|
|
简介 Zna
}h{ 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。 Y"G$^3% (] U#@:"v| 模型 Ab8~'<F$B F1gDeLmJ 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。 {ZN{$Ad3/ W=PDOzB>K Table 1. AZ眼睛模型的定义 ';zLh 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. gO_^{>2 bAt!9uFn 光源 *)g*5kKN 024*IoVZ 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。 0Rrz
p;X[_h l<GRM1^kU 图1. 光源和提示信息使用 l&U3jeW-o 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。 E8#y9q |LiFX5!\ 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。 3l<)|!f]g ,Lox?}t 图2. 字母F光源的设定方法光 $aG]V-M> \MK)dj5uUJ 图3. 字母F在视网膜上位置点列图 OlMCF.W#3 视网膜的散射 .oAg
(@^6 XlDVJx<&J 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 CDoZv"" ]:m*7p\uk *!'00fv 图4. 视网膜朗伯散射设定 ;bkS0Vmg 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 >Py; 6K umI#P,%[ ,7>_Lp_v 图5. 视网膜重点采样规格设定 <$,iYx 脚本 oPm1`x P^VV8Z>\& 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: ax7ub Ho\K
%#u 图6. 用户对话框的创建与编辑 x/bO;9E%U4 图7. 用户对话框编辑器 3l5q?" $ 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。 rbQA6_U 5A 余下的脚本计算与屈光度有关的所有参数。 aH,0+ | @fbvu_-]. 分析 nb(#;3DQ \muyL? 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 j$N`JiKM %6kD^K- 图7. 字母F在视网膜上颜色分析 _aa3Qwx 脚本代码 78y4nRQ* [<8<+lH=P Option Explicit 'Remove this to enable non-dimensioned variables to be used. 1B,RRHXn6 !\+SE"ml Dim entity As T_ENTITY Vk{0)W7 Dim op As T_OPERATION NVJvCs)3f Dim mat As T_MODELMATERIAL 0y2iS't
Dim A As Double 2$\Du9+ Dim pupilDiam As Double B@.U\. Dim eID As Long +% '0; Dim parID As Long mZMLDs: Dim count As Integer qhL e[[> Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double EDL<J1% Dim tlens As Double, nlens As Double f<0-'fGJd Dim curv As Double, conic As Double e,:@c3I Dim ok As Long +#'exgGU^[ <Pg.N Sub Main \HTXl] GMB%A '用户输入对话框 CNfeHMT Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 G)'cd D1 TextBox 220,21,40,21,.TextBox1 'default: 0 {Qlvj.Xw Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 HO&#Lv OKButton 40,91,90,21 8~}Ti*Urc CancelButton 190,91,90,21
%|l*=v Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 w9i1ag TextBox 220,49,40,21,.TextBox2 'default: 4 ]>*Z 1g; End Dialog :mY(d6#A> Dim dlg As UserDialog \u",bMQF +4B>gS[ F ok = Dialog (dlg) !mq+Oz~ YujhpJ< If ok=0 Then 'cancel button was pressed j/dNRleab Print "Execution cancelled." t6s#19g End o`h F1*yp End If %UgyGQeo
CW, Kw 'Assign accommodation and pupil diameter & use defaults if field left empty M0"xDvQ If dlg.TextBox1 = "" Then $p}7CP A = 0 'Default accommodation S(9fGh Else /v=MGX@r A = CDbl(dlg.TextBox1) XZIj' a0d End If C!~&c7 (Cqhk:F If dlg.TextBox2 = "" Then Q6"r^wWx pupilDiam = 4 'Default pupil diameter )P\ec Else UT]LF#.( pupilDiam = CDbl(dlg.TextBox2) ^EM##Ss_ End If DkQy. sh E>gTe Print " " e9N"{kDs6 Print "Accommodation = " & A & " Diopters" \BUr2] Print "Pupil Diameter = " & pupilDiam & " mm" M nH4p AGS?<6W- ' Calculate new parameters with accommodation /R 2:Js taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness VT;$:>!+ om;jXf}A Rant = 12.0 - 0.4*A 'Radius of anterior lens hPD2/M
CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ~qco -b vYrqZie< Rpost = -5.224557 + 0.2*A 'Radius of posterior lens o;_v' CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens kCLz@9>FQ n\wO[l) tlens = 3.767 + 0.04*A 'Lens thickness h]vA%VuE'E ` *h-j/M nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 4CfPa6_ V= !!;KR0 'Adjust parameters to account for accommodation |HhUU1! ZU7,=B= '************************************************************************* I>b!4?h 'Aqueous thickness (Position of Lens) ?_}[@x '************************************************************************* 9m%[
y1v0 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 7L? ~;;L$ GetCustomElement eID, entity "qR
qEpD% D~U4K- parID = FindFullName( "Geometry.Arizona Eye" ) |jO&qT]{ iK= {pd ' Delete any shift(s) in z W?5^cEF count = 0 -HS(<V=a?k While GetOperationCount(eID)>count yG2j!D GetOperation eID, count, op P*)}ENY If op.Type="ShiftZ" Then )TBBYCL3 DeleteOperation eID,count u])N^AY"sj count=count-1 aQ46euth End If Ef:.)!;jy count=count+1 E@Q+[~H } Wend [#M^:Q rpQB#
Pz 'Set new shift in ^e8~eL+ op.Type = "ShiftZ" s(r(! FZ op.val1 = taq =Y?M#3P.I op.parent = parID
-[" .km AddOperation eID, op %Z}A+Rv+*m Print "Set aqueous humor thickness = " & taq-0.55 'k{pWfn=<
TB1E1 '************************************************************************* pg [F{T< 'Radius and conic constant of anterior lens gj0gs '************************************************************************* CES^
c-. k eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) DnMfHG[< GetConic eID, entity, curv, conic /P Qz$e-!Y G=!Gy.
SetConic eID, entity, 1/Rant, CCant #Bj.#5 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant "z1\I\
^ gp$oQh#37; '************************************************************************* @M?;~M?B]J 'Radius and conic constant of posterior lens WIa4!\Ky! '************************************************************************* N3!x7J7A eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) h%8[];*DpN GetConic eID, entity, curv, conic %J5zfNe)& KtG|m'\D SetConic eID, entity, 1/Rpost, CCpost nNSq6 Cj Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost \/xWsbG\ PeEC|&x '************************************************************************* Pe6MDWR 'Lens thickness (Position of posterior lens surface) 4nN%5c~= '************************************************************************* ' jf$3 E=_M=5] parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 1
`hj]@.] $8kc1Q ' Delete any z-shift(s) A36 dj count = 0 ps\A\aggML While GetOperationCount(eID)>count U7bbJ>U_| GetOperation eID, count, op $Y5R^Y If op.Type="ShiftZ" Then
p-POg%|&< DeleteOperation eID,count \tc4DS count=count-1 Z@nWx]iz End If Y6~/H count=count+1 k|(uIU* ] Wend ,B_Nz}\8 j7IX"O%f\ 'Set new z-shift PHU#$LG op.Type = "ShiftZ" dMK|l op.val1 = tlens rvgArFf}] op.parent = parID Ikv@}^p 7 AddOperation eID, op }1=V`N( Print "Set lens thickness = " & tlens OSY$qL2 9lbe[w@
'************************************************************************* b_ +dNoB 'Lens index of refraction 2Dgulx5kGZ '************************************************************************* >k)}R|tJ eID = FindMaterial( "Lens" ) kq&xH;9=. GetModelMaterial eID, mat u(iEuF;7 h;?=:( mat.Nd = nlens *p0n{F9 SetModelMaterial eID, mat P1tc*2Z Print "Set lens index of refraction = " & nlens FH:^<^M \ bNN]= '************************************************************************* *8{PoD 'Pupil diameter A Ch!D>C1 '************************************************************************* SIQ 7oxS4 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) fTQRn ?WyL|;b* 'Adjust pupil diameter (trimming volume inner hole)
_+73Y' Eh/B[u7T[ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" wQ-pIi{G hfw$820y[ ' Adjust pupil location to just in front of the lens BV_rk^}Ur parID = FindFullName( "Geometry.Arizona Eye" ) >={?H?C eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) VSns_>o count = 0 ZZ|a`U While GetOperationCount(eID)>count M*li; GetOperation eID, count, op nQbF~ If op.Type="ShiftZ" Then AWsy9 DeleteOperation eID,count ElLDSo@WvR count=count-1 M+4>l\ End If 30cZz count=count+1 4&]Sb} Wend rV;X1x}l op.Type = "ShiftZ" B'<k*9=Nv8 op.val1 = taq-0.01 Jse;@K5y op.parent = parID 3Run.Gv\ AddOperation eID, op mNhVLB 4B?8$&b Print "Set pupil diameter = " & pupilDiam @)n xX))a bWU4lPfP 'Update AZ Eye subassembly Description r: Ij\YQ eID = FindFullName( "Geometry.Arizona Eye" ) O_-Lm4g?4 GetEntity eID, entity {6}H}_(] entity.Description = "Accommodation = " & A & "D" P|c[EUT SetEntity eID, entity B q/<kEgM tgeX~. Update O)v?GQRj Print "DONE!" Nmu;+{19M Y.FqWJP=p End Sub hdW}._ R<wPO-dX 如果屈光度是4,光瞳直径是4,则会输出如下数据: ;QZ}$8D 6Q ~\HGV+S!g} Accommodation = 4 Diopters W%$sA}O Pupil Diameter = 4 mm 5MU-Eu|*> Set aqueous humor thickness = 2.81 :g@H=W Set anterior lens radius = 10.4 and conic constant = -2.375869 }C6RgE.6< Set posterior lens radius = -4.424557 and conic constant = -3.081019 SbrKNADH% Set lens thickness = 3.927 y$-;6zk\] Set lens index of refraction = 1.42672 )g;*u,C Set pupil diameter = 4 P[Q3z$I} DONE! R1A|g=kF uUy~$>V (文章来源:讯技光电)
|