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Je 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。 ;ojiJ?jU }[!92WS/ee 模型 1W,(\'^R 74J@F2g}? 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。 j]5WK_~M ;O=h$8] Table 1. AZ眼睛模型的定义 7P**:b 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+(i^=S 7y<1LQ;} 光源 X.#oEmA,P
}31ZX 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。 y8
E}2/ Hfc"L> @,OT/egF4: 图1. 光源和提示信息使用 HuI`#.MpWE 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。 U
?b".hJ2 WeJ@xL 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。 ^k/i-%k0 $yb@
Hhx> 图2. 字母F光源的设定方法光 d8x%SQ!V |m*.LTO 图3. 字母F在视网膜上位置点列图 <"tDAx 视网膜的散射 p 2O~>97t1 +c$I&JO 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。 ocQWQ 1~yZ T B6M+mx"G 图4. 视网膜朗伯散射设定 q{' ~+Nq 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。 "v]%3i.*
- yfj(Q s EbK0j? 图5. 视网膜重点采样规格设定 6NLW(?]
脚本 {=Q7m`1 :E_a0!' 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: +RDJY(Y$ M0'v&g 图6. 用户对话框的创建与编辑 SaDA`JmO 图7. 用户对话框编辑器 -,#+`>w 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。 QwWW!8 余下的脚本计算与屈光度有关的所有参数。 ,T5u'"; r@}bDkx 分析 TkRP3_b 5J.0&Dda 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 F jrINxL7^ &"E
lm 图7. 字母F在视网膜上颜色分析 {7"0,2 Hb? 脚本代码 &xd.Qi2 i'HQQWd Option Explicit 'Remove this to enable non-dimensioned variables to be used. pV\YG B+ Va<eusl Dim entity As T_ENTITY /bVZ::A&_ Dim op As T_OPERATION E4%j. Dim mat As T_MODELMATERIAL j;nb?; Dim A As Double Ib`-pRU; Dim pupilDiam As Double v/Pw9j!r;m Dim eID As Long h0 |}TV^UJ Dim parID As Long vZAv_8S) Dim count As Integer B(5c9DI` Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double (/{aJV Dim tlens As Double, nlens As Double Lc2QXeo8 Dim curv As Double, conic As Double 1Y/$,Oa5 Dim ok As Long ]7YNIS -*ELLY[ Sub Main _^S]g mE I["j=r '用户输入对话框 F2I 5qC/ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 x~DLW1I TextBox 220,21,40,21,.TextBox1 'default: 0 PGn);Baq Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 nHOr AD|& OKButton 40,91,90,21 =t0tK}Y+4 CancelButton 190,91,90,21 >t+
qe/ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 =\kMXB TextBox 220,49,40,21,.TextBox2 'default: 4 oOU1{[ End Dialog J ++v@4Z Dim dlg As UserDialog ^rAa"p 9 5]Da{Wmgs ok = Dialog (dlg) \_]En43mg L=!of{4Z(} If ok=0 Then 'cancel button was pressed YlK7;yrq( Print "Execution cancelled." 7L(eh7 End p.JXSn End If cNK)5-
U @4+#Xd7" 'Assign accommodation and pupil diameter & use defaults if field left empty {,$rkwW If dlg.TextBox1 = "" Then P Ru&3BP A = 0 'Default accommodation -yH,5vD Else @tUoD>f A = CDbl(dlg.TextBox1) n.6T
OF End If B{6<;u)[ QV|>4 ^1D If dlg.TextBox2 = "" Then _r Y,}\ pupilDiam = 4 'Default pupil diameter M!m?#xz'c Else -.I4-6~ pupilDiam = CDbl(dlg.TextBox2) R`'1t3p0i End If %Q"(/jm? v1G"3fy9 Print " " W#F Q,+0) Print "Accommodation = " & A & " Diopters" XFwLz Print "Pupil Diameter = " & pupilDiam & " mm" S7iDTG_@t [j,txe?n ' Calculate new parameters with accommodation r|<DqTc6l taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness x34f9!
't K|S:{9Q Rant = 12.0 - 0.4*A 'Radius of anterior lens VU.@R, CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens y*b3&%.ml 0?Q_@Y Rpost = -5.224557 + 0.2*A 'Radius of posterior lens A&5:ATQ/| CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens .i"W8~<e AC%JC+ tlens = 3.767 + 0.04*A 'Lens thickness 77 r(*.O| c "=N nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 'cZN{ZMWG .10y0FL4 'Adjust parameters to account for accommodation Q+q,!w8 kyw/LE3$- '************************************************************************* i&Fiq&V)[ 'Aqueous thickness (Position of Lens) n]Li->1 '************************************************************************* /*)Tl eID = FindFullName( "Geometry.Arizona Eye.Lens" ) (<*e GetCustomElement eID, entity .N m su+s B~o-l* parID = FindFullName( "Geometry.Arizona Eye" ) Cr ?4Ngw xG2+(f#C1 ' Delete any shift(s) in z AvJ,SQt count = 0 !BIOY!M While GetOperationCount(eID)>count qPGuo5^ GetOperation eID, count, op +_l^ #?o, If op.Type="ShiftZ" Then q%YV$$c DeleteOperation eID,count XL}"1lE count=count-1
W-~n|PX8+ End If (7FW9X; count=count+1 Mz]:}qmFA Wend :nY2O Kn;D?ioY 'Set new shift in [V8fu
qE> op.Type = "ShiftZ" e$)300 o op.val1 = taq {No L op.parent = parID 266oTER]v: AddOperation eID, op SGc8^%-` Print "Set aqueous humor thickness = " & taq-0.55 RJeDEYXeg AV8T '************************************************************************* ~X(UcZ2 'Radius and conic constant of anterior lens B@YyQ' '************************************************************************* Fm_y&7._ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) UaG1c%7?X GetConic eID, entity, curv, conic P(k(m<0 \G@wp5 SetConic eID, entity, 1/Rant, CCant QnouBrhO Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant eW'2AT?2H% =:,xxqy '************************************************************************* P,DC 7\ 'Radius and conic constant of posterior lens `/&SxQB< '************************************************************************* +k<w!B*
eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ~ (On|h GetConic eID, entity, curv, conic `Pn[tuIO `Hx~UH) SetConic eID, entity, 1/Rpost, CCpost T\s)le Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost RC#C\S6 :wqC8&V '************************************************************************* S8Fmy1# 'Lens thickness (Position of posterior lens surface) LA3<=R] '************************************************************************* Q?t^@ 3oZ=k]\ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) qZEoiNH(Tj [k$*4u> ' Delete any z-shift(s) T^<>Xiam count = 0 rX7QbAB While GetOperationCount(eID)>count w2O!M!1 GetOperation eID, count, op ZSy?T If op.Type="ShiftZ" Then 2L_6x<u' DeleteOperation eID,count AwUi+|7r]) count=count-1 3VnQnd E End If gwd (N count=count+1 rx"s!y{!- Wend b
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, (m[bWdANnW 'Set new z-shift = VLS/\A op.Type = "ShiftZ" n(nBRCG)o op.val1 = tlens dx*qb op.parent = parID iTh:N2/-vc AddOperation eID, op y)c5u%( Print "Set lens thickness = " & tlens "&Dx=Yf V==z" '************************************************************************* 5BkV aF7Th 'Lens index of refraction mV^Zy '************************************************************************* OX:O^ (-r, eID = FindMaterial( "Lens" ) \qvaE+ GetModelMaterial eID, mat nn b8Gcr 2g9G{~,@g mat.Nd = nlens q}BzyC=:n SetModelMaterial eID, mat 3=Ec" Print "Set lens index of refraction = " & nlens dUznxZB 5Ky#GuC '************************************************************************* jeyLL< 'Pupil diameter \o-&f: '************************************************************************* |]Z:&[D]i eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 9~rUkHD w=h1pwY 'Adjust pupil diameter (trimming volume inner hole) 8n BL\{'B[ 0Z<I%<8bK SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 3cS2gxF Lj\/Ji_ ' Adjust pupil location to just in front of the lens X2mREt9 parID = FindFullName( "Geometry.Arizona Eye" ) l+][V'zL eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) "N:XzG count = 0 [ao
U5;7 While GetOperationCount(eID)>count h0oMTiA GetOperation eID, count, op ?; YC'bF If op.Type="ShiftZ" Then "jecsqCgK0 DeleteOperation eID,count x6afI<dm count=count-1 %S`
v!*2 End If pu!d qF< count=count+1 G!8Z~CPF Wend qrvsjYi*w op.Type = "ShiftZ"
@=]~\[e\ op.val1 = taq-0.01 {*ZY(6^ op.parent = parID Ogt]_ AddOperation eID, op jJ4qR:] {k.MS-q Print "Set pupil diameter = " & pupilDiam Ed0I WPx \7MHaQvS 'Update AZ Eye subassembly Description ^[Ua46/" m eID = FindFullName( "Geometry.Arizona Eye" ) dLsn\m> GetEntity eID, entity Dlo xrdOY& entity.Description = "Accommodation = " & A & "D" FEPXuCb SetEntity eID, entity fW`&'! &bqT/H18 Update )5JU:jNy Print "DONE!" .,~(%#Wl$ G1t\Q-|l0 End Sub YJs|c\ eq? aw?=hXR! 如果屈光度是4,光瞳直径是4,则会输出如下数据: /:<IIqO. o]{uc, Accommodation = 4 Diopters E|YdcS Pupil Diameter = 4 mm h=kQ$`j6 Set aqueous humor thickness = 2.81 sG~<M"znV Set anterior lens radius = 10.4 and conic constant = -2.375869 6*l^1;U Set posterior lens radius = -4.424557 and conic constant = -3.081019 T&T/C@z'R Set lens thickness = 3.927 Ov-b:lH Set lens index of refraction = 1.42672 2eeQ@]Wj[Z Set pupil diameter = 4 G5dO 3lwq DONE! Hv]7e| d0hhMx6$ S1 _6C:^k QQ:2987619807 +6smsL~<#v
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