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简介 1.SkIu% v_sm 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。 CW:gEm+ 4^Ow^7N? 模型 ?En7_X{C? " OGdE_E 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。 vS M_]fn "E>t,
D Table 1. AZ眼睛模型的定义 *=vlqpG 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. WL\^F#: ">6&+^BN' 光源 W@B7yP7Rz g8yN%)[ 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。 (5;D7zdA K&UE0JO' F^'v{@C 图1. 光源和提示信息使用 WOO%YU = 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。 cw+g
z!! a{_ KSg 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。 <F=Dj*] TmiWjQv` 图2. 字母F光源的设定方法光 /Dw@d,&[ 5.k}{{+ 图3. 字母F在视网膜上位置点列图 ]
C,1%( 视网膜的散射 n+quSF) 2cjEex:& 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。 B~_Spp 1D$::{h *mV&K\_ 图4. 视网膜朗伯散射设定 g+9v$[! 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[(w @xJCn}`Zj zKJ.Tj W 图5. 视网膜重点采样规格设定 |yAK@Hl' 脚本 h]P/KVqR. QUPf*3Oy 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'{sy6 ;\s~%~\ 图6. 用户对话框的创建与编辑 n{{P3f 图7. 用户对话框编辑器 Uk02IOXQ 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。 [tm[,VfA^ 余下的脚本计算与屈光度有关的所有参数。 F;a3 tzNaw %\ 分析 RH=$h! 5 ,F}r@ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 =z-5 (H[ 图7. 字母F在视网膜上颜色分析 Tc,$TCF 脚本代码 %|jzEBz@ (+x]##Q Option Explicit 'Remove this to enable non-dimensioned variables to be used. ;[caiMA- 1C'P)f28 Dim entity As T_ENTITY 3q CHh Dim op As T_OPERATION hpjUkGm5 Dim mat As T_MODELMATERIAL A:c]1 Dim A As Double |1i]L @& Dim pupilDiam As Double xDLMPo& Dim eID As Long !^1[ s@1 Dim parID As Long ,$BgR2^ Dim count As Integer H%cp^G Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double (s Jq;Z Dim tlens As Double, nlens As Double vu ?3$ Dim curv As Double, conic As Double *) }
:l Dim ok As Long R|H[lbw Y.9~Bo<<r Sub Main 3XGB+$]C r!~(R+,c '用户输入对话框 Lb^(E- Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 mw Z'=H TextBox 220,21,40,21,.TextBox1 'default: 0 [NZ-WU&&LP Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 }
m6\C5 OKButton 40,91,90,21 WT?b Bf CancelButton 190,91,90,21 )+*{Y$/U Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 j,4,zA1j| TextBox 220,49,40,21,.TextBox2 'default: 4 $kIo4$.Y$ End Dialog HrDTn&/ Dim dlg As UserDialog mHHzCKE , ?n&$m ok = Dialog (dlg) L=,Y1nO:p n3*UgNg%fK If ok=0 Then 'cancel button was pressed ) (+)Q'* Print "Execution cancelled." ;*.(. End %P(;8sS End If -}< d(c '1]+8E
`Z 'Assign accommodation and pupil diameter & use defaults if field left empty fMyE}z If dlg.TextBox1 = "" Then }U(\~
=D A = 0 'Default accommodation C#ZhsWS!b Else ckAsGF_B~! A = CDbl(dlg.TextBox1) Pf{`/UlD End If rv`2*B -!i;7[N If dlg.TextBox2 = "" Then 6EZ1YG} pupilDiam = 4 'Default pupil diameter ;FcExg|k Else 8znj~7}# pupilDiam = CDbl(dlg.TextBox2) 0n\^$WY End If Oq[i & 'xQna+ %h Print " " /z..5r^,ZZ Print "Accommodation = " & A & " Diopters" L#`7 FaM? Print "Pupil Diameter = " & pupilDiam & " mm" UBL(N r v3?kFd7%H~ ' Calculate new parameters with accommodation c%jsu" taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness (LRNU)vD7$ HgYc@P*b Rant = 12.0 - 0.4*A 'Radius of anterior lens &|s+KP|d CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens [k!-;mi dFx2>6AZt Rpost = -5.224557 + 0.2*A 'Radius of posterior lens T=^jCH & CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens L7s>su|c( KlY,NSlQ tlens = 3.767 + 0.04*A 'Lens thickness \>4v?\8o ^GE^Q\&D& nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction FwXKRZa (QhGxuC 'Adjust parameters to account for accommodation V+peO z~BD(FDI '************************************************************************* |
A3U@>6 'Aqueous thickness (Position of Lens) $Z,i|K; '************************************************************************* t8t}7XD
eID = FindFullName( "Geometry.Arizona Eye.Lens" ) A<mj8qz GetCustomElement eID, entity U)u\1AV5 dFdlB`L parID = FindFullName( "Geometry.Arizona Eye" ) >_&~!Y.Z= 1RCXc>}/ ' Delete any shift(s) in z
T"n>h count = 0 RP,A!pa@ While GetOperationCount(eID)>count D8)O4bh GetOperation eID, count, op :0WkxEY9 If op.Type="ShiftZ" Then \s.1R/TyD DeleteOperation eID,count 0[V&8\S~'T count=count-1 z\e>DdS End If +fC#2%VnU count=count+1 IRlN++I! Wend 1P(%9 wCV>F- 'Set new shift in #DQX<:u op.Type = "ShiftZ" 17WNJ op.val1 = taq E}]I%fi op.parent = parID ls [Ls AddOperation eID, op uo]Hi^r.l Print "Set aqueous humor thickness = " & taq-0.55 1y},9ym nw~/~eM5= '************************************************************************* QpdujtH` 'Radius and conic constant of anterior lens hO^&0? '************************************************************************* b ^uP^](J eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) B*-ToXQQr GetConic eID, entity, curv, conic >(IITt z0T`5NG@ SetConic eID, entity, 1/Rant, CCant -@YVe:$%b Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 4C l,Iw/; =#OHxM '************************************************************************* \Ku9"x 'Radius and conic constant of posterior lens +L^A:}L( '************************************************************************* pi^^L@@d eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) IW5*9)N? GetConic eID, entity, curv, conic `V]egdO r{pI-$ SetConic eID, entity, 1/Rpost, CCpost <{$ev&bQ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost lAdOC5+JX zkjPLeX '************************************************************************* eNIkiJ$uS 'Lens thickness (Position of posterior lens surface) GCcwEl!K^ '************************************************************************* 6'RZ E\{^0vNc parID = FindFullName( "Geometry.Arizona Eye.Lens" ) &/B2)l6a s5c! ^,L8 ' Delete any z-shift(s) 1$:{{% count = 0 2"pE&QNd While GetOperationCount(eID)>count gGtep*k GetOperation eID, count, op y+K7WUwhq If op.Type="ShiftZ" Then `U{o: DeleteOperation eID,count p<Zs*
@ count=count-1 - XE79 fQ End If 8C*6Fjb# count=count+1 vDu0 Wend /Nj:!!
AN PphR4 sIM 'Set new z-shift qT4I Y$h op.Type = "ShiftZ" qPFG+~\c op.val1 = tlens ~[d=s op.parent = parID pr0@sri@ AddOperation eID, op h]J&A Print "Set lens thickness = " & tlens }XfS#Xr1aV p?dGZ2` [I '************************************************************************* 8\qCj.>S 'Lens index of refraction OYqYI!N/ '************************************************************************* <Dt/Rad eID = FindMaterial( "Lens" ) % j[O&[s}
GetModelMaterial eID, mat -4*'WzWr ,cGwtt( mat.Nd = nlens xZ9}8*Q&: SetModelMaterial eID, mat %\(y8QV Print "Set lens index of refraction = " & nlens $I}Hk^X \3n{w
'************************************************************************* 68&6J's; 'Pupil diameter 0[Xt,~ '************************************************************************* %{N$1ht^ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) (ybtXoQs ?)Czl4J 'Adjust pupil diameter (trimming volume inner hole) V e$5w}a4 }}sRTW SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 877EKvsiC ,6EZb[;g^ ' Adjust pupil location to just in front of the lens E< zT parID = FindFullName( "Geometry.Arizona Eye" ) @yU!sE: eID = FindFullName( "Geometry.Arizona Eye.Pupil" )
wzHjEW count = 0 jm#d7@~4 While GetOperationCount(eID)>count l6&v}M GetOperation eID, count, op .R$+#_ If op.Type="ShiftZ" Then APHtJoS DeleteOperation eID,count AhbT/ count=count-1 0p:ClM2O
End If *f0.= ? count=count+1 in=k:j,U0 Wend E&iWtwkz op.Type = "ShiftZ" (PsSE:r}+ op.val1 = taq-0.01 RS||KA])J op.parent = parID uhC= AddOperation eID, op DuO%B A]tf>H#1 Print "Set pupil diameter = " & pupilDiam ~`G;=ITo YmO"EWb 'Update AZ Eye subassembly Description 6yu*a_ eID = FindFullName( "Geometry.Arizona Eye" ) L5zG0mC8 GetEntity eID, entity DSDl[;3O{s entity.Description = "Accommodation = " & A & "D" UALg!M# SetEntity eID, entity L!8 -:)0b ,IT)zCpaBP Update JL.ydH79 Print "DONE!" r'9=kx @R'g@+{I End Sub j^aQ>(t(9 a!0?L0_W& 如果屈光度是4,光瞳直径是4,则会输出如下数据: #5ohmp,u skR,M=F~ Accommodation = 4 Diopters G>q{~HE1 Pupil Diameter = 4 mm oxCs* Set aqueous humor thickness = 2.81 80 s~ae; Set anterior lens radius = 10.4 and conic constant = -2.375869 ArmL, Set posterior lens radius = -4.424557 and conic constant = -3.081019 (AM,4)lW, Set lens thickness = 3.927 _Y
><ih Set lens index of refraction = 1.42672 SVg@xu+ Set pupil diameter = 4 Top#u
DONE! g<hv7?"[ bn*{*=(| ](9{}DHV QQ:2987619807 -;@5Ua1uf
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