Arizona眼睛模型

1!1beR]   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。 LX@/RAd vz   DiEluA&w9   模型 kWe{r5C7   &*7?)eI!i   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。 Sk:ws&D1u   Table 1. AZ眼睛模型的定义 0LfU=X0#7   jGEt+\"/QJ   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. ae*Mf7   \yd s5g!:   光源 9f ',7i   yI ld75 S`   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。 DVK)2La   /u0' 6V   图1. 光源和提示信息使用 rfgI$eu    <oWB0%   除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处，并增加了pre-propagation distance= -8。尽管光线在光瞳处创建，规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射，而不是在光瞳处入射。 NL rPSqz   VGceD$<   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。 '{J&M|<A   图2. 字母F光源的设定方法光 {iv<w8CU)   zD(`B+   图3. 字母F在视网膜上位置点列图 1 29q`u;   ~<k,#^"}X   视网膜的散射 0\:(ageY?   mdq;R*`   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。 '^Ql]% _   =Uj-^qcE   图4. 视网膜朗伯散射设定 |R56ho5C   K,w"_T   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。 3q'&j,, ^   @~#Ym1{W   图5. 视网膜重点采样规格设定 :k3Nt5t!   ; Wl+zw   脚本 V\{tmDE   w^#L9i'v'   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： B?)@u| 0   图6. 用户对话框的创建与编辑 Fb4`|   图7. 用户对话框编辑器 }t;(VynV)   s.x&LG   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。 ~,BIf+\XF   余下的脚本计算与屈光度有关的所有参数。 kf;/c}}   sL@  U   分析 h~(D@/tB   8Y_ol#\L   屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 0%Z]h?EYy|   图7. 字母F在视网膜上颜色分析 '/$d0`3B>   '2laTl]`   脚本代码 <]T`3W9   [ e8x&{L-_   Option Explicit     'Remove this to enable non-dimensioned variables to be used. \igmv]G%   GG0R}',0   Dim entity As T_ENTITY *0}3t<5   Dim op As T_OPERATION ;?6No(/   Dim mat As T_MODELMATERIAL /MF!GM   Dim A As Double l6~-8d+lfN   Dim pupilDiam As Double ]a!xUg!S   Dim eID As Long \|Ul]1pO8   Dim parID As Long 24/XNSE,-   Dim count As Integer fnNYX]_bk   Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ynB_"mg   Dim tlens As Double, nlens As Double 8>.J1C   Dim curv As Double, conic As Double \oEo~   Dim ok As Long 581e+iC~<H   C:uz6i1   Sub Main #_|sgS?1   [b/k3&O'       '用户输入对话框 `AkIK*       Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 (s1k$@d           TextBox 220,21,40,21,.TextBox1 'default: 0 r 3M1e+'fc           Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 sz9G3artK&           OKButton 40,91,90,21 A5+rd{k/           CancelButton 190,91,90,21 h8Xg`C\           Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 |hO~X~P           TextBox 220,49,40,21,.TextBox2 'default: 4 p[@5&_u(z       End Dialog b-Z4 Jo G       Dim dlg As UserDialog &tZG @   oP2fX_v1x       ok = Dialog (dlg) gxT4PQDy   'Vr $MaO       If ok=0 Then    'cancel button was pressed ; h`0ir4[A           Print "Execution cancelled." R.s^o]vT           End b:(-       End If C'!;J   2TES>}       'Assign accommodation and pupil diameter & use defaults if field left empty { K_kPgKS       If dlg.TextBox1 = "" Then Cv*x2KF G           A = 0           'Default accommodation QeDQo       Else NB7Y{) w           A = CDbl(dlg.TextBox1) M@(^AK{mU       End If 9M /SH$Qy   >?]_ <:       If dlg.TextBox2 = "" Then z*a8sr           pupilDiam = 4   'Default pupil diameter 1TM~*<Jb       Else `Rdm-[&           pupilDiam = CDbl(dlg.TextBox2) jS!`2li?{       End If G|m1.=DJm   20TCG0%x       Print " " Qe'g3z>       Print "Accommodation = " & A & " Diopters" ?,=f\Fz!       Print "Pupil Diameter = " & pupilDiam & " mm" ,=~z6[   $fpq 3       ' Calculate new parameters with accommodation ]O TH"*j       taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 3^StIw{X   axk"^gps       Rant = 12.0 - 0.4*A                     'Radius of anterior lens E"|4Y(G       CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens &5%dhc4&!&   ow/57P       Rpost = -5.224557 + 0.2*A               'Radius of posterior lens npD IX       CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens #n   phYDs9-K       tlens = 3.767 + 0.04*A                  'Lens thickness OI0B:()   k{AyD`'Q       nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction !$g+F(:(c   }Z`(aDH       'Adjust parameters to account for accommodation B(DrY1ztj   hKlZi!4J       '************************************************************************* WV"jH9"[       'Aqueous thickness (Position of Lens) *RR[H6B^]X       '************************************************************************* b}G24{       eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Zw] ?.       GetCustomElement eID, entity %vO<9fE|1   ;U`X 6d       parID = FindFullName( "Geometry.Arizona Eye" ) .5Q:Xp   ]fe yJLF       ' Delete any shift(s) in z t=R6mjb       count = 0 >J=<bhR       While GetOperationCount(eID)>count '+*-s7o{           GetOperation eID, count, op p{=QGrxB*           If op.Type="ShiftZ" Then quo^fqS&a               DeleteOperation eID,count (vJ2z =z               count=count-1 ~"!a9GZ           End If 3,);0@I           count=count+1 Ze!92g       Wend 8@M'[jT   m=b~i^@       'Set new shift in A%vsno!       op.Type = "ShiftZ" eeUp 1g       op.val1 = taq m_!U}!       op.parent = parID P|^$kK       AddOperation eID, op D6Y6^eS-       Print "Set aqueous humor thickness = " & taq-0.55 \NXQ   z8Q"% @       '************************************************************************* z]Acs       'Radius and conic constant of anterior lens &!y]:CC{       '************************************************************************* -U>7 H`5       eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Jbp5'e _       GetConic eID, entity, curv, conic C;a@Jjor'   RP(/x+V       SetConic eID, entity, 1/Rant, CCant hN(L@0)       Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant >]}yXg=QK+   L"rcv:QWZa       '************************************************************************* WwW^[k (X       'Radius and conic constant of posterior lens *+8%kn`c       '************************************************************************* PM4>ThQ       eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) vZajT!h       GetConic eID, entity, curv, conic zfjTQMaxh   +=8X8<Pu       SetConic eID, entity, 1/Rpost, CCpost  ggou*;'       Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ?An,-N-ezf   H2Eb\v`#       '************************************************************************* l_v*7d       'Lens thickness (Position of posterior lens surface) XKq@]=\F       '************************************************************************* %{STz   * Zd_ HJi       parID = FindFullName( "Geometry.Arizona Eye.Lens" ) K!b8= K`   DMkhbo&+       ' Delete any z-shift(s) bZ#X9fT       count = 0 >IR$e=5$       While GetOperationCount(eID)>count ma9ADFFT           GetOperation eID, count, op 2q%K)h           If op.Type="ShiftZ" Then 9NWloK6bT               DeleteOperation eID,count =w<VT%               count=count-1 $o^e:Y, a           End If %yaG,;>U           count=count+1 PZ34*q       Wend 6.Bh3p   H4skvIl       'Set new z-shift *fP(6e#G,       op.Type = "ShiftZ" F14(;'Az       op.val1 = tlens h#{T}[       op.parent = parID > %c*Xe       AddOperation eID, op \n@V-b       Print "Set lens thickness = " & tlens p`GWhI?   Zu=kT}aGg       '************************************************************************* feCqbWq:       'Lens index of refraction uu>lDvR*       '************************************************************************* VD#!ztcY'       eID = FindMaterial( "Lens" ) ,U%=rfB~       GetModelMaterial eID, mat e}Q>\t45   =hcPTU-QU       mat.Nd = nlens  9d"5wx       SetModelMaterial eID, mat pruWO'b`       Print "Set lens index of refraction = " & nlens /p$=Cg[K   ? : m d       '************************************************************************* 5w-JPjH       'Pupil diameter Ea4 * o       '************************************************************************* %FlA":W       eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) QV/";A3k   C<t RU5|       'Adjust pupil diameter (trimming volume inner hole) Yzd2G,kZ=   _:5=|2-E       SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" }Z-I2 =]   ?48AY6       ' Adjust pupil location to just in front of the lens "=ElCaP}       parID = FindFullName( "Geometry.Arizona Eye" ) 0l1.O2-       eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) %uEtQh[       count = 0 ;>C9@S+       While GetOperationCount(eID)>count <~O}6HQ#           GetOperation eID, count, op i7f%^7!           If op.Type="ShiftZ" Then M1(9A>|nF               DeleteOperation eID,count &gWiu9WbS               count=count-1 (+x]# #Q           End If &>V/X{>$`K           count=count+1 jIZ+d;1       Wend `A"Q3sf%       op.Type = "ShiftZ" fD(7FN8       op.val1 = taq-0.01 <c\]Ct       op.parent = parID /4H[4m]I       AddOperation eID, op :K;T Q   ?k::tNv0       Print "Set pupil diameter = " & pupilDiam T\cR2ZT~   2R] XH 0        'Update AZ Eye subassembly Description hU)'OKe       eID = FindFullName( "Geometry.Arizona Eye" ) a6qwL4       GetEntity eID, entity &_YtY47       entity.Description = "Accommodation = " & A & "D" PnJ*Zea       SetEntity eID, entity HNFhH0+^   X [!X>w&z|       Update jjX%$Hr       Print "DONE!" 7y;u} 1        g#Mv&tU   End Sub 5=m3J!?   E\_ W   如果屈光度是4，光瞳直径是4，则会输出如下数据：  *0-v!\{   PC[cHgSYU   Accommodation = 4 Diopters +/w(K,   Pupil Diameter = 4 mm <g*.p@o   Set aqueous humor thickness = 2.81 ?n&$m   Set anterior lens radius = 10.4 and conic constant = -2.375869 r/^tzH's   Set posterior lens radius = -4.424557 and conic constant = -3.081019 *i%.{ YH   Set lens thickness = 3.927 L!&$c&=xf   Set lens index of refraction = 1.42672 IJldN6&\q   Set pupil diameter = 4 cP,;Qbe   DONE!

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