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简介 {
ML)F ]] |/M^q{h&7s 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。 KB\A<(o, F5(D A 模型 }R\;htmc; <`P7^
'z! 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。 d>YX18'<Q +p\+15 Table 1. AZ眼睛模型的定义 <W2YG6^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. ro8c-[V GX@=b6#- 光源 bPL.8hX
\5q0nB@i5y 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。 $;Nw_S@ +DR,&; iYR`|PJi 图1. 光源和提示信息使用 }[O/u <Z 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 f8vWN Mf_urbp] 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 k "Qr 0/~20 KD{s 图2. 字母F光源的设定方法光 2$=I+8IL "NOll:5"( 图3. 字母F在视网膜上位置点列图 f$I$A(0P 视网膜的散射 kWm[Lt ~z$+uK 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 _2Hehw '6zk>rN 47yzI-1H+ 图4. 视网膜朗伯散射设定 zYZ^/7) 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 v;$cx*? (V:)`A_- 0WO-+eRB/ 图5. 视网膜重点采样规格设定 %;-r-> 脚本 hG! |ts ^>/] Qi 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: /~6)Vt O@7={)6qc 图6. 用户对话框的创建与编辑 rpn&.#KS 图7. 用户对话框编辑器 >DkRl 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。 &l;wb.%ijW 余下的脚本计算与屈光度有关的所有参数。 ~H\1dCW f
J$>VN 分析 mJFFst, GW~ ZmK 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 bQBYzvd |*te69RX 图7. 字母F在视网膜上颜色分析 3^2P7$W= 脚本代码 Ew$-,KC[ LPK[^ Option Explicit 'Remove this to enable non-dimensioned variables to be used. em,j>qp A>Y!d9]ti Dim entity As T_ENTITY D FN Dim op As T_OPERATION .~jn
N Dim mat As T_MODELMATERIAL 6 ,j&u7 Dim A As Double @(I)]Ca%O Dim pupilDiam As Double )sBbmct_S Dim eID As Long ^h~oxZJw Dim parID As Long k`;&?? Dim count As Integer eczS(KoL4 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double W;y ,Xs Dim tlens As Double, nlens As Double `bMwt?[* Dim curv As Double, conic As Double t#sw{RO Dim ok As Long yr,Oq~e C=!YcJ9 Sub Main /aX#j`PrH u(b Pdf@kz '用户输入对话框 GJP\vsaQ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 `@#,5S$ E TextBox 220,21,40,21,.TextBox1 'default: 0 UukHz}(E Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 e_z"<yq OKButton 40,91,90,21 :j4i(qcF CancelButton 190,91,90,21 bP3S{Jt-| Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 [X=J]e^D TextBox 220,49,40,21,.TextBox2 'default: 4 |C_sP,W End Dialog :^*9Eb Dim dlg As UserDialog
avwhGys# $kCXp.#k@~ ok = Dialog (dlg) (14J~MDB uU#7SX(uu If ok=0 Then 'cancel button was pressed 9<Kc9Z Print "Execution cancelled." zm`^=cV End BBUXoz End If 3GUJlFj J2P5< 'Assign accommodation and pupil diameter & use defaults if field left empty 9_5tA'Q If dlg.TextBox1 = "" Then =h/0k
y A = 0 'Default accommodation +'fdAc:5', Else '@
C\ ,E A = CDbl(dlg.TextBox1) L.1pO2zPe End If Xh*p\ $ `Z!NOC If dlg.TextBox2 = "" Then gt=
_;KZ pupilDiam = 4 'Default pupil diameter W$_@9W(Bl Else r-SQk>Y} pupilDiam = CDbl(dlg.TextBox2) Y/aNrIK7 End If p/GYfa
dU Ls~F4ar$/ Print " " JJe?Zu\ Print "Accommodation = " & A & " Diopters" "Ca?liy Print "Pupil Diameter = " & pupilDiam & " mm" M.QXwIT $YCy,Ew ' Calculate new parameters with accommodation c7$U0JO taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness zZ\2fKrpg a|\ZC\(xI Rant = 12.0 - 0.4*A 'Radius of anterior lens KN"V(<!)~ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens <^,5z!z} ?a]uyw, Rpost = -5.224557 + 0.2*A 'Radius of posterior lens #Kp/AN5YC CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ,0=@cJ lY_&P.B tlens = 3.767 + 0.04*A 'Lens thickness >kJEa8 u teI[Q nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ctg[C$<q| 2rK<UPIq 'Adjust parameters to account for accommodation hiN6]jL|O 1vF^<{%v '************************************************************************* nS}XY 'Aqueous thickness (Position of Lens) "77 j(Vs9 '************************************************************************* $A/$M\: eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ]c \gUU GetCustomElement eID, entity T;u>]"S Zk.LG Yz parID = FindFullName( "Geometry.Arizona Eye" ) :"aCl~cy9g C$1}c[ ' Delete any shift(s) in z LOkNDmj count = 0 b6k'`vLA While GetOperationCount(eID)>count fem>WPvG GetOperation eID, count, op oKJj?%dHK9 If op.Type="ShiftZ" Then ^BruRgc+ DeleteOperation eID,count p7A&r:qq# count=count-1 ttwfWfX End If i-b++R/WN count=count+1 hl[!4#b]K Wend HZ1e~IIw jI8qiZ);~ 'Set new shift in ,ij"&XA op.Type = "ShiftZ" L##lXUl op.val1 = taq Xh,{/5m op.parent = parID &a>fZ^Y=k AddOperation eID, op @Ee'nP Print "Set aqueous humor thickness = " & taq-0.55 'j)xryw IR+dGqIjZb '************************************************************************* Q`Q%;%t 'Radius and conic constant of anterior lens 'y
[eH '************************************************************************* J/j?;qx]j eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) T>&d/$;]
GetConic eID, entity, curv, conic -
T,;Fr' K>h= SetConic eID, entity, 1/Rant, CCant $f-f0t' Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant @eRR#S T
#&9| '************************************************************************* t&SC>8M< 'Radius and conic constant of posterior lens X;7gh>Q'4 '************************************************************************* 1Z +3=$P eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) _(}{=:M? GetConic eID, entity, curv, conic !79^M ,OX(z=i_ SetConic eID, entity, 1/Rpost, CCpost IRemF@ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost -;TqdL@ SSKn7` '************************************************************************* Uj)~ >V' 'Lens thickness (Position of posterior lens surface) M ]dS>W%U '************************************************************************* eU"!X9 :h
tOz. parID = FindFullName( "Geometry.Arizona Eye.Lens" ) +-=w` `/:ZB6 ' Delete any z-shift(s) O!}TZfC count = 0 Fg)Iw<7_2 While GetOperationCount(eID)>count .$/Su3]K/ GetOperation eID, count, op y]B?{m``6 If op.Type="ShiftZ" Then ,~-"EQT DeleteOperation eID,count 6.},y<E count=count-1 C`z[25o End If hHsCr@i count=count+1 hBf0kl Wend kzqW&`xn? X !g"D6' 'Set new z-shift Gpws_jw op.Type = "ShiftZ" wRn] op.val1 = tlens ~F^(O{EG op.parent = parID 0b9;vlGq$ AddOperation eID, op <=A1d\ Print "Set lens thickness = " & tlens _ji"##K .7Zb,r '************************************************************************* MzRwsf 'Lens index of refraction LfEeFF=#n '************************************************************************* B]dvX eID = FindMaterial( "Lens" ) =B g GetModelMaterial eID, mat @UCGsw &v7$*n27 mat.Nd = nlens *Ppb; SetModelMaterial eID, mat 5t`< KRz)I Print "Set lens index of refraction = " & nlens ]a)o@FI luYkC@I@a '************************************************************************* QS:dr."k 'Pupil diameter ld8 E!t[ '************************************************************************* }{Ab:+aNd eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ?El8:zt? | g5X;]%: 'Adjust pupil diameter (trimming volume inner hole) m?DI]sIv# @:\Iw"P SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ;/w-7O: 1*\JqCR ' Adjust pupil location to just in front of the lens ~0"(C#l9 parID = FindFullName( "Geometry.Arizona Eye" ) @: u> eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) q(sEN!^L` count = 0
n4; While GetOperationCount(eID)>count k%|7H,7 GetOperation eID, count, op TbqH-R3W If op.Type="ShiftZ" Then @> n7 DeleteOperation eID,count h.PVR Awk count=count-1 b^[Ab:`}[V End If e&WlJ count=count+1 oc+TsVt Wend hK F*{,' op.Type = "ShiftZ" 1p&e:v op.val1 = taq-0.01 K.s\xA5`_ op.parent = parID u~WBu| AddOperation eID, op t*Hr(|. &[u%ZL Print "Set pupil diameter = " & pupilDiam ]X
y2km] %M8m 8
) 'Update AZ Eye subassembly Description H9}z0VI eID = FindFullName( "Geometry.Arizona Eye" ) `}t<5_ GetEntity eID, entity :.8@ xVH entity.Description = "Accommodation = " & A & "D" 4D+S\S0bk SetEntity eID, entity hKVj\88 jcrLUs+\ Update v_M-:e3` Print "DONE!" kr ,&aP<, !'|^`u=eL End Sub P2la/jN h9<*+T 如果屈光度是4,光瞳直径是4,则会输出如下数据: SU>2MT^ +9LIpU&5 Accommodation = 4 Diopters \ZN> 7?Vs Pupil Diameter = 4 mm .nDB{@# Set aqueous humor thickness = 2.81 jSi\/(E Set anterior lens radius = 10.4 and conic constant = -2.375869 Rq`B'G9|c Set posterior lens radius = -4.424557 and conic constant = -3.081019 mhh^kwW Set lens thickness = 3.927 {}gx;v) Set lens index of refraction = 1.42672 JZ=ahSi
Set pupil diameter = 4 2F5*C DONE! lICpfcc(+ 90g=&O5@O fcaUj9qN QQ:2987619807 okwkMd-yW
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