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简介 W&A22jO.1 Vv
B%,_\ 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。 w3:Y]F.ot Ja4O*C< 模型 smoz5~ vnw83a%3 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。 </5uB'
B ^ 9F(<n Table 1. AZ眼睛模型的定义 Be68 Fu0 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. Dr^#e N32!*TsWs 光源 V&-pgxf; =nh/w# 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,K]TJ S#/[>Cb ;$ D*,W
* 图1. 光源和提示信息使用 I:P/
?- 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。 lM3UjR|@ ,P3nZ 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。 ]E .+)> nbj &3z, 图2. 字母F光源的设定方法光 c`yLn%Of% :rnn`/L 图3. 字母F在视网膜上位置点列图 QeuIAs* _ 视网膜的散射 ArDkJ`DE @/@#,+ 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。 N?eWf +C
)[|`-M~u 3fgVvt-2 图4. 视网膜朗伯散射设定 5`53lK.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。 y/Fv4<X `f,SY $vnshU8/v 图5. 视网膜重点采样规格设定 byR|L:L 脚本 8_US.52V 3Kc 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: 8
;y N NRe{0U}nO 图6. 用户对话框的创建与编辑 |QHDg( 图7. 用户对话框编辑器 Zg"g/I.+d 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。 Sc_#BD. 余下的脚本计算与屈光度有关的所有参数。 <t>"b|fW GD<xmuo 分析 jc)[5i0 d#9
\]Ul& 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 \R#]}g0! ?B3
图7. 字母F在视网膜上颜色分析 ZT:&j4A|0 脚本代码 *~~ >? I?}YS-2 Option Explicit 'Remove this to enable non-dimensioned variables to be used. JE9SPFQx9M }ac0} Dim entity As T_ENTITY >0z(+}]3z Dim op As T_OPERATION RoCX*3 d Dim mat As T_MODELMATERIAL A0Pg|M Dim A As Double r9G}[#DO Dim pupilDiam As Double [LDsn]{ Dim eID As Long &,/_"N"?D Dim parID As Long ~UA:_7#\M Dim count As Integer 8R<2I1xn2 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 't'~p#$,F Dim tlens As Double, nlens As Double {XAm3's Dim curv As Double, conic As Double FGY4 u4y Dim ok As Long kXK D>."E* b2]1Dfw Sub Main 5]D"y Ay81 ^t,sehpR:l '用户输入对话框 ?.Z4GWyXa Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 N=R|s$,Oy9 TextBox 220,21,40,21,.TextBox1 'default: 0 ,$BbJQ5 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 n\Y{?x OKButton 40,91,90,21 ;LSdY}*%0 CancelButton 190,91,90,21 L6S!?t.{Yv Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 V`Ve__5; TextBox 220,49,40,21,.TextBox2 'default: 4 F)rU*i7 End Dialog R3=PV{`M Dim dlg As UserDialog y^pzqv
naE;f) ok = Dialog (dlg) M_asf7|v =w&JDj If ok=0 Then 'cancel button was pressed :=9?XzCC Print "Execution cancelled." !;EG<ji,gj End >Wvb!8N End If }Jfi"L yv1Z*wTpO 'Assign accommodation and pupil diameter & use defaults if field left empty >~C*m `# If dlg.TextBox1 = "" Then $}kT)+K A = 0 'Default accommodation >HMuh) Else *Xm$w A = CDbl(dlg.TextBox1) !##OQ End If ^W}(]jL V}de|= If dlg.TextBox2 = "" Then o ;nw;]oR pupilDiam = 4 'Default pupil diameter ON"F
h'? Else 6%'bo`S# pupilDiam = CDbl(dlg.TextBox2) <*I%U] End If 6XU1w =P>c1T1- Print " " \Nd8,hE Print "Accommodation = " & A & " Diopters" `x%(
n@ g Print "Pupil Diameter = " & pupilDiam & " mm" s az<NT Td~CnCor ' Calculate new parameters with accommodation ?&v+-4%4PI taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness o\ss zl~`> Rant = 12.0 - 0.4*A 'Radius of anterior lens (vL-Z[M! CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens wCT. (d_ aH@GhI^@ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens X'BFR]cm CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens doeYc \jlem <& tlens = 3.767 + 0.04*A 'Lens thickness YXeL7W x""gZzJ$L nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 9UF^h{X +v$,/~$tI 'Adjust parameters to account for accommodation >;|~
z\8 3eOwy~ '************************************************************************* ZY NHVR 'Aqueous thickness (Position of Lens) !cblmF;0 '************************************************************************* |"7F`M96I eID = FindFullName( "Geometry.Arizona Eye.Lens" ) rK^Sn7 U GetCustomElement eID, entity zB,Vi-)vH u7L!&/ 6On parID = FindFullName( "Geometry.Arizona Eye" ) T&@xgj|!) j A/xe ' Delete any shift(s) in z =}SH*xi6 count = 0 /da5" While GetOperationCount(eID)>count <K6:" GetOperation eID, count, op {[Bo"a>% If op.Type="ShiftZ" Then }r%Si DeleteOperation eID,count A}./ ;[ count=count-1 AHa%?wb End If 7t8[M( count=count+1 3}U {~l!K Wend >b6!*Lrhs Ab|
tE5% 'Set new shift in TgFj-"L\ op.Type = "ShiftZ" +@n8DM{b op.val1 = taq x d9+P op.parent = parID oRJ!J-Z] AddOperation eID, op UJhmhI Print "Set aqueous humor thickness = " & taq-0.55 OC(S"&D w]<a$C8*y: '************************************************************************* fMGL1VN 'Radius and conic constant of anterior lens 960[.99 '************************************************************************* xbZx&`( eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) M|HW$8V3_2 GetConic eID, entity, curv, conic &Nzq/~uqP }(*eR F' SetConic eID, entity, 1/Rant, CCant `,-w+3?Al Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant xK7xAO |$hBYw '************************************************************************* ;F)j,Ywi)H 'Radius and conic constant of posterior lens UG@9X/l} '************************************************************************* }8joltf eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 8XS_I{}? GetConic eID, entity, curv, conic CxvL!ew nU^ -D1s{ SetConic eID, entity, 1/Rpost, CCpost {>x6SVF Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost FabDK : S-^:p5{r '************************************************************************* 9FGe(t< 'Lens thickness (Position of posterior lens surface) 1=*QMEv1G
'************************************************************************* q?&Ap* #pe#(xoI parID = FindFullName( "Geometry.Arizona Eye.Lens" ) $oPx2sb +-s$Htx ' Delete any z-shift(s) .dbZ;`s count = 0 D'Fj"&LK While GetOperationCount(eID)>count pZVT:qFF GetOperation eID, count, op ( o(, ; If op.Type="ShiftZ" Then ()Tl\ DeleteOperation eID,count 1" k_l.\,0 count=count-1 YI877T9> End If Ci?BJ, count=count+1 -VC
kk Wend ?h$
=] [Dzd39aKr 'Set new z-shift /-{C,+cB op.Type = "ShiftZ" FZk=-.Hk op.val1 = tlens -@I+IKz op.parent = parID -2D/RE7| AddOperation eID, op }|KNw*h$ Print "Set lens thickness = " & tlens Ml"i^LR+ WLO4P '************************************************************************* ' F,.y6QU 'Lens index of refraction Ba8 s '************************************************************************* ?KB+2]7m6 eID = FindMaterial( "Lens" ) ?Q?=I,2bP GetModelMaterial eID, mat D
,U#z =ws iC' mat.Nd = nlens k <EzYh SetModelMaterial eID, mat >.xgo6 Print "Set lens index of refraction = " & nlens Y<ZaW{% 1M={8}3 '************************************************************************* pHftz-RS! 'Pupil diameter 6r]l8*34; '************************************************************************* :j<ij]rsI eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) +46m~" ] 2F
z;TNS 'Adjust pupil diameter (trimming volume inner hole) }hm"49,O @L-] %C SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" f[XsnN2 c}-WK*v ' Adjust pupil location to just in front of the lens *LZB.84 parID = FindFullName( "Geometry.Arizona Eye" )
'gaa@ !bg eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) qQ{i2D%)?f count = 0 xY=%+o.?* While GetOperationCount(eID)>count r8wip\[ GetOperation eID, count, op #~JR_oQE! If op.Type="ShiftZ" Then f|r+qe DeleteOperation eID,count A8zh27[w% count=count-1 &tjv.t End If y@'~fI!E4 count=count+1 E*W|>2nx] Wend 'CfM'f3uu op.Type = "ShiftZ" &F 3'tf? op.val1 = taq-0.01 [
U`}) op.parent = parID w vnuE<o8 AddOperation eID, op . 1q4Q\B< M3EB=tU Print "Set pupil diameter = " & pupilDiam gP^p7aYwn !uxma~ZH- 'Update AZ Eye subassembly Description xULcS :Q eID = FindFullName( "Geometry.Arizona Eye" ) .B? J@, GetEntity eID, entity *?`<Ea entity.Description = "Accommodation = " & A & "D" JA]qAr SetEntity eID, entity r.vezsH FWb`F& Update 5;:964Et Print "DONE!" 'VQ
mK# SmMJ%lgA6 End Sub =
a54 LvcGh 如果屈光度是4,光瞳直径是4,则会输出如下数据: V.?Oly WWtksi, Accommodation = 4 Diopters ;XDGlv% Pupil Diameter = 4 mm TPi=!*$& Set aqueous humor thickness = 2.81 >$/PfyY7@# Set anterior lens radius = 10.4 and conic constant = -2.375869 vUD>+*D Set posterior lens radius = -4.424557 and conic constant = -3.081019 [CAV"u)0 Set lens thickness = 3.927 xU(yc}vw, Set lens index of refraction = 1.42672 *D:"I!Ho Set pupil diameter = 4 5n#@,V.O/ DONE! iqAME%m
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