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简介 .K;*uq:0 Vad(PS0 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。 jHTaG%oh %\Ig{Rj; 模型 D("['`{ XOVZ'V 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。 a{el1_DIGK }a|SgI Table 1. AZ眼睛模型的定义 ZXe[>H 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. q$~S?X5\ ;m{[9i`2 光源 "EQ}xj r]"
> 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 |4x&f!%m VqbMFr<k Su-LZ'C\ 图1. 光源和提示信息使用 fh:=ja?bM3 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 ?^5W.`Y2i YtxBkKiJ2V 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 hFs0qPVY R qOEQ*k 图2. 字母F光源的设定方法光 yV=hi?f-[V ^7~=+0cF] 图3. 字母F在视网膜上位置点列图 OCY7Bls4 视网膜的散射 Et# }XVCJ JwxI8Pi*y 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 C7eaioW$ Pg|q{fc x.>z2. 图4. 视网膜朗伯散射设定 X}h{xl 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。 MoO
jM&9 LHR%dt|M HOtays,#<} 图5. 视网膜重点采样规格设定 ^5QSV\X 脚本 ]'DtuT?Z pG:FDlR~ 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: I^0bEwqZ~ bXC;6xZV 图6. 用户对话框的创建与编辑 /p?h@6h@y 图7. 用户对话框编辑器 YdhrFw0`~r 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。 @fPiGu`L 余下的脚本计算与屈光度有关的所有参数。 I `p44}D3 m 9.QGX\] 分析 V?0|#=_mE i!ejK6Q 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 e8--qV#< ?v8B;="#w 图7. 字母F在视网膜上颜色分析 YmNBtGhT 脚本代码 }eULcgRG FwmE1, Option Explicit 'Remove this to enable non-dimensioned variables to be used. qf(!3 .#lQZo6$\| Dim entity As T_ENTITY gj$gqO`B Dim op As T_OPERATION H:a(&Zb Dim mat As T_MODELMATERIAL P;mmK&& Dim A As Double p+#uPY1# Dim pupilDiam As Double #eR*|W7o Dim eID As Long yngSD`b_P Dim parID As Long J:M^oA'N:> Dim count As Integer kplyZ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double fW <qp Dim tlens As Double, nlens As Double &HT
PeB Dim curv As Double, conic As Double 11%^K=dq Dim ok As Long i*nNu-g 'FO^VJ;ha Sub Main V:2|l!l* r#d~($[93 '用户输入对话框 y~]>J^ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 pc:~_6S TextBox 220,21,40,21,.TextBox1 'default: 0 C(xdiQJh Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ^Me__Y OKButton 40,91,90,21 $*`fn{2 CancelButton 190,91,90,21 \; $j
"i& Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 CP["N(fF TextBox 220,49,40,21,.TextBox2 'default: 4 coyy T End Dialog ^W3xw[{ Dim dlg As UserDialog eiJ $}\qJL QVQe9{ "0 ok = Dialog (dlg) L&. 9.Ll l2X'4_d If ok=0 Then 'cancel button was pressed 87r#;ND Print "Execution cancelled." `:R8~>p End $
[0 End If v>;6pcp[F ko=vK%E[ 'Assign accommodation and pupil diameter & use defaults if field left empty FJ}/g
? If dlg.TextBox1 = "" Then z;2kKQZm A = 0 'Default accommodation BQ2DQ7q Else q: ?6 A = CDbl(dlg.TextBox1) nH/V2>Lm End If zxT&K| D-69/3 PvP If dlg.TextBox2 = "" Then Xj.6A,}^ pupilDiam = 4 'Default pupil diameter
" q0lh Else :>\ i pupilDiam = CDbl(dlg.TextBox2) mj{TqF End If kOs_] P!0uAkt9C Print " " v0apEjT Print "Accommodation = " & A & " Diopters" o/)]z Print "Pupil Diameter = " & pupilDiam & " mm" z|<6y~5, B24wn8< ' Calculate new parameters with accommodation j_j~BXhIS taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness (w6 024~ LS?3 >1g Rant = 12.0 - 0.4*A 'Radius of anterior lens [y W0U:m CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens OLXG0@ 8I$>e ( Rpost = -5.224557 + 0.2*A 'Radius of posterior lens &?#V*-;^ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens o vvR{MTc !w(J]< tlens = 3.767 + 0.04*A 'Lens thickness R]/3`X9!d> 6H53FMqr nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction -V%"i,t 9NBFG~)|l[ 'Adjust parameters to account for accommodation 5.q2<a : 4703\
HK '************************************************************************* ;1'X_tp 'Aqueous thickness (Position of Lens)
+ZQf$@+ '************************************************************************* }N&}6U eID = FindFullName( "Geometry.Arizona Eye.Lens" ) si.ZTG9m GetCustomElement eID, entity 4%Z! *W* O@ F0UM`! parID = FindFullName( "Geometry.Arizona Eye" ) %-/[.DYt x&@. [FJhO ' Delete any shift(s) in z 0r*E$|zZ count = 0 F w)#[ While GetOperationCount(eID)>count _)"-zbh}{ GetOperation eID, count, op bqWo*>l If op.Type="ShiftZ" Then !D!~4h) DeleteOperation eID,count ;}@.E@s%' count=count-1 F>dB@V- End If c>6dlWTqX count=count+1 MX2]Q Wend #^|y0:
%@k@tD6 'Set new shift in ]bLI!2Kr op.Type = "ShiftZ" 3CL/9C> op.val1 = taq 4>-'w MW") op.parent = parID :PE{2* AddOperation eID, op 'y[74?1 Print "Set aqueous humor thickness = " & taq-0.55 #>iBu:\J @.0>gmY;: '************************************************************************* _kg<KD=P 'Radius and conic constant of anterior lens Q,9"/@:c, '************************************************************************* -d1 YG[1| eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) kVz9}Xp" GetConic eID, entity, curv, conic *:gx1wd ~_8Dv<"a SetConic eID, entity, 1/Rant, CCant n=J~Rssp Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant VHyH't_&s \@&oK2f '************************************************************************* 8eq*q 'Radius and conic constant of posterior lens 1j"G~TM '************************************************************************* DA]<30w eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) uatY:GSR GetConic eID, entity, curv, conic q!iTDg*$ gB|>[6 SetConic eID, entity, 1/Rpost, CCpost FjR/_GPo6 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost @6h,#8# IJa6W`} '************************************************************************* fIe';a 'Lens thickness (Position of posterior lens surface) ])OrSsV} '************************************************************************* diHK Z*/{^ zsE parID = FindFullName( "Geometry.Arizona Eye.Lens" ) XuS3#L/3p 2^ uP[ ' Delete any z-shift(s) qW+'#Jh@TV count = 0 4PK/8^@7)> While GetOperationCount(eID)>count Cm@rXA/ GetOperation eID, count, op _|+}4 ap If op.Type="ShiftZ" Then m';j#j)w DeleteOperation eID,count bpP-wA^Hd count=count-1
IR JN End If -&q@|h' count=count+1 ;>hRj! Wend @=_4i&]$ rebnV&- 'Set new z-shift 3bYPi^ op.Type = "ShiftZ" pPL)!=o! op.val1 = tlens m.F}9HI%hN op.parent = parID 43wm_4C!H AddOperation eID, op >AK9F.
_z Print "Set lens thickness = " & tlens {E=BFs I]GGmN '************************************************************************* o8 _)) 'Lens index of refraction 5PY4PT=G '************************************************************************* /cHUqn30a eID = FindMaterial( "Lens" ) OSoIH`tA GetModelMaterial eID, mat Me 5Xd| f$>KTb({B mat.Nd = nlens R7\T.;8+ SetModelMaterial eID, mat A1Ru&fd! Print "Set lens index of refraction = " & nlens M$u.lI gn//]|#H+ '************************************************************************* 5Ve`j,`=< 'Pupil diameter K_!R '************************************************************************* t=nZ1GZyM eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) L|hELWru A_eO 'Adjust pupil diameter (trimming volume inner hole)
5ENU}0W rU4;yy*b SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" niA>afo RGgePeaw ' Adjust pupil location to just in front of the lens ^>wlj parID = FindFullName( "Geometry.Arizona Eye" ) o$QC:%[# eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) knn9s0'Q count = 0 *@I/TX'\rY While GetOperationCount(eID)>count ]l7 r M" GetOperation eID, count, op E3hXs6P If op.Type="ShiftZ" Then |)VNf.aJZ DeleteOperation eID,count ="p,~ivrz count=count-1 *iX PG9XZ End If {x,d9I count=count+1 n\ 'PNB Wend !C(U9p. 0 op.Type = "ShiftZ" mE\)j*Nnv op.val1 = taq-0.01 8]K+,0m6 op.parent = parID z0H+Or AddOperation eID, op )O],$\u 23d*;ri5 Print "Set pupil diameter = " & pupilDiam BT)PD9CN( IM$ d~C 'Update AZ Eye subassembly Description s%QCdU ] eID = FindFullName( "Geometry.Arizona Eye" ) |.z4 VJi4 GetEntity eID, entity `pb=y} entity.Description = "Accommodation = " & A & "D" cYgd1 SetEntity eID, entity kyi"U A82 >*MGF=.QG Update ."Kp6s `k Print "DONE!" DHg)]FQ/ (gRTSd T? End Sub {SF'YbY h,\5C/ 如果屈光度是4,光瞳直径是4,则会输出如下数据: MQe|\SMd (A )f
r4 Accommodation = 4 Diopters Nwj M=GG Pupil Diameter = 4 mm G#Kw6 Set aqueous humor thickness = 2.81 x4i&;SP0 Set anterior lens radius = 10.4 and conic constant = -2.375869 W|Cs{rBc? Set posterior lens radius = -4.424557 and conic constant = -3.081019 uZTbJ3$$ Set lens thickness = 3.927 XU<XK9EA Set lens index of refraction = 1.42672 nx(jYXVT Set pupil diameter = 4 bt* DONE! rf^u&f
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