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简介 JXrMtSp\ iM-@?!WF 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。 4?`7XJ0a Q =Z-vTD+ 模型 K7|BXGL8r8 U<$ |ET' 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。 ^+88z> t5S S] Table 1. AZ眼睛模型的定义 TeHR,GB 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. ;TYkJH" &0'BCT 光源 kAMt8 3LG)s:p$/ 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 C
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8 HQ"D>hsuU r>Vgo):s 图1. 光源和提示信息使用 O:4.xe 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 uXXwMc<p 1r$q $\ 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 Y`%:hvy~ _ 95V"h 图2. 字母F光源的设定方法光 E=7~\7TE *g7dB2{ 图3. 字母F在视网膜上位置点列图 tcfUhSz,I 视网膜的散射 )!'SSVaRs e(cctC|l 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 vtmvvv z"|^Y|`m 1N2s[ \q$ 图4. 视网膜朗伯散射设定 |dXmg13( - 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。 tT'+3 S7@.s`_{w 0GEK xV\F 图5. 视网膜重点采样规格设定 CtS*"c,j 脚本 C,.$g>)MZK `8EHhN; 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:
d x?4)lb wUab)L 图6. 用户对话框的创建与编辑 s-[ _% 图7. 用户对话框编辑器 Ry8@U9B6,t 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。 1 %K^(J; 余下的脚本计算与屈光度有关的所有参数。 *s}dtJ zrri&QDF< 分析 6p])2]N>p =otJf~ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ND77(I$3s a!vF;J-Zqa 图7. 字母F在视网膜上颜色分析 Hn+w1v&3 脚本代码 jNBvy1 C;QIp6"1 Option Explicit 'Remove this to enable non-dimensioned variables to be used. 0P_qtS :=3Ty]e Dim entity As T_ENTITY *DcJ). Dim op As T_OPERATION .-Yhpw>f Dim mat As T_MODELMATERIAL =J:6p-\* Dim A As Double p'tB4V qT Dim pupilDiam As Double Zl^#U c" Dim eID As Long +zn&DG0\X Dim parID As Long }}y~\TB~} Dim count As Integer KF(N=?KO Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double >VIb|YA Dim tlens As Double, nlens As Double kqdF)Wa am Dim curv As Double, conic As Double s~V%eq("} Dim ok As Long j+YA/54` Q4i@y6z Sub Main V/"P};n OiAP%7i9 '用户输入对话框 +X#JCLD Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 tj7{[3~-[ TextBox 220,21,40,21,.TextBox1 'default: 0 0Rgo#`7l Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 #[=%+ *Q OKButton 40,91,90,21 T$)N2]FE CancelButton 190,91,90,21 tj<a , l Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 m$6u K0 TextBox 220,49,40,21,.TextBox2 'default: 4 zI1-l9 o End Dialog !}
~K'1" Dim dlg As UserDialog 2vbm=~)$F *PEk+e ok = Dialog (dlg) &b~if}vcb z86[_l: If ok=0 Then 'cancel button was pressed 6'E3Q=}d Print "Execution cancelled." d'y\~M9( End fdk]i/*) End If 1VRexp $=) i{kGS@ 'Assign accommodation and pupil diameter & use defaults if field left empty <B"M} Y>_P If dlg.TextBox1 = "" Then TX/Ng+v S A = 0 'Default accommodation gN./u Else /8](M5X]f A = CDbl(dlg.TextBox1) (x"TM),Q End If WJD1U?` 1"7Rs}l7 If dlg.TextBox2 = "" Then B}Lz#'5_ pupilDiam = 4 'Default pupil diameter ;G
27S<Q Else >M1m(u84# pupilDiam = CDbl(dlg.TextBox2) X"'c2gaa_ End If ;ndsq[k> /1s|FI$-L Print " " pz L !42 Print "Accommodation = " & A & " Diopters" _DlkTi5(w Print "Pupil Diameter = " & pupilDiam & " mm" KaRdO gtizgUS7 ' Calculate new parameters with accommodation 7*D*nY4+ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ]gxt+'iAFS {i}z|'! Rant = 12.0 - 0.4*A 'Radius of anterior lens \Pv_5LAo CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens S w<V/t Mwm=r// Rpost = -5.224557 + 0.2*A 'Radius of posterior lens P[|FK(l CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens i Eh
- aahAUhF tlens = 3.767 + 0.04*A 'Lens thickness xUp[)B6?: G'*_7HD nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction w>RBth^p z%
ln} 'Adjust parameters to account for accommodation 3M/iuu -]!m4xvK '************************************************************************* ]{`
8C 'Aqueous thickness (Position of Lens) +Xa^3 =B '************************************************************************* ?52{s"N0> eID = FindFullName( "Geometry.Arizona Eye.Lens" ) /hC[>t< GetCustomElement eID, entity .iDxq8l %D::$,;<< parID = FindFullName( "Geometry.Arizona Eye" ) F4=+xd >0 K2=`. ' Delete any shift(s) in z &3jq'@6 count = 0 1-HL#y*7$ While GetOperationCount(eID)>count ;=&D_jGf]
GetOperation eID, count, op $6&P 69< If op.Type="ShiftZ" Then 95`Q=I|i DeleteOperation eID,count jGM+ count=count-1 bu;3Ib3\ End If Y}'8`. count=count+1 994 Wend Mn<G9KR Pc=S^}+ 'Set new shift in A7{l60(5 op.Type = "ShiftZ" -uho; op.val1 = taq !11x&Db op.parent = parID FQV]/ AddOperation eID, op 6usy0g
D Print "Set aqueous humor thickness = " & taq-0.55 ^uU'Qc4S= t>04nN_@,s '************************************************************************* ?dWfupO{ 'Radius and conic constant of anterior lens 3YtFO;- '************************************************************************* I'23$IzPA eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) fS( )F*J GetConic eID, entity, curv, conic $!+t2P@d.5 auV'`PR SetConic eID, entity, 1/Rant, CCant c"vF i~Db Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant >a5M:s) f87>ul!* '************************************************************************* EYe)d+E* 'Radius and conic constant of posterior lens a@1r3az '************************************************************************* Ch`nDIne eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) b!>w4MPe GetConic eID, entity, curv, conic z8#c!h<@; 410WWR&4_ SetConic eID, entity, 1/Rpost, CCpost R]oi&"H@r) Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 9.bMA<X }]-SAM '************************************************************************* ya+eGD@N': 'Lens thickness (Position of posterior lens surface) %h"+J '************************************************************************* IIN"'7Z^R #MZ0Sd8]& parID = FindFullName( "Geometry.Arizona Eye.Lens" ) _g%Wx?K9 |( %3'"Z ' Delete any z-shift(s) 5W0'r'{ count = 0 ?V6+o`bm While GetOperationCount(eID)>count myp}DI( GetOperation eID, count, op PI"&-lXI-m If op.Type="ShiftZ" Then Z19d Ted33 DeleteOperation eID,count
8&AHu count=count-1 .3(=UQ End If $(2c0S{ 1 count=count+1 #8N9@ Wend C*e)UPK` kNX(@f 'Set new z-shift R~-r8dWcw op.Type = "ShiftZ" 7\'ow|)}v op.val1 = tlens 6B4s6 op.parent = parID !ul)e;a AddOperation eID, op X#s:C=q1 Print "Set lens thickness = " & tlens 'E/vE0nN? O/gBBTB '************************************************************************* |?c
v5l7E 'Lens index of refraction Dh*>361y- '************************************************************************* H}}]Gh.T eID = FindMaterial( "Lens" ) AJRfl% 3 GetModelMaterial eID, mat J~Gq#C^e E'p5 mat.Nd = nlens O,Xf.O1c SetModelMaterial eID, mat M5C}*c9 Print "Set lens index of refraction = " & nlens 05".;( =2VM(GtK> '************************************************************************* s'LY)_n 'Pupil diameter MSPzOJQPy '************************************************************************* )t
G`a ; eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 6gS<h\h0 xUYUOyV 'Adjust pupil diameter (trimming volume inner hole) u7!X#< y8U |A0@$` SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" oB27Y&nO Im{I23.2 ' Adjust pupil location to just in front of the lens a;p3Me7 parID = FindFullName( "Geometry.Arizona Eye" ) ?YY'-\h? eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) w'q}aQS count = 0 %YhZ#>WT While GetOperationCount(eID)>count A_: Bz: GetOperation eID, count, op ?i*kwEj= If op.Type="ShiftZ" Then *Yk3y-
DeleteOperation eID,count #UH|,>W6 count=count-1 WU-.lg'c' End If /}?"O~5M" count=count+1 [((P,v* Wend /H+j6*}r op.Type = "ShiftZ" zBWn*A[4 op.val1 = taq-0.01 D_,}lsrb op.parent = parID gIS<"smOo AddOperation eID, op ukV1_QeN[ qw[)$icP Print "Set pupil diameter = " & pupilDiam d$<HMs:o@ y\Z7]LHCqw 'Update AZ Eye subassembly Description ^{8r(1, eID = FindFullName( "Geometry.Arizona Eye" ) Oy$*ZG ) GetEntity eID, entity z65|NO6JW. entity.Description = "Accommodation = " & A & "D" x$9UHEb kM SetEntity eID, entity )*N]Q [3++Q-rR= Update #SQao;> Print "DONE!" n~\"W Y5fwmH,a- End Sub E1:{5F5/ 5haJPWG|' 如果屈光度是4,光瞳直径是4,则会输出如下数据: ;5 cg<~t \R45#.
P6X Accommodation = 4 Diopters D0,U2d Pupil Diameter = 4 mm IbQ3* Set aqueous humor thickness = 2.81 %-?HCjT Set anterior lens radius = 10.4 and conic constant = -2.375869 gW'aK>*c Set posterior lens radius = -4.424557 and conic constant = -3.081019 ^G{3x Set lens thickness = 3.927 c[ @-&o` Set lens index of refraction = 1.42672 -~eNC^t;W Set pupil diameter = 4 fB[I1Z DONE! XoM+"R"
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