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简介 8u!"#S#>a gIA@l`" 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。 6%Be36< O$IjNx 模型 >J u]2++lx Cuc$3l(% 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 <L&m4O#| wO2_DyMm@ Table 1. AZ眼睛模型的定义 Tr^nkD{ 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. P,sjo u^ Bo5ZZY 光源 .'a&33J XT;u<aJs 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 ~^+0 xV%6k{_:G i|1^+; 图1. 光源和提示信息使用 r=c<--_@ 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 =!m}xdTP "(qw-kil 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 s|y:UgD GJqE!I,. 图2. 字母F光源的设定方法光 JJRK7\~$ f{0F|w<gf 图3. 字母F在视网膜上位置点列图 uytE^ 视网膜的散射 T)\"Xj $`Ix:gi 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。 U?.9D vd6l7"0/ [%&ZPJT%i 图4. 视网膜朗伯散射设定 t20PP4FWM 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。 $H$j-)\D /pp1~r.s?> ;l$ \6T 图5. 视网膜重点采样规格设定 -X+H2G 脚本 JMdPwI "`[!L z 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: z#F.xVg' jjM{] 图6. 用户对话框的创建与编辑 W[+|} 图7. 用户对话框编辑器 ly WwGR 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。 fqu}Le 余下的脚本计算与屈光度有关的所有参数。 [=%TnT+^9 -7!&@wuQ 分析 `>o?CIdp ;60.l! 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 z6py"J@ lgpW@g 图7. 字母F在视网膜上颜色分析 bqQq=SO 脚本代码 yz2Ci0Dwy fm~kM
J Option Explicit 'Remove this to enable non-dimensioned variables to be used. M,}|tsL ps$7bN C Dim entity As T_ENTITY !`bio cA Dim op As T_OPERATION Z0De!?ALV\ Dim mat As T_MODELMATERIAL sE{ pzPq! Dim A As Double 5'a3huRtV Dim pupilDiam As Double #P#-xz Dim eID As Long &Z?ut*%S Dim parID As Long a?YCn! Dim count As Integer m?HZ; Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double U:F/iXz Dim tlens As Double, nlens As Double #0 6-: Dim curv As Double, conic As Double m*X[ Jtr Dim ok As Long .WQ<jZt> RllY-JBO Sub Main {YUIMd!Y 'Pvm8t '用户输入对话框 @Mvd'.r<; Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 fJZp?e" TextBox 220,21,40,21,.TextBox1 'default: 0 fIF<g@s Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 e4FM} z[ OKButton 40,91,90,21 `]Bxn)b( CancelButton 190,91,90,21 Il.Ed-&62 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 rw)kAe31 TextBox 220,49,40,21,.TextBox2 'default: 4 y$81Zq End Dialog #}^-C&~ Dim dlg As UserDialog |
nJZie8m *Ywpz^2?: ok = Dialog (dlg) 1+`l7'F 0N=X74 If ok=0 Then 'cancel button was pressed .lhn;*Yi Print "Execution cancelled."
_if|TFw;h End LflFe@2 End If yk2 !8 >\ST-7[^L 'Assign accommodation and pupil diameter & use defaults if field left empty :ug4g6;#H0 If dlg.TextBox1 = "" Then p1c3Q$>i A = 0 'Default accommodation FZiW|G Else c.\O/N
A = CDbl(dlg.TextBox1) i~J;G#b End If *=Z26 &/.hx(#d If dlg.TextBox2 = "" Then W\f9jfD pupilDiam = 4 'Default pupil diameter (SVWdgb Else (eCFWmO pupilDiam = CDbl(dlg.TextBox2) SvvUkQ#1w End If a'\By?V]
n3MWs);5 Print " " t]1ubt2W Print "Accommodation = " & A & " Diopters" U-wLt(Y< Print "Pupil Diameter = " & pupilDiam & " mm" H(0q6~| 4\.V ' Calculate new parameters with accommodation ,~zj=F taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness `nR %Cav,U ?j7vZ}iRi Rant = 12.0 - 0.4*A 'Radius of anterior lens cD1o"bq CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens &@"]+33 0e["]Tlnm Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Uh.Zi3X6}6 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 1gO2C$ Q4s&E\} tlens = 3.767 + 0.04*A 'Lens thickness "%8A:^1 v}J;ZIb nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 2}}?'PwwT vAP{;Q0i 'Adjust parameters to account for accommodation XC15 K@K M4Z@O3OIE '************************************************************************* z1 i &Ge 'Aqueous thickness (Position of Lens) 'k&?DZ! '************************************************************************* V[pvJ( eID = FindFullName( "Geometry.Arizona Eye.Lens" ) o?Sla_D GetCustomElement eID, entity bAxTLIf NCA{H^CL
parID = FindFullName( "Geometry.Arizona Eye" ) !a1i Un9 PM$Ee #62R ' Delete any shift(s) in z (g :p5Rl count = 0 4aZCFdc While GetOperationCount(eID)>count ?3sT"r_d@ GetOperation eID, count, op $7I]`Jt If op.Type="ShiftZ" Then Ni[4OR$-O DeleteOperation eID,count "C%!8`K{a* count=count-1 *.y' (tj[ End If IKvBf'%- count=count+1 %IpSK 0<Sp Wend D_|B2gdZY (U.**9b; 'Set new shift in Wf02$c0#K op.Type = "ShiftZ" {7Cx#Ewd op.val1 = taq e/e0d<(1 op.parent = parID `!\ivIi^ AddOperation eID, op d+z[\i Print "Set aqueous humor thickness = " & taq-0.55 ^[h2% c$ h\,5/ )Y '************************************************************************* X<Za9 'Radius and conic constant of anterior lens ]>:^d%n,} '************************************************************************* O{KB0"s>i eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ZcPUtun GetConic eID, entity, curv, conic (b/d0HCND [h}K$q SetConic eID, entity, 1/Rant, CCant $CtCOwKZ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant PNF4>) AfWl6a?T8: '************************************************************************* d5xxb _oE 'Radius and conic constant of posterior lens ]H 2R '************************************************************************* 993d/z|DX eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) }F{=#Kqn^ GetConic eID, entity, curv, conic vrcE]5(:s FuP}Kec SetConic eID, entity, 1/Rpost, CCpost M1=_^f=&. Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 5]"BRn1* 2tr
:xi@ '************************************************************************* ./maY1>T 'Lens thickness (Position of posterior lens surface) ,zgNE*{Y"4 '************************************************************************* oW'POAr 'tWAu I parID = FindFullName( "Geometry.Arizona Eye.Lens" ) l=Wd,$\ A|vP$zy ' Delete any z-shift(s) *m_93J count = 0 t!l%/$- While GetOperationCount(eID)>count S!j^|! GetOperation eID, count, op Fe="EDh If op.Type="ShiftZ" Then 4]6 Qr DeleteOperation eID,count !P|5#.eC count=count-1 i>Iee^_( End If ]t/f<jKN^ count=count+1 |QYZRz Wend O<`R~ }K8Lm-.= 'Set new z-shift _^;;i4VZ op.Type = "ShiftZ" ('WY5Yps op.val1 = tlens RWE~&w G} op.parent = parID ##~!M(c AddOperation eID, op a>b8-j=J Print "Set lens thickness = " & tlens N$'>XtO nYov>x] '************************************************************************* ``-k{C#F 'Lens index of refraction G.ud1,S# '************************************************************************* qz:]-A eID = FindMaterial( "Lens" ) I q,v GetModelMaterial eID, mat }J;~P
9Y i`~~+6`J mat.Nd = nlens .}p|`3$P SetModelMaterial eID, mat )VY10R)$ Print "Set lens index of refraction = " & nlens !QTPWA LVmY=d> '************************************************************************* D Q 5W6W 'Pupil diameter @KJV1t` '************************************************************************* &|z|SY]DL eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) #NJ<[Gew ;Vo mFp L 'Adjust pupil diameter (trimming volume inner hole) e?vj+ZlS$f \1{_lynD SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" PSEWL6=]N V2QW\2@$ ' Adjust pupil location to just in front of the lens 86{ZFtv parID = FindFullName( "Geometry.Arizona Eye" ) sS'{QIRC' eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) cKpQr7]ur count = 0 /#IH-2N While GetOperationCount(eID)>count paYz[Xq GetOperation eID, count, op 82.HH5Z{ If op.Type="ShiftZ" Then iPkT*Cl8 DeleteOperation eID,count ~ a>S#S count=count-1 '8={ sMy End If I9,8HtnA count=count+1 9@etg4#] Wend R25-/6_V> op.Type = "ShiftZ" l]u7.~b op.val1 = taq-0.01 hOn op.parent = parID r"[L0Cbb AddOperation eID, op "MTq{f2? }
Ab_o#Zy Print "Set pupil diameter = " & pupilDiam .> ,Z kS 8'%+G 'Update AZ Eye subassembly Description :1NYpsd.i eID = FindFullName( "Geometry.Arizona Eye" ) [[$Mh_MD GetEntity eID, entity >E~~7Yal entity.Description = "Accommodation = " & A & "D" .Map SetEntity eID, entity hvL6zCi qAbd xd[ Update (Otur Print "DONE!" uAQg"j 0O^U{#*$I End Sub XC2Q*Z Ul9b.`6 如果屈光度是4,光瞳直径是4,则会输出如下数据: ]ci RiMkT( xNx`J@xt$ Accommodation = 4 Diopters E~qK&7+ Pupil Diameter = 4 mm [@zkv)D6 Set aqueous humor thickness = 2.81 Hj1k-Bs&'w Set anterior lens radius = 10.4 and conic constant = -2.375869 ~(M*6b Set posterior lens radius = -4.424557 and conic constant = -3.081019 78gob&p? Set lens thickness = 3.927 -/1d& Set lens index of refraction = 1.42672 r*>QT:sB Set pupil diameter = 4 /T{mS7EpYc DONE! %va[jJ (s.o VgUvD1v?} QQ:2987619807 FmR\`yY_,
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