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简介 0;x&\x7K 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。 ok6t|
7sq j![1 模型 kmW/{I9,ua @@@}FV& 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。 <IIz-6*V U
_pPI$ = Table 1. AZ眼睛模型的定义 !>'A2V~F 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. @=G[mc\ S.[L?uE~F 光源 S?Cd,WxT 0]f/5jvLj 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。 ,fiV xn Q `Cd! # [i3cn
图1. 光源和提示信息使用 Iep_,o.Sk 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。 kJ%a;p`O l`#rhuy` 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。 gs+nJ+b #-b}QhxH 图2. 字母F光源的设定方法光 pzt<[; A1;'S<a 图3. 字母F在视网膜上位置点列图 "%Ief4 视网膜的散射 B4HMs$> 7*K2zu3 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 3w>1R>7 KtJc9dnX EPwU{*F 图4. 视网膜朗伯散射设定 N
G vb] 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 y%9Hu QeT~s5 H oR%cG"y 图5. 视网膜重点采样规格设定 oNYFbZw 脚本 6i+AJCkC 8B+C[Q:+' 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: H/*slqL 3-AOB3]( 图6. 用户对话框的创建与编辑 !yi*Zt~ 图7. 用户对话框编辑器 >bI\pJ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 ,Y|
;V 余下的脚本计算与屈光度有关的所有参数。 p< pGqW *'?V>q, 分析 CXuMNa (I6Q"&h] 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 a;a1>1 >`[+24e 图7. 字母F在视网膜上颜色分析 i"+TKo- 脚本代码 b%x=7SMXO H>D? Option Explicit 'Remove this to enable non-dimensioned variables to be used. Pxkh;:agD L)<~0GcP Dim entity As T_ENTITY "5ISKuL Dim op As T_OPERATION O9<oq Dim mat As T_MODELMATERIAL F(/Ka@
Dim A As Double X%og}Cfi Dim pupilDiam As Double 7wY0JS$fz Dim eID As Long #y"LFoJn Dim parID As Long pKLNBR| Dim count As Integer oV9{{ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double M<=e~';H Dim tlens As Double, nlens As Double =eS?`| Dim curv As Double, conic As Double cM,g,E} Dim ok As Long f8UJ3vB o*E32#l Sub Main Z:<wB#G Z<=L '用户输入对话框 BaUuDo/ZO Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 U|QP]6v TextBox 220,21,40,21,.TextBox1 'default: 0 p1.3)=T Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 )p#L "r^) OKButton 40,91,90,21 9GT}_
^fb CancelButton 190,91,90,21 2dB]Lw@s Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Wwr TextBox 220,49,40,21,.TextBox2 'default: 4 B>I:KGkV End Dialog u|\?6fz Dim dlg As UserDialog G pO*As_2 *5XOYb?'v. ok = Dialog (dlg)
x|c_( _KT'W!7 If ok=0 Then 'cancel button was pressed sV0NDM0 Print "Execution cancelled." N9*QQ0 End {:\LFB_ End If II=!E 4MzPm~Ct 'Assign accommodation and pupil diameter & use defaults if field left empty @.)[U:N If dlg.TextBox1 = "" Then /<-=1XJI
A = 0 'Default accommodation oxUBlye Else WCk. K A = CDbl(dlg.TextBox1) rXBCM End If c4Q9foE
.kkhW8: If dlg.TextBox2 = "" Then !I&,!$ pupilDiam = 4 'Default pupil diameter 9&6P,ts%Q Else mQSn*;9\T3 pupilDiam = CDbl(dlg.TextBox2) QUZ+#*:s End If 'mm>E 1U^KN~! Print " " mfffOG Print "Accommodation = " & A & " Diopters" k!bJ&} Q(b Print "Pupil Diameter = " & pupilDiam & " mm" 19[!9ci _I3v"d ' Calculate new parameters with accommodation 8X278^
# taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness B~@Gfb>`' zMO#CZ t Rant = 12.0 - 0.4*A 'Radius of anterior lens l,3,$ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens p*T[(\8{n L(k`1E Rpost = -5.224557 + 0.2*A 'Radius of posterior lens h qhX CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 9%"\s2T >vYb'%02 tlens = 3.767 + 0.04*A 'Lens thickness (J%>{?"ij CvEIcm=t nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction $b7@S`5 ,&fZo9J9 'Adjust parameters to account for accommodation *WFd[cKE
{gD`yoPrV '************************************************************************* K:Z(jF!j 'Aqueous thickness (Position of Lens) nqTOAL9FF '************************************************************************* B[#n,ay eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ;kR=vv GetCustomElement eID, entity a0 PU&o1EF z!.cc6R parID = FindFullName( "Geometry.Arizona Eye" ) F!4V!VWA} 5Fj9.K~k ' Delete any shift(s) in z 1A#/70Mo count = 0 ^-|~c`&}B While GetOperationCount(eID)>count G+k wG)K GetOperation eID, count, op ;KEie@Ry If op.Type="ShiftZ" Then [gZR}E DeleteOperation eID,count $"MVr5q6 count=count-1 p&)d]oV> End If cnw+^8 count=count+1 1,]FLsuy Wend Je2&7uR0 `CBXz!v!O 'Set new shift in L
8;H_:~_' op.Type = "ShiftZ" Tow! 5VAM op.val1 = taq hn/yX|4c( op.parent = parID sX*L[3!vN AddOperation eID, op l%?4L/J)# Print "Set aqueous humor thickness = " & taq-0.55 c5 AaUza DO+~ '************************************************************************* ^SsnCn-e 'Radius and conic constant of anterior lens y9LO;{( '************************************************************************* [?qzMFb eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) KK6z3"tk5 GetConic eID, entity, curv, conic
s_+.xIZ h;y}g/HZ SetConic eID, entity, 1/Rant, CCant C~"UOFX Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant V\e1NS &5z9C=]e '************************************************************************* cu'( Hj 'Radius and conic constant of posterior lens iWFtb)3B '************************************************************************* /` nkz eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) -Lb7=98 GetConic eID, entity, curv, conic j(K)CHH &
BY\h: SetConic eID, entity, 1/Rpost, CCpost ~3Zz.!F Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost [F;\NJp6?^ Oo FMOlb.Z '************************************************************************* \7#w@3* 'Lens thickness (Position of posterior lens surface) x2r.4 '************************************************************************* 'Nuy/\[{\ .n4{xQo,EJ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) FKL@,>!<e v ;Q*0%~ ' Delete any z-shift(s) j8PeO&n> count = 0 9}Z;(,6/.\ While GetOperationCount(eID)>count fE&s 6w& GetOperation eID, count, op ,oSn<$%/q If op.Type="ShiftZ" Then +xsGa{` DeleteOperation eID,count 6BEpnw>p( count=count-1 F< 5kcu#iL End If jvD_{r count=count+1 =1(7T.t Wend v}D0t] 9ZatlI, 'Set new z-shift )R?uzX^qf op.Type = "ShiftZ" a~LdcUYs op.val1 = tlens /"m#mhL op.parent = parID *PB /I4>{ AddOperation eID, op }bdoJ5 Print "Set lens thickness = " & tlens BafNFPc 0=t2|,} '************************************************************************* yGrnzB6| 'Lens index of refraction "L1LL
iS '************************************************************************* bb\XZ~)F eID = FindMaterial( "Lens" ) ZU`~@.`i GetModelMaterial eID, mat Bt5 P][< e8oAGh" mat.Nd = nlens ,O:p`"3`0= SetModelMaterial eID, mat \*qradgx$ Print "Set lens index of refraction = " & nlens PApr8Xe $sg- P|Wo '************************************************************************* ^,vFxN--q 'Pupil diameter PYs0w6o '************************************************************************* L;L_$hu) eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Z(tO]tQE ;lrO?sm 'Adjust pupil diameter (trimming volume inner hole) I.|b:c
xN I|K!hQ"m SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" v<)&JlR !g}@xwWax ' Adjust pupil location to just in front of the lens o"L8n(\ parID = FindFullName( "Geometry.Arizona Eye" ) Qt_KUtD eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) jq8TfJ| count = 0 2Q@Jp`#,4 While GetOperationCount(eID)>count -)Vy)hD, GetOperation eID, count, op D+! S\~u If op.Type="ShiftZ" Then =OV5DmVmQ DeleteOperation eID,count V>E7!LIn. count=count-1 \w1',"l` End If l,(:~KH| count=count+1 #.fJ
M:"tG Wend dn?'06TD op.Type = "ShiftZ" V=5*)i/ op.val1 = taq-0.01 +|8.ymvm op.parent = parID Dd/]?4 AddOperation eID, op
< .e4 -e_TJA Print "Set pupil diameter = " & pupilDiam fkX86 AcH!KbYf 'Update AZ Eye subassembly Description $]}K ; eID = FindFullName( "Geometry.Arizona Eye" ) TgDT GetEntity eID, entity M6qNh`+HO entity.Description = "Accommodation = " & A & "D" Mw-L?j0o[k SetEntity eID, entity .]zZw B 7t}s5}Z 4 Update -'d`(G" Print "DONE!" 4x4[ gGBRfq> End Sub iyr8*L\ )\2KDXc 如果屈光度是4,光瞳直径是4,则会输出如下数据: 1|ddG010 HrFbUK@@ Accommodation = 4 Diopters z[R
dM#L Pupil Diameter = 4 mm n@"<NKzh Set aqueous humor thickness = 2.81 ;V?(j3b[ Set anterior lens radius = 10.4 and conic constant = -2.375869 COw!a\Jl Set posterior lens radius = -4.424557 and conic constant = -3.081019 q+<,FdG Set lens thickness = 3.927 4MW oGV9 Set lens index of refraction = 1.42672 tQUKw@@Q Set pupil diameter = 4 Otq1CD9 DONE! KD+&5=Y )1@%!fr (文章来源:讯技光电)
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