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简介 0?ZJJdI3 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。 iy8UrgG;l :a3Pnq$]E 模型 w1aa5-aF J(S.iTD 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。 \<~[uv' bxO8q57 Table 1. AZ眼睛模型的定义 &&|*GAjJ 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. 0,nDyTS^ ?DkMzR)u 光源 ,'F;s:WM, Z*nC
;5Kd 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。 [X=-x=S, vKDRjrF- ,~gY'Ql 图1. 光源和提示信息使用 yuk64o2QE 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。 NZ'S~Lr 9rtcI[&?0 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。 :Cw|BX@??U R\MM2_I 图2. 字母F光源的设定方法光 Q,Hw@w<1 k#E D#']N 图3. 字母F在视网膜上位置点列图 f5Zx:g 视网膜的散射 RT8xU;
sn/^#Aa=N 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。 N|T%cdh:/ &2MW.,e7s 2IqsBK` 图4. 视网膜朗伯散射设定 :p(3Ap2TY 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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ip%m 图5. 视网膜重点采样规格设定 I2qC,Nkk 脚本 "Nn/vid; [(w_!|S 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: &n6mXFF#>P Ytc 图6. 用户对话框的创建与编辑 %w,
图7. 用户对话框编辑器 Zk)]=<H 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。 Gb<)U[Hfd 余下的脚本计算与屈光度有关的所有参数。 ,+KZn}> S>aN# 分析 u} JL*}Q \('8_tqI" 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 qXkc~{W_ SY["dcx+ 图7. 字母F在视网膜上颜色分析 Z+=W gEu1 脚本代码 pN&5vu30 OA_:_%a( Option Explicit 'Remove this to enable non-dimensioned variables to be used. A{Z=[]r1`E S`BLwnU`# Dim entity As T_ENTITY xpKD 'O=T Dim op As T_OPERATION KO<Yc`Fs Dim mat As T_MODELMATERIAL ddmTMfH Dim A As Double SgHLs Dim pupilDiam As Double .%h.b6^ Dim eID As Long 9;k_"@A6 Dim parID As Long ny|ni\6 Dim count As Integer } '. l'% Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double =4"D8UaHr Dim tlens As Double, nlens As Double @|6n.'f+ Dim curv As Double, conic As Double 4iBp!k7 Dim ok As Long G \?fWqx ec[S?- Sub Main D:e9609 0
ML=] '用户输入对话框 YBN@{P$ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 u{,e8. Z TextBox 220,21,40,21,.TextBox1 'default: 0 0PIC| Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 EkgS*q_ OKButton 40,91,90,21 }xn\.M:ic CancelButton 190,91,90,21 v9(->X' Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 'xm _oGWE TextBox 220,49,40,21,.TextBox2 'default: 4 #Sr_PEo
_ End Dialog z/)HJo2# Dim dlg As UserDialog ]vMr@JM-G IExo#\0'6 ok = Dialog (dlg) y~w2^VN= ZMy0iQ@ If ok=0 Then 'cancel button was pressed mVg-z~44T Print "Execution cancelled." X#j-Ld{j End rP>iPDf End If n$g g$< B?'`\q)UL 'Assign accommodation and pupil diameter & use defaults if field left empty K4YpE}]u If dlg.TextBox1 = "" Then 2--"@@ A = 0 'Default accommodation ya0L8`q Else %| }obiV) A = CDbl(dlg.TextBox1) ;t{Ew+s End If ^6bU4bA Q"n*`#Yt' If dlg.TextBox2 = "" Then @tWyc%t pupilDiam = 4 'Default pupil diameter OW-[#r
Else X}Bo[YoY$ pupilDiam = CDbl(dlg.TextBox2) :3M2zV
cf End If <RS@, x+x6F Print " " {O9CYP: Print "Accommodation = " & A & " Diopters" v*SSc5gFG Print "Pupil Diameter = " & pupilDiam & " mm" ,4zwd@&O tT'*Uu5 ' Calculate new parameters with accommodation zs<W>gBq taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness %Sr/'7 K 4n @}X-) Rant = 12.0 - 0.4*A 'Radius of anterior lens ;,![Lar5L CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens o?$kcI4 jFY6}WY)}7 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens (lq7 ct CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens kRo
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@ m=<Tylv tlens = 3.767 + 0.04*A 'Lens thickness &^3KF0\Q ="<5+G nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction !
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dG-t(k 'Adjust parameters to account for accommodation kwU~kcM FtXd6)_S '************************************************************************* _-eF
&D 'Aqueous thickness (Position of Lens) 8d|omqe~P '************************************************************************* wDswK "T eID = FindFullName( "Geometry.Arizona Eye.Lens" ) eL3HX _2( GetCustomElement eID, entity -.-je"E WJbdsPs parID = FindFullName( "Geometry.Arizona Eye" ) 64;F g/t kY*3)KCp ' Delete any shift(s) in z ]#=43 count = 0 M>W-lp^3 While GetOperationCount(eID)>count >Y=HP&A< GetOperation eID, count, op /HbxY If op.Type="ShiftZ" Then ]L#6'|W DeleteOperation eID,count c6FKpdn% count=count-1 ~L $B]\/A5 End If ^j&'2n@9a count=count+1 :9un6A9JS Wend Rj 2N+59rg lc9aDt 'Set new shift in 0vOt.LC/S op.Type = "ShiftZ" B7r={P!0 op.val1 = taq r \+&{EEG op.parent = parID eQ_dO]Q AddOperation eID, op 8}9|hT;
Print "Set aqueous humor thickness = " & taq-0.55 q}gj.@Q" y57]q#k '************************************************************************* [5K&J-W 'Radius and conic constant of anterior lens !T;*F%G9 '************************************************************************* 4np,"^c eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) e+jp03m\W GetConic eID, entity, curv, conic "Y0:Y?Vz" kx,9n) SetConic eID, entity, 1/Rant, CCant i(R&Q;{E^ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 9l).L L *#+e_)d '************************************************************************* (qd $wv^h 'Radius and conic constant of posterior lens ?w'a^+H '************************************************************************* tdZ,sHY6 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) \`?#V xz GetConic eID, entity, curv, conic 8m,PsUp7 62lG,y_L SetConic eID, entity, 1/Rpost, CCpost N2:};a[ui5 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost fFP>$ YT7,=k _ '************************************************************************* Sh'>5z2 'Lens thickness (Position of posterior lens surface) Ei!t#'*D< '************************************************************************* lrSdFJ% + E8\g parID = FindFullName( "Geometry.Arizona Eye.Lens" ) `k y>M- sVP[7&vr~ ' Delete any z-shift(s) 3=o^Vv count = 0 `H+~LVH While GetOperationCount(eID)>count S~jl%] GetOperation eID, count, op #hL<9j If op.Type="ShiftZ" Then ,Q|[Yr DeleteOperation eID,count KV1zx(WI count=count-1 w?_y;&sbR End If 1(!w xJ count=count+1 +g36,!q Wend 1Xy{&Ut\ :NB|r 'Set new z-shift T&Dt;CSF op.Type = "ShiftZ" Z}bUvr XP op.val1 = tlens c\GJfsVk op.parent = parID vd7%#sHH& AddOperation eID, op (?MRbX]@ Print "Set lens thickness = " & tlens *&p `8: "=)i'x"0" '************************************************************************* -$Bom 'Lens index of refraction d{_tOj$ '************************************************************************* nLK%5C eID = FindMaterial( "Lens" ) 5G.A\`u% GetModelMaterial eID, mat N<wy"N{iS &sbA:xZBA mat.Nd = nlens fsc^8 SetModelMaterial eID, mat 0gY,[aQ2 Print "Set lens index of refraction = " & nlens n]&/?6} :@LFNcWE '************************************************************************* B ;Zsp 'Pupil diameter s_Y1rD*B '************************************************************************* Xh==F: eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" )
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fmT Hb&-pR@e\? 'Adjust pupil diameter (trimming volume inner hole) 0gNwC~IA8 xLht6%o* SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" |a@$KF$ s=`1wkh0 ' Adjust pupil location to just in front of the lens gE8=#%1< parID = FindFullName( "Geometry.Arizona Eye" ) :nki6Rkowt eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) $LUNA. count = 0 $q#|B3N% While GetOperationCount(eID)>count rg
U$&O GetOperation eID, count, op ?_9cFo59: If op.Type="ShiftZ" Then 7aTo!T DeleteOperation eID,count c_b^t09 count=count-1 G
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Cv-zm count=count+1 CL/8p; Wend u?[P@_i< op.Type = "ShiftZ" xQs2) op.val1 = taq-0.01 .E:QZH' M op.parent = parID v ?@Ys+V AddOperation eID, op ^T\JFzV *LJN2; Print "Set pupil diameter = " & pupilDiam )W9$_<Z & i|x2;
v 'Update AZ Eye subassembly Description ~ar8e eID = FindFullName( "Geometry.Arizona Eye" ) "El$Sat` GetEntity eID, entity <~# ZtD$G entity.Description = "Accommodation = " & A & "D" #p~tkQ:'1 SetEntity eID, entity W&`_cGoP l= 5kd.{ Update q[]EVs0$ew Print "DONE!" d|Wpub _[h1SAJ End Sub #tG/{R 2&fIF}vk>m 如果屈光度是4,光瞳直径是4,则会输出如下数据: -[OGZP`8 N,|:=gD_ Accommodation = 4 Diopters "PGEiLY Pupil Diameter = 4 mm %Bg}
a Set aqueous humor thickness = 2.81 Bt|S!tEy Set anterior lens radius = 10.4 and conic constant = -2.375869 ry}CND(nB Set posterior lens radius = -4.424557 and conic constant = -3.081019 !pl< Set lens thickness = 3.927 B]]_rl, Set lens index of refraction = 1.42672 5o\yhYS: Set pupil diameter = 4 ~]?Q'ER DONE! ^.jIus5 YhFB*D; (文章来源:讯技光电)
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