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简介
L]wk Ba ('1]f?: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。 j]'ybpMT" '7JM/AcC#K 模型 8iUYZF >)6k)$x%% 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 9}$'q$0R] :wY(</H Table 1. AZ眼睛模型的定义 wo5fGQJ 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. c1ptN J936o3F_ 光源 SQ-CdpT< Dio)orc 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 D9%t67s MeDlsO &~V6g(9 图1. 光源和提示信息使用 [!Zyp`: 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 FJ] ?45 zbAyYMtEk
在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 W.nr&yiQ V6kJoSyde 图2. 字母F光源的设定方法光 UO4z~ #k|f%!-Vo 图3. 字母F在视网膜上位置点列图 \pVNJy$`< 视网膜的散射 5%]O'h En{<
OMg 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。 KJi8LM .f9&.H# wxE'h~+ 图4. 视网膜朗伯散射设定 ,qwVDYJ 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。 r1[#_A`Yn PYyT#AcW2 @dc4v_9 图5. 视网膜重点采样规格设定 qo7jrY5G 脚本 e'2w-^7 Ntlbn&lc;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: nK6(0?/ O{Y*a )" 图6. 用户对话框的创建与编辑 q"VC#97` 图7. 用户对话框编辑器 TJUYd9O4[ 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。 ?*:BgaR_ 余下的脚本计算与屈光度有关的所有参数。 ^?S lM n!h952" 分析 r#B{j$Rw
u-R;rf5%k 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ]SUW"5L- s&M#]8x;x 图7. 字母F在视网膜上颜色分析 juB /?'$~ 脚本代码 y*T@_on5 "c*#ZP Option Explicit 'Remove this to enable non-dimensioned variables to be used. 5`)[FCQ T/P
Dim entity As T_ENTITY kiu#THF Dim op As T_OPERATION 8gJg7RxL Dim mat As T_MODELMATERIAL $k^&
X
` Dim A As Double +,UuJ6[n Dim pupilDiam As Double x,Z:12H0 Dim eID As Long ,'byJlw_pv Dim parID As Long \RmU6(;IQ Dim count As Integer 3j\Py'}; Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double &H/3@A3 Dim tlens As Double, nlens As Double l} W">
yQ0 Dim curv As Double, conic As Double p~z\&&0U0 Dim ok As Long
vu3zZMl :.crES7<[X Sub Main &:#"APX TRFza}4:i '用户输入对话框 pt%Y1<9Eh? Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 wp<f{^ et TextBox 220,21,40,21,.TextBox1 'default: 0 USV;j%U4* Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 t:%u4\nZ; OKButton 40,91,90,21 TE-(Zil\ CancelButton 190,91,90,21 W.>}5uVl6 Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 @Uqcym. TextBox 220,49,40,21,.TextBox2 'default: 4 @wh-.MD End Dialog K
Vnz{cx` Dim dlg As UserDialog 6t'vzcQs $u,
~183 ok = Dialog (dlg) mV|Z5 =f M<ba+Qn$ If ok=0 Then 'cancel button was pressed Ur(< ] Print "Execution cancelled." +K48c,gt? End 3-_`x9u* End If t]+h. v(l:N@L 'Assign accommodation and pupil diameter & use defaults if field left empty v
K!vA-7 If dlg.TextBox1 = "" Then }VqCyJu&{ A = 0 'Default accommodation vY]7oX+ Else E2Ec`o A = CDbl(dlg.TextBox1) rhC
x&L End If 8>'vzc/*> J'*`K>wV If dlg.TextBox2 = "" Then -NUA pupilDiam = 4 'Default pupil diameter i)@H Else Dj{=Y`Tw pupilDiam = CDbl(dlg.TextBox2) _@O.EksY3r End If mBDzc(_\$'
\1?: Print " " @|fT%Rwho< Print "Accommodation = " & A & " Diopters" 4]no#lVRJ Print "Pupil Diameter = " & pupilDiam & " mm" AizLzR$OG [ N0"mE< ' Calculate new parameters with accommodation a>egH
og taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ,j%feC3 ;&
zBNj Rant = 12.0 - 0.4*A 'Radius of anterior lens gqDSHFm: CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens BCt>P?,UO [q~3$mjQ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens gNSsT]) CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens -qpe;=g&f 8YO` TgW tlens = 3.767 + 0.04*A 'Lens thickness `}#n#C) VTn6@z_ x nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Z+
)<FX iM~qSRb#mJ 'Adjust parameters to account for accommodation 8xYeaK *P+8^t#Vp '************************************************************************* 1
Lz 'Aqueous thickness (Position of Lens) g4GU28 l '************************************************************************* J+YoAf`hi eID = FindFullName( "Geometry.Arizona Eye.Lens" ) a
t%qowt GetCustomElement eID, entity mf\@vI =HHb ]JE parID = FindFullName( "Geometry.Arizona Eye" ) <'vtnz I~25}(IDZ" ' Delete any shift(s) in z "*N]Y^6/A count = 0 >C -N0H While GetOperationCount(eID)>count s;xErH@RA GetOperation eID, count, op >H,PST If op.Type="ShiftZ" Then jNW/Biy4u DeleteOperation eID,count K4^mG count=count-1 7QHrb'c End If Y{2L[5_1 count=count+1 :@J.!dokF Wend 3.@ir"vy )`}4rD^b 'Set new shift in ig4mj47wJ op.Type = "ShiftZ" <ugy-vSv op.val1 = taq / a$B8, op.parent = parID w>&g' AddOperation eID, op )<_:%oB Print "Set aqueous humor thickness = " & taq-0.55 >C/O >g xcQ:&q '************************************************************************* pR3K~bx^ 'Radius and conic constant of anterior lens U9h@1: '************************************************************************* "PC9[i eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) F,JqHa9 GetConic eID, entity, curv, conic nw mxl"Y&l2< SetConic eID, entity, 1/Rant, CCant idNg&' Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant n hGh5, pt~b=+bBm '************************************************************************* UKf0cU 'Radius and conic constant of posterior lens K"VRHIhfg '************************************************************************* %SwhNn eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Mgg m~|9) GetConic eID, entity, curv, conic \(ju0qFqH ^zR*s |1Q SetConic eID, entity, 1/Rpost, CCpost I=&Kn@^ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost nH|7XY9" g UA_&_ '************************************************************************* +P;&/z8i*g 'Lens thickness (Position of posterior lens surface) ^4{"h '************************************************************************* P
yN{ ^( 1S`z$ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) w~WW2w ]gDX~]f[ ' Delete any z-shift(s) P#qQde/y count = 0
@+!u{ While GetOperationCount(eID)>count p-B
|Gr| GetOperation eID, count, op /t_AiM,( If op.Type="ShiftZ" Then "i;" DeleteOperation eID,count $
1v'CT count=count-1 q 1+{MPJ End If 7SjWofv count=count+1 zl@hg<n Wend `_>44!M N3?hu} 'Set new z-shift oPR?Ar op.Type = "ShiftZ" YUQKy2 op.val1 = tlens N6%M+R/Q op.parent = parID swG!O}29OX AddOperation eID, op 'klYGp Print "Set lens thickness = " & tlens #>O>=#Q i3o;G"IcD '************************************************************************* vXeI)vFK 'Lens index of refraction +cC$4t0$^A '************************************************************************* 9M1 UkS$`@ eID = FindMaterial( "Lens" ) ,2lH*=m; GetModelMaterial eID, mat obSLy
Ed nx@h mat.Nd = nlens T#-U\C~o SetModelMaterial eID, mat 5ii:93Hlj Print "Set lens index of refraction = " & nlens yPVK>em5 9Vtn62+ '************************************************************************* El|Y]f 'Pupil diameter JId|LHf*P '************************************************************************* TV*@h2C"i eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 0i/!nke. [K"&1h<> 'Adjust pupil diameter (trimming volume inner hole) 2t`d.s= ZMmf!cKY:' SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" _?a.S8LxJZ MUvgmJsN ' Adjust pupil location to just in front of the lens w4j,t parID = FindFullName( "Geometry.Arizona Eye" ) xaW9Sj0ZM eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) dn:/8~B"X count = 0 {}N=pL8MS While GetOperationCount(eID)>count <,I]=+A GetOperation eID, count, op T {zz3@2? If op.Type="ShiftZ" Then b0
y*} DeleteOperation eID,count
A!^gF~ 5 count=count-1 s.XLC43Rs End If @]X5g8h count=count+1 _p\O!y Wend P%Tffsl
op.Type = "ShiftZ" `nEe-w^9)I op.val1 = taq-0.01 q,*([yX op.parent = parID U$^ $7g 3 AddOperation eID, op _e94 sL\W6ej Print "Set pupil diameter = " & pupilDiam @t<KS& 5nv1%48Ri 'Update AZ Eye subassembly Description %M
u$0~ct" eID = FindFullName( "Geometry.Arizona Eye" ) L5A?9zum/! GetEntity eID, entity N_| '`]D entity.Description = "Accommodation = " & A & "D" zE1=*zO` SetEntity eID, entity gkL{]*9&% ##|]el%Y Update #Iwxt3K Print "DONE!" *W$bhC'w dI)
9@UL End Sub ,'>O#kD
p@jwHlX 如果屈光度是4,光瞳直径是4,则会输出如下数据: _ 68{
{. ,BE4z2a Accommodation = 4 Diopters E% d3}@ Pupil Diameter = 4 mm GLr7sack Set aqueous humor thickness = 2.81 T7~Vk2o%( Set anterior lens radius = 10.4 and conic constant = -2.375869 D);w)` Set posterior lens radius = -4.424557 and conic constant = -3.081019 j/uu&\e Set lens thickness = 3.927 o2W^!#]= Set lens index of refraction = 1.42672 22FHD4 Set pupil diameter = 4 G'f5MP1 DONE! 0t(js_
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