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简介 Z?.*.<"Sj 6bNW1]rD 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。 E/ZJ\@gzD *u/|NU&X 模型 hD1AK+y i =N\[& 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。 1Q SIZoK7 mM*yv Table 1. AZ眼睛模型的定义 Rda1X~-g 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. "yTh + = -ZP&zOsDr 光源 iyYY)roB V|\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。 8>Z$/1Mh &8_;: Jche79B 图1. 光源和提示信息使用 49oW 'j 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 41o!2(e$ >iH).:j 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。 GB?#1|, 1fW4=pF-K 图2. 字母F光源的设定方法光 x{>Y$t] `^L<db^A 图3. 字母F在视网膜上位置点列图 6 ]PM!6 视网膜的散射 3:joSQa {(}w4.! 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 ^70 .g?(f[ :{:?D\%6 )O@^H 图4. 视网膜朗伯散射设定 }c4E 2c 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 2ZbY|8X$r o
U}t'WU -\'.JA_ 图5. 视网膜重点采样规格设定 -`dxx)x 脚本 Kn#xY3W6 kgI=0W> 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: ~,!hE&LE~ HwW[M[qA 图6. 用户对话框的创建与编辑 udD*E~1q 图7. 用户对话框编辑器 W(a'^
#xe 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。 5u)^FIBj 余下的脚本计算与屈光度有关的所有参数。 A
Ok7G?Y d =(Yl r 分析 }gi1?a59 9Ir~X|}\iL 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 mXU?+G0 Z"~6yF 图7. 字母F在视网膜上颜色分析 P}+|`>L 脚本代码 >9tkx/J nUud?F^_ Option Explicit 'Remove this to enable non-dimensioned variables to be used. .l( r8qY# "UoCT7X Dim entity As T_ENTITY wAYzR$i Dim op As T_OPERATION ?Y0$X>nm Dim mat As T_MODELMATERIAL !
jX+ox Dim A As Double ( X
'FQ Dim pupilDiam As Double Ec*--]j*c Dim eID As Long ay:\P.`5) Dim parID As Long h`EH~ W0:z Dim count As Integer Z|:_c Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Ag>>B9 Dim tlens As Double, nlens As Double 1Fvv/Tj Dim curv As Double, conic As Double $: 4mOl Dim ok As Long j |'#5H` 7o965h Sub Main ZaRr2Z:! |,a%z-l '用户输入对话框 zfjD b Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 vN0L(B TextBox 220,21,40,21,.TextBox1 'default: 0 g~Nij~/ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 yA!3XUi OKButton 40,91,90,21 4lY&=_K[) CancelButton 190,91,90,21 lNh=>DPu Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 (Y'UvZlM%P TextBox 220,49,40,21,.TextBox2 'default: 4 3)C6OF>7
End Dialog K{=r.W Dim dlg As UserDialog {m+S{dWp v E3{H ok = Dialog (dlg) c+E//X| 6zp@#vYI If ok=0 Then 'cancel button was pressed ;Z!~A"~$> Print "Execution cancelled." $LxG>db End m0BG9~p| End If ,<;l"v(
+eDN,iv 'Assign accommodation and pupil diameter & use defaults if field left empty ^B<PD] If dlg.TextBox1 = "" Then uGP[l`f|FQ A = 0 'Default accommodation ubzb Else kH>vD =q> A = CDbl(dlg.TextBox1) c6?c>*z End If uHUvntr SgCqxFii If dlg.TextBox2 = "" Then t3
uB pupilDiam = 4 'Default pupil diameter x%IXwP0 Else 'FPcAW^8 pupilDiam = CDbl(dlg.TextBox2) rnMG0 End If @H3 s2| fw1;i Print " " pjX%LsX\ Print "Accommodation = " & A & " Diopters" E,*JPK-A x Print "Pupil Diameter = " & pupilDiam & " mm" wL8bs-
U b[{m>Fa+o# ' Calculate new parameters with accommodation z^ aCQ3E taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness AQnJxIL: 8CP9DS Rant = 12.0 - 0.4*A 'Radius of anterior lens OQytgXED CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens Z%Tq1O z`86-Ov Rpost = -5.224557 + 0.2*A 'Radius of posterior lens q7O,I`KaJ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ==-7F3QP ;uM34^ tlens = 3.767 + 0.04*A 'Lens thickness vWqyZ-p,q r!=]Q}`F nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction dl*_ m3T ]/aRc=Gn 'Adjust parameters to account for accommodation VL_)]LR*) e/]O<, * '************************************************************************* >~`Y 'Aqueous thickness (Position of Lens) }|Hw0z P. '************************************************************************* QmWC2$b eID = FindFullName( "Geometry.Arizona Eye.Lens" ) <_BqpZ^` GetCustomElement eID, entity [ -9)T ILkjz^ parID = FindFullName( "Geometry.Arizona Eye" ) 4B:\ -,K*~z.l ' Delete any shift(s) in z .x)>f count = 0 vO}qjw While GetOperationCount(eID)>count a-T*'F GetOperation eID, count, op \b_-mnN" If op.Type="ShiftZ" Then =gMaaGg p, DeleteOperation eID,count Qq`3S> count=count-1 92P,:2`a End If 9l]UE0yTL/ count=count+1 07$/]eO%C Wend R7E]*:0} c0!Te'? 'Set new shift in q*HAIw[<y op.Type = "ShiftZ" paq8L{R op.val1 = taq B8bvp:Ho| op.parent = parID 'P@=/ AddOperation eID, op .K $p`WQ{ Print "Set aqueous humor thickness = " & taq-0.55 J>f
/u:. M*g2VyZ '************************************************************************* "_nX5J9 'Radius and conic constant of anterior lens t!6\7Vm/ '************************************************************************* y-E1]4?}) eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) GIl:3iB49 GetConic eID, entity, curv, conic sl~b\j #D!$~h&i SetConic eID, entity, 1/Rant, CCant Y;fuh[# Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant #[no~&E )v${&H '************************************************************************* =ied}a
:[ 'Radius and conic constant of posterior lens 21.YO]Et '************************************************************************* Eem 2qKj eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) pWMiCXnW GetConic eID, entity, curv, conic bcq@N Zr\2BOcc.l SetConic eID, entity, 1/Rpost, CCpost 3cmbK Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost re7!p(W?, V[#6yMU @ '************************************************************************* Vil@?Y" 'Lens thickness (Position of posterior lens surface) EwTS!gL '************************************************************************* cNdu.c[@ L=d$"Q parID = FindFullName( "Geometry.Arizona Eye.Lens" ) slu$2-H ceqFQ ' Delete any z-shift(s) fy9uLl}h count = 0
=Ov9Kf While GetOperationCount(eID)>count ^it4z gx@ GetOperation eID, count, op OZ eiHX! If op.Type="ShiftZ" Then V78Mq:7d DeleteOperation eID,count g;$E1U=R-E count=count-1 w+Ad$4Pf" End If gs$3)t count=count+1 cL6 6gOEL Wend (&q@~
dJ FL59 'Set new z-shift g* %bzfk=| op.Type = "ShiftZ" }%_qx|(P|t op.val1 = tlens >r~0SMQr op.parent = parID fwRGT|":B AddOperation eID, op 7}gA0fP9 Print "Set lens thickness = " & tlens 2q12yY f 4"LPJX)Q '************************************************************************* ;9K[~ 'Lens index of refraction mG
X\wta '************************************************************************* X88F>1} eID = FindMaterial( "Lens" ) AlUJ1^o) GetModelMaterial eID, mat MY&<)|v\ wbBE@RU>! mat.Nd = nlens TV?
^c?{5 SetModelMaterial eID, mat L%f-L.9`u Print "Set lens index of refraction = " & nlens 2%bhW,?I ,Ak ^nX '************************************************************************* =1O?jrl~q 'Pupil diameter R j-jAH '************************************************************************* *8/VSs eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 6{L F-`S% E`~i-kf 'Adjust pupil diameter (trimming volume inner hole) 6ezcS}:+ OthG7+eF SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" dZF8R 9-B@GFB;8 ' Adjust pupil location to just in front of the lens k@7kNMl parID = FindFullName( "Geometry.Arizona Eye" ) ehU"*9 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) g/x_m. count = 0 S3; lKr While GetOperationCount(eID)>count av$ GetOperation eID, count, op *jGPGnSo If op.Type="ShiftZ" Then CK=ARh#|
DeleteOperation eID,count R3cg2H count=count-1 (s&ORoVGn End If >;m{{nj count=count+1 {Wh BoD Wend Vw7WK op.Type = "ShiftZ" iW'_R{)T op.val1 = taq-0.01 }N@n{bu+ op.parent = parID QJQJR/g AddOperation eID, op >cTjA): iFSJ4 W( Print "Set pupil diameter = " & pupilDiam !f@XDW&R Rw/Ciw2@? 'Update AZ Eye subassembly Description nYhp`!W4; eID = FindFullName( "Geometry.Arizona Eye" ) R<>tDwsZGa GetEntity eID, entity Q@3B{ entity.Description = "Accommodation = " & A & "D" R#D#{cC( SetEntity eID, entity 8'+7i8e H)\4=^ Update <M=';h^w2 Print "DONE!" s_TD4~
$ NfOp=X?Y End Sub ) ,yH= 6 $:(z}sYQ7 如果屈光度是4,光瞳直径是4,则会输出如下数据: =Aj"j-r&{ 4Q$!c{Y
r Accommodation = 4 Diopters loLKm]yV Pupil Diameter = 4 mm x+K gc[r Set aqueous humor thickness = 2.81 .ByU Set anterior lens radius = 10.4 and conic constant = -2.375869 O hi D Set posterior lens radius = -4.424557 and conic constant = -3.081019 N70zjy4?fL Set lens thickness = 3.927 y>)MAzz~\ Set lens index of refraction = 1.42672 Qd?CTYNsv Set pupil diameter = 4 u|T%Xy=LU DONE! V+.Q0$~F5 bK?MT]%}r ]r!QmWw~V QQ:2987619807 g[AA,@p+
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