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简介 #N?EPV$ ika/ GG 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。 yT<yy>J9l# vlAYKtl3] 模型 VQO6!ToKY 6u`E{$ 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。 TpLlbsd ^<#08L; Table 1. AZ眼睛模型的定义 =l
TV2C< 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. :4PK4D s7 j()<.h;' 光源 't:|>;Wx 9pD=E>4?# 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。 445}Yw5;9 FWv-_ &y/ 图1. 光源和提示信息使用 8r7~ >p~ 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。 \J r ta Nh7+Vl 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。 y-qbK0=X4 RfVVAaI 图2. 字母F光源的设定方法光 i>w'$ { K
r9 P#Y 图3. 字母F在视网膜上位置点列图 C~F do0D 视网膜的散射 B>}=x4-8 ;ZMm6o 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。 B:om61Dn 47b=>D8 _,Wb`P 图4. 视网膜朗伯散射设定 Z&gM7Zo8 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。 :|3n`, Gj[`r kGsd3t!' 图5. 视网膜重点采样规格设定 F3$@6J8<[z 脚本 ]5X=u(} [m3[plwe 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: E? 1"&D
m IKx]?0sS 图6. 用户对话框的创建与编辑 zWYm*c"n\ 图7. 用户对话框编辑器 >6ul\xMU 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 8.4 1EKr2 余下的脚本计算与屈光度有关的所有参数。 t{n|!T& ]]~tFdh 分析 Y;ytm
#= SXfuPM 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 K]4XD1n7 bkfwsYZx 图7. 字母F在视网膜上颜色分析 C'mYR3?m; 脚本代码 ;fLYO6 i`-,=RJ Option Explicit 'Remove this to enable non-dimensioned variables to be used. #p@8m_g "L'0" Dim entity As T_ENTITY VPG+]>* Dim op As T_OPERATION dLb9p"EE# Dim mat As T_MODELMATERIAL 0'T*l2Z`2 Dim A As Double AnK-\4 Dim pupilDiam As Double >*#clf;@p Dim eID As Long jiS|ara" Dim parID As Long *7: )k Dim count As Integer |_q:0qo Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double bqjj6bf'o Dim tlens As Double, nlens As Double 5ve4 u Dim curv As Double, conic As Double 6( 1xU\x Dim ok As Long f>$Ld1 [C)JI; \ Sub Main ^B[%|{cO !vNZ-} '用户输入对话框 *~b3FLzq Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 2n}nRv/' TextBox 220,21,40,21,.TextBox1 'default: 0 t Dx!m~[ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 HZ$q`e OKButton 40,91,90,21 F0,-7<G CancelButton 190,91,90,21 72oiO[>N' Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 L`E^BuP/ TextBox 220,49,40,21,.TextBox2 'default: 4 H]v"_!(\ End Dialog &^WJ:BvA|^ Dim dlg As UserDialog iwb]mJUA @Y2"=QVt ok = Dialog (dlg) n^OWz4 B{IYVviiP If ok=0 Then 'cancel button was pressed 1o5DQ'~n Print "Execution cancelled." CS[[TzC=5 End 'M"JF;*r End If e~7h8?\.q ofeSGx 'Assign accommodation and pupil diameter & use defaults if field left empty BzFD_A>j;_ If dlg.TextBox1 = "" Then YDEUiZ~ A = 0 'Default accommodation jn+NX)9 Else }T!2IaAB A = CDbl(dlg.TextBox1) z:PH _N~ End If /+pPcK wFr}]<=Mi If dlg.TextBox2 = "" Then zPwU'TbF pupilDiam = 4 'Default pupil diameter W`zY\] Else I{Pny/d` pupilDiam = CDbl(dlg.TextBox2) 4fe$0mye End If JI1O( 5 fGUJ[F= Print " " z?C;z7eT Print "Accommodation = " & A & " Diopters" MZ_+doN Print "Pupil Diameter = " & pupilDiam & " mm" F_Q,j]0 F12tOSfu* ' Calculate new parameters with accommodation qK
,mG{ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness
0>D: #L\t)W Rant = 12.0 - 0.4*A 'Radius of anterior lens l@}BWSx&ms CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens C9oF*{ Kgi| 7w Rpost = -5.224557 + 0.2*A 'Radius of posterior lens !*8x>,/> CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens U'iL|JRF o!Vs{RRu} tlens = 3.767 + 0.04*A 'Lens thickness ,Mwyk1:xix *,9.Bx* nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Ln;jB&t <&'Y e[k 'Adjust parameters to account for accommodation x~."P*5 ns.[PJ"8 '************************************************************************* !x9j~D'C` 'Aqueous thickness (Position of Lens) %]9
<a '************************************************************************* y%T5"p$, eID = FindFullName( "Geometry.Arizona Eye.Lens" ) HLMEB0zh^ GetCustomElement eID, entity yVPkJ "i$uV3d parID = FindFullName( "Geometry.Arizona Eye" ) tMaJ; 4 WWF#&)ti ' Delete any shift(s) in z SfE^'G\ count = 0 UV>^[/^O While GetOperationCount(eID)>count k
fx<T GetOperation eID, count, op qL^}t_> If op.Type="ShiftZ" Then SM:SxhrGt DeleteOperation eID,count ZIAiVq2) count=count-1 mY9u/;dK End If 8uME6]m
i count=count+1 F<q3{}1zR Wend R6 wK' Y^gK^?K 'Set new shift in \\jB@O op.Type = "ShiftZ" WG
9f>kE op.val1 = taq ak50]KYo op.parent = parID l79jd%/m AddOperation eID, op qx5X2@-;: Print "Set aqueous humor thickness = " & taq-0.55 qQR>z :>lica_ '************************************************************************* >vg!<%]W] 'Radius and conic constant of anterior lens :V2j'R, '************************************************************************* /2oTqEqaV eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 3OHP-oa. GetConic eID, entity, curv, conic x+5Q}ux'G *qg9~/ SetConic eID, entity, 1/Rant, CCant RVfRGc^lK Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant z]>aWH}$ 3Z'{#<1>^; '************************************************************************* >p!d(J? 'Radius and conic constant of posterior lens HSx~Fs^J '************************************************************************* my")/e eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) s<qSelj GetConic eID, entity, curv, conic CGg:e:4 =!xeki]|9 SetConic eID, entity, 1/Rpost, CCpost <9bQAyL9 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost xtjTU;T :5?ti '************************************************************************* >c7/E 'Lens thickness (Position of posterior lens surface) t; n6Q0 '************************************************************************* #RJy sXTt)J parID = FindFullName( "Geometry.Arizona Eye.Lens" ) i`r,B`V`08 "}K/ b ' Delete any z-shift(s) k`js~/Xv count = 0 +nd'Uf
While GetOperationCount(eID)>count d8M"vd GetOperation eID, count, op I(Nsm3L If op.Type="ShiftZ" Then W<2%J)N< DeleteOperation eID,count ]T^m>v)X count=count-1 GMU<$x8o End If (W+9 u0Zq count=count+1
-/ Wend QAi(uL5 W _b$E
= 'Set new z-shift D4'?
V
Iz op.Type = "ShiftZ" ao{>.b op.val1 = tlens 8)rv.'A((E op.parent = parID t@.gmUUA AddOperation eID, op E yNI]XEj Print "Set lens thickness = " & tlens NOx&`OU+ G !1- 20 '************************************************************************* &t%CuU]/@ 'Lens index of refraction {r&M '************************************************************************* w^|,[G^}H eID = FindMaterial( "Lens" ) /N%f78
Z GetModelMaterial eID, mat 3N+P~v)T' =La}^ mat.Nd = nlens d?N"NqaN SetModelMaterial eID, mat Pms3X Print "Set lens index of refraction = " & nlens v/+ dx/ ?%Y?z]L# '************************************************************************* q'(WIv@ 'Pupil diameter `8FC&%X_ '************************************************************************* )SA$hwR eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) &K>]!yn 9^a>U(, 'Adjust pupil diameter (trimming volume inner hole) YfMe69/0I F5
LQgK-z SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" V2 VsJ 8@hzw~> ' Adjust pupil location to just in front of the lens o95O!5 hl parID = FindFullName( "Geometry.Arizona Eye" ) 2zFdKs, eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ]nX.zE|F count = 0 R8'yQ#FVy While GetOperationCount(eID)>count k 5 "3* GetOperation eID, count, op 3]N}k|lb% If op.Type="ShiftZ" Then h*MR5qa DeleteOperation eID,count (X>y)V count=count-1 W$'pUhq\H End If klf<=V count=count+1 Z}NAH`V`:+ Wend W77JXD93 op.Type = "ShiftZ" H&03>.b op.val1 = taq-0.01 Q`vyDoF op.parent = parID EW5S%Y AddOperation eID, op A^K,[8VX k2t?e:)3zr Print "Set pupil diameter = " & pupilDiam 3$Is==>7 NPoXz 'Update AZ Eye subassembly Description B4|`Z'U#; eID = FindFullName( "Geometry.Arizona Eye" ) EPa3Yb?BGb GetEntity eID, entity Y43#]; entity.Description = "Accommodation = " & A & "D" B8_l+dXO SetEntity eID, entity fwq|8^S@ (|[3/_!;v Update vj^UF(X Print "DONE!" 5z]dA~;*2 ("lcL2Bq End Sub %x927I> dX$])b_Uw 如果屈光度是4,光瞳直径是4,则会输出如下数据: Bw_Ih|y,w 25ayYO%PTc Accommodation = 4 Diopters -:~`g*3# Pupil Diameter = 4 mm 8m1zL[.8g Set aqueous humor thickness = 2.81 x.^vWka( Set anterior lens radius = 10.4 and conic constant = -2.375869 6VE >$`m Set posterior lens radius = -4.424557 and conic constant = -3.081019 ,gOQIS56 Set lens thickness = 3.927 }oN(nPxv9 Set lens index of refraction = 1.42672 q~w;C([k_ Set pupil diameter = 4 gMGg9U$@ DONE! v
PGuEfz N )!v-z,k <>e<Xd:77{ QQ:2987619807 D/:)rj14b
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