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简介 G.2ij%Zz ,Vz
1l_7 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。 *B7+rd Mp=2}d%P 模型 jseyT#2
2BLcun 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。 >#}MDwKZD V`OeJVe Table 1. AZ眼睛模型的定义 Vvuw gJX 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. Mg
H,"G hLyD#XCFA 光源 >[ r
TUn; s;'XX}Y 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。 T+z]ztO YqsN#E3pf ueO&% 图1. 光源和提示信息使用 ViV"+b#gu 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。 BJI}gm2y +u%^YBr 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。 7XKPC+)1ya ,?Pn-aC+ 图2. 字母F光源的设定方法光 +I$c+WfU b #U
nE 图3. 字母F在视网膜上位置点列图 v)|[= 视网膜的散射 D}|PBR
zzsQfI# 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 FLI\SF< >
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<in/ V[-4cu,Ph^ 图4. 视网膜朗伯散射设定 JcsJfTI 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 +0U{CmH
%{\|/#>: 0HUSN_3F 图5. 视网膜重点采样规格设定 aC0[ OmbG 脚本 >$=-0?. :'aT4 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: cstSLXD o:ki IZ] 图6. 用户对话框的创建与编辑 {9sA'5 图7. 用户对话框编辑器 Jy)E!{#x 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。 6e,|HV 余下的脚本计算与屈光度有关的所有参数。 :34#z.O ^R* _Q,o# 分析 L/1zG/@ 0z)
8i P 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。
,lX5-1H Rk2V[R.`S 图7. 字母F在视网膜上颜色分析 ji(W+tQ2Y' 脚本代码 &V7@ TZ QjH;'OVt Option Explicit 'Remove this to enable non-dimensioned variables to be used. :TU;%@7 ,]?Xf> Dim entity As T_ENTITY ,L#Qy>MOb Dim op As T_OPERATION sBP.P7u Dim mat As T_MODELMATERIAL \u@4eBAV Dim A As Double CW*Kdt Dim pupilDiam As Double [:gPp)f, Dim eID As Long ;-p1z%
u Dim parID As Long xW@y=l Cu Dim count As Integer yM$@*od Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double DQ7+ Dim tlens As Double, nlens As Double O]{3aMs!Y Dim curv As Double, conic As Double S,Q!Xb@ Dim ok As Long "&jA
CI f8`K8Y]4 Sub Main QC7Ceeh]4 R;,&s!\< '用户输入对话框 WP, Ll\K)7 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _DPWp,k<~ TextBox 220,21,40,21,.TextBox1 'default: 0 n1OxT"tD Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ;,T3C:S? OKButton 40,91,90,21 c$?(zt; CancelButton 190,91,90,21 VW^6qf/, Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Cz=HxU80J TextBox 220,49,40,21,.TextBox2 'default: 4 zfvMH"1
End Dialog X._skq Dim dlg As UserDialog A4RA5N/} D<}z7W- ok = Dialog (dlg) oBZ\mk L pME17 af If ok=0 Then 'cancel button was pressed j8p</gd Print "Execution cancelled." <a/TDW End U ObI&*2 End If #/fh_S'Z 6*`KC)a 'Assign accommodation and pupil diameter & use defaults if field left empty ~B!O
X If dlg.TextBox1 = "" Then d-e6hI4b A = 0 'Default accommodation MfNxd
6w Else *a_U2}N A = CDbl(dlg.TextBox1) -2NXQ+m ; End If SMHQo/c r e~#;ux If dlg.TextBox2 = "" Then 2=Sv# pupilDiam = 4 'Default pupil diameter eF]`?AeWQ Else H&K(,4u^ pupilDiam = CDbl(dlg.TextBox2) S/YT
V End If g)7~vm2/, qYD$_a Print " " lJaR,, Print "Accommodation = " & A & " Diopters" HUF],[N Print "Pupil Diameter = " & pupilDiam & " mm" u{#}Lo>B # %@/"BF;r ' Calculate new parameters with accommodation zrt \]h+ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 2$=U#!OtU Q]j[+e Rant = 12.0 - 0.4*A 'Radius of anterior lens L%G/%*7;c CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ,(d\! T/]' rG7E[kii Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ? yL3XB> CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens }DH3_M! p;;4b@ tlens = 3.767 + 0.04*A 'Lens thickness a=(D`lQ8 Z(Styn/x nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction L $R"?O7 l=EnK"aU 'Adjust parameters to account for accommodation aYTVYg 8 xfn$ '************************************************************************* KGsS2 'Aqueous thickness (Position of Lens) 50,`=Z '************************************************************************* k'O^HMAn! eID = FindFullName( "Geometry.Arizona Eye.Lens" ) \o-9~C\c* GetCustomElement eID, entity a%\6L !O;su~7
parID = FindFullName( "Geometry.Arizona Eye" ) ]=X6*
E*/E -Ky<P<@ezm ' Delete any shift(s) in z %6A."sePO count = 0 Po(Y',xI[ While GetOperationCount(eID)>count x`7Ch3`4} GetOperation eID, count, op 3y&N}'R(F If op.Type="ShiftZ" Then X`-7: !+ DeleteOperation eID,count R]dN-'U count=count-1 %:yp>nm End If w'Y(doY, count=count+1 ~_l@
_P5yz Wend 12 {F X#;n Gq)5 'Set new shift in 9jwcO)p^ op.Type = "ShiftZ" c@SNbY4}% op.val1 = taq '6^+|1 op.parent = parID Z;=h= AddOperation eID, op Zv[D{ Print "Set aqueous humor thickness = " & taq-0.55 ]~a;tF>Fw
z@bq*':~J '************************************************************************* qq
Vjx?bKe 'Radius and conic constant of anterior lens \[\4= !v '************************************************************************* Iax-~{B3AY eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) @wvgMu GetConic eID, entity, curv, conic F747K);_ d_v]mfUF SetConic eID, entity, 1/Rant, CCant 6XP>qI,AJ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant w\V1pu^6@ 0o2*X|i( '************************************************************************* s<z`<^hRe 'Radius and conic constant of posterior lens ON(OYXj '************************************************************************* Dx)>`yJk$; eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) GGM|B}U p GetConic eID, entity, curv, conic <K
g=?wb XAb%V' SetConic eID, entity, 1/Rpost, CCpost ]|JQH Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost DB~3(r?K ^"dVz. '************************************************************************* V8w7U:K 'Lens thickness (Position of posterior lens surface)
%wFz4: '************************************************************************* R"wBDWs uOQ!av2"Rf parID = FindFullName( "Geometry.Arizona Eye.Lens" ) *|gY7Av* kC,=E9)O ' Delete any z-shift(s) J#>)+ count = 0 O'Mo/
u1- While GetOperationCount(eID)>count 1'NJ[
C` GetOperation eID, count, op }}Zwdpo If op.Type="ShiftZ" Then ;\]&k DeleteOperation eID,count bUzo> fm_ count=count-1 1 5heLnei End If pD@:]VP count=count+1 TdU'L:<4l Wend 0dTHF})m @$Xl*WT7 'Set new z-shift "|Ke/0rGB op.Type = "ShiftZ" /IxoS op.val1 = tlens cv{icz,%w op.parent = parID f7lt|.p AddOperation eID, op $+k|\+iJ Print "Set lens thickness = " & tlens vh$If0 0&~JC>S '************************************************************************* ~xa yGk 'Lens index of refraction 7z2Q!0Sz '************************************************************************* ;tJ}*!z
W eID = FindMaterial( "Lens" ) NR>&1aRbyb GetModelMaterial eID, mat HUFm@? .9u0WP95 mat.Nd = nlens 9xN` SetModelMaterial eID, mat *g*~+B
: Print "Set lens index of refraction = " & nlens n2(`O^yd7C lt{D f~c '************************************************************************* 2/iBk'd 'Pupil diameter 1!%T<!A. '*************************************************************************
@+6cKP eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) u?F^gIw eP|_ 'Adjust pupil diameter (trimming volume inner hole) MpVZL29) mP ]a}[ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" .iV-Y *3< 1`sTGNo ' Adjust pupil location to just in front of the lens O[|_~v:^ parID = FindFullName( "Geometry.Arizona Eye" ) ;=UkTn}N?l eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) e#AmtheZR count = 0 +h)1NX;o1 While GetOperationCount(eID)>count Ihd{tmr< GetOperation eID, count, op Pil_zQ4 If op.Type="ShiftZ" Then F-XL DeleteOperation eID,count }*P?KV ( count=count-1 M9QYYo@ End If (F j"< count=count+1 IkuE | Wend nK)hv95i_ op.Type = "ShiftZ" V}MRdt7 op.val1 = taq-0.01 9'=ZxV op.parent = parID gF2,Jm@"6 AddOperation eID, op =D`:2k~
, ;lQ>>[* Print "Set pupil diameter = " & pupilDiam M1q_gHA ydTd.` 'Update AZ Eye subassembly Description 7.*Mmx~]= eID = FindFullName( "Geometry.Arizona Eye" ) d3]<'B:nb GetEntity eID, entity Ftdx+\O_i& entity.Description = "Accommodation = " & A & "D" 2xBYJoF( SetEntity eID, entity 7fC:'1]G m@W>ku Update g_JSgH!4 Print "DONE!" G-TD9OgZ 3ESrd"W= End Sub b(Yxsy{U Yw6uh4 如果屈光度是4,光瞳直径是4,则会输出如下数据: n= q7*<l R:`)*=rL% Accommodation = 4 Diopters } 4ZWAzH Pupil Diameter = 4 mm -br): }f Set aqueous humor thickness = 2.81 @Hl+]arUh Set anterior lens radius = 10.4 and conic constant = -2.375869 1pz-jo,2' Set posterior lens radius = -4.424557 and conic constant = -3.081019 &bigLe Set lens thickness = 3.927 y7Nd3\v [\ Set lens index of refraction = 1.42672 AqT}^fS Set pupil diameter = 4 PVSz%" DONE! C;%1XFzM
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