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简介 y44FejH(v Y5&Jgn.l 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。 :~3sW< PR "aHY]E{ 模型 \:mx Ri 5V!L~# 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。 3Bee6N> }jBr[S5 Table 1. AZ眼睛模型的定义 JryDbGc8 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. 7Te`#" M8X*fYn 光源 VQ5T$,& WCA`34( 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 !f-mC,d }`{>]2 s
Z(LT'} 图1. 光源和提示信息使用 {>tgNW>) 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 rVowHP 9a 9<I 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 BoYWx^VHx^ V|zzj[c 图2. 字母F光源的设定方法光 E@^`B9;Q7 }@=m[Zx# 图3. 字母F在视网膜上位置点列图 X&nkc/erx 视网膜的散射 <&\HXAOd -U)6o"O_CV 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 zB/$*Hd m663%b(5> I~y[8 图4. 视网膜朗伯散射设定 u4bPj2N8I 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。 7GY[l3arxv vNlYk o)F^0t 图5. 视网膜重点采样规格设定 !yU!ta Q 脚本 RKFj6u ~j}di^<{ 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: c) Zid1 oNY;z-QK 图6. 用户对话框的创建与编辑 vT"T*FKh: 图7. 用户对话框编辑器 &MsnQP 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。 *i|O!h1St 余下的脚本计算与屈光度有关的所有参数。 N(q%|h<Z/= :$."x
' 分析 Ug*:o d u:tLO3VfJ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 vS%o>"P S~0 mY}
m 图7. 字母F在视网膜上颜色分析 ba& \~_4 脚本代码 =Y#)c]` o7<pI8\ Option Explicit 'Remove this to enable non-dimensioned variables to be used. qFp }+s gfG Mu0FjB Dim entity As T_ENTITY 8X!^ 2B}J Dim op As T_OPERATION KZUB{Y^) Dim mat As T_MODELMATERIAL hd1(q33 Dim A As Double <iVn!P Dim pupilDiam As Double [}q6bXM* Dim eID As Long 4CVtXi_Y Dim parID As Long :pj#t$:! Dim count As Integer ~K]5`(KV Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double JYA$_T Dim tlens As Double, nlens As Double -:b0fKn Dim curv As Double, conic As Double | YmQO#'' Dim ok As Long Jj4!O3\I ' _Ij9{M Sub Main f{MXH&d 1\ pe$"
nUy| '用户输入对话框 ]+\;pb}bq Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 %Ez= TextBox 220,21,40,21,.TextBox1 'default: 0 jPU:&1(_ n Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 PrqN5ND OKButton 40,91,90,21 2Sbo7e CancelButton 190,91,90,21 bzD <6Z Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 oG~a`9N%C TextBox 220,49,40,21,.TextBox2 'default: 4 swV/Mi> End Dialog 2iC7c6hc Dim dlg As UserDialog /\P3UrQ&] rKg~H=4x2 ok = Dialog (dlg) ^[6eo8Ck> U86bn(9K If ok=0 Then 'cancel button was pressed sc
dU Print "Execution cancelled." },G6IuH% End h}r64<Y2{ End If `7$0H]*6 F,}wQN 'Assign accommodation and pupil diameter & use defaults if field left empty ]FV,}EZ If dlg.TextBox1 = "" Then Xr'Y[E[ A = 0 'Default accommodation .vHSKd{ Else V("@z<b| A = CDbl(dlg.TextBox1) :MPWf4K2s End If [)UL}vAO\q A3D"b9<D If dlg.TextBox2 = "" Then :4RD.l pupilDiam = 4 'Default pupil diameter j"o8]UT/ Else 5%M 'ewu pupilDiam = CDbl(dlg.TextBox2) d Bn/_ End If gI<e=|J6w ~5LlIpf36| Print " " 6\"g,f Print "Accommodation = " & A & " Diopters" K. [2uhB) Print "Pupil Diameter = " & pupilDiam & " mm" nP`#z&C yneIY-g(p ' Calculate new parameters with accommodation +Y;/10p taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness l]tda( b.HfxYt( Rant = 12.0 - 0.4*A 'Radius of anterior lens NvCq5B$C CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens *b#00)d
1N8gH&oF Rpost = -5.224557 + 0.2*A 'Radius of posterior lens NKyaR_q` CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens lS<T|:gz@ $M%<i~VXe& tlens = 3.767 + 0.04*A 'Lens thickness esE5#Yq4.k T^FeahA7; nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction +pDZ,c, <X]'": 'Adjust parameters to account for accommodation
%T9'dcM IJX75hE0g '************************************************************************* [!Uzw2 'Aqueous thickness (Position of Lens) o2p;$W4` '************************************************************************* tx0`#x eID = FindFullName( "Geometry.Arizona Eye.Lens" ) +<qmVW^X GetCustomElement eID, entity D}4*Il? {|dU|h parID = FindFullName( "Geometry.Arizona Eye" ) 7bcl^~lY 4rXjso| ' Delete any shift(s) in z q u>5 rg- count = 0 ;&="aD While GetOperationCount(eID)>count fd Vye|% GetOperation eID, count, op %K@s0uQ If op.Type="ShiftZ" Then 79}voDFd DeleteOperation eID,count Z?@1X`@ count=count-1 }?PvNK]", End If ::'DWD1 count=count+1 &U<t*" Wend O [Q;[@ t4HDt\}&k~ 'Set new shift in IC5[:UZ5] op.Type = "ShiftZ" @log=^ op.val1 = taq #fT1\1[] op.parent = parID 8&d s AddOperation eID, op B^8]quOH Print "Set aqueous humor thickness = " & taq-0.55 Y<1]{4Wt rID_^g_tP8 '************************************************************************* V*
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^ 'Radius and conic constant of anterior lens WsHC%+\' '************************************************************************* ur*a!U eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) wO\,?SI4 GetConic eID, entity, curv, conic G3 h&nH,> G'>?/l# SetConic eID, entity, 1/Rant, CCant Ed&;d+NM Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant kd0~@rPL Z]Zs"$q@ '************************************************************************* "l83O8 L 'Radius and conic constant of posterior lens ,Oqd4NS '************************************************************************* gW0{s[}T eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Y@&1[Z GetConic eID, entity, curv, conic Ky6.6Y<.| l;u_4`1H SetConic eID, entity, 1/Rpost, CCpost ,gdf7&r Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost G5;N#^myJ `EFPY$9`D '************************************************************************* H2EKr#(
'Lens thickness (Position of posterior lens surface) [X9s\H '************************************************************************* 'a&( r; oh>X/uj parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 4KO2oIR )Fa6'M ' Delete any z-shift(s) %Fb4 count = 0 G"_ 8`l While GetOperationCount(eID)>count K/^70;/!. GetOperation eID, count, op D7'P^*4_B If op.Type="ShiftZ" Then |Wo_5|E DeleteOperation eID,count PP+-D~r`} count=count-1 vbol70 End If ~\0uy3% count=count+1 Er 4P Wend {9 PeBc /CXrxeo 'Set new z-shift S7/0B4[ op.Type = "ShiftZ" Py}`k 1t*f op.val1 = tlens ,{KjVv< op.parent = parID vocXk_ AddOperation eID, op >icL,n"] Print "Set lens thickness = " & tlens a.oZ}R7'Y QH?}uX'x)G '************************************************************************* OJ2O?Te8 'Lens index of refraction Glt%%TJb '************************************************************************* z3 zN^ZT eID = FindMaterial( "Lens" ) R^nkcLFb/q GetModelMaterial eID, mat 8ec6J*b oH[4<K> mat.Nd = nlens ^5"2s:vP SetModelMaterial eID, mat Y<A593 Print "Set lens index of refraction = " & nlens <%@S-+D`] )ifEgBT '************************************************************************* /^BaQeH?R 'Pupil diameter kX\\t.nH '************************************************************************* ]["=K!la: eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) !!WSGZUR i]qVT)j 'Adjust pupil diameter (trimming volume inner hole) gEejLyOag Q%x | SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" }w,^]fC: Z(' iZ'55F ' Adjust pupil location to just in front of the lens ?<Tt1fpG parID = FindFullName( "Geometry.Arizona Eye" ) im}= eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) AbWnDqv count = 0 ka3(sctZ5 While GetOperationCount(eID)>count W~TT`%[ GetOperation eID, count, op 2 g)W-M If op.Type="ShiftZ" Then (l|:$%[0 DeleteOperation eID,count ("UzMr, count=count-1 T'n~QfU End If R4?OFhN9 count=count+1 G! y~Y]e Wend JZCRu_M>| op.Type = "ShiftZ" sQBl9E'!be op.val1 = taq-0.01 f* +eu@ op.parent = parID &=seIc>x@ AddOperation eID, op "`sr# z[7j`J|Kk Print "Set pupil diameter = " & pupilDiam F]#rH **zh>Y}6 'Update AZ Eye subassembly Description ?5%0zMC eID = FindFullName( "Geometry.Arizona Eye" ) Jgf73IX[ GetEntity eID, entity ~AD%aHR entity.Description = "Accommodation = " & A & "D" |{KZ< SetEntity eID, entity Sdc
yL%6! Nb))_+/ Update sj)$o94= Print "DONE!" $;9zD11 /Dn,;@ZwAi End Sub M]S&vE{D t+R8{9L- 如果屈光度是4,光瞳直径是4,则会输出如下数据: Ol }^'7H i.0}d5Y Accommodation = 4 Diopters N8<Wm>GLX~ Pupil Diameter = 4 mm sC8C><y
Set aqueous humor thickness = 2.81 I?).D?o Set anterior lens radius = 10.4 and conic constant = -2.375869 Z#-:zD7_ Set posterior lens radius = -4.424557 and conic constant = -3.081019 l?+67cQLA Set lens thickness = 3.927 MjO.s+I Set lens index of refraction = 1.42672 C?UV3 Set pupil diameter = 4 mN_KAln DONE! !'4HUB>+
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