[技术]Arizona眼睛模型 [复制链接]

简介 KBFAV&  
k||DcwO  
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。 rJm%qSZz  
)Z 3fytY  
模型 ;EfMTI}6K  
KhV; />(  
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。 ^5~[G%G4  
{N,w5!cP  
 0-+`{j  
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. v)2@;Q  
{\e wf_pFk  
光源 d|sI>6jD  
CQ3{'"b  
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。 VU*{E  
T't^pO-`  
:PaFC{O)*  
'17u W
q  
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。 ?Xo9,4V1  
{:enoV"  
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。 Cst>'g-yB  
:1>R~2  
<`9:hPp0  
/bylA`IMW  
视网膜的散射 tIC_/ 6  
i,,>@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。 uyG4zV\h*  
es(vW
f'  
j{P,(-  
%/MK$  
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。 o#wF/ I  
6CU8BDN  
?t}[Wi}7  
pp[? k}@  
脚本 X>|.BvY|  
.[Sv|;x"E  
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： 95
wV+ q*  
73.o{V  
r%'2a+}D  
W3 8=fyD  
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。 vFCp=8h  
余下的脚本计算与屈光度有关的所有参数。 D1O7S]j  
?j
0blXl  
分析 y_QxJ~6t  
f3l >26  
屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 WuGm~<NS  
h=4{.EegG&  
);|~4#  
脚本代码 ?0;b}Xl-  
t8)Fkx#8}  
Option Explicit     'Remove this to enable non-dimensioned variables to be used. ^LC5orO  
T)Nis~  
Dim entity As T_ENTITY JrL/LGY  
Dim op As T_OPERATION H[Pb Wy:  
Dim mat As T_MODELMATERIAL kb7\qH!n  
Dim A As Double BS|-E6E<  
Dim pupilDiam As Double oG*lUh}  
Dim eID As Long eNNgxQw>m  
Dim parID As Long 8w*fg6,=  
Dim count As Integer t583Q/1@  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double FUcs=7c  
Dim tlens As Double, nlens As Double Jc%>=`f  
Dim curv As Double, conic As Double ;Ok11wOw  
Dim ok As Long }5]s+m  
X7 ZaQ .  
Sub Main r2H'r ,N  
tt[_+e\4  
    '用户输入对话框 x
.r`(  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 -=sxbs.aA  
        TextBox 220,21,40,21,.TextBox1 'default: 0 m9B3]H  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 4*9Dh  
        OKButton 40,91,90,21 g<dCUIbcQ  
        CancelButton 190,91,90,21 RY~)MS _C  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ntkinbbD  
        TextBox 220,49,40,21,.TextBox2 'default: 4 ``E;!r="v  
    End Dialog YJ6vyG>%C  
    Dim dlg As UserDialog Ti/iD2g  
yED^/=\)}  
    ok = Dialog (dlg) ;_SS3q  
<|`@K|N  
    If ok=0 Then    'cancel button was pressed QNtr
=  
        Print "Execution cancelled." 4*,q1yK  
        End %8{_;-f  
    End If d!LV@</  
.6;B3  
    'Assign accommodation and pupil diameter & use defaults if field left empty dDuA%V0  
    If dlg.TextBox1 = "" Then T8(wzs  
        A = 0           'Default accommodation Yptsq@s  
    Else eS=k 48'U  
        A = CDbl(dlg.TextBox1) :hr@>Y~r  
    End If m{5$4v,[
 
<&Uk!1Jd  
    If dlg.TextBox2 = "" Then V$_0VN'+Z  
        pupilDiam = 4   'Default pupil diameter 4>Y\2O?**  
    Else j`GbI0,bT  
        pupilDiam = CDbl(dlg.TextBox2) bYgYP|@  
    End If
;' W5|.ZN  
7fEV/j  
    Print " " Zll^tF#  
    Print "Accommodation = " & A & " Diopters" :y %~9=  
    Print "Pupil Diameter = " & pupilDiam & " mm" 1G;Ns] u  
ri;M7rg`.{  
    ' Calculate new parameters with accommodation Ww@;9US 3  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness o'4@]ae   
iLgt_@g  
    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 8JrGZ8Q4RM  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens I7_D $a=  
Mfr#IzNHN  
    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens //,'oh~W  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens eC{Z  
y~=hM   
    tlens = 3.767 + 0.04*A                  'Lens thickness . R}y"O\  
.%<&W1  
    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 9"RfL7{  
~b[4'm@  
    'Adjust parameters to account for accommodation 7tpZE+OX  
\@3  
    '************************************************************************* 8} k,!R[J  
    'Aqueous thickness (Position of Lens) )It4al^\  
    '************************************************************************* W>
bW1h  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) sZB6zTX J  
    GetCustomElement eID, entity "6.p=te  
yy1r,dw  
    parID = FindFullName( "Geometry.Arizona Eye" ) 9tEKA|8  
kAliCD)  
    ' Delete any shift(s) in z |Z^g\l.j{  
    count = 0 /xbZC{R  
    While GetOperationCount(eID)>count l,L=VDEz,  
        GetOperation eID, count, op O*{H;7Pv  
        If op.Type="ShiftZ" Then Kc\'s65.]  
            DeleteOperation eID,count e:D"_B  
            count=count-1 s3Ce]MH  
        End If *SMPHWH[c  
        count=count+1 RbM~E~$  
    Wend jGhg~-m  
f4T0Y["QA  
    'Set new shift in WGluY>C;  
    op.Type = "ShiftZ" 9prsL#Fn  
    op.val1 = taq b
[;3KmUB  
    op.parent = parID gtGKV  
    AddOperation eID, op
N:[;E3?O  
    Print "Set aqueous humor thickness = " & taq-0.55 5 h
adA>d  
l_-n&(N2<[  
    '************************************************************************* *m@w^In^  
    'Radius and conic constant of anterior lens n{r#K_  
    '************************************************************************* 08?MS_  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) xBfe8lor  
    GetConic eID, entity, curv, conic U hhmG+  
0_mvz%[J  
    SetConic eID, entity, 1/Rant, CCant -+>r4P  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant v@uaf=x-  

$jh>zf  
    '************************************************************************* ^[[b$h$  
    'Radius and conic constant of posterior lens -b0'Q  
    '************************************************************************* )$h9Y   
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) arQ%  
    GetConic eID, entity, curv, conic GR[>mkW!M  

&N_c-@2O  
    SetConic eID, entity, 1/Rpost, CCpost N$&ePU J  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Cj 2Xl  
kz;_f  
    '************************************************************************* :U.)YHY  
    'Lens thickness (Position of posterior lens surface) i!$^NIcJ  
    '************************************************************************* 9Y%?)t.2  
:+Q"MIU  
    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) =&VXn{e  
n_n|^4w  
    ' Delete any z-shift(s) Gb|}Su  
    count = 0 J-\?,4mcP  
    While GetOperationCount(eID)>count X/8iJ-KB  
        GetOperation eID, count, op SKpPR;=q|:  
        If op.Type="ShiftZ" Then >-@ U_p  
            DeleteOperation eID,count ;;'a--'"  
            count=count-1 53t-'K0l  
        End If YATdGLTeq  
        count=count+1 MR_bq_)  
    Wend mHEf-6|C`  
-+=:+LhSMb  
    'Set new z-shift >`<2}Me6  
    op.Type = "ShiftZ" "x|NG,<[9  
    op.val1 = tlens 99Yo1Q0  
    op.parent = parID iE^a%|?}  
    AddOperation eID, op %|(?!w7  
    Print "Set lens thickness = " & tlens 2vkB<[
tSs  
IiK(^:~%  
    '************************************************************************* Az< 9hk  
    'Lens index of refraction u[i7:V%  
    '************************************************************************* \;*}zX  
    eID = FindMaterial( "Lens" ) 8q?;Hg  
    GetModelMaterial eID, mat .y7)XLC  
Sn
0gTsZ  
    mat.Nd = nlens N~$Zeq=  
    SetModelMaterial eID, mat TA0D{
  
    Print "Set lens index of refraction = " & nlens !-5S8b  
E!I  
    '************************************************************************* SE^b0ZV*x  
    'Pupil diameter 8_IOJ]:w  
    '************************************************************************* xEiX<lguyN  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) %7]XW2u  
<m>l-]  
    'Adjust pupil diameter (trimming volume inner hole) }
PFt  
(}C^_q:7d  
    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" /iUUM t'  
r6n5Jz  
    ' Adjust pupil location to just in front of the lens zvGK6qCk  
    parID = FindFullName( "Geometry.Arizona Eye" ) L8dU(P  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) IypWVr  
    count = 0 k%l_N)38  
    While GetOperationCount(eID)>count e$Bf[F#;-  
        GetOperation eID, count, op i$bzdc#s  
        If op.Type="ShiftZ" Then j6e}7  
            DeleteOperation eID,count ^RV  
            count=count-1 "X5_-l  
        End If ;V~rWzKM(  
        count=count+1 e?!L}^f6X  
    Wend If-,c^i  
    op.Type = "ShiftZ" &]VQR2J}:  
    op.val1 = taq-0.01 7?MB8tJ5r4  
    op.parent = parID `c'  
    AddOperation eID, op Ak6MPuBB-  
~M ,{ _  
    Print "Set pupil diameter = " & pupilDiam M?Ndy*]  

={`CHCI  
    'Update AZ Eye subassembly Description V#NG+U.B  
    eID = FindFullName( "Geometry.Arizona Eye" ) i,#k}CNu  
    GetEntity eID, entity ;}/U+`=D?  
    entity.Description = "Accommodation = " & A & "D" VT% KN`l  
    SetEntity eID, entity _%'L@[ H  
sTtX$&Qu  
    Update pcy<2UV  
    Print "DONE!" tlV &eN  
     Qz@IK:B}  
End Sub 2mqK3-c  
/2;dH]o0  
如果屈光度是4，光瞳直径是4，则会输出如下数据： WR/o @$/  
46bl>yk9<  
Accommodation = 4 Diopters 7v_i>_m]  
Pupil Diameter = 4 mm D<U 9m3  
Set aqueous humor thickness = 2.81 D XV@DQ  
Set anterior lens radius = 10.4 and conic constant = -2.375869 N0Efw$u  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 r{\BbUnf)  
Set lens thickness = 3.927 ?;|@T ty%  
Set lens index of refraction = 1.42672 c,y|c`T 2  
Set pupil diameter = 4 +T0op4  
DONE! weAn&h|