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简介 a|s64+ oD=6D9c? 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。 ]*Tnu98G} aRh1Q=^@(4 模型 0k7kmDW y,OwO4+y\ 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。 PM
A61g V,W":&!x Table 1. AZ眼睛模型的定义 IUJRP 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. >dTJ nLfITr|5 光源 nYv`{0S+m VIi/=mO] 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。 yN Bb(!u ?g5u#Q>! t'F_1P^*/ 图1. 光源和提示信息使用 1 iWe&I: 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。 F|seBBu JnT1-=t. 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。 ; {P"~(S% 2'8$I}h 图2. 字母F光源的设定方法光 "Y7
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7z?rx 图3. 字母F在视网膜上位置点列图
Owa]ax5 视网膜的散射 c_33.i"I} )^ky @V 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 G \S >H 6a=Y_fma 96&Y 图4. 视网膜朗伯散射设定 &>Ko}?w 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 Fk 5; >;;tX3( 8#S}.|"?F 图5. 视网膜重点采样规格设定 qC%[J:RwF 脚本 M_4:~&N$ njk1x 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: U;_b4S: LcA~ a<_ 图6. 用户对话框的创建与编辑 LD~s@}yH> 图7. 用户对话框编辑器 aC&ZV}8of 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。 .kGlUb?^Q 余下的脚本计算与屈光度有关的所有参数。 P0En&g+~ ?rD`'B 分析 ^rKA=siz R`RLq1WA 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 B f_oIc nA\9UD<G. 图7. 字母F在视网膜上颜色分析 f.o,VVYi 脚本代码 -%U 15W; Tu'/XUs;k Option Explicit 'Remove this to enable non-dimensioned variables to be used. O@
GEl U~mv1V^. Dim entity As T_ENTITY 4RH'GnLa Dim op As T_OPERATION WG{mg/\2(C Dim mat As T_MODELMATERIAL q]\bJV^/U Dim A As Double G*;}6 bj|? Dim pupilDiam As Double f|*vWHSM Dim eID As Long 6PS #Zydb Dim parID As Long tp3>aNj Dim count As Integer NjCdkT&g Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double M@>EZ Dim tlens As Double, nlens As Double >t/P^fr_F Dim curv As Double, conic As Double C^hHt,& Dim ok As Long fC2 3q>6gaTv Sub Main _d$0( :\*<EIk( '用户输入对话框 hm%'k~ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 r~sx]=/ TextBox 220,21,40,21,.TextBox1 'default: 0 R?Dbv'lp> Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 93Yo}6> OKButton 40,91,90,21 FA.h?yfr CancelButton 190,91,90,21 M1MpR+7S Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 H(^O{JC]y! TextBox 220,49,40,21,.TextBox2 'default: 4 _u`NIpXSP End Dialog e#YQA Dim dlg As UserDialog 1`tE Hu. h SZ0 }/ ok = Dialog (dlg) ZD9UE3- &=sVq^d@qe If ok=0 Then 'cancel button was pressed -}lcMZY Print "Execution cancelled." T4dYC'z End l_lm)'ag End If ?I` BbT} r@&d88U: 'Assign accommodation and pupil diameter & use defaults if field left empty uA?_\z? If dlg.TextBox1 = "" Then fb5]eec A = 0 'Default accommodation yJaQcGxE" Else OXC7
m A = CDbl(dlg.TextBox1) <ByR!Y End If =?`5n|A* GfAt-huL( If dlg.TextBox2 = "" Then p_$03q>oQ pupilDiam = 4 'Default pupil diameter PMJe6*(x/ Else 8@)/a pupilDiam = CDbl(dlg.TextBox2) w#Y<~W& End If OCzWP, 1NO<K` Print " " rsP3?.E Print "Accommodation = " & A & " Diopters" q|,I\H5} Print "Pupil Diameter = " & pupilDiam & " mm" v/]Bo[a _/"m0/, ' Calculate new parameters with accommodation \A\a=A[ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness U9;C#9E _wWh7'u~G Rant = 12.0 - 0.4*A 'Radius of anterior lens ui4H(A'} CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 0@rrY Aa;R_Jz Rpost = -5.224557 + 0.2*A 'Radius of posterior lens 5Qp5JMK CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens `zHtfox! k/vE| tlens = 3.767 + 0.04*A 'Lens thickness Z8$@}|jN Ga-AhP nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Bv$;yR ,jyNV<dI 'Adjust parameters to account for accommodation --0z"`@{ @]Ye36v0#L '************************************************************************* }-m/
'Q 'Aqueous thickness (Position of Lens) da3]#%i0 '************************************************************************* Y%$57,Bu n eID = FindFullName( "Geometry.Arizona Eye.Lens" ) vJ$#m_aa GetCustomElement eID, entity OGNjn9av 1Y410-.3w{ parID = FindFullName( "Geometry.Arizona Eye" ) YJ]]6 K+ @b2{'#9]} ' Delete any shift(s) in z 8#S|jBV count = 0 tFvti5 While GetOperationCount(eID)>count %@L(A1"#D GetOperation eID, count, op xtKWh`[& If op.Type="ShiftZ" Then
SX|b0S, DeleteOperation eID,count MpM-xz~ count=count-1
o@_pV End If +nRO< count=count+1 HoGrvt<:.P Wend /Cr0jWu
_ ,,oiL 'Set new shift in m~\BkE/[l op.Type = "ShiftZ" :|oH11y op.val1 = taq i\G@ kJNnF op.parent = parID 7|3Z+#|T AddOperation eID, op \;p5Pagx0- Print "Set aqueous humor thickness = " & taq-0.55 z6bTcs"7h Oh<[8S7]C '************************************************************************* \1f$]oS 'Radius and conic constant of anterior lens ghJ81 '************************************************************************* IuTZ2~ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) pL>Q'{7s3 GetConic eID, entity, curv, conic xfqgK D> .@.,D% 7< SetConic eID, entity, 1/Rant, CCant <FmrYwt Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant [V()7 .hlr)gF&) '************************************************************************* }4Lv-9s, 'Radius and conic constant of posterior lens nJ.pPzH2g '************************************************************************* UDV,c o eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) {) 4D1 GetConic eID, entity, curv, conic 13s!gwE) {AqN@i SetConic eID, entity, 1/Rpost, CCpost 3> -/sii Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost qHg\n)R"x! ?stx3sZ '************************************************************************* * 4GJ< 'Lens thickness (Position of posterior lens surface) `DO`c>>K '************************************************************************* E=GCq=Uw {FraM,w: parID = FindFullName( "Geometry.Arizona Eye.Lens" ) -DhF> 4f K
4I ?1 ' Delete any z-shift(s) Yt!UIl\< count = 0 dx}()i\@ While GetOperationCount(eID)>count / O6n[qj| GetOperation eID, count, op +wwpaR` If op.Type="ShiftZ" Then <6U{I ' DeleteOperation eID,count ^10*s,(uS? count=count-1 tTe\#o` End If %Vrl"4^}t count=count+1 i 4lR$]@ Wend il\#R%';5 &G5+bUF, 'Set new z-shift ,*a8]L op.Type = "ShiftZ" O[3J Px op.val1 = tlens $
w:QJ~,s op.parent = parID 3>yb$ZU"- AddOperation eID, op O*rKV2\ Print "Set lens thickness = " & tlens TZi%,yK A!H6$-W|p '************************************************************************* J %jfuj 'Lens index of refraction d"uR1rTk '************************************************************************* lyfLkBF eID = FindMaterial( "Lens" ) V'
"p
a GetModelMaterial eID, mat KQaw*T[Q3w d%VGfSrKq mat.Nd = nlens 8b!&TP~m1 SetModelMaterial eID, mat 1$?O5.X: Print "Set lens index of refraction = " & nlens Erl"X}P jY$Bns&.w '************************************************************************* 1Jc-hrN- 'Pupil diameter U:c!9uhp '************************************************************************* nBjfR2TuF eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *bDuRr?v9 lLxKC7b 'Adjust pupil diameter (trimming volume inner hole) .Gh-T{\V' $TtCVR SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" GfD!Z3 ko@I]gi2 ' Adjust pupil location to just in front of the lens ~0>g 4
D. parID = FindFullName( "Geometry.Arizona Eye" ) &!2
4l=! eID = FindFullName( "Geometry.Arizona Eye.Pupil" )
;B o 2$ count = 0 Hwklk9U While GetOperationCount(eID)>count Q?L-6]pg GetOperation eID, count, op Ui@Q&%b If op.Type="ShiftZ" Then ;VeC(^-eh6 DeleteOperation eID,count |L.QIr,jCC count=count-1 *I(>[m! End If @sav8] count=count+1 {jcrTjmxe Wend UMpC2)5 op.Type = "ShiftZ" ~A}"s-Kq5 op.val1 = taq-0.01 %L:e~* op.parent = parID |0ACapp! AddOperation eID, op #n]js7 tmDI2Z%7 Print "Set pupil diameter = " & pupilDiam M['8zN 29z+<?K{ 'Update AZ Eye subassembly Description =<y$5"| eID = FindFullName( "Geometry.Arizona Eye" ) qS*qHT(u19 GetEntity eID, entity 8GN0487H entity.Description = "Accommodation = " & A & "D" *eH[~4 SetEntity eID, entity 8TD:~ee F +D2
xN@ Update =PP]LDlJs Print "DONE!" ]$KyZHj{ Z+' 7c|a End Sub CA7tI >y_ U2$e?1y 如果屈光度是4,光瞳直径是4,则会输出如下数据: $fPf/yQmC |t1D8){! Accommodation = 4 Diopters J)oa:Q Pupil Diameter = 4 mm {UQpD Set aqueous humor thickness = 2.81 iS&fp[Th Set anterior lens radius = 10.4 and conic constant = -2.375869 *JZU
0Xb Set posterior lens radius = -4.424557 and conic constant = -3.081019 AH;0=<n Set lens thickness = 3.927 2BS2$#c> Set lens index of refraction = 1.42672 Vx;f/CH3! Set pupil diameter = 4 z|=l^u6uS DONE! r4@!QR<h ?9mFI (r~ %E3|b6k\ QQ:2987619807 8|.(Y
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