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简介 %a'Nf/9=: E}YJGFB7" 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。 ~!t# M2Sk l0
Eh? 模型 BXzn-S %ZKP d8 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。 2aDjt{7P GBh$nVn$ Table 1. AZ眼睛模型的定义 Rhfx 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. MAv-`8@| 80'!XKSP 光源 b6]MJ0do vzXfJP 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。 >'/KOK" ?W27
h XABB6J] 图1. 光源和提示信息使用 L
`\>_ 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。 2#i*'. uQ(C,f[6p 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。 O
,9,=2j VR'R7 图2. 字母F光源的设定方法光 EF8~rKO3 N I*x):bx 图3. 字母F在视网膜上位置点列图 w3<%wN>tE 视网膜的散射 S;I>W&U o/J2BZ<_< 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。 $2kZM4 (#)-IdXXO< {:%A
图4. 视网膜朗伯散射设定 ,f[`C-\Q% 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。 \]Nt-3|`0 ~MpcVI_K 3g{T+c* 图5. 视网膜重点采样规格设定 ~43T$^<w; 脚本 U+4W9zhwo cns~)j~ 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: _rN1(=J F7"v}K]X 图6. 用户对话框的创建与编辑 ES>iM)M 图7. 用户对话框编辑器 (K74Qg 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 ]lgI Q;r 余下的脚本计算与屈光度有关的所有参数。 !vY5X2?tr, Z'<I
Is:J 分析 |<aF)S4 &*\-4)Tf 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 bCSgdK +lNAog 图7. 字母F在视网膜上颜色分析 (p1}i::Y8 脚本代码 Y+ Qm. d%(4s~y Option Explicit 'Remove this to enable non-dimensioned variables to be used. P.t0o~hoK; vNn$dc Dim entity As T_ENTITY k@Q>(` Dim op As T_OPERATION QqdVN3#1z Dim mat As T_MODELMATERIAL I;5:jT ` Dim A As Double 9x]yu6 Dim pupilDiam As Double Ij_h #f Dim eID As Long hLo>jE
Dim parID As Long v-MrurQ4 Dim count As Integer U 6`E\?d` Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double P-LdzVt(^ Dim tlens As Double, nlens As Double gwQk
M4 Dim curv As Double, conic As Double p+y2w{{ Dim ok As Long h+ggrwg' !C>'a: Sub Main 8j^3_lD wc~k4B9" '用户输入对话框 lDf:~ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 -udKGrT+ TextBox 220,21,40,21,.TextBox1 'default: 0 ln&9WF\I Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 0XLoGQ= OKButton 40,91,90,21 )2Dm{T CancelButton 190,91,90,21 {{+woL'C Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 T/YvCbo TextBox 220,49,40,21,.TextBox2 'default: 4 .8~zgpK End Dialog G@+AB*Eu Dim dlg As UserDialog k4!z;Yq &"/IV$H ok = Dialog (dlg) c%O8h c)Ep<W<r1 If ok=0 Then 'cancel button was pressed hL(zVkYI Print "Execution cancelled." 1cvH End Xt%>XP End If slRD / 0%OV3` 'Assign accommodation and pupil diameter & use defaults if field left empty 8^U+P% If dlg.TextBox1 = "" Then Ip&Q'"HYj A = 0 'Default accommodation jC3)^E@:" Else kM o7mkV A = CDbl(dlg.TextBox1) r_EuLFM A End If TQiDbgFo |h{#r7H0 If dlg.TextBox2 = "" Then !3JYG pupilDiam = 4 'Default pupil diameter TxDzGC Else zZ})$Ny( pupilDiam = CDbl(dlg.TextBox2) ^Ss4< End If
#->#mshd4 -'F? | Print " " E2xcd#ZD Print "Accommodation = " & A & " Diopters" =0gfGwD{ Print "Pupil Diameter = " & pupilDiam & " mm" `GQ'yv k2t#O%_f ' Calculate new parameters with accommodation Kulh:d:w taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness =j$!N# L DAHQ7#qfQC Rant = 12.0 - 0.4*A 'Radius of anterior lens Lr ;PESV CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens tw?\bB "<LVA2v; Rpost = -5.224557 + 0.2*A 'Radius of posterior lens e/nc[ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens VsTa!V^~ S-D=-{@ tlens = 3.767 + 0.04*A 'Lens thickness w=K!U] " +n\0j; nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction g#b uy *]]C.t-cd 'Adjust parameters to account for accommodation /N?vVp q(YFt*(;w '************************************************************************* @c{rqa
v 'Aqueous thickness (Position of Lens) wNt-mgir-Q '************************************************************************* yccF#zU eID = FindFullName( "Geometry.Arizona Eye.Lens" ) DTi\ 4&41 GetCustomElement eID, entity Dw-i!dq #Emz9qTsce parID = FindFullName( "Geometry.Arizona Eye" ) ++ZtL\h{7 rh%-va9 ' Delete any shift(s) in z )VoQ/ch< count = 0 Pcox~U/j While GetOperationCount(eID)>count `kERM-@A GetOperation eID, count, op bo%v( If op.Type="ShiftZ" Then ( /): DeleteOperation eID,count ~3F\7%Iqc count=count-1 M(+;AS?; End If IQ3]fLb count=count+1 MG6y Wend ))z1T 8 hr)CxsPoRQ 'Set new shift in j^&{5s op.Type = "ShiftZ" |Vq&IfP op.val1 = taq h~zG*B5F op.parent = parID |'bRVqJ AddOperation eID, op f} _d`?K Print "Set aqueous humor thickness = " & taq-0.55 ; Da[jFP rt5eN:'qY '************************************************************************* i9FtS7 'Radius and conic constant of anterior lens b}OOG '************************************************************************* C1YG=! eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Nr(3!- GetConic eID, entity, curv, conic [q5N 4&q\ :a#pzEK SetConic eID, entity, 1/Rant, CCant 1G6MO Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant pPX ~pPIj2 q%Fc?d9 '************************************************************************* ^twJNm{99 'Radius and conic constant of posterior lens z%pD3J?> '************************************************************************* _=\=oC eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) `T \"B% GetConic eID, entity, curv, conic G',*"mZQ[ 0-9.u`)#yu SetConic eID, entity, 1/Rpost, CCpost l*+5WrOS Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost *~0Ko{Avc w_ sA8B '************************************************************************* %^C.e* 'Lens thickness (Position of posterior lens surface) .}V&*-ep '************************************************************************* =:;KYuTr 8%;K#,> parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 5v
uB87` ~il{6Z+#n ' Delete any z-shift(s) lv*fK count = 0 3nJd0E While GetOperationCount(eID)>count xa?#wY
b GetOperation eID, count, op ps*dO If op.Type="ShiftZ" Then s.)nS$ DeleteOperation eID,count [v!TQwMU count=count-1 sMikTwR/^ End If >(t_ count=count+1 {MaFv Wend ZPISclSA+
Q6|~ks+Y 'Set new z-shift |4F3Gu op.Type = "ShiftZ" >,JA=s op.val1 = tlens ,VM)ZK=Tr op.parent = parID Du3nK"-g AddOperation eID, op :Gdfpz-{? Print "Set lens thickness = " & tlens $YyN-C 2+Tu"oG;rB '************************************************************************* nnZ|oEF 'Lens index of refraction DjX*2O '************************************************************************* ^.d97rSm eID = FindMaterial( "Lens" ) 7fOk]Yl[ GetModelMaterial eID, mat P
K]$D[a0 x-e?94}^ mat.Nd = nlens <Y(lRM{ SetModelMaterial eID, mat G\?q{ Print "Set lens index of refraction = " & nlens bLfbzkNV\1 c
QjzI# '************************************************************************* KvM}g2" 'Pupil diameter $:YJ<HvG< '************************************************************************* B`/cKfg eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) +P&;cCV`S3 3xJ_%AD\' 'Adjust pupil diameter (trimming volume inner hole) j|u6TG =DhzV
D SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" gGiLw5o, \y-Lt!} ' Adjust pupil location to just in front of the lens 0wzq{~\{=_ parID = FindFullName( "Geometry.Arizona Eye" ) +;}XWV eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) QX*HvT count = 0 8G>;X;W While GetOperationCount(eID)>count %mhnd): GetOperation eID, count, op ' Vp6=,P If op.Type="ShiftZ" Then l"\W] 'T:r DeleteOperation eID,count ?5%|YsJP_ count=count-1 zk[%YG& End If Daa2.* count=count+1 .Jt&6N Wend SOyE$GoOsx op.Type = "ShiftZ" 3zO'=gwJ op.val1 = taq-0.01 *CA7
{2CX op.parent = parID );^]
is~ AddOperation eID, op dnby &-+T FuZ7xM, Print "Set pupil diameter = " & pupilDiam M~/%V NX y:0j$%^ 'Update AZ Eye subassembly Description {-sy,EYcw eID = FindFullName( "Geometry.Arizona Eye" ) %}U-g"I GetEntity eID, entity x+}6qfc$9k entity.Description = "Accommodation = " & A & "D" n=vW oU9 SetEntity eID, entity yTDlDOmV! `hD\u@5Tw Update G_wzUk=L Print "DONE!" C^@~ o9!DK End Sub x,\PV> hCX}* 如果屈光度是4,光瞳直径是4,则会输出如下数据: y[*Bw)F\N -ISI!EU$ Accommodation = 4 Diopters %bnDxCj" Pupil Diameter = 4 mm nj*B-M\p Set aqueous humor thickness = 2.81 eCYgi7? Set anterior lens radius = 10.4 and conic constant = -2.375869
#'Q_eBX Set posterior lens radius = -4.424557 and conic constant = -3.081019 +"!,rZ7,A Set lens thickness = 3.927 t@Qs&DZ7k Set lens index of refraction = 1.42672 _MZqH8 Set pupil diameter = 4 PrIS L[@ DONE! N#')Qz:P Hnwir!=7 ;r[@;2p*( QQ:2987619807 */Oq$3QGsV
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