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简介 [1Dg_>lz U+!H/R)( 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。 kMS[ xi6Fs, 2S 模型 `nO!_3 (YjY=F 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。 5Dy800.B2 /:a~;i Table 1. AZ眼睛模型的定义 ^ ,Bxq^'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. 0VV 1!g Kl[WscR 光源 13]sZ([B%| #![i
{7 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。 ^Slwg|t*~P Riq5Au?*) /tno`su; 图1. 光源和提示信息使用 n_@YKz;8 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。 uBk$zs 1rV?^5 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 ku*|?uF ~BVg#_P 图2. 字母F光源的设定方法光 n>X +:2(xgOP.V 图3. 字母F在视网膜上位置点列图 V%pdXM5 视网膜的散射 yZ aQ{]" GYiUne$ 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。 ,\5]n&T;r l_LfV ON #(@dN+ 图4. 视网膜朗伯散射设定 T7YzO,b/
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。 kImGSIJ 17G7r\iNYq Dyp'a 图5. 视网膜重点采样规格设定 0Bn$C,- 脚本 f #414ja 0[0</"K%1m 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: Z94D<X" =5_8f 图6. 用户对话框的创建与编辑 4qjY,QJ 图7. 用户对话框编辑器 .N]^g# 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。 }rVnuRq 余下的脚本计算与屈光度有关的所有参数。 (@`+Le R+Ke|C 分析 9Dd/g7 _y`'T;~OY 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 |mrAvm}
0; OpT0 图7. 字母F在视网膜上颜色分析 2:i`, 脚本代码 FFtj5e $$\| 3rj! Option Explicit 'Remove this to enable non-dimensioned variables to be used. lXm]1
*< 2`t4@T Dim entity As T_ENTITY 1S\q\kz->D Dim op As T_OPERATION GVY_u@6 Dim mat As T_MODELMATERIAL <s-_ieW' Dim A As Double $|z8WCJ Dim pupilDiam As Double pz?.(AmU\ Dim eID As Long QsI>_<r Dim parID As Long ,[+gE\z{{u Dim count As Integer p=9G)VO Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Old5E& Dim tlens As Double, nlens As Double L<QqQ"` Dim curv As Double, conic As Double GS$OrUA Dim ok As Long 34]f[jJ| [F+lVb Sub Main G?=X!up( 'fcJ]%-= '用户输入对话框 |!I# T Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 KWy4}7a@,s TextBox 220,21,40,21,.TextBox1 'default: 0 S! ,.#e (Y Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 UX2`x9 OKButton 40,91,90,21 H*yX
Iq: CancelButton 190,91,90,21 j4H,*fc Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 8!me$k& TextBox 220,49,40,21,.TextBox2 'default: 4 (sO;etW End Dialog Y.F:1<FAtf Dim dlg As UserDialog :(A]Bm3 lGjmw"/C ok = Dialog (dlg) athU bbiDY If ok=0 Then 'cancel button was pressed T\8|Q@ Print "Execution cancelled." hV'JTU]H End GRO[&;d` End If Gt\F),@ '!{zO"
1* 'Assign accommodation and pupil diameter & use defaults if field left empty ?KI_>{ If dlg.TextBox1 = "" Then "+&|$* A = 0 'Default accommodation N}VKH5U| Else D19uI&U4 A = CDbl(dlg.TextBox1) 7qgHH p End If |53Zg"! E;D9S If dlg.TextBox2 = "" Then ~;il{ym pupilDiam = 4 'Default pupil diameter cL< Else QF'N8Kla pupilDiam = CDbl(dlg.TextBox2) LurBqr End If io$AGi ?J6J#{LRd Print " " J03yFT,dF Print "Accommodation = " & A & " Diopters" 0j7\.aaK Print "Pupil Diameter = " & pupilDiam & " mm" >=6tfLQ EmVE<kY. ' Calculate new parameters with accommodation MPT*[&\- taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness R BwI*~%g{ b!5W!vcK Rant = 12.0 - 0.4*A 'Radius of anterior lens z[}[:H8 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens !m'lOz vitmG'|WG Rpost = -5.224557 + 0.2*A 'Radius of posterior lens j5G8IP_Wx CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens { >bw:^F k[gO>UGB; tlens = 3.767 + 0.04*A 'Lens thickness +VI2i~ \;.\g6zX nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 68+9^ $3W[fC 'Adjust parameters to account for accommodation tO)mKN+
( +/-#yfn!TR '************************************************************************* O9dIobu4 'Aqueous thickness (Position of Lens) M@E*_U!U '************************************************************************* j0Kj> eID = FindFullName( "Geometry.Arizona Eye.Lens" ) f,k'gM{K GetCustomElement eID, entity y5RcJM L#M9 ! parID = FindFullName( "Geometry.Arizona Eye" ) +(` 1<\@i{;xsU ' Delete any shift(s) in z -s,^_p{H count = 0 (w-z~#< While GetOperationCount(eID)>count )d2 <;c GetOperation eID, count, op 4=%Uv^M If op.Type="ShiftZ" Then S}cpYjnH8 DeleteOperation eID,count C~yfuPr\B count=count-1 XWf8ZZj End If :0Rd )*k,v count=count+1 /![S 3Ol Wend -sh S?kV Wr a W 'Set new shift in cWA9 n}Z op.Type = "ShiftZ" %r=uS.+hrF op.val1 = taq VL?ubt< op.parent = parID J3Qv|w[3Y AddOperation eID, op Yo/U /dB Print "Set aqueous humor thickness = " & taq-0.55 4h@jJm
<IC=x(T '************************************************************************* `|XE B 'Radius and conic constant of anterior lens _*>bf G '************************************************************************* {Uz@`QO3 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ^&03D5@LoY GetConic eID, entity, curv, conic N /p9Ws Vl%AN;o SetConic eID, entity, 1/Rant, CCant m$ )yd~ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant eB%KXPhMm {KxeH7S '************************************************************************* c*-8h{} 'Radius and conic constant of posterior lens ,^pM]+NF| '************************************************************************* @{iws@. eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) zH0%;
o} GetConic eID, entity, curv, conic XI}
C|]# jrbEJ. SetConic eID, entity, 1/Rpost, CCpost n#uH^@#0 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost n (7m J;W(}"cFq '************************************************************************* gbsRf&4h 'Lens thickness (Position of posterior lens surface) Uq5wN05 '************************************************************************* `KqMcAW ^VK-[Sz& parID = FindFullName( "Geometry.Arizona Eye.Lens" ) m4bfW 5+vCuVZ ' Delete any z-shift(s) \V
/s count = 0 %6+J]U While GetOperationCount(eID)>count 3FT%.dV^ GetOperation eID, count, op L$=@j_V2 If op.Type="ShiftZ" Then Q&]
}`Rp= DeleteOperation eID,count 7F5t& count=count-1 !C
*%,Ak End If 1t_$pDF} count=count+1 7-6Z\.- Wend }`8g0DPuD9 9I0/KuZd
O 'Set new z-shift O#
.^} op.Type = "ShiftZ" @kvgq 0ab op.val1 = tlens dB+x,+%u+ op.parent = parID kMWu%,s4 AddOperation eID, op 8
!Pk1P Print "Set lens thickness = " & tlens q>/#
P5V 2.ud P '************************************************************************* S(9Xbw)T 'Lens index of refraction R $HIJM '************************************************************************* "D}PbT[V eID = FindMaterial( "Lens" ) fu?5gzT+b GetModelMaterial eID, mat gP"p7\
( /%EKq+ZP mat.Nd = nlens X0O0Y>" SetModelMaterial eID, mat F`SOF O Print "Set lens index of refraction = " & nlens 79U
Th@r} no- Lx-x '************************************************************************* 1@q~(1-o 'Pupil diameter ^"7tfo8 '************************************************************************* #P.jlpZk eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) `2c>M\c4U }hrLM[ 'Adjust pupil diameter (trimming volume inner hole) 1|bu0d\] 06"p^# SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" k@JDG]R<{ qg#TE-Y` ' Adjust pupil location to just in front of the lens }M'h5x parID = FindFullName( "Geometry.Arizona Eye" ) 5W"nn eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Uhfm@1 cz& count = 0 2
*IF While GetOperationCount(eID)>count )W95)] GetOperation eID, count, op Qna
^Ry?6) If op.Type="ShiftZ" Then /%C6e
)7BL DeleteOperation eID,count "u5Hm ^H count=count-1 xnmIo?
hC End If :-ZE~bHJ count=count+1 ztf
VXmi' Wend [RCUP. op.Type = "ShiftZ" IG0$OtG op.val1 = taq-0.01 drP2%u op.parent = parID &I:[ 'l! AddOperation eID, op [Av#Z)R %[\:
8 Print "Set pupil diameter = " & pupilDiam kF.!U/C Tl5K'3 'Update AZ Eye subassembly Description z!;n\CV @ eID = FindFullName( "Geometry.Arizona Eye" )
YW"}hU GetEntity eID, entity $T{,3;kt entity.Description = "Accommodation = " & A & "D" *cxmQ SetEntity eID, entity 3":ef|w] {MdxIp[ Update # eqt{ Print "DONE!" LO]D
XW 9 ZOc1 vj End Sub J2Y-D'*s "r @RDw
如果屈光度是4,光瞳直径是4,则会输出如下数据: J~KWn. @*q WV*$h Accommodation = 4 Diopters F+PIZ% Pupil Diameter = 4 mm 8v@6 &ras@ Set aqueous humor thickness = 2.81 EW*!_| Set anterior lens radius = 10.4 and conic constant = -2.375869 pg~vteq5 Set posterior lens radius = -4.424557 and conic constant = -3.081019 P7QOlTQI Set lens thickness = 3.927 <h|XB}s+ Set lens index of refraction = 1.42672 Q:eIq<erY Set pupil diameter = 4 2
P+RfE`o
DONE! ;Q&38qI u8qL?Aj^ O-Hu:KuIf QQ:2987619807 {9U<!
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