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简介 KM"BHaSkF xXlx}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。 vnWt8?)]^ g/frg(KF 模型 dVg'v7G&V( EM(%|# 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。 .k$Yleg g:Q:cSg< Table 1. AZ眼睛模型的定义 Y-lwS-Ii 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. 85e*um^ eA*We 光源 fr'DV/T b;FaTm@ 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 :k-@w5( ;d<O/y,:4 SAiaC _ 图1. 光源和提示信息使用 wrc1N?[bn 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 ;l^'g}dQ^ pedyWA> 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 z%BX^b$Hj Lr9E02 图2. 字母F光源的设定方法光 k!bG![Ie| I@5$ <SN 图3. 字母F在视网膜上位置点列图 B2Rpd &[ 视网膜的散射 5g.w"0MkY MV w.Fl 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。 BNe>Lk o TqSjL{l%
fda4M 图4. 视网膜朗伯散射设定 /;vHAtt;f 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。 nch#DE82 el\xMe^SY )3 R5cq 图5. 视网膜重点采样规格设定 65nK1W`i 脚本 -?l`LbD rp^:{6O 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: ej7L-~lxQ xs
)jO+. 图6. 用户对话框的创建与编辑 #3tC"2MZ 图7. 用户对话框编辑器 \%B7M]P 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。 Al]*iw{ 余下的脚本计算与屈光度有关的所有参数。 .4l
cES~ {6%-/$LX 分析 7{l~\]6d OO'zIC<z 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 GXk
|p8 GvvKM=1 图7. 字母F在视网膜上颜色分析 a_]l?t 脚本代码 8Q"1I7U UkXa mGoy3 Option Explicit 'Remove this to enable non-dimensioned variables to be used. 11k}Ly 6$kh5$[ Dim entity As T_ENTITY |j{]6Nu Dim op As T_OPERATION M`8c|*G Dim mat As T_MODELMATERIAL lon9oraF' Dim A As Double $e{[fmx Dim pupilDiam As Double fdHFSnQ g Dim eID As Long 2 <@g * Dim parID As Long 2kk; z0f Dim count As Integer ;@:-T/= Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double rVRv*W Dim tlens As Double, nlens As Double rg=Ym. Dim curv As Double, conic As Double Ck>]+rl Dim ok As Long 6!USSipn ]>ndFE6kl Sub Main :."6 g)T %mD{rG9 '用户输入对话框 5iI(A'R[7 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Dd,i^,4Gj TextBox 220,21,40,21,.TextBox1 'default: 0
t@a&& Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ^t *Ba>A OKButton 40,91,90,21 X<pNc6 CancelButton 190,91,90,21 VS!v7-_N5 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 9Zmq7a
E TextBox 220,49,40,21,.TextBox2 'default: 4 ;g;1<?
[ End Dialog OF)*kiJ Dim dlg As UserDialog E cSu[b
/d/]#T[Z9 ok = Dialog (dlg) P2 qC[1hYH .TDg`O24c, If ok=0 Then 'cancel button was pressed VR%*8= Print "Execution cancelled." ;j[:tt\k End )>^ Ge9d] End If FFe{=H,= Xy`'h5
'Assign accommodation and pupil diameter & use defaults if field left empty -N6ek` If dlg.TextBox1 = "" Then \qlz< A = 0 'Default accommodation )O$S3ojZ Else PfB9 .f{ A = CDbl(dlg.TextBox1) 94]i|2qj* End If 5*Qzw[[= *UXa.kT@ If dlg.TextBox2 = "" Then %o0 H#7' pupilDiam = 4 'Default pupil diameter ${}9/(x/^ Else 1'iQlnMO@ pupilDiam = CDbl(dlg.TextBox2) 3+
2&9mm End If k,; (`L #JY> Print " " F1L[C4' Print "Accommodation = " & A & " Diopters" <b\8<mTr Print "Pupil Diameter = " & pupilDiam & " mm" .7:ecFKk q_L. Sy|) ' Calculate new parameters with accommodation 1mR@Bh taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness -V[!qI p,uM)LD
Rant = 12.0 - 0.4*A 'Radius of anterior lens
U z[#ye CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 'A\0^EvVv l<ZHS'-;8 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens (:%t CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens x9 n(3Oa rY1jC\ tlens = 3.767 + 0.04*A 'Lens thickness Lxv_{~I* ;B(16&l=q nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 86dz Jh @+)T"5_Y[ 'Adjust parameters to account for accommodation "Vp:Sq9y ac966<# '************************************************************************* ae2SU4Jx 'Aqueous thickness (Position of Lens) '?fGI3b~/ '************************************************************************* |}/KueZ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) b^()[4M; GetCustomElement eID, entity Goy[P2m FFmXT/K"/j parID = FindFullName( "Geometry.Arizona Eye" ) ,OP\^ \_i22/Et ' Delete any shift(s) in z lH@goh count = 0 1=!2|D:C)i While GetOperationCount(eID)>count nPl,qcyY GetOperation eID, count, op }#Iqq9[ If op.Type="ShiftZ" Then aD6!x3c/ DeleteOperation eID,count PGVp1TQ count=count-1 p6)6Gcx End If i=pfjC count=count+1 MBU4Awj Wend
fD8GAav $?VYHkX 'Set new shift in U2~|AkL op.Type = "ShiftZ" P=9UK`n op.val1 = taq 0m\( @2E op.parent = parID /+. m.TF AddOperation eID, op ^EW6}oj[ Print "Set aqueous humor thickness = " & taq-0.55 :b_hF }*aj& '************************************************************************* +bb-uoZf 'Radius and conic constant of anterior lens hgwS_L '************************************************************************* 5Fq+^ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Nd@/U
c GetConic eID, entity, curv, conic w_LkS/ U7,.L SetConic eID, entity, 1/Rant, CCant =KD[#au6a Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant iU=:YPE+. LfCgvq6/pO '************************************************************************* :6m"}8*q8 'Radius and conic constant of posterior lens /len8FRf '************************************************************************* b.}J'?yLm eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) W3^^aD- GetConic eID, entity, curv, conic <KStlfX h7m$P^=U SetConic eID, entity, 1/Rpost, CCpost U9Q[K ` Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 5>=4$!` 04}c_XFFE '************************************************************************* RmOkb~ 'Lens thickness (Position of posterior lens surface) oJ#;X R '************************************************************************* rg]z Eq8:[o parID = FindFullName( "Geometry.Arizona Eye.Lens" ) J%!vhQ hQvI} ' Delete any z-shift(s) \Il?$Kb/ count = 0 1$:O9{F While GetOperationCount(eID)>count =vDDfPR GetOperation eID, count, op 0wF)bQv1 If op.Type="ShiftZ" Then XXD4T9Wy DeleteOperation eID,count ofgNL .u count=count-1 r CUs End If d4A:XNKB count=count+1 b'ir$RL] c Wend )2u_[Jc= e. E$Ej]w 'Set new z-shift @B ?'Mu* op.Type = "ShiftZ" %.fwNS op.val1 = tlens TIF =fQ op.parent = parID e#WASHZN AddOperation eID, op V,?])=Ax Print "Set lens thickness = " & tlens /IHF 6J cXhlB` '************************************************************************* @Yw42`>!s 'Lens index of refraction i@%a!].I '************************************************************************* *fLVzYpo eID = FindMaterial( "Lens" ) Sg\+al7 GetModelMaterial eID, mat y~VLa a,n#E!zT?w mat.Nd = nlens TpHzf3.I SetModelMaterial eID, mat @Q!Tvw/ Print "Set lens index of refraction = " & nlens SF"r</c[ 'S9jMyZrZ '************************************************************************* fEGnI\ 'Pupil diameter #;;A~d:V '************************************************************************* "wxyY^" eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) _! ?a9 T]\'D&P~D 'Adjust pupil diameter (trimming volume inner hole) xF
3Z> dMI G2log SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Q*e\I8R} EK\xc'6M ' Adjust pupil location to just in front of the lens }5Km \OI parID = FindFullName( "Geometry.Arizona Eye" ) :1v.Jk eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Qr-,J_ count = 0
Yq{R*HO While GetOperationCount(eID)>count }z2[w@M GetOperation eID, count, op Q4g69IE If op.Type="ShiftZ" Then FB3}M)G>M DeleteOperation eID,count MaF4lFmS count=count-1 E[FE-{B# End If 1`~.!yd8( count=count+1 7IrH(~Fo Wend :edy(vC< op.Type = "ShiftZ" m+x$LkP op.val1 = taq-0.01 m.lzkS]P op.parent = parID NuXII- AddOperation eID, op 0L d"df* ,Z8)DC= Print "Set pupil diameter = " & pupilDiam ROO@EQ#`Z TrQUhmS/! 'Update AZ Eye subassembly Description T5dnj&N ] eID = FindFullName( "Geometry.Arizona Eye" ) [7,q@>:CS GetEntity eID, entity NFqGbA| entity.Description = "Accommodation = " & A & "D"
L08lkq, SetEntity eID, entity 7s Gf_`Z N_l_^yD Update F4IU2_CnPD Print "DONE!" <driD'=F k=O End Sub vz&88jt 4v9d&
m!< 如果屈光度是4,光瞳直径是4,则会输出如下数据: Y<_;8%S c IPOI'3d Accommodation = 4 Diopters \Qf2:[-V0 Pupil Diameter = 4 mm xrv0% Set aqueous humor thickness = 2.81 |w5,%#AeO$ Set anterior lens radius = 10.4 and conic constant = -2.375869 X3?RwN:P Set posterior lens radius = -4.424557 and conic constant = -3.081019 /0XmU@B Set lens thickness = 3.927 *n6L3"cO Set lens index of refraction = 1.42672 /-+hMYe Set pupil diameter = 4 2AEVBkF;M DONE! FB
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