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简介 'YvRkWf:KC 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。 ZxB7H{ ]sZ!
-q'8 模型 Ctx`b[&KXX CB^.N>' 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。 YY4q99^K /m|U2rrqb Table 1. AZ眼睛模型的定义 &4{!5r 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. Ajm4q_ F%IvgXt5 光源 {I8C&GS \l1==,wk 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。 Zo<j"FG &embAqW: gy Ey=@L 图1. 光源和提示信息使用 I8f=' 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。 ~L4L|q 7 Z;y(D_;_ 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。 w+u1" N/78Ub 图2. 字母F光源的设定方法光 N6HeZB": <q&4Y+b 图3. 字母F在视网膜上位置点列图 }<^QW't_Y 视网膜的散射 $`[TIyA9! X?U'GLm 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&
Nou .(99f#2M: 1:!H`*DU& 图4. 视网膜朗伯散射设定 Lp)P7Yt- 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。 xqb*;TBh* SuXeUiK.[ 8Si3
aq3 图5. 视网膜重点采样规格设定 xp}M5| 脚本 =~>g--^U 55FRPNx-x 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: U$46=F| nS](d2 图6. 用户对话框的创建与编辑 G@txX
' 图7. 用户对话框编辑器 hHZ'*,9 y 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。 V8Ri2&|3 余下的脚本计算与屈光度有关的所有参数。 6{quO#! iK=QP+^VN 分析 cn Ohj wXtp(YwlH 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 adPd}rt; GVhy
}0| 图7. 字母F在视网膜上颜色分析 fejC,H4I 脚本代码 e/&^~ $h hd]ts. Option Explicit 'Remove this to enable non-dimensioned variables to be used. _u]%K-_ VeSQq Dim entity As T_ENTITY 4fL`.n1^ Dim op As T_OPERATION v-BQ>-& s Dim mat As T_MODELMATERIAL A"z9t#dv@ Dim A As Double >g m Dim pupilDiam As Double lQd7p+21 Dim eID As Long Nv^byWqu Dim parID As Long :a^/&LbLm Dim count As Integer o{hX?,4i Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Au6Y] Dim tlens As Double, nlens As Double SF`(`h0e Dim curv As Double, conic As Double +~~2OU L Dim ok As Long }*C*!?pcd D*j^f7ab Sub Main p{}4#+-<#H oEX^U4/= '用户输入对话框 ~Hu!iZ2] Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 YN+vk}8 < TextBox 220,21,40,21,.TextBox1 'default: 0 Z/dhp0k Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 p!5'#\^f OKButton 40,91,90,21 yRIXUCy CancelButton 190,91,90,21 e,,O Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 lB0`|UEb ( TextBox 220,49,40,21,.TextBox2 'default: 4 ^,#my<{ End Dialog bAbR0) Dim dlg As UserDialog x|O^#X(, .`Q^8|$-K ok = Dialog (dlg) #y[U2s Se Nk<^ Qv If ok=0 Then 'cancel button was pressed OQ-
Hn-H Print "Execution cancelled." D$7#&2y End 3%hq< End If ZPyzx\6\ kY @(- 'Assign accommodation and pupil diameter & use defaults if field left empty .r2*tB). If dlg.TextBox1 = "" Then *yaS^k\ A = 0 'Default accommodation 1`YU9? Else DzQ A = CDbl(dlg.TextBox1) OZ+v ~'oD End If TN1pg fCwE1r*^ If dlg.TextBox2 = "" Then fx(h fz pupilDiam = 4 'Default pupil diameter !?(7g2NP) Else TS#[[^!S pupilDiam = CDbl(dlg.TextBox2) _'LZf=V0 End If m3TR}=n NC#F:M;b Print " " __2<v?\ Print "Accommodation = " & A & " Diopters" h%krA<G9 Print "Pupil Diameter = " & pupilDiam & " mm" LP=j/qf|
fT|A^ ' Calculate new parameters with accommodation W*t]
d taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness @phVfP"M G[A3H>
> Rant = 12.0 - 0.4*A 'Radius of anterior lens e=WjFnK[x7 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens )@X0'X< }:Gs , Rpost = -5.224557 + 0.2*A 'Radius of posterior lens D%abBE1 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens b7Jxv7$e
v6s,lC5qR tlens = 3.767 + 0.04*A 'Lens thickness w?8SQI,~X tqZ+2c<W3 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction )](ls@* 1|(Q| 'Adjust parameters to account for accommodation =c'4rJ$+ Z*ip=FYR '************************************************************************* 6e%@uB}$ 'Aqueous thickness (Position of Lens) >%k6k1CZ '************************************************************************* RqtBz3v eID = FindFullName( "Geometry.Arizona Eye.Lens" ) WJ25fTsG GetCustomElement eID, entity du66a+@t +cfEyiub parID = FindFullName( "Geometry.Arizona Eye" ) `8ac;b N)H "'#- ' Delete any shift(s) in z #*'Qm
A count = 0 S^eem_C While GetOperationCount(eID)>count (Jk&U8y GetOperation eID, count, op AJ bCC If op.Type="ShiftZ" Then sD:o
2(G* DeleteOperation eID,count x#J9GP. count=count-1 #wI}93E End If
u]P| count=count+1 9{*{Ba Wend #;]#NqFX U!aM63F3 'Set new shift in D%p*G5Bg3 op.Type = "ShiftZ" rD].=.?1 op.val1 = taq ,~1'L6Ri? op.parent = parID R}ki%i5| AddOperation eID, op *M1GVhW(+ Print "Set aqueous humor thickness = " & taq-0.55 eQuu\/z*H @-
STo/ '************************************************************************* *nCA6i 'Radius and conic constant of anterior lens apo)cR '************************************************************************* jk9f{Iu eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 2.D2
o GetConic eID, entity, curv, conic 0%ul6LvM EtKq.<SJ SetConic eID, entity, 1/Rant, CCant _MBhwNBxZ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant eV[{c %wN: &h-_|N '************************************************************************* ]n!V 'Radius and conic constant of posterior lens T/_u;My; '************************************************************************* wa"0`a:`; eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 'D+xs}\ GetConic eID, entity, curv, conic ye^x>a[' |U%NPw5 SetConic eID, entity, 1/Rpost, CCpost T$5wH )< Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost oY)eN?c jeu'K vhe '************************************************************************* )9YDNVo*- 'Lens thickness (Position of posterior lens surface) g:o/^_ '************************************************************************* l<v{8:,e # Lce,]z\_ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) y, l[v39 AxH;psj ' Delete any z-shift(s) j3Od7bBS] count = 0 5 pCicwea# While GetOperationCount(eID)>count -9b=-K.y GetOperation eID, count, op _3`GZeGV If op.Type="ShiftZ" Then 4uXGpsL DeleteOperation eID,count $*C
}iJsF count=count-1 Kxsd@^E End If gP%<<yl count=count+1 !j6k]BgZ Wend yKML{N1D {7:1F)Pj 'Set new z-shift e>MtDJ5 op.Type = "ShiftZ" Hn/t'D3 op.val1 = tlens j1_>>xB op.parent = parID q,P.)\0A AddOperation eID, op +^AdD8U Print "Set lens thickness = " & tlens k79OMf<v 56pj(}eq '************************************************************************* !VD$uT 'Lens index of refraction C*YQ{Mz(f '************************************************************************* ([8*Py| eID = FindMaterial( "Lens" ) w7MRuAJ4 GetModelMaterial eID, mat .\b.l@O<Z `wi+/^); mat.Nd = nlens y" =?l SetModelMaterial eID, mat ?p{-Yp*h Print "Set lens index of refraction = " & nlens < se ~wR h4n~V:nNm '************************************************************************* +L 09^I 'Pupil diameter v[$e{ Dz( '************************************************************************* ;~F*2) eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) (Yy#:r;U Te+# 'Adjust pupil diameter (trimming volume inner hole) C6>_wl] Y1Ql_ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ) 8xbc&M jZ~girA ' Adjust pupil location to just in front of the lens k)+{Y v* parID = FindFullName( "Geometry.Arizona Eye" ) 8(? &=>@ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) g0 Q,]\~ count = 0 (cVIjo+:: While GetOperationCount(eID)>count -c>3|bo GetOperation eID, count, op 4zs0+d+ If op.Type="ShiftZ" Then pW[TufTa DeleteOperation eID,count ;1~ n|IY count=count-1 *L<EGFP End If E?]$Y[KJKs count=count+1 e/4C` J- Wend HL{aqT2 op.Type = "ShiftZ" Q%6zr9 op.val1 = taq-0.01 >_Tyzl>z op.parent = parID |K.I%B AddOperation eID, op ~vYFQKrb ` 0@m, Print "Set pupil diameter = " & pupilDiam %0&,_jM/9 Lq3<&$ 'Update AZ Eye subassembly Description @Ov}X]ELi eID = FindFullName( "Geometry.Arizona Eye" ) c6b51)sQ" GetEntity eID, entity I!!cA?W entity.Description = "Accommodation = " & A & "D" j~bNH~3 SetEntity eID, entity n%WjU)< 5Y;&L!T Update C#[P<= v Print "DONE!" ea{zL PC5$TJnj3 End Sub =Fe4-B?I ,./n@.na 如果屈光度是4,光瞳直径是4,则会输出如下数据: ~;b}_?%o /pRv
i>_(: Accommodation = 4 Diopters #+<YFm\i Pupil Diameter = 4 mm n:a~=^IV Set aqueous humor thickness = 2.81 A#`$#CO Set anterior lens radius = 10.4 and conic constant = -2.375869 B|o@|zF Set posterior lens radius = -4.424557 and conic constant = -3.081019 D_(NLC Set lens thickness = 3.927 I>8_gp\1 Set lens index of refraction = 1.42672 $J4)z&%dr Set pupil diameter = 4 ;Mmu} DONE! gDJ} <^ %V1j M (文章来源:讯技光电)
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