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简介 7'g'qUW+~ Wy{xTLXk2 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。 ^.5`jdk PMER~}^ 模型 #-b0U[,. GORu*[U8 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。 T=6fZ;7 P%`|Tu!B Table 1. AZ眼睛模型的定义 +X)n} jh 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. ?+{=>{1 4 [2^#t[ 光源 EugQr<sM# CG!/Lbd 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。 i[obQx S94 gd~# uR\ VJ1(|v{D4[ 图1. 光源和提示信息使用 KLqn`m`O; 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。 ATq)8Rm\ >iefEv\ 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。 Rv R,V .I%p0ds1r 图2. 字母F光源的设定方法光 ,VK! 3$;| H"hL+F ^ 图3. 字母F在视网膜上位置点列图 "YLH]9"= 视网膜的散射 Xq"@Z =Kdd+g! 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 H]v"_!(\ tEEeek(! a&yIH;- 图4. 视网膜朗伯散射设定 Ta;'f7Oz 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 M
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fX TE+d? rG7S^,5o 图5. 视网膜重点采样规格设定 C~\/FrO? 脚本 {4u8~whLp X
?p_O2#k 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: hVQ
TW[ 6L--FY>.- 图6. 用户对话框的创建与编辑 WH Zz?|^ 图7. 用户对话框编辑器 yP :/F|E$ 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。 F$ a?} } 余下的脚本计算与屈光度有关的所有参数。 .;6G?8` nsChNwPX 分析 Y XC?q ni @Mqb 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'(\>
q3.L6M 图7. 字母F在视网膜上颜色分析 &=SP"@D 脚本代码 <.c@l,[.z 9:tvkl Option Explicit 'Remove this to enable non-dimensioned variables to be used. 1iOQ8hD ~z''kH=e
Dim entity As T_ENTITY ,,+ ~./) Dim op As T_OPERATION Z
Mp Dim mat As T_MODELMATERIAL _E({!t"` Dim A As Double :UuPy|> Dim pupilDiam As Double gR `:)> Dim eID As Long G$\2@RT9[ Dim parID As Long S30@|@fTz Dim count As Integer :sT\-MpQvn Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double !oXA^7Th6] Dim tlens As Double, nlens As Double pa0'\ Dim curv As Double, conic As Double A=X2zm>9 Dim ok As Long C#]% xJ"CAg|B Sub Main -"L)<J@gQ? ?L|Jc_E '用户输入对话框 kqYvd]ss Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 8.ek_r TextBox 220,21,40,21,.TextBox1 'default: 0 a$p2I+lX Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 5- Q`v/w; OKButton 40,91,90,21 Q
!5P CancelButton 190,91,90,21 @Yua%n6]#D Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 }K=TB}yY TextBox 220,49,40,21,.TextBox2 'default: 4 &lYKi3}x End Dialog ,j~R ^j Dim dlg As UserDialog ?
C2 bA5M /*GRE#7S ok = Dialog (dlg) H~~I6D{8 rN|c0N If ok=0 Then 'cancel button was pressed EXz5Rue
LV Print "Execution cancelled." tK&.0)*= End LX<c(i End If 6p/gvpZ 0y4z`rzTn 'Assign accommodation and pupil diameter & use defaults if field left empty kmM4KP#&| If dlg.TextBox1 = "" Then @URLFMFi A = 0 'Default accommodation t/cjz/] Else ~Z5?\a2Ld A = CDbl(dlg.TextBox1) NF=FbvNe End If eafy5vN[zX u!2.[CV If dlg.TextBox2 = "" Then q>&F%;q1] pupilDiam = 4 'Default pupil diameter pj,.RcH@o Else ;%
*e}w0 pupilDiam = CDbl(dlg.TextBox2) v>Il# End If ]>@;
2%YvY {jzN Print " "
mQ#@"9l% Print "Accommodation = " & A & " Diopters" RIX0AE Print "Pupil Diameter = " & pupilDiam & " mm" v8Nc quv GK}?*Lfs ' Calculate new parameters with accommodation . iq.H taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 8xmw-s) G#'3bxI{f+ Rant = 12.0 - 0.4*A 'Radius of anterior lens ?Gl'-tV CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens =S@$"_& ^ j@Q2>&? Rpost = -5.224557 + 0.2*A 'Radius of posterior lens @6GM)N\{[ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens *Kt7"J *Rshzv[ tlens = 3.767 + 0.04*A 'Lens thickness (7
Mn%Jp 8aGZ% UI nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction vnz.81OR C5Q|3d 'Adjust parameters to account for accommodation SPsq][5eR '2]u{rr~+ '************************************************************************* {549&]/o 'Aqueous thickness (Position of Lens) w0~iGr}P '************************************************************************* CzzG eID = FindFullName( "Geometry.Arizona Eye.Lens" ) `.%;|"xR GetCustomElement eID, entity iyOd&|. 'KQ]7 parID = FindFullName( "Geometry.Arizona Eye" ) *6*#"#D Wnl8XHPn ' Delete any shift(s) in z ?9vBn count = 0 #`GW7(M While GetOperationCount(eID)>count +,>f-kaV GetOperation eID, count, op aJMh> If op.Type="ShiftZ" Then >^:g[6Sj DeleteOperation eID,count o;Zoj} count=count-1 }p t5. 'l End If '*>LZo4 count=count+1 &X+V} Wend =&"Vf!7YR7 j`BFk> 'Set new shift in 5?;'26iC op.Type = "ShiftZ" QVn0!R{ op.val1 = taq ^&&dO*0{ op.parent = parID DHt 8 f AddOperation eID, op [tMf KO Print "Set aqueous humor thickness = " & taq-0.55 LEhku4U. RW(AjDM '************************************************************************* )[oU|!@ 'Radius and conic constant of anterior lens Ef,@}S '************************************************************************* @hzQk~Gdi eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) xxkP4,(p GetConic eID, entity, curv, conic FZ=6x}QZ ts;_T..L SetConic eID, entity, 1/Rant, CCant 'dWJ#9C Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant YGWb!|Z$ *~!xeL '************************************************************************* oTI*mGR1Z 'Radius and conic constant of posterior lens ]Vb#(2<2 '************************************************************************* f=K1ZD eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) tEN]0` GetConic eID, entity, curv, conic lR.a3.~ Z$zUy|s[ SetConic eID, entity, 1/Rpost, CCpost iLmU|jdE Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost FG#j0#|* p~8~EQFj '************************************************************************* u/.srK!K 'Lens thickness (Position of posterior lens surface) R1Pnj '************************************************************************* hsqUiB tc6 ^<E+7 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) rG\m]C3 E MT6kJDyLu ' Delete any z-shift(s) &]LwK5SR count = 0 5?O/Aub While GetOperationCount(eID)>count Vj2GK"$v GetOperation eID, count, op =rBFMTllM If op.Type="ShiftZ" Then ,xTbt4J DeleteOperation eID,count #Ejly2C, count=count-1 d:pp,N~2o End If ]#BXaBVMY count=count+1 MxdfuFss Wend \B}W(^\wg; (Wx)YI 'Set new z-shift JG( < op.Type = "ShiftZ" 8fe"#^"s R op.val1 = tlens pRU6jV 6e) op.parent = parID /yykOvUO AddOperation eID, op 'nT#3/rL Print "Set lens thickness = " & tlens ?1N0+OW &\"fH+S '************************************************************************* tLvli>y@ 'Lens index of refraction 1)YFEU&] '************************************************************************* ;! 9_5Ar% eID = FindMaterial( "Lens" ) ! 4oIx` GetModelMaterial eID, mat > T-O3/KN *z+\yfOO" mat.Nd = nlens F}AbA pTv SetModelMaterial eID, mat J,D{dYLDD Print "Set lens index of refraction = " & nlens T^nX+;:| xlwsZm{V '************************************************************************* 9{TOFjsF 'Pupil diameter I"!gzI`Sd '************************************************************************* [e}]K: eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) bv+e'$U3 IL\mFjZ' 'Adjust pupil diameter (trimming volume inner hole) SRD&Uf0M XBY"7} SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" yBe/UFp+
=#V11j ' Adjust pupil location to just in front of the lens (mD]}{> parID = FindFullName( "Geometry.Arizona Eye" ) %om7h$D=` eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) B_&PK7vA count = 0 s Y6'y'a95 While GetOperationCount(eID)>count ('lnQD.Hd GetOperation eID, count, op !6%G%ZG@3- If op.Type="ShiftZ" Then ZF
t^q/pw DeleteOperation eID,count q@sH@-z4] count=count-1 z<fEJN End If x$Oz0 [ count=count+1 '" tieew Wend :RQ[(zD] op.Type = "ShiftZ" #NE^f2 op.val1 = taq-0.01 sy`s$Ed! op.parent = parID BdKtpje AddOperation eID, op u#,]>; :$tW9*\KY Print "Set pupil diameter = " & pupilDiam ^0&] .m Y o(B8}?0! 'Update AZ Eye subassembly Description Sy'>JHx eID = FindFullName( "Geometry.Arizona Eye" ) >YfOR%mS4 GetEntity eID, entity 4eEs_R entity.Description = "Accommodation = " & A & "D" =_H39)|T SetEntity eID, entity OZ" <V^"` etoE$2c Update <S}qcjG Print "DONE!" LF~#4)B
)q^vitkjup End Sub q"Md)?5N GWVdNYpmr 如果屈光度是4,光瞳直径是4,则会输出如下数据: gQEV;hCO 8<kme"%s Accommodation = 4 Diopters '=H^m D+gl Pupil Diameter = 4 mm 9y5\4&v Set aqueous humor thickness = 2.81 u J`&hX Set anterior lens radius = 10.4 and conic constant = -2.375869 3XnXQ/({ Set posterior lens radius = -4.424557 and conic constant = -3.081019 #'8PFw\zw Set lens thickness = 3.927 8Vn6* Xn Set lens index of refraction = 1.42672 }j?S?= ;m= Set pupil diameter = 4 *X\c
$=* DONE! 5);#\&B %p9bl ,x a
98 QQ:2987619807 !{Y#<tG]
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