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2016-02-24 12:53 |
FRED运用:Arizona眼睛模型
简介 z|<oxF. 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。 5{a(
+' qWpC e*C 模型 9vTQ^*bm !VHIl&Mos 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。 ZX;k*OrW c #!6
Table 1. AZ眼睛模型的定义 [attachment=67931] Yel(}Ny 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. Mh|`XO.5I qtN29[x 光源 rsv!mY,Em 48Lmy<}* 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。 @,&m`qzd+ DxgT]F% gL"}5 3A
[attachment=67932] 图1. 光源和提示信息使用 X-,y[ ) 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。 j*u9+. W~F/ZrT3A 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。 =.oWg uzu N^]>R:Stu
[attachment=67933] 图2. 字母F光源的设定方法光 Q$0%~`t ]M(f^
[attachment=67934] 图3. 字母F在视网膜上位置点列图 cmU+VZ#pk 视网膜的散射 ebe@.ZVSi *F*fH>?C# 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。 x2sOEkcQ j2 ^T:q[ {\/nUbo[
[attachment=67935] 图4. 视网膜朗伯散射设定 6a7iLQA 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。 @%nUfG7TQ +fQL~0tA ^(JHRH~=h
[attachment=67936] 图5. 视网膜重点采样规格设定 AdW2o|Uap 脚本 '?gIcWM u2BW]T] 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: Ju7C?)x X&?lDL7?
[attachment=67937] 图6. 用户对话框的创建与编辑 w00\1'-Kz
[attachment=67938] 图7. 用户对话框编辑器 qetP93N_* 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。 )v{41sM+ 余下的脚本计算与屈光度有关的所有参数。 +4g%?5' doO
Ap9% 分析 <`_OpNxqW d"6]? 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Fg\| e% ^s~n[
[attachment=67939] 图7. 字母F在视网膜上颜色分析 KBRg95E~]l 脚本代码 HL}~W}!j :KP'xf. Option Explicit 'Remove this to enable non-dimensioned variables to be used. d3G{0PX ]|t.wr3AU Dim entity As T_ENTITY -0o6*?[Z Dim op As T_OPERATION W}2 &Pax Dim mat As T_MODELMATERIAL fk7Cf"[w Dim A As Double LL[#b2CKa Dim pupilDiam As Double "]s|D@^4#b Dim eID As Long RvS q KW8 Dim parID As Long Y-3[KH D Dim count As Integer $jed{N7Y Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double QS [B Dim tlens As Double, nlens As Double +
lB+|yJ+ Dim curv As Double, conic As Double J&"?m.~@ Dim ok As Long )=E~CpKV EPe]-C` Sub Main CxA\yG3L& #}!>iFBcH '用户输入对话框 aDl,
K;GL Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 (OyY_` TextBox 220,21,40,21,.TextBox1 'default: 0 +8)]m< Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 HCx%_9xlm OKButton 40,91,90,21 .5!sOOs$P CancelButton 190,91,90,21 ,M@m4bx Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 |pH*
CCA TextBox 220,49,40,21,.TextBox2 'default: 4 qbU1qF/ End Dialog [|[sYo Dim dlg As UserDialog (' Ko#3b Cl9SPz ok = Dialog (dlg) ?z@v3(b[ ik Y]8BCc If ok=0 Then 'cancel button was pressed zyZok*s Print "Execution cancelled." (~7m"? End @4_rx u& End If " _:iK] prlyaq;4 'Assign accommodation and pupil diameter & use defaults if field left empty DN"S, If dlg.TextBox1 = "" Then ^%5~; A = 0 'Default accommodation 6MQs \ J6. Else f3zfRhkIk A = CDbl(dlg.TextBox1) jom}_ End If Ig02M_ 5y%un If dlg.TextBox2 = "" Then GX7 eRqz > pupilDiam = 4 'Default pupil diameter c?.r"5# Else :Hzz{' pupilDiam = CDbl(dlg.TextBox2) @ .Z[M End If Z6IJ o%s lrs0^@.+ Print " " f@!
fW& Print "Accommodation = " & A & " Diopters" hJw
|@V Print "Pupil Diameter = " & pupilDiam & " mm" Y]~ HAv ' "Ju/[#VCJ ' Calculate new parameters with accommodation vo(g0Au) taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness M<{5pH(K 0'yG1qG Rant = 12.0 - 0.4*A 'Radius of anterior lens smfG,TI CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens `1fJ:b/M 5)d,G9 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens 1V|< A CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens &'5@azU }BI~am_ tlens = 3.767 + 0.04*A 'Lens thickness @<D'-mMt MkG`w, nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ?G$Om KInUe(g<9M 'Adjust parameters to account for accommodation 'Q:i&dTg (dzH3_U '************************************************************************* 3>-[B`dD( 'Aqueous thickness (Position of Lens) !,cQ'*<W8- '************************************************************************* gYTyH. eID = FindFullName( "Geometry.Arizona Eye.Lens" ) @-'/__cgt GetCustomElement eID, entity P0%N
Q1bn {S5RK-ax parID = FindFullName( "Geometry.Arizona Eye" ) 2d-TU_JqX fL ~1 ' Delete any shift(s) in z K&=1Ap count = 0 |d,F-9iw While GetOperationCount(eID)>count \%sPNw=e GetOperation eID, count, op { 1+Cw?1d If op.Type="ShiftZ" Then q';&SR#"`K DeleteOperation eID,count $|4cJ#;^L count=count-1 F(Lb8\to\M End If Uc_jQ4e_ count=count+1 [Ja)<!]< Wend ]Nnxnp Err4
%- 'Set new shift in UZzNVIXA% op.Type = "ShiftZ" N]B)Fb op.val1 = taq =nJ{$%L\x, op.parent = parID =yl4zQmg$ AddOperation eID, op }x*7l`1 Print "Set aqueous humor thickness = " & taq-0.55 u?Fnlne4@ /8f>':zUb '************************************************************************* 8';m)Jc 'Radius and conic constant of anterior lens #v{ Y=$L '************************************************************************* :lUX5j3 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 'S =sj}X GetConic eID, entity, curv, conic 8O,?|c=> h,^BC^VU9- SetConic eID, entity, 1/Rant, CCant
+"jl(5Q Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ?nQ_w0j EJ1Bq>u7 '************************************************************************* j]rXoV> 'Radius and conic constant of posterior lens ?#d6i$ '************************************************************************* z8IPhE@ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) $j57LY|r GetConic eID, entity, curv, conic }$l8d/_$[ GxxDY]! SetConic eID, entity, 1/Rpost, CCpost 1Fv8T' Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost *D2Nm9sl <>%,}j
9 '************************************************************************* v2d<o[[C 'Lens thickness (Position of posterior lens surface) *P`v^& '************************************************************************* vB^uxdt|m 'iJDWxCD parID = FindFullName( "Geometry.Arizona Eye.Lens" ) $H'8
#:[d_ Re>AsnA[ ' Delete any z-shift(s) 2+z1h^)W count = 0 tE@FvZC'= While GetOperationCount(eID)>count cv2]* GetOperation eID, count, op hR-K@fS%l' If op.Type="ShiftZ" Then 2Zy_5>~ DeleteOperation eID,count UVrQV$g! count=count-1 {V}qwm? End If k}GjD2m count=count+1 _g[-=y{Bb Wend -;$nb~y k0L] R5W 'Set new z-shift r088aUO
P op.Type = "ShiftZ" 'TL2%T/)t op.val1 = tlens G8eD7%{b:) op.parent = parID -ey)J
+?t AddOperation eID, op >L gVj$Z Print "Set lens thickness = " & tlens {Bh("wg$Lk % #u.J
'************************************************************************* P^pFqUL7# 'Lens index of refraction /t*YDWLg '************************************************************************* &f-hG3/M eID = FindMaterial( "Lens" ) iwU[6A GetModelMaterial eID, mat wd/G|kNO V>Fesm"aq mat.Nd = nlens ;\qXbL7 SetModelMaterial eID, mat YGp)Oy}: Print "Set lens index of refraction = " & nlens /4*W DiH Z,
T#, '************************************************************************* oaK.kOo 'Pupil diameter FbAW_Am( '************************************************************************* v8m`jxII64 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) dQD$K|aUp 9C/MRmv` 'Adjust pupil diameter (trimming volume inner hole) ='}#`', $
KB SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" %?9Ok ?iv=53<c# ' Adjust pupil location to just in front of the lens &$=! dA parID = FindFullName( "Geometry.Arizona Eye" ) H=p`T+ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 'N\&<dT> count = 0 [} -3PpF While GetOperationCount(eID)>count Qqc]aVRF GetOperation eID, count, op d]SYP If op.Type="ShiftZ" Then _fn1) DeleteOperation eID,count +BL{@,zr count=count-1 eh(<m8I End If $shp(T,q count=count+1 )K;]y-Us[ Wend D//=m= op.Type = "ShiftZ" FOH@OY op.val1 = taq-0.01 Dz;HAyPj op.parent = parID d(;4`kd*N AddOperation eID, op M:n 6BC>t" fvqd'2 t Print "Set pupil diameter = " & pupilDiam I4=Xb^Ux ^A9M;q 'Update AZ Eye subassembly Description $4m*kQ eID = FindFullName( "Geometry.Arizona Eye" )
)h_8vO2 GetEntity eID, entity <+v{GF#R entity.Description = "Accommodation = " & A & "D" z-r2!^q27 SetEntity eID, entity p?# pT}1 3^,QIG Update HC*?DJ, Print "DONE!" e,gyQjJR Z9K})47T End Sub ?X9UTOx Kct@87z 如果屈光度是4,光瞳直径是4,则会输出如下数据: 8)j@aiF` 3n]79+w@z Accommodation = 4 Diopters FwG!> Pupil Diameter = 4 mm pQa:pX Set aqueous humor thickness = 2.81 `<frgXu64 Set anterior lens radius = 10.4 and conic constant = -2.375869 Vzg=@A# Set posterior lens radius = -4.424557 and conic constant = -3.081019 N|usFqCNk^ Set lens thickness = 3.927 >IfV\w32 Set lens index of refraction = 1.42672 4aUiXyr*2 Set pupil diameter = 4 G~,:2
o3 DONE! 6'vbT~S! [?0d~Q(R#
(文章来源:讯技光电)
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