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简介 Fgx{ s%&- OcA_m. 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。 eGwO!Lv}B scf.>K2 模型 6x'F0{U
n[vwwY 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。 >@b]t,rrK |fL|tkGEa Table 1. AZ眼睛模型的定义 GI+x,p 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. aVg~/ :3J0Q 光源 *oby(D"p !"v[\||1 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。 rr@h9bak;g S:bYeD4 !lVOZ% 图1. 光源和提示信息使用 J0ysZ] 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。 {\1:2UKkr 86*9GS?U( 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。 jmp0 %:+L eD|p1+76 图2. 字母F光源的设定方法光 CPW^pGT+i Tv d}5~
5? 图3. 字母F在视网膜上位置点列图 Fy;
sVB 视网膜的散射 j8cIpbp8x syJLcK+e 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。 XIGz_g;#'w y*G3dWb LD=e Mk:
~ 图4. 视网膜朗伯散射设定 ME0vXi 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。 }508wwv 5*O*p `Ba URd0|?t9^L 图5. 视网膜重点采样规格设定 ~WjK'N4n5 脚本 AV>_bw. ]<3n;*8k? 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: %.h&W; mn].8F 图6. 用户对话框的创建与编辑 %(uYYr
6 图7. 用户对话框编辑器 C`@gsF"<7 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。 %`_Rl>@K= 余下的脚本计算与屈光度有关的所有参数。 }T5
E^ x5(6U>-Y 分析 *8bj3A]vf Sx0/Dm 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 t] CA!i` E0*KKo% 图7. 字母F在视网膜上颜色分析 gTS}'w{ 脚本代码 ? K ,d :MP*Xy\7&J Option Explicit 'Remove this to enable non-dimensioned variables to be used. &-$27 j|KjQ'9 Dim entity As T_ENTITY 1KUM!DUD Dim op As T_OPERATION +SB>> Dim mat As T_MODELMATERIAL ~.<QC<dN Dim A As Double 8FIk|p|l^ Dim pupilDiam As Double xZ]QT3U+ Dim eID As Long cBD#F$K2 Dim parID As Long |iA8aHFU Dim count As Integer &7
K= Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ri`; Dim tlens As Double, nlens As Double hh-a+]
c0 Dim curv As Double, conic As Double L>Y3t1= Dim ok As Long :O'QL, j "s7P% Sub Main [v+5|twxpU _-T^YeQ/ '用户输入对话框 s&4&\Aq}x# Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 O'Q,;s`uC TextBox 220,21,40,21,.TextBox1 'default: 0 dBkM~" Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 WfXwI 'y OKButton 40,91,90,21 cy(4g-b]@e CancelButton 190,91,90,21 r;9 V7C Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 x*sDp3f[* TextBox 220,49,40,21,.TextBox2 'default: 4 X<D fzd oI End Dialog n)j0h- Dim dlg As UserDialog 8B(=Y;w #P1U]@ ok = Dialog (dlg) aX2N
Qq>s O I0N(V If ok=0 Then 'cancel button was pressed vqAEF^HYry Print "Execution cancelled." ~:
fSD0 End 8OMMV,QF End If >WA'/Sl<A< m5o$Dus+?' 'Assign accommodation and pupil diameter & use defaults if field left empty >"+ho If dlg.TextBox1 = "" Then ["#H/L]3 A = 0 'Default accommodation 1bFGoLAEFl Else 4T TrHs A = CDbl(dlg.TextBox1) D4N(FZ0~ End If gBO, sPMICIv| If dlg.TextBox2 = "" Then o`Af6C;Q pupilDiam = 4 'Default pupil diameter 1cc~UQ Else njZJp|y6 pupilDiam = CDbl(dlg.TextBox2) }4T `) End If yk'L_M(= $NCR
V:J Print " "
ilXKJJda Print "Accommodation = " & A & " Diopters" JeN]sK)8x Print "Pupil Diameter = " & pupilDiam & " mm" |@~_&g P+Gz' ' Calculate new parameters with accommodation C23p1%#1 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness '"+Gn52# A.mFa1lH Rant = 12.0 - 0.4*A 'Radius of anterior lens &8pGq./lr= CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens E+ |K3EJ eso-{W,D Rpost = -5.224557 + 0.2*A 'Radius of posterior lens V'gJtF CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens C=(Q0-+L| 8f1M6GK? tlens = 3.767 + 0.04*A 'Lens thickness pN)x,<M) d&AO4^ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction c&P/v#U_ k&uh 'Adjust parameters to account for accommodation 5rf Dm Hj(K*z '************************************************************************* g\?v 5 'Aqueous thickness (Position of Lens) }30Sb&" '************************************************************************* T*gG <8 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) x[$KZGK+GL GetCustomElement eID, entity eXD~L&s[ ]l C2YD} parID = FindFullName( "Geometry.Arizona Eye" ) 7M
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mR Vh .zl[nx[9"D ' Delete any shift(s) in z }K@m4`T count = 0 P(FlU]q While GetOperationCount(eID)>count d"IZt;s/, GetOperation eID, count, op ul~6zBKO If op.Type="ShiftZ" Then b !y DeleteOperation eID,count |5%T) count=count-1 n$XEazUb0N End If Wz#Cyjo count=count+1 /t`,7y3T Wend ?hGE[.(eh] I]i(
B+D 'Set new shift in F\&{ >& op.Type = "ShiftZ" M)!"R [V op.val1 = taq ~Kt1%&3{a? op.parent = parID Woj5
yr AddOperation eID, op y2#"\5dC Print "Set aqueous humor thickness = " & taq-0.55 |1tpXpe vK@UK"m '************************************************************************* 9) ,|h 'Radius and conic constant of anterior lens Ynvf;qs '************************************************************************* ']>9/r# eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) +p63J GetConic eID, entity, curv, conic zCQP9oK! NN2mOJ:- SetConic eID, entity, 1/Rant, CCant $OdBuJA Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant =R'O5J {J
izCUo_' '************************************************************************* fz`)CWo: 'Radius and conic constant of posterior lens AEaN7[PQx| '************************************************************************* |hw.nY]J eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 3~bB2APk GetConic eID, entity, curv, conic yyljyE FG[rH] SetConic eID, entity, 1/Rpost, CCpost i0$*):b Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost O1c:X7lHc 1P[x.t# '************************************************************************* zG<<MR/< 'Lens thickness (Position of posterior lens surface) yc~<h/}# '************************************************************************* B~ i /+JnEFf parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 2aCf?l( _~;%zFX ' Delete any z-shift(s) 2b"DkJj' count = 0 |u?VlRt While GetOperationCount(eID)>count "Kp#Lx GetOperation eID, count, op ssx#|InY If op.Type="ShiftZ" Then K$Vu[!l` DeleteOperation eID,count GW'v\O count=count-1
5N$XY@ End If O+|C<;K count=count+1 J_Tz\bZ3) Wend Q17dcgd t4#gW$+^?H 'Set new z-shift cjPXrDl{\ op.Type = "ShiftZ" ~`QoBZ.O& op.val1 = tlens 7~QI4'e op.parent = parID D0xQXC3$` AddOperation eID, op }}$@Tij19[ Print "Set lens thickness = " & tlens h#O9TB $'3xl2T '************************************************************************* 9/29>K_ 'Lens index of refraction pg4pfi^__V '************************************************************************* eIalcBY eID = FindMaterial( "Lens" ) 5[SwF&zZ GetModelMaterial eID, mat Jg[Ao#,== N4C7I1ihq mat.Nd = nlens .>F4s_6l SetModelMaterial eID, mat #DFi-o&- Print "Set lens index of refraction = " & nlens iBAP,cR?` ]$Z:^"JS3 '************************************************************************* ]5S`y{j1 'Pupil diameter 0GrM:Lh y '************************************************************************* T8z?_ *k eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ft(o-f7, &N/t%q 'Adjust pupil diameter (trimming volume inner hole) hk4t #Km ? /z[Jx. SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ?$109wZ:9 \OVtvJV] ' Adjust pupil location to just in front of the lens i>YQ<A1 parID = FindFullName( "Geometry.Arizona Eye" ) tj@(0}pi4 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 0dC5
-/+ count = 0 s/IsrcfM While GetOperationCount(eID)>count &R<aRE:+R GetOperation eID, count, op :LNE?@ If op.Type="ShiftZ" Then 1]2]l*&3 DeleteOperation eID,count
< v] count=count-1 YkWHI(p End If 4kM/`g6?,q count=count+1 w7?fJ")
Wend 6Kpq~o op.Type = "ShiftZ" >Dr(%z6CN op.val1 = taq-0.01 H\ejW@<;h op.parent = parID f+ceL'fr AddOperation eID, op )Wk_|zO- D:/ n2_ Print "Set pupil diameter = " & pupilDiam jn V=giBu A%.mIc. 'Update AZ Eye subassembly Description o2ggHZe/=@ eID = FindFullName( "Geometry.Arizona Eye" ) J/4T =:\ GetEntity eID, entity XJ4f;U entity.Description = "Accommodation = " & A & "D" f*XCWr SetEntity eID, entity 1z-.e$&z xGwImF$r Update LN5LT'CE Print "DONE!" C.92FiC ^r\rpSN End Sub I1E9E$m5\< uPz+*4+ 如果屈光度是4,光瞳直径是4,则会输出如下数据: }~I!'J#) c}o 6Rm50 Accommodation = 4 Diopters D9oNYF-V Pupil Diameter = 4 mm h4pS~/ Set aqueous humor thickness = 2.81 c
3QgX4vq Set anterior lens radius = 10.4 and conic constant = -2.375869 !'jq.RawP Set posterior lens radius = -4.424557 and conic constant = -3.081019 ]5Uuz?:e Set lens thickness = 3.927 LW]fme<V? Set lens index of refraction = 1.42672 '9V/w[mI Set pupil diameter = 4 %PYl DONE! dM-cQo:
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