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简介 @U.}Ei 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。 kd4*Zab FEi,^V 模型 Y&Vbf>Hi+ x 3co? 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。 %>:)4A 2uR4~XjF Table 1. AZ眼睛模型的定义 nz?BLO= 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. 4Jy,IKPp xcRrI|?eC 光源 }~,cCtg:o !<^j!'2 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。 t:@A)ip =xWW+w!r <?@46d?C 图1. 光源和提示信息使用 ZZJ"Ny.2 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。 ..{^"`FQ .0;k|&eBD 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。 #K*q(ei,7h tfIBsw.
图2. 字母F光源的设定方法光 gY^TBR0?m !Kqj&y5 图3. 字母F在视网膜上位置点列图 WG=r? xE 视网膜的散射 @ y2Bq[' {ZI6!zh' 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。 Vw@x ;j\$[4W.i h pes 图4. 视网膜朗伯散射设定 2Sd6b 2- 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。 Vk=<,<BB _IGa8=~ " yl"A4p
S 图5. 视网膜重点采样规格设定 j|8{Vyqd 脚本 X"59`Yh @!HMd{r 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: ptL}F~ BnY|t2r 图6. 用户对话框的创建与编辑 *"L:"i`*$ 图7. 用户对话框编辑器 3/<^R}w\
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。 j~>
#{"C 余下的脚本计算与屈光度有关的所有参数。 WZ-{K"56 5.UgJ/ 分析 *Z(C')7r l_IX+4(@b| 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 !Bbwl-e` .y/?~+N^ 图7. 字母F在视网膜上颜色分析 jl29~^@}1i 脚本代码 itMc!bUQ }+Z;zm@/6 Option Explicit 'Remove this to enable non-dimensioned variables to be used. ;]o^u.PC \:28z Dim entity As T_ENTITY UZ0O
j5B. Dim op As T_OPERATION ,fLe%RP Dim mat As T_MODELMATERIAL G?(:Z= Dim A As Double {D.0_=y~2 Dim pupilDiam As Double pMrfi}esx Dim eID As Long e+aQ$1^t Dim parID As Long #?|z&9 Dim count As Integer ZWW}r~d{ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double r{;4(3E2 Dim tlens As Double, nlens As Double skArocs Dim curv As Double, conic As Double [$+61n}.12 Dim ok As Long zOp"n\ N=x,96CF Sub Main K",]_+b @isqFKjph '用户输入对话框 YR#1[fe*_ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ~qxc!k!w4 TextBox 220,21,40,21,.TextBox1 'default: 0 GoXHVUyp Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ^<b.j.$<z OKButton 40,91,90,21 Ctx K{: CancelButton 190,91,90,21 EFO Q;q Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 M,lu)~H TextBox 220,49,40,21,.TextBox2 'default: 4 x&p=vUuukP End Dialog |%9~W^b Dim dlg As UserDialog Dn!V)T sNTfRPC ok = Dialog (dlg) 1 crjRbi w|#79,& If ok=0 Then 'cancel button was pressed "fwuvT
1 Print "Execution cancelled." ThB2U(Wf End EaL+}/q& End If '93&? O;tn5 'Assign accommodation and pupil diameter & use defaults if field left empty 4 .qjTR If dlg.TextBox1 = "" Then }=)"uv A = 0 'Default accommodation m 9Q{)?J7 Else %M:"Ai5: A = CDbl(dlg.TextBox1) )A"7l7?.n) End If 2|EoP-K7 %J'_c|EQM If dlg.TextBox2 = "" Then ABf#!G pupilDiam = 4 'Default pupil diameter }%|OnEk" Else ],m-,K pupilDiam = CDbl(dlg.TextBox2) ,;}RIcvQV End If -ybupUJcbv % *hBrjbj Print " " ,kI1"@Tu Print "Accommodation = " & A & " Diopters" xCD+qP^ Print "Pupil Diameter = " & pupilDiam & " mm" g'@+#NMw V00zk`PH ' Calculate new parameters with accommodation &bNj/n/ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness AmFHn z'*>Tk8h Rant = 12.0 - 0.4*A 'Radius of anterior lens "tIx$?I CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens FeJ5^Gh. p-_j0zv Rpost = -5.224557 + 0.2*A 'Radius of posterior lens 9:>vl0 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens #t*c*o Urr1K) tlens = 3.767 + 0.04*A 'Lens thickness "~6BC E&AR=yqk nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction "`wq:$R "k/x+%!Spc 'Adjust parameters to account for accommodation *@Z'{V\ dEnhNPeRl '************************************************************************* ubw ]}sfM# 'Aqueous thickness (Position of Lens) Z'~FZRF '************************************************************************* bBf+z7iyc eID = FindFullName( "Geometry.Arizona Eye.Lens" ) el<nY"c GetCustomElement eID, entity sQ$FtKm6 s&l[GKR parID = FindFullName( "Geometry.Arizona Eye" ) nK[$ID Y;WrfO$J ' Delete any shift(s) in z :0l(Ll KD count = 0 0 N(2[s_A While GetOperationCount(eID)>count >=(e}~5y GetOperation eID, count, op (`N/1}vk If op.Type="ShiftZ" Then xHmc8G$zu DeleteOperation eID,count _<$=n6# count=count-1 3 ren1 End If +}!eAMQ count=count+1 VI4d/2e Wend i8]r}a ~tWBCq 6 'Set new shift in POf \l op.Type = "ShiftZ" l d@^$ op.val1 = taq ^/,s$dj op.parent = parID W~qo
`r AddOperation eID, op Hcpw[%( Print "Set aqueous humor thickness = " & taq-0.55 F&\o1g-L 'nul{RE* '************************************************************************* Kj7Osqu2bE 'Radius and conic constant of anterior lens )]}*oO '************************************************************************* sC$X7h(Q+ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) m-:k]9I GetConic eID, entity, curv, conic s}.nh>Q (]JJ?aAF SetConic eID, entity, 1/Rant, CCant er_aol e Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant cb+!H>+ @1pdyKK '************************************************************************* ^ZsME, 'Radius and conic constant of posterior lens P_;oSN|> '************************************************************************* nL$tXm-x eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) BBX4^;t GetConic eID, entity, curv, conic {|fA{ Q_R 1Dbe0u SetConic eID, entity, 1/Rpost, CCpost c}Qc2D3* Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost *?uF&( 0 F'K{= '************************************************************************* 9'tM65K 'Lens thickness (Position of posterior lens surface) zUh(b=, '************************************************************************* ,Ya&M@^Z 3K'3Xp@A parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ZE :oK -{O2Nv- ]] ' Delete any z-shift(s) dO=<3W count = 0 2XE4w# [j While GetOperationCount(eID)>count \nLO., GetOperation eID, count, op H=dj\Br` If op.Type="ShiftZ" Then Bg3^BOT DeleteOperation eID,count n4:WM+f4 count=count-1 [~J4:yDd= End If WN0^hDc- count=count+1 ZK;HW Wend k~?@~xm,R >Nov9<p 'Set new z-shift 'HC4Q{b` op.Type = "ShiftZ" wC[J=:]tA5 op.val1 = tlens &1I0i[R op.parent = parID 4-TM3Cw`d& AddOperation eID, op }/=VnCfU Print "Set lens thickness = " & tlens 'd28YjtoX F4k`x/ak '************************************************************************* $}&6p6| 'Lens index of refraction _ K9jj '************************************************************************* /g_}5s-Z eID = FindMaterial( "Lens" ) n>@(gDq GetModelMaterial eID, mat ThHK1{87X} uv@4/M` mat.Nd = nlens ]-O:| q>] SetModelMaterial eID, mat 7==Uoy*O Print "Set lens index of refraction = " & nlens $GcVC (] # wG}T
.* '************************************************************************* rUj]6j=e 'Pupil diameter rc$G0O '************************************************************************* {RzlmDStV eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) b[/-lNrc UCl,sn 'Adjust pupil diameter (trimming volume inner hole) `=FfzL s Ce{V*ua SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" \}cEHLq /{Nx%PqL ' Adjust pupil location to just in front of the lens IQR?n}ce parID = FindFullName( "Geometry.Arizona Eye" ) Jo2:0<VL eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) <%|2yPb] count = 0 3.8d" While GetOperationCount(eID)>count WT1ch0~2 GetOperation eID, count, op E$RH+):| If op.Type="ShiftZ" Then chxO*G DeleteOperation eID,count vmL0H)q count=count-1 %POoyH@D} End If ^xFZ;Yf count=count+1 g&&5F>mF Wend ^hLAMaR op.Type = "ShiftZ" 10t9Qv/ op.val1 = taq-0.01 H htAD Y op.parent = parID y 1z4qSeM AddOperation eID, op aO6w:IO }fdo
Aid~ Print "Set pupil diameter = " & pupilDiam :IvKxOv :Fu.S1j$ 'Update AZ Eye subassembly Description dy`K5lC@ eID = FindFullName( "Geometry.Arizona Eye" ) >}Fe9Y.o GetEntity eID, entity g"^<LX- entity.Description = "Accommodation = " & A & "D" 9*U3uyPi SetEntity eID, entity m&cVda/ HvLvSy1U
Update ~}PB&`%7 Print "DONE!" \= =rdW- tWT@%(2~0 End Sub -ich N/U]s CWHTDao 如果屈光度是4,光瞳直径是4,则会输出如下数据: r<
sx On }y;s(4 Accommodation = 4 Diopters 1>|2B&_^ Pupil Diameter = 4 mm 09HlL=0q Set aqueous humor thickness = 2.81 :*k Set anterior lens radius = 10.4 and conic constant = -2.375869 t&*X~(Yb! Set posterior lens radius = -4.424557 and conic constant = -3.081019 }\?UmuolQ Set lens thickness = 3.927 @Ge\odfF: Set lens index of refraction = 1.42672 s8Bbet Set pupil diameter = 4 tUaDwIu# DONE! 5R"iF+p4 2M1}`H\ (文章来源:讯技光电)
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