|
|
简介 U66}nN9 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。 hcJny _
ATIV 模型 R)u ${ Q%Y rm 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。 V+MhS3VD QVJvuiUh Table 1. AZ眼睛模型的定义 ]>"q>XgnI 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. uJ_"gPO 6u-aV 光源 M
hJ;)( $/XR/ 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。 Yv7`5b{N. r<XlIi AOVoOd+6 图1. 光源和提示信息使用 $0wF4$) 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。 [R9!Tz 1u\kxlZ 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。 .!`v2_ eK_Yt~dj 图2. 字母F光源的设定方法光 ypA)G /; NX5NE2@^qH 图3. 字母F在视网膜上位置点列图 DUOSL 视网膜的散射 u*C"d1v= _0c$SK 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 o7#Mr`6H |=U(8t QnPgp(d< 图4. 视网膜朗伯散射设定 cQ<* (KU 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 GP._C=] ?c Vo-]&u&cr
jpW(w($XL 图5. 视网膜重点采样规格设定 WKB@9Vfju 脚本 AG==A&d>$ kFi^P~3D[ 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: ;th]/ G 0-{l4;o 图6. 用户对话框的创建与编辑 xB&6f") 图7. 用户对话框编辑器 t1h2ibO 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。 <1EmQ)B 余下的脚本计算与屈光度有关的所有参数。 O&c~7tM% 6"UL+$k 分析 B%e#u.'6 `+go|
5N2 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 eS{ xma ;n-IpR#|
图7. 字母F在视网膜上颜色分析 YvP u%=eF 脚本代码 [va7+=[1= 9&t!U+ Option Explicit 'Remove this to enable non-dimensioned variables to be used. .Iret: UIl^s8/ Dim entity As T_ENTITY $EuWQq7OI2 Dim op As T_OPERATION ->S6S_H/+& Dim mat As T_MODELMATERIAL ]CIZF, Dim A As Double (KDv>@5 Dim pupilDiam As Double b[I;6HW Dim eID As Long -S(_ZbeN Dim parID As Long h c9?z} Dim count As Integer ,UD,)ZPf[ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double i%R2#F7I Dim tlens As Double, nlens As Double BkTGH.4G% Dim curv As Double, conic As Double "[LSDE"( Dim ok As Long 8/|~E pd rF/U+ Sub Main sa71Vh{ bof{R{3q '用户输入对话框 I@f">&^ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 u/h!i@_w[ TextBox 220,21,40,21,.TextBox1 'default: 0 |F'k5Lh Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 e!5nz_J1} OKButton 40,91,90,21 y&.[Nt '+ CancelButton 190,91,90,21 :K)=Hf2y Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 `[+nz
rLkO TextBox 220,49,40,21,.TextBox2 'default: 4 =lf&mD
_/ End Dialog |Gw[vY Dim dlg As UserDialog X%1fMC gr/o!NC
ok = Dialog (dlg) n+EK}=DK 3-Q*umh If ok=0 Then 'cancel button was pressed 3psCV=/z Print "Execution cancelled." <Dr*^GX>? End ;NrkX?Y End If xwH+Q7O&l QrP$5H{[E 'Assign accommodation and pupil diameter & use defaults if field left empty @
P=eu3 If dlg.TextBox1 = "" Then T1y,L<7? A = 0 'Default accommodation 'xdM>y#S Else eqSCNYN A = CDbl(dlg.TextBox1) lxRzyx End If GLe(?\Ug= `ecuquX' If dlg.TextBox2 = "" Then qO<'_7TN[ pupilDiam = 4 'Default pupil diameter H].
4~ 8 Else !P, 9Sg&5) pupilDiam = CDbl(dlg.TextBox2) UC^Bn1 End If -o+_PL
$\ sBuVm<H Print " " c
25wm\\ Print "Accommodation = " & A & " Diopters" yT42u|xZA Print "Pupil Diameter = " & pupilDiam & " mm" $
;/Ny)" v UAYYe ' Calculate new parameters with accommodation #;RP ?s taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness @NXGVmY1} -K`0`n} Rant = 12.0 - 0.4*A 'Radius of anterior lens ->- CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens %>uGzQ61 x7J| Rpost = -5.224557 + 0.2*A 'Radius of posterior lens hGH{Xp[mW CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens #ZIV>(Q\H Osb"$8im tlens = 3.767 + 0.04*A 'Lens thickness
1;ulqO 3MC| O5R4 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction P,!k^J3:l /|y3M/;F 'Adjust parameters to account for accommodation *g5df[ AQ-P3`bCb '************************************************************************* V|{ )P@Q 'Aqueous thickness (Position of Lens) IPcAE!h6zN '************************************************************************* \PzC:H eID = FindFullName( "Geometry.Arizona Eye.Lens" ) `X]-blHo GetCustomElement eID, entity sp[nKo^ o><~ .T=d& parID = FindFullName( "Geometry.Arizona Eye" ) sm}v0V.Js @]dN ' Delete any shift(s) in z MUNeGqv count = 0 )%C482GO- While GetOperationCount(eID)>count DRi!WWivn GetOperation eID, count, op ##,i< If op.Type="ShiftZ" Then tqrvcnQr^ DeleteOperation eID,count BoP%f'0N count=count-1 G#Z%jO-XN End If 1z~;c| count=count+1 6(oGU4 Wend f9D7T|J?10 mCtuyGY 'Set new shift in i,ku91T op.Type = "ShiftZ" 3OFv_<6 op.val1 = taq p7 !q#o op.parent = parID QA.B.U7! AddOperation eID, op (H+'sf^h Print "Set aqueous humor thickness = " & taq-0.55 &}w,bG$ V:!fe+Er '************************************************************************* gSu+]N 'Radius and conic constant of anterior lens QE!cf@~n" '************************************************************************* *NDLGdQqz eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) xVKx#X9yk GetConic eID, entity, curv, conic "S[VtuxPCU 4cJ7.Pez SetConic eID, entity, 1/Rant, CCant %dL|i2+*8 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant a|5GC pp yN~=3b> '************************************************************************* c.&vWmLSGE 'Radius and conic constant of posterior lens 8c__ U< '************************************************************************* u|8`= eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 3 %dbfT j GetConic eID, entity, curv, conic ClVMZ H:9(
XW SetConic eID, entity, 1/Rpost, CCpost |fTQ\q]W Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost &.<{c
`- AGCqJ8`|T '************************************************************************* G~4 ^`[elB 'Lens thickness (Position of posterior lens surface) zK:/
1 '************************************************************************* v1 oS f #)>>f parID = FindFullName( "Geometry.Arizona Eye.Lens" ) f*5=,$0 LAf!y"A# ' Delete any z-shift(s) [ Q=)f count = 0 <`|}bt While GetOperationCount(eID)>count h{<^?= GetOperation eID, count, op giaO7Qh~ If op.Type="ShiftZ" Then W
.Hv2r3 DeleteOperation eID,count fb`VYD9[^ count=count-1 kHz3_B9[ End If 2E2J=Do count=count+1 {Fb)Z"8] Wend (: ZOoL #wM0p:< 'Set new z-shift (eO0Ic[c op.Type = "ShiftZ" sur2Mw(M" op.val1 = tlens -+Q,xxu op.parent = parID %iD>^ Dp AddOperation eID, op &% M^:WT Print "Set lens thickness = " & tlens mL6/NSSz =nid #<X '************************************************************************* O%c6 vp7 'Lens index of refraction )\VUAD%~e7 '************************************************************************* ]vT eID = FindMaterial( "Lens" ) c}v:X
Slh7 GetModelMaterial eID, mat uVscF
4 @4$F%[g
h mat.Nd = nlens V!}, a@>p SetModelMaterial eID, mat |UR.7rOV Print "Set lens index of refraction = " & nlens Uut,cQ". d &nz1[, '************************************************************************* YuPgsJ[m 'Pupil diameter X% _~9'#% '************************************************************************* tanuP@O eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) C7+TnJ $(zJ 'Adjust pupil diameter (trimming volume inner hole) -BoN}xE4 NoYu"57\ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" `+zr PpX fG,qax`:c ' Adjust pupil location to just in front of the lens B0R[f parID = FindFullName( "Geometry.Arizona Eye" ) &G<ZK9Ot}0 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 9wWjl}% count = 0 k+i}U9c" While GetOperationCount(eID)>count 5@Py` GetOperation eID, count, op {5%<@<?) If op.Type="ShiftZ" Then 8d$~wh DeleteOperation eID,count !%@n067 count=count-1 O]2h=M@q. End If ^?J:eB! count=count+1 j 6v +S Wend R [uo:. op.Type = "ShiftZ" 1^Caz- op.val1 = taq-0.01 P_ZguNH op.parent = parID Vq<|DM3z< AddOperation eID, op 'Ob5l: MESQAsx% Print "Set pupil diameter = " & pupilDiam qx!IlO Rwy:.)7B$q 'Update AZ Eye subassembly Description 'GW@P eID = FindFullName( "Geometry.Arizona Eye" ) Hpsg[d)! GetEntity eID, entity TR%?U/_4;r entity.Description = "Accommodation = " & A & "D" #bdJ]v.n SetEntity eID, entity 2G'G45Q ^WD[>E~ Update \h0e09& I Print "DONE!" ^ul `b "?S#vUS+ 2 End Sub 0cS.|\ZTA _`D_0v(X 如果屈光度是4,光瞳直径是4,则会输出如下数据: :YV!;dKJ m=}kGzIY4 Accommodation = 4 Diopters d+^4;Hv4 Pupil Diameter = 4 mm Jp,ohVRNq Set aqueous humor thickness = 2.81 igo7F@_, Set anterior lens radius = 10.4 and conic constant = -2.375869 I}8F3_b,# Set posterior lens radius = -4.424557 and conic constant = -3.081019 !.w S+ Set lens thickness = 3.927 (ZI&'"H Set lens index of refraction = 1.42672 6"=e+V@ Set pupil diameter = 4 T[;{AXLeI DONE! }h]:I'R! bC@b9opD (文章来源:讯技光电)
|