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简介 cgi:"y F 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。 E&N~h|CL :8`~dj. 模型 aJQzM X'88W- 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。 b Rc,Y< +s;>@j()V Table 1. AZ眼睛模型的定义 .I?~R:(Ig 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. M1icj~Jr =4$ErwI_dm 光源 4T-"\tmg/ c'>_JlG~ 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 DL<;qhte )$ h!lAo JOz4O 图1. 光源和提示信息使用 WvZt~x&2 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。 {- &`@V TlowEh8r 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。 G
c\^Kg^# I~;w Q 图2. 字母F光源的设定方法光 F{4v[WP) :dqZM#$d 图3. 字母F在视网膜上位置点列图 T 5F) 视网膜的散射 ('{aOiSH Sn0kJIb
} 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 o*Xfgc p|(SR~;6 _RIlGs\. 图4. 视网膜朗伯散射设定 ah%Ws#& 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 ;:&|DN3; ^ |SiqE dr(-k3ex 图5. 视网膜重点采样规格设定 Mg2 e0}{ 脚本 rvlvk" 1Au+X3 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: R+U$;r8l g60k R7;\ 图6. 用户对话框的创建与编辑 zO---}[9a 图7. 用户对话框编辑器 h!ogH >S~ 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。 51`&%V{daL 余下的脚本计算与屈光度有关的所有参数。 r^a:s] LRg]'? 分析 eXMIRus( J&s$Wqf 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 7nPcm;Er F(#?-MCs 图7. 字母F在视网膜上颜色分析 4=o vm[ 脚本代码 -pIz-* W7Y@]QMX Option Explicit 'Remove this to enable non-dimensioned variables to be used. y|)VNnWM Aj|->Y Dim entity As T_ENTITY k qL.ZR Dim op As T_OPERATION f@$W5*j Dim mat As T_MODELMATERIAL BM/o7%]n Dim A As Double - om9 Z0e Dim pupilDiam As Double "a=Hr4C*r Dim eID As Long e MHz/;I Dim parID As Long /OWwC%tM/ Dim count As Integer Scx!h. \5 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double uDP:kM Dim tlens As Double, nlens As Double OxYAM,F Dim curv As Double, conic As Double DnFzCJ Dim ok As Long /IG{j} Uns%6o Sub Main Ps>:|j+ e.skE>& '用户输入对话框 _
,s^ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 `!/[9Y#H p TextBox 220,21,40,21,.TextBox1 'default: 0 '9Z`y_~)G Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 `hZh}K^ OKButton 40,91,90,21 =aZ d>{Y CancelButton 190,91,90,21 aZ4?!JW . Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ZX` \so,&, TextBox 220,49,40,21,.TextBox2 'default: 4 KCW2
UyE] End Dialog VaY#_80$s Dim dlg As UserDialog )\#*~73 h AAh ok = Dialog (dlg) mLqqo2u v>#Njgo If ok=0 Then 'cancel button was pressed P,ueLG= Print "Execution cancelled." N?ccG\t End 3fhY+$tq End If {KNaJ/:>W J<;io! 'Assign accommodation and pupil diameter & use defaults if field left empty xy7A^7Li If dlg.TextBox1 = "" Then I09 W= A = 0 'Default accommodation Tj#S')s8 Else ~c35Y9-5 A = CDbl(dlg.TextBox1) ?!P0UTe~ End If J`U]Ux/L xeSch?} If dlg.TextBox2 = "" Then 'RV96lX< pupilDiam = 4 'Default pupil diameter >)u;X Else BV
B2$&eJ pupilDiam = CDbl(dlg.TextBox2) (|K+1R End If PPB/-F]rr .DhI3'Jrl Print " " x.*^dM@V Print "Accommodation = " & A & " Diopters" .oyAi|| Print "Pupil Diameter = " & pupilDiam & " mm" |${4sUR ~^1y(-cw ' Calculate new parameters with accommodation 1`K-f
m) taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ZPmqoR[ Eo6N'h >h Rant = 12.0 - 0.4*A 'Radius of anterior lens VGc*aQYa CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens q*UHzE:LI miaH,hm Rpost = -5.224557 + 0.2*A 'Radius of posterior lens
]
#@:VR CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens lH4Nbluc^ Gk*u^J( tlens = 3.767 + 0.04*A 'Lens thickness (p[#[CI9 %=UD~5!G0 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ik(Du/ ?>h
~"D# 'Adjust parameters to account for accommodation [t?tLUg|6 x
vs=T '************************************************************************* .D
4G;=Q 'Aqueous thickness (Position of Lens) jg710.v: '************************************************************************* 'Gn>~m eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ojy^A GetCustomElement eID, entity <R7{W"QTA) O`~#X w parID = FindFullName( "Geometry.Arizona Eye" ) lV$JCNe -wXeue},> ' Delete any shift(s) in z +>#SNZ[ count = 0 rkjnw@x\ While GetOperationCount(eID)>count A3a/ /e GetOperation eID, count, op ~.W]x~X$ If op.Type="ShiftZ" Then UH!(`Z\C DeleteOperation eID,count i<"lXu count=count-1 +-j-)WU?, End If G?$@6 count=count+1 .yj@hpJM Wend |fgUW. =x8[%+ 'Set new shift in ]bY|>q op.Type = "ShiftZ" L+8ar9es op.val1 = taq ~bZ$ d{o^ op.parent = parID ]Lub.r AddOperation eID, op dEJqgp}\p Print "Set aqueous humor thickness = " & taq-0.55 <N vw*yA E{orezP '************************************************************************* msmW2Zc 'Radius and conic constant of anterior lens =
wD#H@ h '************************************************************************* u"HGT=Nl eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 1,fR kQ
GetConic eID, entity, curv, conic hTtn
/j ai_ve[A SetConic eID, entity, 1/Rant, CCant zKd@Ab Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant f;{Q ~ axnlI*! '************************************************************************* eN=jWUoCh 'Radius and conic constant of posterior lens v&d1ACctJ '************************************************************************* '#+&?6 p eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Z mJ<h& GetConic eID, entity, curv, conic OXEEpoU?V p3M!H2W SetConic eID, entity, 1/Rpost, CCpost ;M3%t=KV Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost UGO#o`.G} (.4lsKN< '************************************************************************* (DiduSJ 'Lens thickness (Position of posterior lens surface) iww/ s '************************************************************************* aFTWzz O52/fGt parID = FindFullName( "Geometry.Arizona Eye.Lens" ) O&l4/RtQ\) oai=1vt@
' Delete any z-shift(s) dVbFMQ& count = 0
^ }7O|Y7 While GetOperationCount(eID)>count (uC8M,I\ GetOperation eID, count, op !eF(WbU0 If op.Type="ShiftZ" Then 4'O,xC DeleteOperation eID,count b}K,wAx
count=count-1 *5feB# End If HA,o2jZ?In count=count+1 q}LDFsU Wend .ck?JXg aZmN(AJ8v 'Set new z-shift ?Lg(,-: op.Type = "ShiftZ" *~^63Nx! op.val1 = tlens c~R'`Q op.parent = parID [M\ an6h6O AddOperation eID, op RIMSXue*Ha Print "Set lens thickness = " & tlens al2lC#Sy <X)\P}"L4 '************************************************************************* l)NkTZ<] 'Lens index of refraction w/6X9d '************************************************************************* 2^o7 ^S eID = FindMaterial( "Lens" ) =%W:N|k GetModelMaterial eID, mat p{w- flmQNrC.8 mat.Nd = nlens .!o]oM
U/ SetModelMaterial eID, mat 8US#SI'x Print "Set lens index of refraction = " & nlens njs: ray3gM%JLj '************************************************************************* h.EI(Ev"GN 'Pupil diameter pAy4%|( '************************************************************************* ^-"Iwy eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) AT&K> NG \;&;K'
'Adjust pupil diameter (trimming volume inner hole) gzs\C{4D "6jt$-? SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 3x;UAi+& KfiSQ!{ ' Adjust pupil location to just in front of the lens &>\;4E.O5 parID = FindFullName( "Geometry.Arizona Eye" ) So1TH% eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Q a (Sb count = 0 Jpapl%7v While GetOperationCount(eID)>count [.}qi[=n GetOperation eID, count, op KqGb+N-@ If op.Type="ShiftZ" Then h*fN]k6 DeleteOperation eID,count T~E;@weR count=count-1 tW UI?\ End If s;vt2>;q+e count=count+1 NW[K/`-CTH Wend NVMn7H}>
op.Type = "ShiftZ" Qf~>5(,h op.val1 = taq-0.01 nqy*>X` op.parent = parID Q4cCg7|0 AddOperation eID, op {xZY4b2 &Sd5]r@+ Print "Set pupil diameter = " & pupilDiam U6&`s%mIa q=X<QhK 'Update AZ Eye subassembly Description "L~Oj&AN[ eID = FindFullName( "Geometry.Arizona Eye" ) uz!8=,DFw GetEntity eID, entity lAN&d;NU6Z entity.Description = "Accommodation = " & A & "D" @[;'b$T$ SetEntity eID, entity )-4c@ 6$b=Tr=0 Update 3;v)f": [ Print "DONE!" 1K9.3n zQ=b|p]|W End Sub oLoc jj~T <MS>7Fd2 如果屈光度是4,光瞳直径是4,则会输出如下数据: ?,$:~O*w 2PQBUq Accommodation = 4 Diopters )Eozo4~ Pupil Diameter = 4 mm 4FaO+Eo,8 Set aqueous humor thickness = 2.81 -9dZT Set anterior lens radius = 10.4 and conic constant = -2.375869 $V87=_} Set posterior lens radius = -4.424557 and conic constant = -3.081019 ]'pfw9"f~ Set lens thickness = 3.927 Zv
%>m Set lens index of refraction = 1.42672 wH|%3@eJ Set pupil diameter = 4 {"'M2w:|D1 DONE! @(#vg\UH }uIQ@f` (文章来源:讯技光电)
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