=~LJ3sIX 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。 N?`' /e !^G\9"4A 模型 l,aay-E .O<obq~;C 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。 AbW6x Table 1. AZ眼睛模型的定义 C\hM =% JC}D`h 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. }"%N4(Kd _Y m2/3! 光源 {Qj~M<@3 (S Yln>o 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。 Bk{]g=DO H3oFORh 图1. 光源和提示信息使用 %
|L=l{g =($xG#g` 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 0JujesUw( buHJB*?9 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 86a\+Kz%%L 图2. 字母F光源的设定方法光 ba9?(+i$h es0hm2HT3 图3. 字母F在视网膜上位置点列图 Ab;.5O$y eS){1 视网膜的散射 ]T) 'Hb @IZnFHN 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 bpa?C [mueZQyI?0 图4. 视网膜朗伯散射设定 F,CTZ~ ;q>ah!"k 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 -$Ih@2"6 i,VMd 图5. 视网膜重点采样规格设定 {id4:^u&; @>7%qS 脚本 Y}KNKO; MiX 43Pk] 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: iH'p>s5L 图6. 用户对话框的创建与编辑 G^@5H/) 图7. 用户对话框编辑器 RPbZ(. h;'~,xA 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。 +
>!;i6| 余下的脚本计算与屈光度有关的所有参数。 Vi|#@tC' 3PF_H$`oJ 分析 qmP].sA b7ZSPXV 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ?gXp*>Kg[ 图7. 字母F在视网膜上颜色分析 b#o|6HkW gnHbb-<i, 脚本代码 ksm~<;td iU:cW=W|M\ Option Explicit 'Remove this to enable non-dimensioned variables to be used. aDN`6[ TkF[x%o Dim entity As T_ENTITY Pc]HP Dim op As T_OPERATION 7-V/RChBm Dim mat As T_MODELMATERIAL W}ofAkF Dim A As Double u$`a7Lp,n Dim pupilDiam As Double Ew$C
;&9 Dim eID As Long !ubD/KE Dim parID As Long wdoR%b{M Dim count As Integer f?)-}\[IR{ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double .A|@?p[ Dim tlens As Double, nlens As Double *=xr-!MEk Dim curv As Double, conic As Double $Ygue5{c Dim ok As Long Qv ?"b FC4wwzb Sub Main H6gSO(U Kf-JcBsrT '用户输入对话框 $Z>'Jp Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 K|s,ru TextBox 220,21,40,21,.TextBox1 'default: 0 H0cA6I Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 [.}oyz;}N OKButton 40,91,90,21 V G~Vs@c( CancelButton 190,91,90,21 oD@7
SF Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 P+HXn8@ TextBox 220,49,40,21,.TextBox2 'default: 4 EBmt9S End Dialog d0 /#nz Dim dlg As UserDialog Ht&YC<X y~HP>~Oh ok = Dialog (dlg) xd0 L{ue. &Hnz8Or! If ok=0 Then 'cancel button was pressed cl/_JQ& Print "Execution cancelled." 8a"%0d# End S`]k>'
l End If '4<1 1(U N4HqLh23H 'Assign accommodation and pupil diameter & use defaults if field left empty ijU*|8n{> If dlg.TextBox1 = "" Then K~EmD9 A = 0 'Default accommodation 2b8L\$1q Else SZCze"`[ A = CDbl(dlg.TextBox1) rQ snhv End If j_7mNIr j*m%*_kO If dlg.TextBox2 = "" Then ;xn0;V'= pupilDiam = 4 'Default pupil diameter p{dj~ &v Else GsM<2@? pupilDiam = CDbl(dlg.TextBox2) caX<
n>
End If 1yY0dOoLG) @9|hMo Print " " T&7qC=E#5 Print "Accommodation = " & A & " Diopters" 8Xs8A. Print "Pupil Diameter = " & pupilDiam & " mm" |
VDV<g5h oe~b}: ' Calculate new parameters with accommodation #A8sLkY taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ( &x['IR sW8dPw
O Rant = 12.0 - 0.4*A 'Radius of anterior lens r9G>jiw8 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens P{^6v=8) Z;)%%V%o Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ]')RMg zM* CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ~4cC/"q$X R0-j5&^jju tlens = 3.767 + 0.04*A 'Lens thickness y1L,0 ] ENY+^7 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction |]*/R^1>2 l%i+cO D
'Adjust parameters to account for accommodation %D "I ^5
Tqy(M '************************************************************************* e\75:oQ 'Aqueous thickness (Position of Lens) <1M-Ro?5k '************************************************************************* ,
++ `=o eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Kx JqbLUC GetCustomElement eID, entity h@@=M SByW[JE parID = FindFullName( "Geometry.Arizona Eye" ) y"wShAR S>1Iky|
' Delete any shift(s) in z jWfa;&Ra count = 0 S|+o-[e8O While GetOperationCount(eID)>count jEJT-*I1+ GetOperation eID, count, op xKp4*[}m If op.Type="ShiftZ" Then UW
EV^ &"x DeleteOperation eID,count $* Kvc$D count=count-1 N ZSSg2TX# End If du^J2m{f count=count+1 uu687|Pm Wend
3?
+Hd !%0 *z 'Set new shift in L*JjG sTH op.Type = "ShiftZ" lHX72s|V op.val1 = taq kMd.h[X~ op.parent = parID H7:] ]j1 AddOperation eID, op N87B8rDl Print "Set aqueous humor thickness = " & taq-0.55 B^9j@3Ux ?6Y?a2 | '************************************************************************* 3m)y|$R 'Radius and conic constant of anterior lens -3Vx76Y '************************************************************************* M =r)I~ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) s->^=dy GetConic eID, entity, curv, conic V "h
+L7T J/*`7Pd SetConic eID, entity, 1/Rant, CCant sLQ^F Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ~/P[J |
%Vh`HT '************************************************************************* ea')$gR 'Radius and conic constant of posterior lens d/DB nZN '************************************************************************* [q #\D eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ixD)VcD-f GetConic eID, entity, curv, conic 'Qe;vZ31K 04=c-~&q SetConic eID, entity, 1/Rpost, CCpost E~oOKQ5W Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ]?[fsdAQW BF{Y"8u$ '************************************************************************* d-dEQKI?; 'Lens thickness (Position of posterior lens surface) 0:Ol7 '************************************************************************* ) hfpwdQ >\3V a parID = FindFullName( "Geometry.Arizona Eye.Lens" ) "a U
aotx `+Q%oj#FF ' Delete any z-shift(s) N//KPh count = 0 t{vJM!kdlQ While GetOperationCount(eID)>count a!AA] GetOperation eID, count, op B_m8{44zM If op.Type="ShiftZ" Then OpYY{f DeleteOperation eID,count s,&Z=zt0R count=count-1 pcWPH. End If `RL"AH:+ count=count+1 WEi2=3dV Wend z ~/` 1 03 #lX(MB 'Set new z-shift G*P#]eO op.Type = "ShiftZ" 81
sG op.val1 = tlens YteO6A;
op.parent = parID IB]l1< AddOperation eID, op DN5 7p!z Print "Set lens thickness = " & tlens
wcY?rE9
}?Ai87-{ '************************************************************************* L0WN\|D 'Lens index of refraction 'AS|ZRr/ '************************************************************************* <B6H. P = eID = FindMaterial( "Lens" )
Qjv}$`M GetModelMaterial eID, mat ZX./P0 338k?nHxv mat.Nd = nlens
7\Y0z SetModelMaterial eID, mat zue~ce73J Print "Set lens index of refraction = " & nlens %aVq+kC h i6Emhji '************************************************************************* )
ahA[ 'Pupil diameter PBTnIU '************************************************************************* cB}D^O eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) fHd#u%63K [j/9neaye 'Adjust pupil diameter (trimming volume inner hole) Q:d]imw!O Od,qbU4O SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" @O^6&\s>
57 ' Adjust pupil location to just in front of the lens ,S]7 'UP parID = FindFullName( "Geometry.Arizona Eye" ) =R$u[~Xl2X eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) )W
_v:?A9 count = 0 Tqn@P While GetOperationCount(eID)>count CU2*z(]& GetOperation eID, count, op w-L=LWL\ If op.Type="ShiftZ" Then EaY?aAuS: DeleteOperation eID,count <FkFs{(t count=count-1 XrGglBIV End If 8\A#CQ5b count=count+1 HJ[c M6$2 Wend @>2i+)=E5 op.Type = "ShiftZ" "CQa.% op.val1 = taq-0.01 L2i_X@/ op.parent = parID 4*cEag AddOperation eID, op a![{M<Y~ B7E:{9l~s{ Print "Set pupil diameter = " & pupilDiam tpQ(g% r1{@Ucw2 'Update AZ Eye subassembly Description u.m[u)HQ eID = FindFullName( "Geometry.Arizona Eye" ) ^7WN{0 GetEntity eID, entity "
9wvPC ^ entity.Description = "Accommodation = " & A & "D" 1FL~ndJs SetEntity eID, entity 2E)-M9ds x,pjpx Update Q1I6$8:7 Print "DONE!" :vQrOn18p nRZ]z( b End Sub sfugY(m `*N[jm" 如果屈光度是4,光瞳直径是4,则会输出如下数据: SBk4_J/_ ?(F6#"/E Accommodation = 4 Diopters j[G Pupil Diameter = 4 mm 17"uf.G Set aqueous humor thickness = 2.81 VSI9U3t3w Set anterior lens radius = 10.4 and conic constant = -2.375869 Zbt.t]N Set posterior lens radius = -4.424557 and conic constant = -3.081019 S3*`jF>q Set lens thickness = 3.927 XZ]uUP Set lens index of refraction = 1.42672 bP$dU,@p~ Set pupil diameter = 4 lc1(t:"[ DONE! |