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wk\[I`; 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。 iS{)Tll}& :]x)lP(3E 模型 REa%kU Z"P{/~HG 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。 7+ c?eH Table 1. AZ眼睛模型的定义 nC z[#t {T$;BoR#O
在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. Cnc77EUD z*FlZLHY 光源 4>(?R[:p) "?]5"lNC| 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 a].Bn#AH!C !0cfz5t 图1. 光源和提示信息使用 S_^ "$j 9,,1\0-T* 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。 %o~zsIl c45Mv_ 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。 _ TUw0:& 图2. 字母F光源的设定方法光 aPWFb.JO4 mv5!fp_*7 图3. 字母F在视网膜上位置点列图 U5Rzfm4 )p&xpB( 视网膜的散射 D0uf=BbS ,u$$w 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。 r,F'Jd5 L/V3sSt 图4. 视网膜朗伯散射设定 7%JXVP}A DD;PmIW 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。 ZgN*m\l B^eea [ 图5. 视网膜重点采样规格设定 X]`\NNx u6I# D
_ 脚本 vhT9#) HI rsrv1A=t? 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: 5o&L|7] 图6. 用户对话框的创建与编辑 `,TPd ~#~ 图7. 用户对话框编辑器 $U!w#|& Yh"R# 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 Ey)ox$ 余下的脚本计算与屈光度有关的所有参数。 w:pc5N>we0 l46O=?usDX 分析 T_pE 'U%[ G$ip Wi 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ; <3w ,r 图7. 字母F在视网膜上颜色分析 KPKby?qQ^ WC}mt%H*O 脚本代码 (Iu5QLE @Yy=HV Option Explicit 'Remove this to enable non-dimensioned variables to be used. 7v1}8Uk b@nbXm]Z Dim entity As T_ENTITY ?jy^WF` Dim op As T_OPERATION l~!#<=. Dim mat As T_MODELMATERIAL 0!xD+IA!8 Dim A As Double ~d28"p.7 Dim pupilDiam As Double V5R``Tp Dim eID As Long D,]m7yFT Dim parID As Long QiY7m<3 Dim count As Integer aNfgSo05@n Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 0p![&O Dim tlens As Double, nlens As Double M=@U]1n*c Dim curv As Double, conic As Double ^k~{6S, Dim ok As Long T7&itgEYG/ ?DM-C5$ Sub Main :N(L7&< &:w{[H$- '用户输入对话框 (,HAOs
Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ("wPkm^ TextBox 220,21,40,21,.TextBox1 'default: 0 jUdW o}/ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 CfA
F.H OKButton 40,91,90,21 I5PaY.i CancelButton 190,91,90,21 ;v#~o* Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 'Zk&AD ~ TextBox 220,49,40,21,.TextBox2 'default: 4 /9W-;l{=z End Dialog d7P|
x Dim dlg As UserDialog Yr!<O&= o"K{^ L~u ok = Dialog (dlg) Kq{9:G @^/JNtbH! If ok=0 Then 'cancel button was pressed yP~D." Print "Execution cancelled." {U7j End IB(5 &u. End If u]CW5snz QfRt3\^` 'Assign accommodation and pupil diameter & use defaults if field left empty *T*MLD]Q If dlg.TextBox1 = "" Then >e"1a/2%>& A = 0 'Default accommodation \/lH]u\x Else {H"xC~. A = CDbl(dlg.TextBox1) L<5go\!bV End If F71.%p7C8" c7'I'~ If dlg.TextBox2 = "" Then ln#Lx&r;| pupilDiam = 4 'Default pupil diameter MhHygZT[} Else Z6
(;~"Em pupilDiam = CDbl(dlg.TextBox2) MZ6?s(mkx End If EVrOu"" |Ax~zk; Print " " T<?JL.8 g_ Print "Accommodation = " & A & " Diopters" !dStl:B Print "Pupil Diameter = " & pupilDiam & " mm" !Vv$ !&ac}uD^g ' Calculate new parameters with accommodation EivZI<<a taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness {>>f5o3 5k<qJ9 Rant = 12.0 - 0.4*A 'Radius of anterior lens ^~8l|d_ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens @R(6w{h9 \} P} H Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ``K.4sG CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens dy#dug6j xsV(xk4 tlens = 3.767 + 0.04*A 'Lens thickness &3'II:x( bY&s$Ry3" nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction mf^(Tq[ mS0*%[S { 'Adjust parameters to account for accommodation KKl8tI\u~ J*A<F'^F1 '************************************************************************* @ 4j#X 'Aqueous thickness (Position of Lens) iVREkZ2SC '************************************************************************* }"2
0: eID = FindFullName( "Geometry.Arizona Eye.Lens" ) > & \QLo[5 GetCustomElement eID, entity `4gm'C ;:a7rN"( parID = FindFullName( "Geometry.Arizona Eye" ) r8}GiP0| }I9\=jT ' Delete any shift(s) in z ^t?P32GJ count = 0 tA Pqbi$a While GetOperationCount(eID)>count a$l/N{<. GetOperation eID, count, op "#qyX[\ If op.Type="ShiftZ" Then hd8:| _ DeleteOperation eID,count Cj31' count=count-1 -_4U+Cfmtl End If {xMY2I++ count=count+1 hF.9\X] Wend Ti=~y cwi KaZ$!JfT 'Set new shift in th2a'y=0 op.Type = "ShiftZ" #xNLr op.val1 = taq Wx;:_F7'\ op.parent = parID C3:4V2<_ AddOperation eID, op .UU BAyjm Print "Set aqueous humor thickness = " & taq-0.55 &w- QMjM> &zynfj#o '************************************************************************* @c9VCG D 'Radius and conic constant of anterior lens (B}+uI{ '************************************************************************* (sq4 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) CZS{^6Ye GetConic eID, entity, curv, conic l+*^P'0u w q% 4'( SetConic eID, entity, 1/Rant, CCant fj[B,ua Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 2n2{Oy>L Sdy\s5 '************************************************************************* NgaX&m` 'Radius and conic constant of posterior lens pkWzaf '************************************************************************* `Jq
?+W eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) -y1%c^36_J GetConic eID, entity, curv, conic a<B[~J 4i l23_K7 SetConic eID, entity, 1/Rpost, CCpost +FP*RNM Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost k+f!)7_ #Wey)DI '************************************************************************* 7q<I7Wt 'Lens thickness (Position of posterior lens surface) }:5AB93( '************************************************************************* FYFP6ti !=;^Grv> parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 4=9To|U* ): ' Delete any z-shift(s) U+3,(O count = 0 <]r.wn=}M While GetOperationCount(eID)>count R%Gh4y\nF GetOperation eID, count, op :[3{-.c If op.Type="ShiftZ" Then TPZZln'3 DeleteOperation eID,count 5P9hm[ count=count-1 Xm8
1axyf End If N 3i,_ count=count+1 OW<i"?0 Wend {'4h.PB+r 0K <@?cI 'Set new z-shift RY2`v
pv op.Type = "ShiftZ" g4cmYg3 op.val1 = tlens 'j6PL;~c op.parent = parID ~@S5*(&8 AddOperation eID, op f^@`[MJj1C Print "Set lens thickness = " & tlens O,>1GKw"\ I2hX;pk, '************************************************************************* (Hb
i+IHV 'Lens index of refraction W'hE, '************************************************************************* /-TJtR4> eID = FindMaterial( "Lens" ) M:z)uLDw GetModelMaterial eID, mat 9JV(}v5[ X3vTyIsn mat.Nd = nlens /-Y*V*E SetModelMaterial eID, mat /Y_F"GQ Print "Set lens index of refraction = " & nlens ,'?%z>RZm 3/+9# '************************************************************************* n*(Vf'k 'Pupil diameter {y0#(8-& '************************************************************************* Mt (wy%{zK eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ^B8%Re% /.l8Jb4 'Adjust pupil diameter (trimming volume inner hole) xWWfts1t O?/\hZ"&c SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" c+c3C8s*8 -(V]knIF ' Adjust pupil location to just in front of the lens -} \g[| parID = FindFullName( "Geometry.Arizona Eye" ) 6*u#^">,< eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) r e.chQ6 count = 0 D ksSD While GetOperationCount(eID)>count _IBIx\F GetOperation eID, count, op 6 "U&i9 If op.Type="ShiftZ" Then TkXD#%nFY DeleteOperation eID,count lp3 A B count=count-1 R
h zf.kp End If 'yxRz5 count=count+1 H6X]D"Y, Wend I9O!CQCTt op.Type = "ShiftZ" VRurn>y0 op.val1 = taq-0.01 FZ'|z8Dm op.parent = parID (NK$2A/p AddOperation eID, op +a_eNl, F#>?i} Print "Set pupil diameter = " & pupilDiam 0(\ybppx g
N76 'Update AZ Eye subassembly Description k_?xiOSh eID = FindFullName( "Geometry.Arizona Eye" ) ;S5*n:d GetEntity eID, entity j3jf:7 /\ entity.Description = "Accommodation = " & A & "D" :=WiT_M SetEntity eID, entity E:/G!1 ImO\X`{ Update [<`K%1GQ Print "DONE!" H~UxVQLPp {)nm
{IV, End Sub HTiqErD2_ Q/&H3N 如果屈光度是4,光瞳直径是4,则会输出如下数据: Y^$^B, HEH Tj,T Accommodation = 4 Diopters yo]!Zn Pupil Diameter = 4 mm m"*j J.MX Set aqueous humor thickness = 2.81 -02cI}e Set anterior lens radius = 10.4 and conic constant = -2.375869 yk OJhd3 Set posterior lens radius = -4.424557 and conic constant = -3.081019 m`CcU`s Set lens thickness = 3.927 +InAK>NZ' Set lens index of refraction = 1.42672 GADb Xp3 Set pupil diameter = 4 p.^glz >B DONE! |