-
UID:317649
-
- 注册时间2020-06-19
- 最后登录2026-02-11
- 在线时间1927小时
-
-
访问TA的空间加好友用道具
|
简介 )N*Jc @Y@ MT7B'hd 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。 oKCv$>Y #IJeq0TVB 模型 ITg<u?z_ 0?}n( f!S 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 X`1R&K;z^ ,ga6 Table 1. AZ眼睛模型的定义 6']HmM 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. \EsT1aT lB0`|UEb ( 光源 ^,#my<{ bAbR0) 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 x|O^#X(, .`Q^8|$-K #y[U2s Se 图1. 光源和提示信息使用 Nk<^ Qv 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。
EY:IwDA.} D$7#&2y 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 U`lK'.. z:@:B:E 图2. 字母F光源的设定方法光 WN<g _8QR |JP19KFx'B 图3. 字母F在视网膜上位置点列图 0y6M;"&~E 视网膜的散射 Z %Ozzp/ uKd4+Km 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 &w#! Fs].Fa AYgXqmH~+ 图4. 视网膜朗伯散射设定 #c5jCy}n 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 ?3p7MjvZ 993f6 "4;nnq 图5. 视网膜重点采样规格设定 3+15
yEeA 脚本 |K"Q>V2y u8]FJQ*\6+ 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: ]"lB!O~ u '7h(1@ 图6. 用户对话框的创建与编辑 %IX)+
Lp` 图7. 用户对话框编辑器 ](A2,F
9(U 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 xC,x_:R` 余下的脚本计算与屈光度有关的所有参数。 @phVfP"M G[A3H>
> 分析 e=WjFnK[x7 )@X0'X< 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 }:Gs , D%abBE1 图7. 字母F在视网膜上颜色分析 b7Jxv7$e
脚本代码 v6s,lC5qR L23}{P Option Explicit 'Remove this to enable non-dimensioned variables to be used. BtZ]~S}v K5jt(7i Dim entity As T_ENTITY *y!O\-\S#> Dim op As T_OPERATION )63
$,y-;$ Dim mat As T_MODELMATERIAL +yp:douERi Dim A As Double <;6{R#Tuh Dim pupilDiam As Double pA6KiY& Dim eID As Long jYFJk&c Dim parID As Long /{\ /e"5 Dim count As Integer ]7O<|8n!d Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double UowvkVa Dim tlens As Double, nlens As Double motK}G Dim curv As Double, conic As Double =/!lK& Dim ok As Long z*EV>Y[ s*ZE`/SM3 Sub Main G
aV&y gvA}s/ '用户输入对话框 e@Lxduq Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 IT1YF.i TextBox 220,21,40,21,.TextBox1 'default: 0 G}fBd Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 <w{?b'/q OKButton 40,91,90,21 ?vFy3 CancelButton 190,91,90,21 6OAs%QZ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 d+
jX49Vt TextBox 220,49,40,21,.TextBox2 'default: 4 ^$K&Met End Dialog UqOBr2UmG Dim dlg As UserDialog %.Ma_4o
Z #i[:oC6m: ok = Dialog (dlg) DB5J3r81 SM2Lbfp!u If ok=0 Then 'cancel button was pressed dU$VRgP/ Print "Execution cancelled." :\\NK/" End 0O9b
7F End If ;=Ma+d# s-$Wc)l 'Assign accommodation and pupil diameter & use defaults if field left empty H<(F$7Q!\ If dlg.TextBox1 = "" Then
/MGapmqV9 A = 0 'Default accommodation {^WK#$] Else cZYy+ A = CDbl(dlg.TextBox1) &-3e3) End If y9r4]45 }a7d(7 If dlg.TextBox2 = "" Then `tk oS pupilDiam = 4 'Default pupil diameter c*;oR$VW Else #\0m(v pupilDiam = CDbl(dlg.TextBox2) 3~~X,ZL End If S,c{LTL E^1yU Print " " Q$E.G63Wl Print "Accommodation = " & A & " Diopters" !l (Vk Print "Pupil Diameter = " & pupilDiam & " mm" ,/\`Rc^n (S~kyU!)0 ' Calculate new parameters with accommodation n<.7tr0f\ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness A2|Bbqd @dWA1tM Rant = 12.0 - 0.4*A 'Radius of anterior lens 0D(8-H CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens x?Abk GV0\+A"vD Rpost = -5.224557 + 0.2*A 'Radius of posterior lens \@gV$+{9 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens D+]mKPB J,=K1>8s tlens = 3.767 + 0.04*A 'Lens thickness .U!EA0B ;_,jy7lf nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Jt_=aMY:7 K4Q{U@ZJ 'Adjust parameters to account for accommodation kR<sSLEb yu;EL>G_AY '************************************************************************* Bhv;l/K]) 'Aqueous thickness (Position of Lens) TO6F '************************************************************************* Y&6jFT_ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) QVT0.GzR GetCustomElement eID, entity '12m4quO ynsYU( parID = FindFullName( "Geometry.Arizona Eye" ) >z<L 60S ,U{dqw8E{ ' Delete any shift(s) in z ;jzJ6~< count = 0 mdc?~?? 8 While GetOperationCount(eID)>count F5*-HR GetOperation eID, count, op n!4}Hwz! If op.Type="ShiftZ" Then o?a2wY^_ DeleteOperation eID,count 3r~8:F"g count=count-1 8-;.Ejz!\A End If 6s@!Yn|? count=count+1 D?KLV_Op Wend Otq3nBZ YEv\!%B 'Set new shift in RuHDAJ"&a op.Type = "ShiftZ" G#7*O` op.val1 = taq awzlLI<2p op.parent = parID ,a5q62)q AddOperation eID, op >!fTWdD^ Print "Set aqueous humor thickness = " & taq-0.55 ;~F*2) (Yy#:r;U '************************************************************************* Te+# 'Radius and conic constant of anterior lens Id?-Og2iV '************************************************************************* )u(,.O[cw eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) c]*yo GetConic eID, entity, curv, conic EZj rX>"# 94!}
Z> SetConic eID, entity, 1/Rant, CCant {L$$"r, Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant #?Ix6 {R JrBPx/?(,; '************************************************************************* 2m $C;j!D 'Radius and conic constant of posterior lens $?ss5:
S '************************************************************************* %s}{5Qcl/ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) T>'w]wi GetConic eID, entity, curv, conic 61_PSScSY 'l<#;{ SetConic eID, entity, 1/Rpost, CCpost ]+G
.S-a Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ^2dQVV. Q%6zr9 '************************************************************************* _#~D{91
j: 'Lens thickness (Position of posterior lens surface) |K.I%B '************************************************************************* ~vYFQKrb ` 0@m, parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Lum=5zDo Lq3<&$ ' Delete any z-shift(s) @Ov}X]ELi count = 0 c6b51)sQ" While GetOperationCount(eID)>count I!!cA?W GetOperation eID, count, op j~bNH~3 If op.Type="ShiftZ" Then n%WjU)< DeleteOperation eID,count 5Y;&L!T count=count-1 W
/v
&V# End If ea{zL count=count+1 PC5$TJnj3 Wend =Fe4-B?I iklZ[G%A0 'Set new z-shift hcW>R op.Type = "ShiftZ" e>_a
( op.val1 = tlens _ow7E\70 op.parent = parID zn/>t-Bc AddOperation eID, op /QB;0PrE Print "Set lens thickness = " & tlens Ho#nM_ q Eg&5tAyM '************************************************************************* 8yIBx%"4MH 'Lens index of refraction P*[wB_^&UP '************************************************************************* E
6#/@C, eID = FindMaterial( "Lens" ) O\!'Ds+gX GetModelMaterial eID, mat LT)I
?ud InL_JobE8r mat.Nd = nlens
"O#
V/( SetModelMaterial eID, mat Ca5LLG Print "Set lens index of refraction = " & nlens B3yTN6- .Tl,Ek( '************************************************************************* k^d^Todq. 'Pupil diameter }x#e.}hf& '************************************************************************* Fsl="RB7f eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) O,7S1 fJNK@F 'Adjust pupil diameter (trimming volume inner hole) 'Jek<
5 ]D~Ibv{Y SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" IPn!iv) w3VgGc~ ' Adjust pupil location to just in front of the lens X!{K`~DRX parID = FindFullName( "Geometry.Arizona Eye" ) "1\GU1x eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) W9}
,f count = 0 $[Ut])4
~ While GetOperationCount(eID)>count 'pUJREb GetOperation eID, count, op /:!l&1l:p If op.Type="ShiftZ" Then 2xUgM}e DeleteOperation eID,count Txl|F\nK` count=count-1 d=D#cs;\ End If cBbumf 9C count=count+1 "Uf1;;b Wend \-Xtbm op.Type = "ShiftZ" t>a D;|Y op.val1 = taq-0.01 ]H{*Z3S op.parent = parID BK)<~I AddOperation eID, op @0
x V^!^wLLi Print "Set pupil diameter = " & pupilDiam d"E3ypPK %TAS4hnu% 'Update AZ Eye subassembly Description a>-qHX-l eID = FindFullName( "Geometry.Arizona Eye" ) B[h^] k GetEntity eID, entity @@-TW`G7 entity.Description = "Accommodation = " & A & "D" @*|UyK. SetEntity eID, entity .nNZdta&= K}
T=j+ Update hi(e%da Print "DONE!" eB_r.R{ raSga'uT; End Sub 0 ;)Q .x] pJ9 如果屈光度是4,光瞳直径是4,则会输出如下数据: :.=j)ljTx \ntUxPox. Accommodation = 4 Diopters m<k6oev$ Pupil Diameter = 4 mm $;$vcV9* Set aqueous humor thickness = 2.81 G; exH$y Set anterior lens radius = 10.4 and conic constant = -2.375869
T*8S7l Set posterior lens radius = -4.424557 and conic constant = -3.081019 liy/uZ Set lens thickness = 3.927 zN;P_@U Set lens index of refraction = 1.42672 br TP}A Set pupil diameter = 4 N5`z S79W DONE! 'Q7^bF^
|