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简介 nc&Jmo7 O k*Z 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。 <ZVZ$ZW~D |by@ :@*y 模型 0E1=W6UZ 6"+8M 3M l 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。 R:f7LRF/\ c|Y!c!9F Table 1. AZ眼睛模型的定义 JjQVzkE 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. MJ\r 4n >(3'Tnu 光源 as#J qE rREzM)GA 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。 ZV(
w 9~~UM<66W HCazwX 图1. 光源和提示信息使用 : u-.T.zZl 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。 "xn|zB Ihqs%;V 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。 r[!(?%>j N~| t!G*9 图2. 字母F光源的设定方法光 ="3,}qR wS%zWdsz 图3. 字母F在视网膜上位置点列图 AerFgQiS 视网膜的散射 @RVOXkVo $H;+}VQ 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-LL*fa {g_@Tuu {cR3.%wX 图4. 视网膜朗伯散射设定 jI0]LD1k 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。 %Rarr a:}E& ,&M eM }W6vIn 图5. 视网膜重点采样规格设定 Q.ukY@L.' 脚本 K'Spbn!nC $"fzBM?5 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: sUciFAb 9I kUZW 图6. 用户对话框的创建与编辑 VYigxhP7 图7. 用户对话框编辑器 O^NP0E 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 YxyG\J\|, 余下的脚本计算与屈光度有关的所有参数。 De]^&qw( #HG&[Ywi 分析 <\ETPL,< (yGQa5v 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Ux_<d?p #_fY4vEO 图7. 字母F在视网膜上颜色分析 m^A]+G#/ 脚本代码 rS,j;8D- 0'@u!m? Option Explicit 'Remove this to enable non-dimensioned variables to be used. Z"DW 2k VA2<r(y~( Dim entity As T_ENTITY kwF] TO
S Dim op As T_OPERATION Pgev) rh[ Dim mat As T_MODELMATERIAL G/(*foT8SE Dim A As Double T.2ZBG~|[ Dim pupilDiam As Double 5p
)IV>G Dim eID As Long =qX*] Dim parID As Long !sG"n&uZq Dim count As Integer Fx5ZwT
t Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 4|F#gK5E Dim tlens As Double, nlens As Double lM+ xU; Dim curv As Double, conic As Double PI63RH8e Dim ok As Long xE1rxPuq)d X'@f"= v9k Sub Main DB~MYOX~ C$K+=jT '用户输入对话框 (H1lqlVWV# Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 zp#:EZ TextBox 220,21,40,21,.TextBox1 'default: 0 0\wi am- Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 H+R7X71{ OKButton 40,91,90,21 1I
\tu CancelButton 190,91,90,21 \gd6Yx^[ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ?} X}# TextBox 220,49,40,21,.TextBox2 'default: 4 J&_3VKrN End Dialog )Oe`s(O@[I Dim dlg As UserDialog V&R$8tpz )2]a8JVf ok = Dialog (dlg)
A!4VjE> 9N1#V
K If ok=0 Then 'cancel button was pressed /yp/9r@T0 Print "Execution cancelled." f)U6p End #!L%J<MX End If O a1'oYIHg Otxa<M+" 'Assign accommodation and pupil diameter & use defaults if field left empty -)6;0 If dlg.TextBox1 = "" Then j9>TTgy@ A = 0 'Default accommodation !pl_Ao~( Else tJz^DXqAc A = CDbl(dlg.TextBox1) m\ ?\6Wk End If F: ,#? R|-j]Ne If dlg.TextBox2 = "" Then 5v+L';wx[T pupilDiam = 4 'Default pupil diameter Pfk{ =y Else IW mHp] pupilDiam = CDbl(dlg.TextBox2) _<3r'Y, End If hRLKb} 4M7^
[G Print " " HGb.656r Print "Accommodation = " & A & " Diopters" -aT=f9u Print "Pupil Diameter = " & pupilDiam & " mm" .X^43
q Bqp&2zg)@ ' Calculate new parameters with accommodation $^ubo5% taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness <0>[c<{V< m3B\)2B Rant = 12.0 - 0.4*A 'Radius of anterior lens C-r."L CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens P.!;Uf}32 4V1|jy3 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens [C2kK *JZ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens y6\ [1nZ EL"4E', tlens = 3.767 + 0.04*A 'Lens thickness 0T=jR{j!o ea>[BB3# nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction BJ"Ay@D* "AV1..mu 'Adjust parameters to account for accommodation H8(C>w-' > e;]mU`, '************************************************************************* q;KshpfRMD 'Aqueous thickness (Position of Lens) rpx0|{m '************************************************************************* 1O|RIv7F[/ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) p
FXd4* GetCustomElement eID, entity r,QJG$ Jo gW/QFZjY parID = FindFullName( "Geometry.Arizona Eye" ) a
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tnA_!$Y
a ' Delete any shift(s) in z :jl
u count = 0 x_]",2 W' While GetOperationCount(eID)>count }k4` GetOperation eID, count, op #/\pUK~km If op.Type="ShiftZ" Then 5?D1][ DeleteOperation eID,count k\Yu5) count=count-1 uPM8GIvZX. End If i0i.sizu count=count+1 8}ii3P y Wend {yGZc3e1j *2w_oKE'+5 'Set new shift in f0:EQYYZ op.Type = "ShiftZ" 50}.Xm@,BO op.val1 = taq @1/Q op.parent = parID #L|JkBia AddOperation eID, op wghFGHgw Print "Set aqueous humor thickness = " & taq-0.55 dqIZ#;:g buMiJzU '************************************************************************* p,M3#^ q 'Radius and conic constant of anterior lens
w0q?\qEX '************************************************************************* ]1YYrgi7 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) M6@'9E]|> GetConic eID, entity, curv, conic c,b`N0dOKL 5`OK- SetConic eID, entity, 1/Rant, CCant ?NL&x Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ~;!i)[- 9RCB$Ka6X '************************************************************************* 0ECO/EuCg 'Radius and conic constant of posterior lens H4,.H,PZ '************************************************************************* [[.&,6 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ^`hI00u( GetConic eID, entity, curv, conic u"Hd55"& 3 cV+A]i SetConic eID, entity, 1/Rpost, CCpost ?%8})^Dd>4 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 0pZ.; /<{
_{Fdw '************************************************************************* 4N%2w(,+8 'Lens thickness (Position of posterior lens surface) &K}(A{ '************************************************************************* W?4&lC^G @wAr[.lZ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) *x#&[> [][:/~q! ' Delete any z-shift(s) l/y
Kc8^< count = 0 ?Uy*6YS While GetOperationCount(eID)>count U{za m GetOperation eID, count, op bdsHA2r`s If op.Type="ShiftZ" Then t3yQ/ DeleteOperation eID,count V.P5v{ count=count-1 3 DO$^JJ. End If B3g82dm count=count+1 9B?t3: Wend 1X!f!0=g+ c|;|%"Mk 'Set new z-shift bTy'5" op.Type = "ShiftZ" CrwcYzrRWl op.val1 = tlens pb2{J# op.parent = parID P20]>Hg AddOperation eID, op l_q>(FoqA Print "Set lens thickness = " & tlens ?/|@ #& i&s=!` '************************************************************************* w]5f3CIm 'Lens index of refraction ptc H>wM! '************************************************************************* %OfDTs eID = FindMaterial( "Lens" ) V]S06>P GetModelMaterial eID, mat Z$m2rZ# .T$9Q Ar5 mat.Nd = nlens :7PSZc:xE SetModelMaterial eID, mat Fi3(glgd- Print "Set lens index of refraction = " & nlens <+1w'- \z2hXT@D '************************************************************************* vJjj+: 'Pupil diameter JjO/u>A3;7 '************************************************************************* .2 SIU4[P eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 4.kkxQR7r @j8L{FGnN 'Adjust pupil diameter (trimming volume inner hole) qA_DQ): GC#95 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" T+{'W SrU ' Adjust pupil location to just in front of the lens f'yd{ihFp parID = FindFullName( "Geometry.Arizona Eye" ) 2iINQK$ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) +CHO0n count = 0 ::b;4QL While GetOperationCount(eID)>count vlKKPS GetOperation eID, count, op /(L1!BPP9m If op.Type="ShiftZ" Then LZbHK.G= DeleteOperation eID,count (#Kvm count=count-1 /OtQk-E End If tZ2iSc count=count+1 b,V=B{(~ Wend w [x+2 op.Type = "ShiftZ" L ]'CA^N op.val1 = taq-0.01 mZ&Mj.0+~ op.parent = parID yBjWPx? AddOperation eID, op 'WgwLE_ -Af`AX Print "Set pupil diameter = " & pupilDiam 1pr_d"#4 @G{DOxE* 'Update AZ Eye subassembly Description ,Yt&PE eID = FindFullName( "Geometry.Arizona Eye" ) {v'Fg GetEntity eID, entity 9r*T3=u.S entity.Description = "Accommodation = " & A & "D" C&"2`ll SetEntity eID, entity
%NoZf^? z,P7b]KVe Update Nr+1N83S} Print "DONE!" >#|Q,hVU5 #ms98pw%5 End Sub >k-poBw i kiy>W8 如果屈光度是4,光瞳直径是4,则会输出如下数据: 5!%/j,? jX,~iZ_B Accommodation = 4 Diopters "MN'%"/ Pupil Diameter = 4 mm A*i_-;W) Set aqueous humor thickness = 2.81 Vs{sB*: Set anterior lens radius = 10.4 and conic constant = -2.375869 FX 3[U+ Set posterior lens radius = -4.424557 and conic constant = -3.081019 Cu7iHh Y5 Set lens thickness = 3.927 > `M\xt Set lens index of refraction = 1.42672 :gtwvM7/B Set pupil diameter = 4 4v
.6_ebL DONE! 95&HsgdxJ
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