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简介 rgv?gaQ> !cLo>,4 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。 KVaiugQ =.U[$~3q% 模型 EIAc@$4 ^4hO 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 t!X.|`h tBWrL{xLe Table 1. AZ眼睛模型的定义 \<>ih)J@tt 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. b<ZIWfs glxsa8 光源 JPUW6e07o P%VSAh\|n 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 }W8;=$jr nYSiS}?S. cn3\kT* 图1. 光源和提示信息使用 w<3#1/g!2B 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。 o4,6.1} eA ?RK.e 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。 o5GcpbZ3k Y%^w:|f^ 图2. 字母F光源的设定方法光 n\D&!y[]F T!kN)#S 图3. 字母F在视网膜上位置点列图 <w9JRpFY 视网膜的散射 9YyLf ; (gU!=F?#m 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。 NB#OCH1/9 g2ixx+`?|: k5e;fA/w 图4. 视网膜朗伯散射设定 KC6.Fr{ 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。 L}b.ulkMD 5m 4P\y^a w3_>VIZJl 图5. 视网膜重点采样规格设定 3M7/?TMw{6 脚本 iy!=6 itP,\k7>d 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: lNh70G8^p 'KL0@l 图6. 用户对话框的创建与编辑 JR21>;l#2 图7. 用户对话框编辑器 @n /nH?L 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。 LL |r
A: 余下的脚本计算与屈光度有关的所有参数。 -3*]G^y2 #q$HQ&k 分析 ED( Sg FVbb2Y?R 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 !i}w~U< _ <V)-Y 图7. 字母F在视网膜上颜色分析 ;[YG@-"XZ 脚本代码 BwpqNQN .!3|&V'< Option Explicit 'Remove this to enable non-dimensioned variables to be used. 4e7-0}0 ;xj?z\=Pg Dim entity As T_ENTITY \?-<4Bc@ Dim op As T_OPERATION V)k4:H Dim mat As T_MODELMATERIAL o5PO=AN Dim A As Double Q&tG4f< Dim pupilDiam As Double lrE5^;/s1 Dim eID As Long l|[N42+ Dim parID As Long Of#u Dim count As Integer h7oo7AP Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ^uc=f2=>, Dim tlens As Double, nlens As Double eM6<%?b Dim curv As Double, conic As Double SKN`2[ahD Dim ok As Long i1d'nxk6 Gb6 'n$g Sub Main &Z@o Q a58H9w"u) '用户输入对话框 +\]\[6 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1
8dA~\a TextBox 220,21,40,21,.TextBox1 'default: 0 ,ZNq,$j Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 oZgjQM$YP OKButton 40,91,90,21 <n$'voR7] CancelButton 190,91,90,21 Z5n1@a__ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ?l{nk5,?-Y TextBox 220,49,40,21,.TextBox2 'default: 4 rs[T=C Q End Dialog M|h3Wt~7 Dim dlg As UserDialog %sP*=5?vA 9cF[seE"0 ok = Dialog (dlg) (ZZ8L-s IEi^kJflU If ok=0 Then 'cancel button was pressed _TZRVa_ Print "Execution cancelled." .`eN8Dl1 End \}b%E'+_T End If dZ@63a>>@ .L~AL|2_ 'Assign accommodation and pupil diameter & use defaults if field left empty 7JH6A'& If dlg.TextBox1 = "" Then ~<bZ1TD A = 0 'Default accommodation wn%A4-%{ Else $6 f3F?y7 A = CDbl(dlg.TextBox1) Ui W>J End If H7n>Vx:L- ;)*eo_tQ If dlg.TextBox2 = "" Then rb.N~ pupilDiam = 4 'Default pupil diameter 1))8
A@, Else gwMNYMI pupilDiam = CDbl(dlg.TextBox2) P=
NDS2 End If lL3U8}vn ?:q*(EC< Print " " q0vQa Print "Accommodation = " & A & " Diopters" V 5mTP' Print "Pupil Diameter = " & pupilDiam & " mm" _Fl9>C"u ^09,"<@k ' Calculate new parameters with accommodation Y$_B1_ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness m-, x<bM? DvvK^+-~ Rant = 12.0 - 0.4*A 'Radius of anterior lens 8l`*]1.W< CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens :$c
| qX{+oy5 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens F]&*ow CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens } q8ASYNc nNn:- tlens = 3.767 + 0.04*A 'Lens thickness NBGH_6DROw W'TZ%K) I nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction kxv1Hn"`{E }|=|s f 'Adjust parameters to account for accommodation b\2
ds, XSLFPTDEc '************************************************************************* a:w#s}bL 'Aqueous thickness (Position of Lens) @o`AmC.
8 '************************************************************************* =Xr.'(U eID = FindFullName( "Geometry.Arizona Eye.Lens" ) NgPk&niM GetCustomElement eID, entity ?Ir:g=RP* WNtW|IV parID = FindFullName( "Geometry.Arizona Eye" ) dy[X3jQB 7%M_'P4 V ' Delete any shift(s) in z 8":Q)9;% count = 0 D0f] $ While GetOperationCount(eID)>count ;2QP7PrSY GetOperation eID, count, op 3JR+O<3D If op.Type="ShiftZ" Then +NUG DeleteOperation eID,count @r1_U,0e count=count-1 R:qW;n%AF End If f!X[c?Xy" count=count+1 Z%UP6% Wend >A"(KSNL G3T]`Atf 'Set new shift in ");a3hD op.Type = "ShiftZ" Ny/MJ#Lq op.val1 = taq Q7CsJzk~) op.parent = parID ;O,jUiQ AddOperation eID, op (TM,V!G+U~ Print "Set aqueous humor thickness = " & taq-0.55 @H8EWTZ dWBA1p '************************************************************************* ns4,@C$ 'Radius and conic constant of anterior lens jPkn[W#
6 '************************************************************************* *oix 6 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) E]r?{t`] GetConic eID, entity, curv, conic 0"z9Q\{} F!K>K z SetConic eID, entity, 1/Rant, CCant |_U= z;Y Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant u*9V&>o 'J|_2* '************************************************************************* .=;
; 'Radius and conic constant of posterior lens Iq.*8Oc '************************************************************************* N'=gep0V@ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) LDa1X2N GetConic eID, entity, curv, conic >yDZw!C |y!A&d=xYn SetConic eID, entity, 1/Rpost, CCpost X}0cCdW Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost q@2siI~W EoDA]6?Lj '************************************************************************* 8q7b_Pq1U 'Lens thickness (Position of posterior lens surface)
!}$$: '************************************************************************* sDV Q#}a |4`{]2C parID = FindFullName( "Geometry.Arizona Eye.Lens" ) g9F?z2^ 7K:PdF>/ ' Delete any z-shift(s) Z3!`J& count = 0 "kF g While GetOperationCount(eID)>count P!k{u^$L GetOperation eID, count, op TL#3;l^ If op.Type="ShiftZ" Then }ad|g6i` DeleteOperation eID,count / XIhj count=count-1 SgOheN- End If <a+Z;> count=count+1 Y<8vw
d Wend 3;Fhg!ZO tLmTjX .6 'Set new z-shift {(}By/_ op.Type = "ShiftZ" 3R VR op.val1 = tlens 3+bt~J0 op.parent = parID nQS|Lt_+ AddOperation eID, op [ikOb8 G# Print "Set lens thickness = " & tlens +nGAz{&@r% "zy7C*)>r '************************************************************************* gZ1?G-Q 'Lens index of refraction @=kSo
-SX '************************************************************************* )dSi/ eID = FindMaterial( "Lens" ) H>@+om GetModelMaterial eID, mat |^H5^k "Bv g=o4Q<
#^y mat.Nd = nlens ,7b[!#?8 SetModelMaterial eID, mat >F&47Yn Print "Set lens index of refraction = " & nlens 7VI*N)OZ8 S21,VpW\ '************************************************************************* X\F|Tk3_ 'Pupil diameter *uvQ\. '************************************************************************* !{41!O,K# eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) t&DEb_"De WMg~Y"W 'Adjust pupil diameter (trimming volume inner hole) &
ZB iG?[<1~ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" sn>~O4" Mb7I[5v ' Adjust pupil location to just in front of the lens Y[S1$(K&* parID = FindFullName( "Geometry.Arizona Eye" ) HUO j0T eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 7J&4akT{9 count = 0 u>/ TE While GetOperationCount(eID)>count GvlS% GetOperation eID, count, op GowH]MO If op.Type="ShiftZ" Then 2)~> R DeleteOperation eID,count ei5~& count=count-1 gltBC${7wZ End If da~],MN count=count+1 c6/=Gq{. Wend W`*r>`krVJ op.Type = "ShiftZ" s&J]zb` op.val1 = taq-0.01 &
"B=/-( op.parent = parID >i-"<jG AddOperation eID, op Vs{|xG7WD :P=(k2 Print "Set pupil diameter = " & pupilDiam -s'-eQF J *k>n<p3dd 'Update AZ Eye subassembly Description pcI uN eID = FindFullName( "Geometry.Arizona Eye" ) ji,kkipY?w GetEntity eID, entity k.15CA` entity.Description = "Accommodation = " & A & "D" cPc</[x[W SetEntity eID, entity -1@<=jX3_ dcWD(- Update _oDz- Print "DONE!" ;P&OX5~V Y:)e(c"A End Sub *G9V'9 8kDp_si 如果屈光度是4,光瞳直径是4,则会输出如下数据: BJo*'US-Q "G9xMffW Accommodation = 4 Diopters ]:/Q]n^ Pupil Diameter = 4 mm ib791 Set aqueous humor thickness = 2.81 zs#@jv$ Set anterior lens radius = 10.4 and conic constant = -2.375869 iMRwp+$ Set posterior lens radius = -4.424557 and conic constant = -3.081019 `n?DU;, Set lens thickness = 3.927 >~+ELVB& Set lens index of refraction = 1.42672 % +\."eC Set pupil diameter = 4 Yk Qd
DONE! -1ub^feJ, j^2j&Ta z,%$+)K QQ:2987619807 IRqy%@)
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