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简介 v=?2S Log|%P\ 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。 PXk?aJ l"+Jc1\ X 模型 \6!W05[ Q q3P+9/6 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。 <q2?S 3n;K!L%zMT Table 1. AZ眼睛模型的定义 z=Cr7- 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. l.+yn91%> jZ*WN|FK? 光源 BS1Ap kg97S 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。 j\&pej I]`-|Q E .qv'6G 图1. 光源和提示信息使用 ,5Vt]#F5@ 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。 gl%`qf6:O 8|^CK|m6* 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。 s Be7"^ EnVuD
9 图2. 字母F光源的设定方法光 {KL5GowH 3'`dFY, 图3. 字母F在视网膜上位置点列图 2?q(cpsN 视网膜的散射 s>n(`?@L F7*wQ{~ 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。 Kg\R+i@#< b;cMl' zZ-\a[F 图4. 视网膜朗伯散射设定 <n"C, 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。 ` uCI Xb 4,p;Km& Fr2N[\>s 图5. 视网膜重点采样规格设定 Cfu=u *u 脚本 V^s0fWa <@v]H@E 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: )?! [}t 5e8AmY8; 图6. 用户对话框的创建与编辑 q8P.,%
图7. 用户对话框编辑器 [{u(C!7L` 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。 [^YA=Khu 余下的脚本计算与屈光度有关的所有参数。 SkQswH w f.T3 分析 BqK(DH^9N ^Q<mV*~ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 m"eteA,"k_ kS5_
图7. 字母F在视网膜上颜色分析 KJn!Ap 脚本代码 O`1! ,MPB/j^o5! Option Explicit 'Remove this to enable non-dimensioned variables to be used. (.Y/ 26?W
nu60 Dim entity As T_ENTITY I{'f|+1 Dim op As T_OPERATION xgu `Q`~ Dim mat As T_MODELMATERIAL >R,'5:Rw Dim A As Double I?#85l{> Dim pupilDiam As Double n"Veem[_4g Dim eID As Long Fh|#u:n Dim parID As Long ] ]U<UJ Dim count As Integer Bh`N[\r Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double PXoz*)tk Dim tlens As Double, nlens As Double X!hIwi A,t Dim curv As Double, conic As Double y;cUl, :v Dim ok As Long B_`y|sn 6Q&r0>^{ Sub Main hOv={: qVqRf.-\ '用户输入对话框 Vgb *% I Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 (:V>Hjt TextBox 220,21,40,21,.TextBox1 'default: 0 $q?$]k|M` Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 e1myH6$W OKButton 40,91,90,21 Psur a$: CancelButton 190,91,90,21 p^kUs0$GS Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 6d[_G$'nk TextBox 220,49,40,21,.TextBox2 'default: 4 620%Z* End Dialog MB
ju![n Dim dlg As UserDialog bu7'oB~:V^ Am0{8
' ok = Dialog (dlg) 'nQVj mbRqJT>@ If ok=0 Then 'cancel button was pressed n]_[NR) i Print "Execution cancelled." 1LJuCI=~ End tY${M^^<J End If `vG,}Pt] -~[9U, 'Assign accommodation and pupil diameter & use defaults if field left empty ,C.:;Ime({ If dlg.TextBox1 = "" Then @oF$LMD A = 0 'Default accommodation 9fnA Else ]?1Y
e8>Y< A = CDbl(dlg.TextBox1) o;a:Dd End If cq&*. c}*2$1 If dlg.TextBox2 = "" Then GDhE[of pupilDiam = 4 'Default pupil diameter `i) 2nNJ" Else mffn//QS pupilDiam = CDbl(dlg.TextBox2) B&+`)E{KB End If EFuvp8^y >h2%[j= Print " " HmfG$Z Print "Accommodation = " & A & " Diopters" 87%*+n:?* Print "Pupil Diameter = " & pupilDiam & " mm" .#u_#=g? L9Z;:``p ' Calculate new parameters with accommodation |{*}| taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness OH^N" L jN-vY<?h] Rant = 12.0 - 0.4*A 'Radius of anterior lens {qW~"z*
CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens :WI.LKlo~ > oA?6x Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Om'+]BBN CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens [ xOzzp4 bPD`+:A_ tlens = 3.767 + 0.04*A 'Lens thickness cfox7FmW tkQH\5 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction P1b'% jV#ahNq; 'Adjust parameters to account for accommodation 8zLY6@ 9][(Iu]h7 '************************************************************************* M<SdPC(+ 'Aqueous thickness (Position of Lens) i&njqK!wS '************************************************************************* >&g}7d% eID = FindFullName( "Geometry.Arizona Eye.Lens" ) )15Z#`x GetCustomElement eID, entity f)c~cJz<q 9Suu-A parID = FindFullName( "Geometry.Arizona Eye" ) 4Wy<?O2 j*e6vX ' Delete any shift(s) in z MS(JR count = 0 ~^u16z, While GetOperationCount(eID)>count [S.ZJUns GetOperation eID, count, op 9jN)I(^D6 If op.Type="ShiftZ" Then nJRS.xs DeleteOperation eID,count J$4wL
F3 count=count-1 Tmh(=
TB' End If "G-1>:
count=count+1 'Y$R~e^Y? Wend 9_\'LJ _,;j7%j 'Set new shift in
:Ih|en^w op.Type = "ShiftZ" A^ _a3$,0 op.val1 = taq ,D\GGRw op.parent = parID %}86D[PF AddOperation eID, op M3p Print "Set aqueous humor thickness = " & taq-0.55 >FhK#*Pa ELh8ltLY '************************************************************************* 2<&Bw2 'Radius and conic constant of anterior lens WwC 5!kZ '************************************************************************* UA[,2MBp eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) L,d
LE-L GetConic eID, entity, curv, conic 2&+#Vsm`V V`adWXu SetConic eID, entity, 1/Rant, CCant $^&ig Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant yCJ Fo as=m`DqOh '************************************************************************* t9&cE:n 'Radius and conic constant of posterior lens zkTp`>9R '************************************************************************* #j@71]GI eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) /h v4x9 GetConic eID, entity, curv, conic h25G/` aNyvNEV3C SetConic eID, entity, 1/Rpost, CCpost kc/{[ME Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost \%sVHt`c @fuM)B1" '************************************************************************* :K\mN/ x 'Lens thickness (Position of posterior lens surface) o!:8nXw '************************************************************************* K1V#cB
WO 9]t[J_YM parID = FindFullName( "Geometry.Arizona Eye.Lens" ) A2}Rl%+X]6 "NRDNqj( ' Delete any z-shift(s) <foCb%$(? count = 0 0!z@2[Pe66 While GetOperationCount(eID)>count Bl9jkq
] GetOperation eID, count, op qO`)F8 If op.Type="ShiftZ" Then +0),xu DeleteOperation eID,count :V2bS count=count-1 kNu'AT#3| End If O]f/r,4@ count=count+1 D>Gt]s Wend \A`hj~ ExHKw~y9
'Set new z-shift .I}:m%zv op.Type = "ShiftZ" sH[
-W- op.val1 = tlens _C\[DR0n op.parent = parID /6O??6g AddOperation eID, op yL;M"L Print "Set lens thickness = " & tlens 56l@a{ v(OBXa9 '************************************************************************* l!#m&'16" 'Lens index of refraction 8 6f2'o+ '************************************************************************* PSawMPw eID = FindMaterial( "Lens" ) nA?Hxos GetModelMaterial eID, mat L6>pGx s4_/&h mat.Nd = nlens 8A{_GH{: SetModelMaterial eID, mat cI]WrI2CQa Print "Set lens index of refraction = " & nlens eMRar<)+#* c*d9'}E '************************************************************************* _2b tfY1U 'Pupil diameter $,xnU.n '************************************************************************* Sx
eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) uP\lCqK, Bx[rC 'Adjust pupil diameter (trimming volume inner hole) 2iu_pjj b;|55Y SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" &rDM<pO #- Y^%T}yTtq ' Adjust pupil location to just in front of the lens y/V%&.$o= parID = FindFullName( "Geometry.Arizona Eye" ) g+-;J+X8 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 7FN<iI&7\ count = 0 ,Ma.V\T[ While GetOperationCount(eID)>count 1Y_w5dU GetOperation eID, count, op X0{/ydGF8 If op.Type="ShiftZ" Then WWT",gio DeleteOperation eID,count c`x7u}C count=count-1 Ax oD8| End If H"2uxhdLK3 count=count+1 %LXM+<N8 Wend HE<1v@jW op.Type = "ShiftZ" yGg,$WM op.val1 = taq-0.01 DoC(Z)o op.parent = parID 9;yn}\N ` AddOperation eID, op )'l*Tl V8=Y@T, Print "Set pupil diameter = " & pupilDiam -st7_3 1B*WfP~ 'Update AZ Eye subassembly Description kF7(f|* eID = FindFullName( "Geometry.Arizona Eye" ) Z -%(~ GetEntity eID, entity bbxLBD' entity.Description = "Accommodation = " & A & "D" PiFD^w SetEntity eID, entity E^w:KC2@ y80ykGPT\& Update R];Oxe Print "DONE!" 1e xl0]- Bh&Ew
End Sub \yrisp#` X\p,%hk \ 如果屈光度是4,光瞳直径是4,则会输出如下数据: *9ywXm&? @{h?+
d Accommodation = 4 Diopters ch5s<x#CE Pupil Diameter = 4 mm j?b\+rr Set aqueous humor thickness = 2.81 3M5#4n\v$ Set anterior lens radius = 10.4 and conic constant = -2.375869 L]a`"CH:a$ Set posterior lens radius = -4.424557 and conic constant = -3.081019 OT
%nr zP Set lens thickness = 3.927 8#R?]Uwq Set lens index of refraction = 1.42672 Gf8s?l Set pupil diameter = 4 'H9=J*9oG DONE! _<ut)G^9
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