oo'9ZE/% 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。 U:7h>Z0W &;PxDlY5 模型 )nm+_U JPI%{@Qc^ 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。 j=sfE qN). Table 1. AZ眼睛模型的定义
[gW eD oz!)x\m*H 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. +gl\l?>sr k!c7eP"%8^ 光源 T3w%y`K J8'"vc} = 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。 zIa={tU 9q;O`& 图1. 光源和提示信息使用 +Mj6.X j0l,1=^>l 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。 ;,{_=n> @c~Z0+Ji 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。 i"Jy>' 图2. 字母F光源的设定方法光 Ww<Y]H$xZ< {&1L &f< 图3. 字母F在视网膜上位置点列图 !HTOE@ h,LSqjf" 视网膜的散射 x^s,<G )%C.IZ_s2 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 . ,|C>^ ^t0!Dbx3SE 图4. 视网膜朗伯散射设定 !j!w$ k+J3Kl09hM 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。 Ym'h
vK BMp'.9Qgm 图5. 视网膜重点采样规格设定 _c>iux; n_kwtWX( 脚本 z}vT8qoX f2gtz{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: `KQx#c>' 图6. 用户对话框的创建与编辑 ;4O[/;i 图7. 用户对话框编辑器 #`Su3~T=S m?S;sew@5 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。 fJFNS
y 余下的脚本计算与屈光度有关的所有参数。 rPk|2l,E,3 b++r#Q
g 分析 xe@e#9N$ rWht},-|1 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 9#DXA} 图7. 字母F在视网膜上颜色分析 fU6YJs.H^8 Ts!'>_<Je 脚本代码 l b( J|WE&5' Option Explicit 'Remove this to enable non-dimensioned variables to be used. Q<sqlh!h IO)Y0J>x Dim entity As T_ENTITY S,5ok0R Dim op As T_OPERATION t<rIg1 Dim mat As T_MODELMATERIAL YZ~MByu Dim A As Double c7mKE`
Dim pupilDiam As Double J;& y?%{@5 Dim eID As Long l>6tEOXt Dim parID As Long 2@S}x@^ Dim count As Integer +Tum K. Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double n>ryS/1 Dim tlens As Double, nlens As Double JBY.er`6C Dim curv As Double, conic As Double .SC*! , Dim ok As Long FJvY`zqB ,z&S;f.f Sub Main rXB;#ypO ~& -h5=3 '用户输入对话框 GxdAOiq; Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 JxIJxhA> TextBox 220,21,40,21,.TextBox1 'default: 0 ;!<}oZp{ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 xXJ*xYn"} OKButton 40,91,90,21 Ph3;;,v ' CancelButton 190,91,90,21 3d}v?q78 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 $zP5Hzx TextBox 220,49,40,21,.TextBox2 'default: 4 FL{Uz+Q End Dialog ?V6,>e_+ Dim dlg As UserDialog iil<zEic HA'~1$#z ok = Dialog (dlg) ]-gyXE1.r
r!R-3LO0s If ok=0 Then 'cancel button was pressed .`Rt Print "Execution cancelled." @&\Y:aRO%i End d:)#-x*h7 End If aHN"I
ACyK#5E 'Assign accommodation and pupil diameter & use defaults if field left empty AE rPd)yk0 If dlg.TextBox1 = "" Then P j A = 0 'Default accommodation Gxw1P@<F: Else fZiAl7b! A = CDbl(dlg.TextBox1) 9q"kM End If Fi``l)Tt R XCn;nM4 If dlg.TextBox2 = "" Then qFm w9\Fn pupilDiam = 4 'Default pupil diameter W,4!"*+ Else v#,queGi pupilDiam = CDbl(dlg.TextBox2) JL6$7h End If
NzgG77> S= 4o@3%$ Print " " Y-ao
yoNS Print "Accommodation = " & A & " Diopters" Q^b& Print "Pupil Diameter = " & pupilDiam & " mm" ;wwc;wQ' KlT:&1SB9 ' Calculate new parameters with accommodation E@GYl85fI taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness >pF* unC; ~HmH#"VP Rant = 12.0 - 0.4*A 'Radius of anterior lens uSfHlN4l CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ed6@o4D/kf <K0epED Rpost = -5.224557 + 0.2*A 'Radius of posterior lens _[HZ[ 9c! CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens %#2$B+ Z|t=t"6" tlens = 3.767 + 0.04*A 'Lens thickness I !hh_ O,r;-t4vYU nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction `;85Mo:qJ 3"x_Y 'Adjust parameters to account for accommodation CXq[VYM&X +p%3pnj:K '************************************************************************* ^L%_kL_7 'Aqueous thickness (Position of Lens) G'JHimP2j '************************************************************************* JX&U?Z eID = FindFullName( "Geometry.Arizona Eye.Lens" ) -PpcFLZ| GetCustomElement eID, entity O=jLZ2os i(.e=
parID = FindFullName( "Geometry.Arizona Eye" ) RBQ8+^ P<vl+&* ' Delete any shift(s) in z ?oYO ! count = 0 NsB]f{7>8+ While GetOperationCount(eID)>count QoYEWXT|g GetOperation eID, count, op Wj.t4XG! If op.Type="ShiftZ" Then \B#tB?rA
DeleteOperation eID,count ^*AI19w!Ys count=count-1 S)U*1t7[
End If |.)LZP, count=count+1 {b!{~q Wend X$!fR >Zc >M#@vIo?<6 'Set new shift in w;,34qbf op.Type = "ShiftZ" i)x0]XF op.val1 = taq f\2IKpF2 op.parent = parID 27!FB@k- AddOperation eID, op v.]{b8RR Print "Set aqueous humor thickness = " & taq-0.55 BHr ,jC Y#os6|MV# '************************************************************************* X7$]qE K 'Radius and conic constant of anterior lens Q+Bl1xl '************************************************************************* $9YQ aN% eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) rn-bfzoDS GetConic eID, entity, curv, conic 7Yg1z%%U "AagTFs(i SetConic eID, entity, 1/Rant, CCant 5|rBb[ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 5len}){ !Q>xVlPVu '************************************************************************* Z1,rN#p9 'Radius and conic constant of posterior lens >J;TtNE: '************************************************************************* ZS.=GjK eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) |"}rdOV) GetConic eID, entity, curv, conic L -Q8iFW' ?-j/X6(\( SetConic eID, entity, 1/Rpost, CCpost `"=Hk@E Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 7{<v$g$ <{W{
Y\_A> '************************************************************************* q|ce7HnK 'Lens thickness (Position of posterior lens surface) Sn[xI9}O '************************************************************************* ;n't:yQW {<{VJGY7T parID = FindFullName( "Geometry.Arizona Eye.Lens" ) h3
HUdu o<5`uV!f ' Delete any z-shift(s) ?;RY/[IX6 count = 0 &>AwG4HW#j While GetOperationCount(eID)>count ;y(;7n_ a GetOperation eID, count, op J=-z~\f56 If op.Type="ShiftZ" Then J!om"h DeleteOperation eID,count I7_8oq\3D count=count-1 ug,AvHEnB End If |pHlBzHj count=count+1 DCp8rvUI Wend _S) K+C|@ &KMI C 'Set new z-shift N'y<<tTA op.Type = "ShiftZ" a
&tWMxBr op.val1 = tlens -Y524
op.parent = parID ,
>WH)+a AddOperation eID, op eZ:iW#YF Print "Set lens thickness = " & tlens ,6]ID1o:y &vmk!wAs '************************************************************************* lZAGoR;0Ra 'Lens index of refraction ] !*K|?VL '************************************************************************* S
}`f& eID = FindMaterial( "Lens" ) #[bosb!R GetModelMaterial eID, mat =+_nVO* bqH
[-mu6 mat.Nd = nlens %1TKgNf SetModelMaterial eID, mat mo<*h&;& Print "Set lens index of refraction = " & nlens |"K%Tvxe oU)(/ '************************************************************************* Y[e.1\d' 'Pupil diameter _1?u AQ3, '************************************************************************* Pt85q?- > eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) mW]dhY 3X KGOhoiR9:C 'Adjust pupil diameter (trimming volume inner hole) l1]N&jN{ 6)sKg{H SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" U~=?I)Ni FV9{u[3m ' Adjust pupil location to just in front of the lens "<|KR{/+ parID = FindFullName( "Geometry.Arizona Eye" ) hYyIC:PXR eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) \j!/l
f) count = 0 }eSy]r[J While GetOperationCount(eID)>count 1
K}gX>F GetOperation eID, count, op @"s<0T^H If op.Type="ShiftZ" Then %qcCv9 DeleteOperation eID,count :sw5@JdJ count=count-1 *i*\dl End If ~hq\XQX count=count+1 _f2rz+ Wend TNh&g. op.Type = "ShiftZ" Otu?J_ d3 op.val1 = taq-0.01 ,l AZ4 op.parent = parID )-X8RRw' AddOperation eID, op &L0Ii)Ns T7i>aM$+ Print "Set pupil diameter = " & pupilDiam Z?S?O#FED Q^<amM! 'Update AZ Eye subassembly Description f'ld6jt|% eID = FindFullName( "Geometry.Arizona Eye" ) .feB
VRg GetEntity eID, entity zU[o_[+7^ entity.Description = "Accommodation = " & A & "D" ri-&3%%z< SetEntity eID, entity a9&[Qv5-/ 8r>\scS Update DCa[?|Y Print "DONE!" r1q'+i Ruq;:5u End Sub ,l!>+@ dSjO12b 如果屈光度是4,光瞳直径是4,则会输出如下数据: _b>z'4_' EyR/ Accommodation = 4 Diopters Wk^{Tn/] Pupil Diameter = 4 mm fqbWD)L] Set aqueous humor thickness = 2.81 X`<z5W] ! Set anterior lens radius = 10.4 and conic constant = -2.375869 |{|B70v3Co Set posterior lens radius = -4.424557 and conic constant = -3.081019 prM)t8SE Set lens thickness = 3.927 J|jvqt9C Set lens index of refraction = 1.42672 tHaHBx1P Set pupil diameter = 4 N/lEfy<&g: DONE! |