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?2O( iY[+Ywh 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。 c"YXxAJ PL0`d`TI 模型 &Y|Xd4: #~:P}<h 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。 n[xkSF^) xIbMs4'iEx Table 1. AZ眼睛模型的定义 ClW'W#*(Y 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. 6@;ha=[+ F
SMj 光源 jX=lAs~6 UyYfpL"$A" 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 l'4AF|
p yT /EHmJ A Ayv 图1. 光源和提示信息使用 n/e
BE q 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 v vu<:16 _fTwmnA 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。
GrJ#. MlO-+}`_+ 图2. 字母F光源的设定方法光 *}b]rjsj ?v]-^X=& 图3. 字母F在视网膜上位置点列图 Pd=,$UQp 视网膜的散射 l?N`{,1^ ucYkxi`x 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。 f*((;*n; 6/ g%\ka T(X:Yw 图4. 视网膜朗伯散射设定 n"{X!(RIcx 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。 JV"NZvjN7d 4z4v\IpB M.%shrJ/ 图5. 视网膜重点采样规格设定 >mu)/kl 脚本 _"f :` <dR,' 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: y%B X]~ g#^|oYuH6 图6. 用户对话框的创建与编辑 =Z0t :{ 图7. 用户对话框编辑器 /"AvOh* 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。 #Fd W/y5 余下的脚本计算与屈光度有关的所有参数。 ^tAO_~4 "X1vZwK8N 分析 60B-ay0e$b mMw;0/n 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 97~K!'/^+y E:A!wS`" 图7. 字母F在视网膜上颜色分析 <bmLy_": 脚本代码 T{MC-j _T9 [$\>~nj= Option Explicit 'Remove this to enable non-dimensioned variables to be used. ksI>IW &~~s6
Dim entity As T_ENTITY I lG:X)V% Dim op As T_OPERATION crmUrF# Dim mat As T_MODELMATERIAL aO1IVESr$ Dim A As Double BA+_C]%ZJ Dim pupilDiam As Double ,"
R>}kPli Dim eID As Long Lyoor1 Dim parID As Long ?C;JJ#Ho Dim count As Integer rg&+ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double B4W\
t{ Dim tlens As Double, nlens As Double (Pi-uL<[a Dim curv As Double, conic As Double av' *u Dim ok As Long UmP'L! F-0UdV Sub Main #s"B-sWE " ~$$ '用户输入对话框 T0|H9>M Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 uEd,rEB> TextBox 220,21,40,21,.TextBox1 'default: 0 xPQL?. Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 zXre~b03ZS OKButton 40,91,90,21 s44iEh=V(I CancelButton 190,91,90,21 9N
Le&o Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 qi=3L TextBox 220,49,40,21,.TextBox2 'default: 4 <MZi<Z` End Dialog HHS45kg[c Dim dlg As UserDialog 'DAltr< sbla`6Fb ok = Dialog (dlg) 31XU7A *8\(FVyG^ If ok=0 Then 'cancel button was pressed LM1b I4 Print "Execution cancelled." j[DIz@^ End Nlt4) End If FMS2.E *T4ge|zUc 'Assign accommodation and pupil diameter & use defaults if field left empty p.Y$A
if. If dlg.TextBox1 = "" Then z\}!RBOq A = 0 'Default accommodation @d)a~[pm Else
5-'vB A = CDbl(dlg.TextBox1) Y><(? End If @hT;Bo2G] BX$hAQ(6Q If dlg.TextBox2 = "" Then `pYE[y+ pupilDiam = 4 'Default pupil diameter FmA-OqEpA Else lG]GlgSs pupilDiam = CDbl(dlg.TextBox2) 7Po/_% End If N1?
iiv TN ci.'] Print " " faVS2TN4 Print "Accommodation = " & A & " Diopters" V_]-`?S Print "Pupil Diameter = " & pupilDiam & " mm" {HuLuP0t >B~?dT m ' Calculate new parameters with accommodation Ihef$, taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness E& ]_U$ 6D^%'[4t Rant = 12.0 - 0.4*A 'Radius of anterior lens -A@U0=o CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens I"V3+2e )dg UmN Rpost = -5.224557 + 0.2*A 'Radius of posterior lens w4}(Ab<Y CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens R6Pz#`n }}s)
+d tlens = 3.767 + 0.04*A 'Lens thickness V'yxqI? KgU[ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction qS82/e)7 SA3Y:( 'Adjust parameters to account for accommodation 4`0;^K. D[W}[r '************************************************************************* &|] Fg5 'Aqueous thickness (Position of Lens) },3R%?89% '************************************************************************* ]Hj`2\KD.d eID = FindFullName( "Geometry.Arizona Eye.Lens" ) fW[.r== Kf GetCustomElement eID, entity YD+QX@ F\P!NSFZV parID = FindFullName( "Geometry.Arizona Eye" ) ~p!QSRu~,b %>NRna ' Delete any shift(s) in z 9;:7e*x]lc count = 0 RA~_]Hk While GetOperationCount(eID)>count c=<v.J@K GetOperation eID, count, op Q,TaJ] If op.Type="ShiftZ" Then &`5 :GLV DeleteOperation eID,count ~pwY6Q count=count-1 D2-O7e End If T/3;NXe6E count=count+1 8Nv-/VQ/b Wend t9n'! "p2u+ 8? 'Set new shift in .Px,=56$X op.Type = "ShiftZ" otZ JY) op.val1 = taq ri;r7Y9V9` op.parent = parID 1 pYsjo~ AddOperation eID, op PE +qYCpP9 Print "Set aqueous humor thickness = " & taq-0.55 a\|X^%2g
pe|\'<>i '************************************************************************* zkvH=wL 'Radius and conic constant of anterior lens JG1LS$p^ '************************************************************************* Is~yVB02 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) fjG /dhr GetConic eID, entity, curv, conic lHRK'?Q _2x uzmz0 SetConic eID, entity, 1/Rant, CCant 7{8)ykBU^ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 5"]aZMua i@%L_[MtA '************************************************************************* lK 9s0t' 'Radius and conic constant of posterior lens ec,z6v^9 '************************************************************************* HKT{IP+7(L eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ZW`HDrP` GetConic eID, entity, curv, conic 96k(XLR gS0,')w SetConic eID, entity, 1/Rpost, CCpost +2f>
M4q Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost +# A|Zp< rUhWZta '************************************************************************* ],WwqD= 'Lens thickness (Position of posterior lens surface) il<gjlyR]L '************************************************************************* d
u_O} x y;*My# parID = FindFullName( "Geometry.Arizona Eye.Lens" ) N>h]mX6 &7JEb]1C ' Delete any z-shift(s) p` ^:Q*C" count = 0 nT(!HDH While GetOperationCount(eID)>count jAsh
GetOperation eID, count, op 6!i(
\Q* If op.Type="ShiftZ" Then /<Gyg7o0 DeleteOperation eID,count K>`m_M"LA count=count-1
s$e K66H End If 4d,qXSKty count=count+1 MX%|hIOpr Wend zV9
= ~r7DEy|+ 'Set new z-shift 1j_aH#Fz: op.Type = "ShiftZ" %!1@aL]pQ op.val1 = tlens 1KNkl,E op.parent = parID @D( KuF AddOperation eID, op C8O7i[uc Print "Set lens thickness = " & tlens gogl[gHO |YMzp8Da( '************************************************************************* gt(X!iN] 'Lens index of refraction ) >-D={ '************************************************************************* %>oT7|x eID = FindMaterial( "Lens" ) Vw6>:l<+< GetModelMaterial eID, mat +^o3}` xV
}:M mat.Nd = nlens fwz5{>ON] SetModelMaterial eID, mat O#<|[Dzw Print "Set lens index of refraction = " & nlens 96^1Ivd 2\kC_o97 '************************************************************************* )4 VLm 'Pupil diameter W,L>'$#pM '************************************************************************* aH~x7N6! eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) W_Ws3L1;N "oKj~:$ 'Adjust pupil diameter (trimming volume inner hole) }-k_?2"A t(LlWd SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ;+#za?w ~`W6O> ' Adjust pupil location to just in front of the lens |R:v< parID = FindFullName( "Geometry.Arizona Eye" ) xP|%rl4 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ]-+.lR%vd9 count = 0 o>QFdx While GetOperationCount(eID)>count N23+1 h GetOperation eID, count, op >"m@qkh If op.Type="ShiftZ" Then Oa3=+_C~$1 DeleteOperation eID,count 96([V|5K count=count-1 9, sCJ5bb" End If 3e!a>Gl* count=count+1 HquB*=^xh Wend e{#a{`?Uez op.Type = "ShiftZ" O_%PBgcJr op.val1 = taq-0.01 8{U]ATx'( op.parent = parID u:qD*zOq AddOperation eID, op -sGWSC !Sr0Im0 Print "Set pupil diameter = " & pupilDiam eO[Cb]Dy: ?Pok-90 'Update AZ Eye subassembly Description C$Hl`>?$ eID = FindFullName( "Geometry.Arizona Eye" ) OL6xMToP GetEntity eID, entity /^es0$Co. entity.Description = "Accommodation = " & A & "D" '"G
%0y SetEntity eID, entity Z1MJ!{@6 m}'t'l4 c Update 8=zM~v) Print "DONE!" `mHOgS>| olQ8s* End Sub `!>dbR&1 S<bz7
k9 如果屈光度是4,光瞳直径是4,则会输出如下数据: j@_) F^12 ^|hRu{QW Accommodation = 4 Diopters zi DlJ3]^ Pupil Diameter = 4 mm o\:f9JL Set aqueous humor thickness = 2.81 spoWdRM2 Set anterior lens radius = 10.4 and conic constant = -2.375869 9OO_Hp#|9 Set posterior lens radius = -4.424557 and conic constant = -3.081019 $'mB 8 S Set lens thickness = 3.927 KE)D =P Set lens index of refraction = 1.42672 B$[%pm`'2 Set pupil diameter = 4 po](6V DONE! TF iM[
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