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简介 i{6wns?KMj 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。 c9R|0Yn^J ]$?\,` 模型 LkIbvJCV -O?&+xIK& 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 j-wz7B Af7&;8pM Table 1. AZ眼睛模型的定义 \o{rw0w0 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. @2)ImgK[ ^ ]CQd
光源 Z^yhSbE{5 Rz!! ;<ye8 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 \P7y&`| -[.A6W ?<-ins 图1. 光源和提示信息使用 6`;+| H<$ 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。 2x dN0S xl;0&/7e 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。 keL!;q|r-) ]~-vU{ 图2. 字母F光源的设定方法光
]<?7CpP WHvU|rJ 图3. 字母F在视网膜上位置点列图 R3Ka^l8R| 视网膜的散射 ?br 4 wl R
SqO$~ 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 zV"oB9\9O UV8K$n< 'ai!6[|SD 图4. 视网膜朗伯散射设定 %H'*7u2 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。 (GI]Uyn f!aE/e\ ;f)o_:(JJ 图5. 视网膜重点采样规格设定 rE&+fSBD 脚本 uw`fC%-xh '`fz|.|cbB 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: A%c)=(, }g|)+V\A 图6. 用户对话框的创建与编辑 ;IYH5sG{ 图7. 用户对话框编辑器 u }~%9Pi 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。 T&PLvyBL 余下的脚本计算与屈光度有关的所有参数。 y OLqIvN t?:Q 分析 K]Onb{QY +1j+%&). 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 rc9Y:(S1l , %%}d9 图7. 字母F在视网膜上颜色分析 '4}c1F1T_ 脚本代码 O FCA~sR jJDYl( [ Option Explicit 'Remove this to enable non-dimensioned variables to be used. "~HV!(dRMC 8x9$6HO Dim entity As T_ENTITY ^HasT4M+x Dim op As T_OPERATION Zc9j_.?* Dim mat As T_MODELMATERIAL ]~A<Q{ Dim A As Double p3YF Dim pupilDiam As Double r(::3TF%#q Dim eID As Long 7yK1Q_XY> Dim parID As Long SJdi*> Dim count As Integer c@1q8, Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double
#RA3 T[A Dim tlens As Double, nlens As Double ko%B` Dim curv As Double, conic As Double @lnM% Dim ok As Long +\ O[)\ `bF]O" Sub Main wuQ>|\Zs k;9"L90 '用户输入对话框 s"solPw Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 )"o+wSI1 TextBox 220,21,40,21,.TextBox1 'default: 0 >)IXc<"wq Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 f YuM`O OKButton 40,91,90,21 +#d}3^_] CancelButton 190,91,90,21
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C Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 BLvI[b|3gn TextBox 220,49,40,21,.TextBox2 'default: 4 t9Nu4yl End Dialog fx783 Dim dlg As UserDialog k v}<u A|esVUo<3^ ok = Dialog (dlg) ?$T39U^ khW9n* If ok=0 Then 'cancel button was pressed 9C{\=?e; Print "Execution cancelled." j_r7oARL End v 8`)h<:W? End If "n3i(sZ ;I+"MY7D 'Assign accommodation and pupil diameter & use defaults if field left empty (3=(g If dlg.TextBox1 = "" Then u8wZ2j4S A = 0 'Default accommodation 8zRb)B+ Else Q:x:k+O- A = CDbl(dlg.TextBox1) $qx&\@O End If [?$| yT>t[t60/S If dlg.TextBox2 = "" Then B
az:N6u pupilDiam = 4 'Default pupil diameter ($oO,
c'z Else ]/+qM)F pupilDiam = CDbl(dlg.TextBox2) $VrKoL\ScA End If <}E^r_NvD |@-%x.y Print " " ; YaR|)B Print "Accommodation = " & A & " Diopters" Qjj:r~l Print "Pupil Diameter = " & pupilDiam & " mm" W].P(A>m Jb~ -)n2 ' Calculate new parameters with accommodation ')9%eBaeK taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness IKK<D'6 >q&Q4E0 Rant = 12.0 - 0.4*A 'Radius of anterior lens p.2>-L CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens LaE;{ jY id-VoHdK Rpost = -5.224557 + 0.2*A 'Radius of posterior lens {tE/Jv $ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens {1GW,T!# s'^zudx tlens = 3.767 + 0.04*A 'Lens thickness a .5s5g)8 4Pljyq: nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction P#H#@:/3 fJCh 'Adjust parameters to account for accommodation JXlFo3< R0<ka[+ '************************************************************************* eh'mSf^=p 'Aqueous thickness (Position of Lens) WRAW%?$ '************************************************************************* v.1= TBh eID = FindFullName( "Geometry.Arizona Eye.Lens" ) >:]fN61# GetCustomElement eID, entity x~GV#c 6QRfju' parID = FindFullName( "Geometry.Arizona Eye" ) ~MY(6P mm=Y(G[_%y ' Delete any shift(s) in z 'KGY;8<x] count = 0 $/C<^}A While GetOperationCount(eID)>count 2t { Cpw GetOperation eID, count, op {K'SOhH4? If op.Type="ShiftZ" Then 81_3{OrE< DeleteOperation eID,count N,ik&NIWy count=count-1 S'-<p<;D\B End If uz4mHyS6 count=count+1 .Qh8I+Q% Wend Hcd> \0 7o
z(hO~ 'Set new shift in (W/jkm op.Type = "ShiftZ" >*} qGk op.val1 = taq y`Pp"!P"O op.parent = parID 1TQ$(bI AddOperation eID, op W7A'5 Print "Set aqueous humor thickness = " & taq-0.55 (r[<g*+3 ?<frU ,{ '************************************************************************* VP 4t~$" 'Radius and conic constant of anterior lens FA^x|C =$ '************************************************************************* %Z{J= eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) d L%E0o GetConic eID, entity, curv, conic Xs?7Whc6 t=\V&, SetConic eID, entity, 1/Rant, CCant ;(0:6P8I Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant X}zKV M]` Q4\ '************************************************************************* Dlj=$25 'Radius and conic constant of posterior lens W,{`)NWg '************************************************************************* H5RHA^p| eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ($(1KE GetConic eID, entity, curv, conic \>=YxB q 3/rvSR! SetConic eID, entity, 1/Rpost, CCpost K[sM)_I Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost x}x@_w Z `\7B e '************************************************************************* 'fAD Dh} 'Lens thickness (Position of posterior lens surface) jZ
D\u% '************************************************************************* vWkKNB T4!]^_t^ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) x>8f#B\Mr <$yer)_J!k ' Delete any z-shift(s) hTG
d Uw] count = 0 |C&eH$?~=R While GetOperationCount(eID)>count ^LU[{HZV GetOperation eID, count, op uBE,z>/,; If op.Type="ShiftZ" Then H4:TYh DeleteOperation eID,count sId5pY! count=count-1 @J<B^_+Se End If Na~_=3+a count=count+1 ;5|EpoM Wend NUnP'X=J, g?$9~/h :; 'Set new z-shift ONGe/CEXT op.Type = "ShiftZ" x b0+4w| op.val1 = tlens =hs@W)-O op.parent = parID @E>^\!nH AddOperation eID, op _@OYC< Print "Set lens thickness = " & tlens /MU<)[*Ro CXQ?P '************************************************************************* t!u*6W|@ 'Lens index of refraction 4a @iR2e '************************************************************************* sMS`-,37u eID = FindMaterial( "Lens" ) -mkync3 GetModelMaterial eID, mat H);'\]_'x ^r& {V"l] mat.Nd = nlens "
}ZD)7K SetModelMaterial eID, mat B7 PmG
f)b Print "Set lens index of refraction = " & nlens B)Q'a3d# rka:.#! '************************************************************************* aBI]' D; 'Pupil diameter ww,c)$ '************************************************************************* l46F3C| eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) @Hf}PBb jF;4
8g@^ 'Adjust pupil diameter (trimming volume inner hole) K?tk&0 $"FdS,*qKl SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" jFXU
xf UJH{vjIv ' Adjust pupil location to just in front of the lens Ji!-G4.n" parID = FindFullName( "Geometry.Arizona Eye" ) -0X> y eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) J9 =gv0 count = 0 @
tIB'|O While GetOperationCount(eID)>count "n6Y^ GetOperation eID, count, op +n, BD C; If op.Type="ShiftZ" Then % KA/ DeleteOperation eID,count X2uX+}h*tA count=count-1 Xdq,
=; End If mCGcM^21-x count=count+1 vRq xZN Wend bevT`D op.Type = "ShiftZ" H+;wnI>@ op.val1 = taq-0.01 LbR-uc?x op.parent = parID +Y~+o-_ AddOperation eID, op
m#nxw vOK;l0% Print "Set pupil diameter = " & pupilDiam =eqI]rVj^ i4I0oRp 'Update AZ Eye subassembly Description AVr!e
eID = FindFullName( "Geometry.Arizona Eye" ) K*Jtyy}r GetEntity eID, entity 9^ r entity.Description = "Accommodation = " & A & "D" Ng"vBycy SetEntity eID, entity &XsLp&Do2 QVW6SY Update j1F+, Print "DONE!" x5SQ+7 +*J4q5;E[? End Sub "AouiZkh )!d1<p3 如果屈光度是4,光瞳直径是4,则会输出如下数据: doc TyWy5J<
:+ Accommodation = 4 Diopters \vsrBM Pupil Diameter = 4 mm X^Y9T`mQ} Set aqueous humor thickness = 2.81 (@E#O$' Set anterior lens radius = 10.4 and conic constant = -2.375869 :6?&FzD` Set posterior lens radius = -4.424557 and conic constant = -3.081019 =.E(p)fz Set lens thickness = 3.927 y^=oYL Set lens index of refraction = 1.42672 kkBU<L2 Set pupil diameter = 4 5uo(z,WLR DONE! FA9e(Ha $-]setdY (文章来源:讯技光电)
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