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简介 HA9Nr.NqC@ Z&]+A, 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。 =,d* {m~A N+s?ZE* 模型 B221}t XiRT|%j 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。 ZcTL#OTP fATA%eA8; Table 1. AZ眼睛模型的定义 >C:"$x2"#( 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. nGv23R(?G \)otu\3/ 光源 c{,y{2c]LT 5]H))}9>d 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。 OY^n0Zof, Oj"pj:fB UbY~xs7_ 图1. 光源和提示信息使用 +f
X}O9 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。 K$<`4#i Ld\LKwo 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 qIDWl{b< s!@=rq 图2. 字母F光源的设定方法光 8<yV xTJSr2f 图3. 字母F在视网膜上位置点列图 P /c
Q1 视网膜的散射 *K+jsVDY '&-5CpDUs 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 Mhv1K|4s b(#"w[| j<ABO")v 图4. 视网膜朗伯散射设定 .'^6QST 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 ~aJW"\{ ;|>q zx nDHHYp 图5. 视网膜重点采样规格设定 7P/?wv9+n* 脚本 'v\1:zi ,7^d9v3t 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: s[G|q5n ),cQUB 图6. 用户对话框的创建与编辑 dGbU{#"3s 图7. 用户对话框编辑器 AI1@- 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 +{,N X 余下的脚本计算与屈光度有关的所有参数。 g08*}0-k pqyWv; 分析 z5XYpi_;[ Ku<b0<` 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 :y+B;qw IL~]m?'V( 图7. 字母F在视网膜上颜色分析 (3
IZ 脚本代码 `z9)YH 7?6xPKQ)H Option Explicit 'Remove this to enable non-dimensioned variables to be used. 81GQijq #4P8Rzl$/ Dim entity As T_ENTITY *Q bM*oH Dim op As T_OPERATION H$z>OS_6U Dim mat As T_MODELMATERIAL { 1+Cw?1d Dim A As Double q';&SR#"`K Dim pupilDiam As Double $|4cJ#;^L Dim eID As Long <8u>_o6 Dim parID As Long UWQtvQ
f Dim count As Integer K :1g" Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 8[8|*8xqs Dim tlens As Double, nlens As Double .)LZ`Ge3F Dim curv As Double, conic As Double YV5Yx-+3w$ Dim ok As Long v6wRME;JA fNmE,~ Sub Main 0CPxIF& \Dn&"YG7 '用户输入对话框 CQ@LmTW[ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 2>F\& TextBox 220,21,40,21,.TextBox1 'default: 0 }5Yj Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 u@<Pu@?xm OKButton 40,91,90,21 PeO] lq CancelButton 190,91,90,21 JZ `>|<W Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 cNe0x2Z$? TextBox 220,49,40,21,.TextBox2 'default: 4 P+[QI
U End Dialog b<[jaI0 Dim dlg As UserDialog 3^{8_^I hT?6sWa ok = Dialog (dlg) +T9Q_e* Vwjk[ DOL If ok=0 Then 'cancel button was pressed \ jECSV| Print "Execution cancelled." $j57LY|r End }$l8d/_$[ End If GxxDY]! +wipfL~&S 'Assign accommodation and pupil diameter & use defaults if field left empty m;dm|4L^ If dlg.TextBox1 = "" Then G3G/xC" A = 0 'Default accommodation 59.$ULQVMY Else &,J*_F<s2< A = CDbl(dlg.TextBox1) Odm#wL~E End If vB^uxdt|m _}D%iJg# If dlg.TextBox2 = "" Then bG"HD?A_ pupilDiam = 4 'Default pupil diameter >QXzMN}o Else l09Fn>wa pupilDiam = CDbl(dlg.TextBox2) )B6# A0 End If <0#^7Z 2gt+l?O<PS Print " " 7AFE-'S Print "Accommodation = " & A & " Diopters" 2Zy_5>~ Print "Pupil Diameter = " & pupilDiam & " mm" kBo;h.[l 2UiR~P]% ' Calculate new parameters with accommodation K}x_nW taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness o+NMA
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#;DI Rant = 12.0 - 0.4*A 'Radius of anterior lens ;J]25j]] CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens _pW_G1U vYdR ht\( Rpost = -5.224557 + 0.2*A 'Radius of posterior lens N>0LQ
MI CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 8!&nKy<Y >L gVj$Z tlens = 3.767 + 0.04*A 'Lens thickness Ry&q1j % #u.J
nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 3V?817&6z K/^
+eoW( 'Adjust parameters to account for accommodation <?YA,"~ e'34Pw!m '************************************************************************* =Q-k'= 6\ 'Aqueous thickness (Position of Lens) ~O{W;Cyh '************************************************************************* %t*[T eID = FindFullName( "Geometry.Arizona Eye.Lens" ) P>(P2~$Y" GetCustomElement eID, entity bHE7yv [ xST4}Mb^f parID = FindFullName( "Geometry.Arizona Eye" ) -p`L%xj\ NgVR,G|1 ' Delete any shift(s) in z ,X68xk.' count = 0 OUI6
ax\[ While GetOperationCount(eID)>count iCP~O GetOperation eID, count, op Ow@v"L;jF! If op.Type="ShiftZ" Then F)SP aC4 DeleteOperation eID,count ^]>aHz9 count=count-1 je%l dY]/@ End If m2xBS!fm count=count+1 +6l]] *H Wend 'N\&<dT> gzf-)J 'Set new shift in X`:'i?(yj op.Type = "ShiftZ" G>w+#{( op.val1 = taq T_LLJ}6M op.parent = parID +BL{@,zr AddOperation eID, op eh(<m8I Print "Set aqueous humor thickness = " & taq-0.55 dz-y}J11 )*|(i] '************************************************************************* E7nFb:zlV 'Radius and conic constant of anterior lens 8]bz(P# '************************************************************************* 6ZOy&fd,Ty eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) xq[Yg15d% GetConic eID, entity, curv, conic D."=k{r. ~Y7dH
Dn SetConic eID, entity, 1/Rant, CCant })Yv9],6 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant @0NJ{ fDh]tua '************************************************************************* X(*!2uS 'Radius and conic constant of posterior lens Y3Oz'%B '*************************************************************************
%w
) +V eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) V5p0h~PK GetConic eID, entity, curv, conic tU@zhGb 3^,QIG SetConic eID, entity, 1/Rpost, CCpost tg\|? Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost e,gyQjJR 3@<zg1.9- '************************************************************************* )OP){/ 'Lens thickness (Position of posterior lens surface) :Ht;0|[H '************************************************************************* r.yK, @Jn!0Y1_3 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) F #`=oM$5 <RXw M6G2 ' Delete any z-shift(s) &7>zURv count = 0 HrM$NRhu While GetOperationCount(eID)>count FX}Gt= GetOperation eID, count, op 2C=Q8ayvX If op.Type="ShiftZ" Then 8sOQ9 DeleteOperation eID,count *O~e
T count=count-1 G~,:2
o3 End If vXE0%QE'Q count=count+1 iE].&>w Wend b:W-l? j;0vAf 'Set new z-shift sG7u}r op.Type = "ShiftZ" Cu;5RSr2Z op.val1 = tlens 78 f$6J q op.parent = parID !l@zT}i?? AddOperation eID, op jgv`>o%<W Print "Set lens thickness = " & tlens 9=`W p6Gmn i)a%!1Ar '************************************************************************* L%"LlSg 'Lens index of refraction YJV% a '************************************************************************* dT|vYK}\ eID = FindMaterial( "Lens" ) |{>ER,<- GetModelMaterial eID, mat yx38g
ca zUJZ`seF mat.Nd = nlens h^UKT`9vt SetModelMaterial eID, mat IxZb$h[ Print "Set lens index of refraction = " & nlens C1kYl0zR[ GL$De,V '************************************************************************* b aV>N[F& 'Pupil diameter Fh$slow4! '************************************************************************* }_9,w;M$ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) =FP0\cQ. co8"sz0(U 'Adjust pupil diameter (trimming volume inner hole) as yZe 4<dcB@v SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" >Gml4vGK i%m"@7.kk ' Adjust pupil location to just in front of the lens k <iTjI*N parID = FindFullName( "Geometry.Arizona Eye" ) m0n)dje eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) T;TA7{B count = 0 Z<[<n0o1 While GetOperationCount(eID)>count bNs4 5hDP GetOperation eID, count, op <7SpEVQ If op.Type="ShiftZ" Then x!LQxoNF DeleteOperation eID,count a8k; (/ count=count-1 `{k"8#4:qA End If Hb} X-6N count=count+1 W!Hm~9fz Wend {9Y+.46S op.Type = "ShiftZ" Dl(3wgA op.val1 = taq-0.01 @hQlrq5c op.parent = parID ~c^>54 AddOperation eID, op XR2~Q)@ MTg:dR_ Print "Set pupil diameter = " & pupilDiam 9vUO*D 'm1N/)F 'Update AZ Eye subassembly Description ^z1&8k"[^ eID = FindFullName( "Geometry.Arizona Eye" ) X+L) -d GetEntity eID, entity DI+]D~N entity.Description = "Accommodation = " & A & "D" 3$.deYa$R SetEntity eID, entity ^k5ll=} |F,R&<2 Update {"oxJ`z4 Print "DONE!" An;MVA M FTkqbc End Sub U*Ge<(v$ drzL.@h| 如果屈光度是4,光瞳直径是4,则会输出如下数据: \$0F-=w`8 D]w!2k%V Accommodation = 4 Diopters mMsTyM-f Pupil Diameter = 4 mm Bjk]ZU0T Set aqueous humor thickness = 2.81 Tc8un. Set anterior lens radius = 10.4 and conic constant = -2.375869 kB?al#` Set posterior lens radius = -4.424557 and conic constant = -3.081019 w0w G-R ? Set lens thickness = 3.927 m'P1BLk Set lens index of refraction = 1.42672 3vcO!6Z5 Set pupil diameter = 4 O+g3X5f+ DONE! rSXh;\MfB4
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