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简介 ~afg)[( 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。 n4lutnF Blq8H"3!: 模型 Zf7&._y. /*Qq[C 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。 'Peni1_ 5'a3huRtV Table 1. AZ眼睛模型的定义 fSDi-I 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. s_.]4bl.8 8.bKb<y 光源 +h_ !0dG 6!^[];%xN 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。 wM[~2C=vx G|8%qd )bx_;9Y{ 图1. 光源和提示信息使用 _tr<}PnZ 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。 A8A~!2V 3sCFHn#c 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。 Q!,<@b) A[WV'!A, 图2. 字母F光源的设定方法光 t:LcNlN| %r)avI 图3. 字母F在视网膜上位置点列图 L!_ZY 视网膜的散射 1{_A:<VBl H UoyLy 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。 >!6i3E^ 4x%(9_8{- 2FD=lR?6 图4. 视网膜朗伯散射设定 4(l?uU$ 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。 u9=SpgB# l<(Y_PE: `bKA+c,f 图5. 视网膜重点采样规格设定 <\zCpkZ'B 脚本 ZDL']*)' xyr+_k-x&q 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: TO,rxf X}P$emr7 图6. 用户对话框的创建与编辑 c.\O/N
图7. 用户对话框编辑器 |_u8mV 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 *]J dHO 余下的脚本计算与屈光度有关的所有参数。 UueD(T;p l!E7AKk8 分析 AGA`fRVx <ktzT&A 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Fyyg`J /9yaW7w 图7. 字母F在视网膜上颜色分析 ,D6v4<jh 脚本代码 nxQ?bk}*d t]1ubt2W Option Explicit 'Remove this to enable non-dimensioned variables to be used. U-wLt(Y< b{DiM098 Dim entity As T_ENTITY sM1RU Dim op As T_OPERATION h?\2_s Dim mat As T_MODELMATERIAL `nR %Cav,U Dim A As Double ?j7vZ}iRi Dim pupilDiam As Double cD1o"bq Dim eID As Long &@"]+33 Dim parID As Long k&hc m Dim count As Integer !0/z>#b Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double y%]8'q$ Dim tlens As Double, nlens As Double .'[/|4H Dim curv As Double, conic As Double v;y0jD#b Dim ok As Long ~fz[x 9\ {mE! Vf Sub Main &Y@#g9G U3vEdw<lV '用户输入对话框 puJ#w1!x` Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 P];JKE% TextBox 220,21,40,21,.TextBox1 'default: 0 0@1:M
Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ~$O1`IT OKButton 40,91,90,21 c.H?4j7ga CancelButton 190,91,90,21 WKA'=,`v Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 @E`?<|B} TextBox 220,49,40,21,.TextBox2 'default: 4 i`%. End Dialog `29TY&p+" Dim dlg As UserDialog \o3"~\|6C $mco0%$ ok = Dialog (dlg) iZ[tHw|| BH0!6Oq If ok=0 Then 'cancel button was pressed %R0v5=2' Print "Execution cancelled." guN4-gGDr< End #:3r4J%+~ End If gvli %9n FYPz 4K 'Assign accommodation and pupil diameter & use defaults if field left empty }wt%1v-10U If dlg.TextBox1 = "" Then ZofHic A = 0 'Default accommodation v@ONo?) Else P`s(kIe A = CDbl(dlg.TextBox1) .")b?#K End If (0*v*kYdL+ 'zSgCgCHX8 If dlg.TextBox2 = "" Then UPCQs", pupilDiam = 4 'Default pupil diameter i8V0Ty4~N Else ].DY" pupilDiam = CDbl(dlg.TextBox2) yYAnwf End If ` DCU>bt&R %u]6KrG18b Print " " si/er"&o Print "Accommodation = " & A & " Diopters" eFQQW`J Print "Pupil Diameter = " & pupilDiam & " mm" l%"`{ *)VAaGUX> ' Calculate new parameters with accommodation cV$lobqO taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 3\!F\tqD \ ;cSGlE | Rant = 12.0 - 0.4*A 'Radius of anterior lens q
G;-o)h CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens *d*oS7 2o{@nN8% Rpost = -5.224557 + 0.2*A 'Radius of posterior lens . A<sr CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens e&J3N 4e%8D`/=M tlens = 3.767 + 0.04*A 'Lens thickness 6zYaA i^%-aBZ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction X7cWgo66T cqQRU 'Adjust parameters to account for accommodation IlHY%8F{ 2:J,2=% '************************************************************************* 9={N4}< 'Aqueous thickness (Position of Lens) u7k|7e=xk
'************************************************************************* RebTg1vGu eID = FindFullName( "Geometry.Arizona Eye.Lens" ) #4y,a_) GetCustomElement eID, entity {;RF D3?N<9g parID = FindFullName( "Geometry.Arizona Eye" ) GJak.,0t _'JRo%{xGX ' Delete any shift(s) in z J/S{FxNe] count = 0 ltEF:{mLe# While GetOperationCount(eID)>count R#0{Wg0O) GetOperation eID, count, op )Xno|$b5Eo If op.Type="ShiftZ" Then Pf8u/?/ DeleteOperation eID,count :o\5K2]: count=count-1 <ZrFOb End If %8Yyj{^!( count=count+1 P0#`anUr1 Wend vvh.@f qz:]-A 'Set new shift in I q,v op.Type = "ShiftZ" }J;~P
9Y op.val1 = taq i`~~+6`J op.parent = parID .}p|`3$P AddOperation eID, op )VY10R)$ Print "Set aqueous humor thickness = " & taq-0.55 !QTPWA ,I39&;Iq '************************************************************************* R92R}=G! 'Radius and conic constant of anterior lens G;2[ '************************************************************************* %^')G+>i eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) e`ex]py<C GetConic eID, entity, curv, conic "UpOY 6h@+?{F. SetConic eID, entity, 1/Rant, CCant $NCm;0\B| Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant QT_^M1% S>EDL '************************************************************************* 8bbVbP 'Radius and conic constant of posterior lens ^N{X " '************************************************************************* cyb(\ fsC eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) qvN"1=nJ GetConic eID, entity, curv, conic x:C@)CAr -R74/GBg SetConic eID, entity, 1/Rpost, CCpost \P?--AIq< Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost FoLDMx( =SL^>HS.fo '************************************************************************* HqRCjD 'Lens thickness (Position of posterior lens surface) D8 wG!X '************************************************************************* GDmv0V$6 Xr2 Wa parID = FindFullName( "Geometry.Arizona Eye.Lens" ) `OLB';D fU`T\ ' Delete any z-shift(s) C,3T!\ count = 0 6>lW5U^yA\ While GetOperationCount(eID)>count XJ\_V[WA GetOperation eID, count, op "Y(%oJS]D If op.Type="ShiftZ" Then No~6s.H DeleteOperation eID,count p`LL count=count-1 sOC|
B End If _]_L F[ count=count+1 d~,n_E$q; Wend kw;wlFU; v'$ykZ!Z 'Set new z-shift YiO3<}Uf op.Type = "ShiftZ" $4:~*IQ op.val1 = tlens X;5 S op.parent = parID H<{*ub4'L* AddOperation eID, op b2W; |
Print "Set lens thickness = " & tlens "|\94 qWkx:-g] '************************************************************************* CCy. 'Lens index of refraction lvG3<ls0K$ '************************************************************************* 2t.fD@ eID = FindMaterial( "Lens" ) qm~Kw!kV GetModelMaterial eID, mat 0x6@{0 @}Pw0vC mat.Nd = nlens }0krSzcn#, SetModelMaterial eID, mat |})rt5|f1! Print "Set lens index of refraction = " & nlens tPA"lBS ! VJGwd`qo*A '************************************************************************* }el,^~ 'Pupil diameter cx<h_ '************************************************************************* <)"iL4 kDI eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ^=3 ^HQ'Zm A03I-^0g+
'Adjust pupil diameter (trimming volume inner hole) ~LSy7$rz p+!f(H SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" <'VA=orD &(GopWR`e ' Adjust pupil location to just in front of the lens =:kiSrBS3t parID = FindFullName( "Geometry.Arizona Eye" ) D_zcOq9 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) kK08W3@&t count = 0 yFIl^Ck% While GetOperationCount(eID)>count N" 8*FiZ| GetOperation eID, count, op '! #On/ If op.Type="ShiftZ" Then 7ucx6J]c DeleteOperation eID,count 6
bYC count=count-1 p^}L End If @^BS# count=count+1 lrq>TJEcx Wend ^V_ku@DY op.Type = "ShiftZ" 4,o
%e,z op.val1 = taq-0.01 oA5<[&~< op.parent = parID ;B,nzx(L AddOperation eID, op N;e}dwh& D<lQoO+ Print "Set pupil diameter = " & pupilDiam tuX =o
U;^CU!a 'Update AZ Eye subassembly Description J{aQ1) eID = FindFullName( "Geometry.Arizona Eye" ) YWybPD4\( GetEntity eID, entity tj`tLYOZ@- entity.Description = "Accommodation = " & A & "D" >|y>e{P SetEntity eID, entity "v*oga% 9(i0"hS^ Update mYzsTUq Print "DONE!" eV@4VxaZ W*1d
X"S End Sub $K5ni {M; 9[6G8;<D& 如果屈光度是4,光瞳直径是4,则会输出如下数据: @&/s~3 <>ZBW9 Accommodation = 4 Diopters DKe6?PG Pupil Diameter = 4 mm ^Tb}]aHg Set aqueous humor thickness = 2.81 $w 5#2Za Set anterior lens radius = 10.4 and conic constant = -2.375869 V,99N'o~x Set posterior lens radius = -4.424557 and conic constant = -3.081019 "H
wVK Set lens thickness = 3.927 ,<R>Hiwg/s Set lens index of refraction = 1.42672 |?4~T: Set pupil diameter = 4 Nv}U/$$S DONE! Uqb]e?@ P]~N-xdV (文章来源:讯技光电)
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