![ EV[ BB;eb tlens = 3.767 + 0.04*A 'Lens thickness HyYol* d
A>6 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction F#KUu3;B vWVQ8S. 'Adjust parameters to account for accommodation pF<KhE*V I''X\/| '************************************************************************* 5b$QXO 'Aqueous thickness (Position of Lens) TR'<D9kn '************************************************************************* &1FyauH eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ;U[W $w[ GetCustomElement eID, entity %(A@=0r# Pj^O8 parID = FindFullName( "Geometry.Arizona Eye" ) 2Kz407|' -7u_ \XFk ' Delete any shift(s) in z %0q)PT\ count = 0 R/P9 =yvg0 While GetOperationCount(eID)>count 8SOfX^;o GetOperation eID, count, op 7bL48W<QD If op.Type="ShiftZ" Then OLE@35"v] DeleteOperation eID,count ge|Cvv count=count-1 CF]#0*MI End If FV\$M6
_ count=count+1 )^7- qy Wend 3(3-#MD0 F0KNkL>&g 'Set new shift in ]zh6[0V7V op.Type = "ShiftZ" of/'
9Tj op.val1 = taq 48LzI@H& op.parent = parID 4$^rzAi5 AddOperation eID, op o+g\\5s Print "Set aqueous humor thickness = " & taq-0.55 /NUu^ N 9)J)r\ '************************************************************************* seiE2F[ 'Radius and conic constant of anterior lens xG:7AGZ$[ '*************************************************************************
LX</xI08W eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) sWFw[Y> GetConic eID, entity, curv, conic IPk"{T3 =~q Xzq SetConic eID, entity, 1/Rant, CCant %o_CD>yD Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Bxk2P<d tUhr gc '************************************************************************* !m?W+z~J 'Radius and conic constant of posterior lens 5!qLJmd= '************************************************************************* ,U=7#Cf! eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) @vPGkM#oW GetConic eID, entity, curv, conic _Kg"l5?B 1i}p?sU SetConic eID, entity, 1/Rpost, CCpost N >k,"=N/ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost YJ{_%z|U S#l)|c_~ '************************************************************************* +t}<e( 'Lens thickness (Position of posterior lens surface) b X4]/4% '************************************************************************* Idr|-s%l6' eb7~\|9l1i parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 0pA>w8 mh Y|L]# ' Delete any z-shift(s) lFD/hz7lc count = 0 M7c53fz While GetOperationCount(eID)>count Y*YV/E. GetOperation eID, count, op pXf5/u8& If op.Type="ShiftZ" Then QA#Jx DeleteOperation eID,count :s#&nY count=count-1 jN{+$ @cI End If c:,K{ZR count=count+1 J-W8wCq` Wend =z9FjK 7vEZb.~4z 'Set new z-shift YiC_,8A~ op.Type = "ShiftZ" ~i=5NUE op.val1 = tlens 2fG[q3` op.parent = parID j] AddOperation eID, op +A<7:`sO Print "Set lens thickness = " & tlens e@L?jBj8m @.l?V6g9T '************************************************************************* iQz
c$y^,9 'Lens index of refraction ^A$p)`KR '************************************************************************* *7K)J8kq eID = FindMaterial( "Lens" ) gF&HJF 0x GetModelMaterial eID, mat H~~>ut6` e`;U9Z mat.Nd = nlens e!
0Y`lQ SetModelMaterial eID, mat #RP7?yGM, Print "Set lens index of refraction = " & nlens !\|L(Paf XZ_vbYTj '************************************************************************* Te@=8-u- 'Pupil diameter CxJH)H$ '************************************************************************* RaAvPIJa | eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) -4t!k
Aw` yA^+<uz} 'Adjust pupil diameter (trimming volume inner hole) V,>uM
>$ ~%u;lr SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" %$zX a%A z+X DN: ' Adjust pupil location to just in front of the lens kcZz WG|n parID = FindFullName( "Geometry.Arizona Eye" ) S3&lkN5 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Cm[^+.=I count = 0 qh/}/Sl; While GetOperationCount(eID)>count 7=pJ)4;ZA GetOperation eID, count, op Q#sLIZ8= If op.Type="ShiftZ" Then kqp*o+Oz', DeleteOperation eID,count |H4f&&Wd count=count-1 g:fzf>oQ>p End If j(];b+> count=count+1 3L-}B#tI Wend _2nNCu ( op.Type = "ShiftZ" gBJM|"_A? op.val1 = taq-0.01 z#t;n op.parent = parID h}f l:J1C AddOperation eID, op j4!oBSp yn KgNi Print "Set pupil diameter = " & pupilDiam "oo
j; 17@#"uT0 'Update AZ Eye subassembly Description Oh/2$72 eID = FindFullName( "Geometry.Arizona Eye" ) dnstm@0k GetEntity eID, entity 5Jm%*Wb entity.Description = "Accommodation = " & A & "D" Wf5ohXm> SetEntity eID, entity m>LC2S;
f VTwJtWnq Update D|X@aUp8} Print "DONE!" !&@!:=X, mNnt9F3Eq End Sub GB`
G(a )L%[(iI,x 如果屈光度是4,光瞳直径是4,则会输出如下数据: 7N
I~47s|v Evb %<`gd Accommodation = 4 Diopters a29rD$ Pupil Diameter = 4 mm &l2C-( Set aqueous humor thickness = 2.81 SZm&2~|J Set anterior lens radius = 10.4 and conic constant = -2.375869 aW7)}"j4 Set posterior lens radius = -4.424557 and conic constant = -3.081019 9zD^4j7 Set lens thickness = 3.927 6YpP/
K Set lens index of refraction = 1.42672 8ZvozQE Set pupil diameter = 4 t+m
ug DONE! iBy
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