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简介 ,S!w'0k|n 2d`c! 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。 F8=nhn 2f,2rW^i 模型 3n48 %5 ~xDw*AC- 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。 E FY@Y[ kg>>D Table 1. AZ眼睛模型的定义 .:9s}%Zr 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. FS@A8Bb A'-_TFwW 光源 [BDGR
B7d" sbS~N*{E 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。 \#6Fm_b]u Yc;ec9~ XUmR{A 图1. 光源和提示信息使用 |vu>;*K 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。 1%`7.;!i GwLFL.Ke 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。 }V`mp ]'h; {;ug 图2. 字母F光源的设定方法光 fn}UBzED\ FxRXPt
FK 图3. 字母F在视网膜上位置点列图 zp4W'8
视网膜的散射 ;t(f1rPyE (OmH~lSO. 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。 9[Qd)%MO NlF}{ shgAhx 图4. 视网膜朗伯散射设定 Q6'nSBi:A_ 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。 ^p=L\SJ &`!^Zq vG 76H!)={ 图5. 视网膜重点采样规格设定 `G$1n#& 脚本 i8PuC^] =Ho"N`Qy 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: -<f;l_( jbmTmh1q 图6. 用户对话框的创建与编辑 A6"Hk0Hf 图7. 用户对话框编辑器 glUo7^ay7 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 Q-eCHr) 余下的脚本计算与屈光度有关的所有参数。 !;
v~^#M]~ c&'JmKV>& 分析 !GK$[9 r\M9_s8 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ]v 29 Rx " I+p 图7. 字母F在视网膜上颜色分析 ~;#MpG;e 脚本代码 m{%t?w$Au )TmtSSS Option Explicit 'Remove this to enable non-dimensioned variables to be used. =A!S/;z> 0ejdKdYN Dim entity As T_ENTITY ,FQK;BU!lh Dim op As T_OPERATION -kj< 1~YW Dim mat As T_MODELMATERIAL C"w
{\
&R Dim A As Double Mz=!w]qDH Dim pupilDiam As Double 'vIx#k4D1 Dim eID As Long xN0*8 Dim parID As Long KEr\nKT1 Dim count As Integer Sp SnoVI Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double t+TYb#Tc Dim tlens As Double, nlens As Double X% {'<baR Dim curv As Double, conic As Double slW3qRT\k Dim ok As Long >G"X J<IO fI|[Z+" Sub Main q/&y*)&'O %_M2N.n '用户输入对话框 Q<"[C
1Lj Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 B]iP't\~ TextBox 220,21,40,21,.TextBox1 'default: 0 3OqX/z, Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 v3RcwySk OKButton 40,91,90,21 e [0w5)X
CancelButton 190,91,90,21 @y|_d Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 `
%?9=h% TextBox 220,49,40,21,.TextBox2 'default: 4 %{5n1w End Dialog I9y.e++/ Dim dlg As UserDialog F[`ZqW eC`pnE ok = Dialog (dlg) HAB#pd9 ; y.E! If ok=0 Then 'cancel button was pressed )Hw:E71h2 Print "Execution cancelled." _YHu96H; End GG6%bF End If yJ2B3i@T4 j|(Z#3J 'Assign accommodation and pupil diameter & use defaults if field left empty w
YNloU If dlg.TextBox1 = "" Then Ca>& A = 0 'Default accommodation (Xxn\*S Else 1yqoA* A = CDbl(dlg.TextBox1) L/r@ S' End If m}Y0xV9 y=sGe!^ If dlg.TextBox2 = "" Then 0Bolv_e pupilDiam = 4 'Default pupil diameter uOi&G:= Else O>0VTW pupilDiam = CDbl(dlg.TextBox2) /!xF?OmVd End If *,WP,-0 UVuDQ Print " " tbDoP
Y Print "Accommodation = " & A & " Diopters" "5|Lz) = Print "Pupil Diameter = " & pupilDiam & " mm" ^HA
%q8| n ?pGkk=,KB ' Calculate new parameters with accommodation \F6LZZ2Lv taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness '\ DSTr:N z4U9n'{ Rant = 12.0 - 0.4*A 'Radius of anterior lens d5 j_6X CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens Ukphd$3J= Jobiq]|> Rpost = -5.224557 + 0.2*A 'Radius of posterior lens $&P?l=UG CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens &XLD S=j iZ,YxN<R tlens = 3.767 + 0.04*A 'Lens thickness JWO=!^ 2&(sa0*y nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction p9ZXbAJ{ o>D 'Adjust parameters to account for accommodation =!MY4&YX
:Ao!ls'= '************************************************************************* Wsj=!Obc 'Aqueous thickness (Position of Lens) -p,x&h,p '************************************************************************* T=Z.U$ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) qCMl!g' GetCustomElement eID, entity b`mj_b B5am1y{P# parID = FindFullName( "Geometry.Arizona Eye" ) hP@(6X," D^F{uDlb ' Delete any shift(s) in z u=+q$Q] count = 0 /\d$/~BFi While GetOperationCount(eID)>count !>^JSHR4t GetOperation eID, count, op LJzH"K[Gg6 If op.Type="ShiftZ" Then gQWd&)'muf DeleteOperation eID,count q }C+tn"\ count=count-1 vR7HF*8 End If n]!fO
6kj count=count+1 6)gd^{ Wend Z0,~V GJ(d&o8 'Set new shift in <I*x0BM= op.Type = "ShiftZ" _O:WG&a6 op.val1 = taq +FFG#6e op.parent = parID 7Hw<ojkt AddOperation eID, op Kf,-4) Print "Set aqueous humor thickness = " & taq-0.55 I?!rOU=0
d}I(`%%) '************************************************************************* 7YIK9edP 'Radius and conic constant of anterior lens I0= NaZ7 '************************************************************************* r8M Zvm2 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) vlWw3>4 GetConic eID, entity, curv, conic N1EezC'^ 8Z#j7)G
SetConic eID, entity, 1/Rant, CCant vxlOh.a|/L Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant tB(4Eq
\ ;^k7zNf- '************************************************************************* \&xl{64 'Radius and conic constant of posterior lens PFSLyV* '************************************************************************* zzpZ19"`1 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 7LZ^QC GetConic eID, entity, curv, conic B33$ u3d cSP*f0n,eo SetConic eID, entity, 1/Rpost, CCpost M++0zhS Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost l3i,K^YL j#A%q"]8 '************************************************************************* m7]hJ,0 'Lens thickness (Position of posterior lens surface) >%b\yl%0 '************************************************************************* &M&{yc*% !4#"!Md4o parID = FindFullName( "Geometry.Arizona Eye.Lens" ) g;p)n MEZ{j%-a ' Delete any z-shift(s) 'w/qcD- count = 0 7G2PMe;$m While GetOperationCount(eID)>count M7}Q=q\9 GetOperation eID, count, op ~XM[>M\qB If op.Type="ShiftZ" Then YZ}cB DeleteOperation eID,count _cqy`p@" count=count-1 0OZ Mlt%z End If 5OLQw(E count=count+1 .#6MQJ]OH Wend JMV50 y o3Ot.9L 'Set new z-shift )6oGF>o> op.Type = "ShiftZ" hXL|22>w< op.val1 = tlens Ws[D{dS/ op.parent = parID U..<iNQE5 AddOperation eID, op !|{IVm/J Print "Set lens thickness = " & tlens '"YYj$>
' n~0z_;5 '************************************************************************* @uleyB 'Lens index of refraction -$8.3\6h '************************************************************************* bi[7!VQf eID = FindMaterial( "Lens" ) <>&=n+i GetModelMaterial eID, mat ;<Qdy`
T D#rrW?-z mat.Nd = nlens %HuyK SetModelMaterial eID, mat |^n3{m Print "Set lens index of refraction = " & nlens AHh#Fx+K 7!V@/S}7 '************************************************************************* #*$p-I= 'Pupil diameter @s*,xHE '************************************************************************* E)p9eU[# eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ]?l{j y.a]r7 'Adjust pupil diameter (trimming volume inner hole) mw$Y 4cgIEw[6 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" fib#CY Utl
t< ' Adjust pupil location to just in front of the lens ?m%h`<wgMc parID = FindFullName( "Geometry.Arizona Eye" ) laREjN/\` eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) cnNOZ$) count = 0 [=M% While GetOperationCount(eID)>count Iin#Wd-/ GetOperation eID, count, op ur%$aX) If op.Type="ShiftZ" Then L10IF DeleteOperation eID,count QJX/7RA count=count-1 pWaPC/,g End If >.%4~\U count=count+1 IM(u<c$ Wend zmFws-+A op.Type = "ShiftZ" Lk,+Tfk" op.val1 = taq-0.01 b5`KB75sbo op.parent = parID @'jfKW AddOperation eID, op CY"i-e"q<Q 5~VosUpe7 Print "Set pupil diameter = " & pupilDiam z/|BH^Vw nfE@R."A 'Update AZ Eye subassembly Description !q/5yEJ>h eID = FindFullName( "Geometry.Arizona Eye" ) D'i6",Z> GetEntity eID, entity BW K IbG entity.Description = "Accommodation = " & A & "D" !k&)EWP? SetEntity eID, entity ! q6hC oK+Lzb\d{M Update g`Md80*Zfk Print "DONE!" ^X1wI9V ej[S u End Sub &a #GXf ^X?D#\ 如果屈光度是4,光瞳直径是4,则会输出如下数据: &9 B_/m3 ;iX<`re~ Accommodation = 4 Diopters Go8F5a@j Pupil Diameter = 4 mm 78Y@OL_$ Set aqueous humor thickness = 2.81 gY5l.& Set anterior lens radius = 10.4 and conic constant = -2.375869 kK[duW=6 Set posterior lens radius = -4.424557 and conic constant = -3.081019 h}Ygb-uZ Set lens thickness = 3.927 C3"&sdLb$ Set lens index of refraction = 1.42672 B@cz
?%] Set pupil diameter = 4 8F6h#%9 DONE! tbur$00 K8Zt:yP r_o<SH QQ:2987619807 (2txM"Dja
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