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简介 #80[q3 \~r`2p-K 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。 AgBXB%). 1Z h4)6x 模型 `<"@&N^d 9i=HZ\s3 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。 + n)_\@aQ ?f8)_t}^\ Table 1. AZ眼睛模型的定义 x @a3STKT 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.
js$L<^7 ~OE1Sd:2 光源 '&;s32']} wDv G5 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。 UZV\]Y NKSK+ll2 F%]ZyO9 图1. 光源和提示信息使用 @mJ#~@*( 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。 )Z" t++
a 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。 C3]"y7 Qms,kX 图2. 字母F光源的设定方法光 S#:yl>2 )@Vz,f\} 图3. 字母F在视网膜上位置点列图 :kU-ol$ 视网膜的散射 v|7=IJ `xq/<U;i 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。 5fT"`FL? "8-;Dq'+ '|7'dlW 图4. 视网膜朗伯散射设定 +W7#G `> 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。 8k0f&Cak= #$^vP/"$ &Rp/y%9 图5. 视网膜重点采样规格设定 }<9IH%sgF 脚本 0DB8[#i%: \,ko'48@ 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: Bs!F |x( E5+-N 图6. 用户对话框的创建与编辑 l2*o@&. 图7. 用户对话框编辑器 TSEv^u)3 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。 8{f~tPY 余下的脚本计算与屈光度有关的所有参数。 11g_!X -g@ GL^84[f-T
分析 h6(\ tRd!\ *De}3-e1b 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 99YgQ Y]HO t9\}!{<s 图7. 字母F在视网膜上颜色分析 )s~szmJoVD 脚本代码 $[xS>iuD ^D5+S`V Option Explicit 'Remove this to enable non-dimensioned variables to be used. Aw)I:d7F 51Q m2,P1^ Dim entity As T_ENTITY O,[9E Dim op As T_OPERATION y7ZYo7avg Dim mat As T_MODELMATERIAL @r*w 84 Dim A As Double `bJ?8~ 8* Dim pupilDiam As Double TZ+- >CG Dim eID As Long lvd`_+P$ Dim parID As Long 5I6u 2k3 Dim count As Integer !zZ3F|+HB Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double )#Le"&D Dim tlens As Double, nlens As Double ]/6i#fTw Dim curv As Double, conic As Double R8%%EEB Dim ok As Long "sU jJ| 1$#1 Sub Main xa[)fk$6 oWb\T
2!m '用户输入对话框 p&$O}AX| Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 fWz=bJ"V TextBox 220,21,40,21,.TextBox1 'default: 0 0Lx,qZ' Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 R^?9V=Y<T OKButton 40,91,90,21 Ju@8_ ?8= CancelButton 190,91,90,21 gjL+8Rk Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 |r+w(TG TextBox 220,49,40,21,.TextBox2 'default: 4 WS6;ad;| End Dialog Xx+eGV";` Dim dlg As UserDialog :LxsiDrF[ ;u*I#)7 ok = Dialog (dlg) \&MJ(F>vJ ,.z?=]'en If ok=0 Then 'cancel button was pressed X-y3CO:&@h Print "Execution cancelled." X#<+D1P End ufn%sA End If t\XA
JU AaLbJYuKd 'Assign accommodation and pupil diameter & use defaults if field left empty ZKTY1JW_ If dlg.TextBox1 = "" Then FI"KJk' A = 0 'Default accommodation *_sSM+S Else z)ndj
1,#) A = CDbl(dlg.TextBox1) tNG[|Bi# End If jRN>^Ur;g .G-L/*&% If dlg.TextBox2 = "" Then bk|?>yd pupilDiam = 4 'Default pupil diameter ~5>k_\G8 Else ix_&os]L_ pupilDiam = CDbl(dlg.TextBox2) A=+1PgL66 End If )W/_2Q. KP)t,\@f! Print " " *|as-!${k Print "Accommodation = " & A & " Diopters" "BZL*hHq Print "Pupil Diameter = " & pupilDiam & " mm" sLd%m+*p &,tj.?NCn ' Calculate new parameters with accommodation B8~bx%)3T taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 6F_:,b^ AfpC >>=@ Rant = 12.0 - 0.4*A 'Radius of anterior lens 'Ll'8 ps CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens .aQ8I1~ *Ksk1T+> Rpost = -5.224557 + 0.2*A 'Radius of posterior lens c"diNbm[ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens v,!`A!{D =wMq!mBd tlens = 3.767 + 0.04*A 'Lens thickness +y^'\KN =9;b|Y"aQ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction uN=f(-" aZ8f>t1Q 'Adjust parameters to account for accommodation c-* *~tb( B9wQ;[gQB '************************************************************************* T>|Y_3YO_a 'Aqueous thickness (Position of Lens) |j4p '************************************************************************* K!8l!FFl eID = FindFullName( "Geometry.Arizona Eye.Lens" ) tB`IBuy9!" GetCustomElement eID, entity oDWNOw 9
^=kt 2[ parID = FindFullName( "Geometry.Arizona Eye" ) 0j2mTF(C BP@V:z ' Delete any shift(s) in z q2U?EP{8~ count = 0 LRR)T: e}q While GetOperationCount(eID)>count A{Qo}F<* GetOperation eID, count, op <tW/9}@p9 If op.Type="ShiftZ" Then ; o(:}d DeleteOperation eID,count Ya}}a count=count-1 ]*D~>q"#\ End If 4|UtE<<b count=count+1 }:S}jo7 Wend +LlAGg]Z -b)3+#f 'Set new shift in s@p:XO op.Type = "ShiftZ" 6]mAtA`Y op.val1 = taq w~3z); op.parent = parID U#%+FLX@w AddOperation eID, op H`,t "I Print "Set aqueous humor thickness = " & taq-0.55 f?TS#jG4} XePGOw))O '*************************************************************************
`)>}b 3 'Radius and conic constant of anterior lens n(.L=VuXn '************************************************************************* %pLqX61t= eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) _p?s[r* GetConic eID, entity, curv, conic B%5"B} nG o*3\xg SetConic eID, entity, 1/Rant, CCant B>[myx Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant $wbIe"| !b$]D?=} '************************************************************************* iu$Y0.H@ 'Radius and conic constant of posterior lens Lj/ '************************************************************************* ZH`(n5 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) `/9I` <y GetConic eID, entity, curv, conic >>cL"m Gz4LjMQ
& SetConic eID, entity, 1/Rpost, CCpost DPCQqV |7 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ZiRCiQ/? h+S]C#X,} '************************************************************************* |pBvy1e4) 'Lens thickness (Position of posterior lens surface) +|H,N7a< '************************************************************************* _UY=y^ c0> S4rm K& parID = FindFullName( "Geometry.Arizona Eye.Lens" ) J ~KygQ3% pktnX-Slt ' Delete any z-shift(s) )P,pW?h$ count = 0 ce*?crOV While GetOperationCount(eID)>count $LG.rJ/* GetOperation eID, count, op t>x!CNb'C If op.Type="ShiftZ" Then IJC]Al,df DeleteOperation eID,count 8"A0@fNz count=count-1 DR]4Tc z# End If aimf,(+ count=count+1 "
t?44[ Wend ?A04qk PR*EyM[T 'Set new z-shift m-#]v}0A op.Type = "ShiftZ" orbz`IQc op.val1 = tlens u68ic1 op.parent = parID t^}"8 AddOperation eID, op D[6wMep^n Print "Set lens thickness = " & tlens f0YBy<a 0#ON}l)> '************************************************************************* #4!f/dWJp 'Lens index of refraction lTVz'ys '************************************************************************* mo,"3YW eID = FindMaterial( "Lens" ) na
0Zb GetModelMaterial eID, mat w2jB6NQX C
=B a|Z mat.Nd = nlens P@x@5uC2 SetModelMaterial eID, mat P.(z)!] Print "Set lens index of refraction = " & nlens KuEM~Q= ~#)9Kl7<X '************************************************************************* 9$}>O] 'Pupil diameter b@sq}8YD|z '************************************************************************* +UX}
"m~W eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ~}SQLYy7Z = )4bf"~8 'Adjust pupil diameter (trimming volume inner hole) qk>M~, c(Fo-4K SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ]\]mwvLT %eGD1.R ' Adjust pupil location to just in front of the lens lQ"t#b+ parID = FindFullName( "Geometry.Arizona Eye" ) Z-M4J;J@} eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) j 20mZ count = 0 *Wcq'S While GetOperationCount(eID)>count [4@@b"H GetOperation eID, count, op 07:h4beT If op.Type="ShiftZ" Then B B^81{A DeleteOperation eID,count W)Y:2P<. count=count-1 )bpdj, End If J7~Kjl count=count+1 KXUJ*l-5 Wend sDu&9+ op.Type = "ShiftZ" |uX&T`7?- op.val1 = taq-0.01 pW>.3pj op.parent = parID ;!OME*?m< AddOperation eID, op I*mBU^<9V buWF6LFC Print "Set pupil diameter = " & pupilDiam +eop4 |Z \lyHQ-gWhc 'Update AZ Eye subassembly Description <l>L8{-3 eID = FindFullName( "Geometry.Arizona Eye" ) ?ZkVk =t? GetEntity eID, entity V;P*/ke entity.Description = "Accommodation = " & A & "D" KqNsCT+j SetEntity eID, entity gEq6[G nE:Wl Update .
ywVGBvJ Print "DONE!" e'=#G$S?g ?3i<^@? End Sub 1 -R4A7+3 RhE|0N= 如果屈光度是4,光瞳直径是4,则会输出如下数据: ZJ[p7XP "c![s% Accommodation = 4 Diopters Ppx 4#j Pupil Diameter = 4 mm s5X51#J#~ Set aqueous humor thickness = 2.81 lg
1r] Set anterior lens radius = 10.4 and conic constant = -2.375869 nQn=zbZ3 Set posterior lens radius = -4.424557 and conic constant = -3.081019 SV^[)p) Set lens thickness = 3.927 9Dyy&$s Set lens index of refraction = 1.42672 {P%\& \{F Set pupil diameter = 4 5o0H7k] DONE! 9FF VY0-18 o T'N/A9{q QQ:2987619807 |1T[P)Q
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