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简介 q![`3m-d. OJ r~iUr 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。 sW@_' Lw (nAL;:$x2 模型 1P?|.W_^1 xSq{pxX 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 w|c200Is}e S? #6{rx Table 1. AZ眼睛模型的定义 |=AaGJx 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. -tfUkGdx;l yt<h!k$ _P 光源 0ZJj5<U 33g$mUB 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 &O#,"u/q` BhhFij4 yMXf&$C 图1. 光源和提示信息使用 JJK-+a6cX 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。 Bk[C=< X
QD%!a{I 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。 2'u% +t3o5& 图2. 字母F光源的设定方法光 ["[v ^h^.;Iqr= 图3. 字母F在视网膜上位置点列图 .wB'"z8L 视网膜的散射 c(aykIVOo ]kd:p*U6P 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。 ;8a9S0eS ~;#sj&~ $O%"[w 图4. 视网膜朗伯散射设定 b0Dco0U( 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 W/g_XQ 4:5M,p m`}mbm^ 图5. 视网膜重点采样规格设定 5XV|*O; 脚本 voQJ!h1 D -d 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: Tl2(%qB <Zvvx 图6. 用户对话框的创建与编辑 [+Fajo;0 图7. 用户对话框编辑器 -E~r?\;X 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 > l]Ble 余下的脚本计算与屈光度有关的所有参数。
HQ]mDo qsQ{`E0 分析 U.X`z3q ~6IY4']m* 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 I]hjv ` FOCX; 图7. 字母F在视网膜上颜色分析 `mA;1S 脚本代码 *<X1M~p$ )K$YL='kX Option Explicit 'Remove this to enable non-dimensioned variables to be used. zc$}4o L^*f$Balz Dim entity As T_ENTITY U8J9 #+: Dim op As T_OPERATION 1\~I "$} Dim mat As T_MODELMATERIAL D, Gv nfY Dim A As Double &>]U c%JK Dim pupilDiam As Double
JJmW%%]i Dim eID As Long }xBDyr63 Dim parID As Long T*%rhnTv0 Dim count As Integer <bb!BS&w Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Tgax ZW Dim tlens As Double, nlens As Double H6{Bx2J1* Dim curv As Double, conic As Double K_~kL0=4 Dim ok As Long OGIv".~s4 {@F'BB\ Sub Main z~3GgR"1d heL`"Y2'y> '用户输入对话框 `a83bF35 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 [NAfy~X* TextBox 220,21,40,21,.TextBox1 'default: 0 ^b$_I31D Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Wy}^5]R0E OKButton 40,91,90,21 2x9.>nwhb CancelButton 190,91,90,21 @&Z^WN,x Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 -gm5Eqi TextBox 220,49,40,21,.TextBox2 'default: 4 ZE-vroh End Dialog qxDMDMN Dim dlg As UserDialog /]^Y\U ^ #:+F ok = Dialog (dlg) >}\s-/ "[!b5f3!I If ok=0 Then 'cancel button was pressed WG3!M/4r H Print "Execution cancelled." fLqjBG]< End !^&VZh End If _dRB=bl"O ^8_yJ=~V 'Assign accommodation and pupil diameter & use defaults if field left empty 2|=hF9
If dlg.TextBox1 = "" Then .|^Gde A = 0 'Default accommodation sv?Fx;d Else 7P<f(@0h$E A = CDbl(dlg.TextBox1) ZnRT$ l O End If -fk;Qq3O ge1. HG If dlg.TextBox2 = "" Then ) WbWp4 pupilDiam = 4 'Default pupil diameter bXvO+I< Else "3\y~<8%' pupilDiam = CDbl(dlg.TextBox2) ;cvMNU$fN End If Y(bB7tR *U,JQ Print " " IH dA2d?.] Print "Accommodation = " & A & " Diopters" z4Zm% Print "Pupil Diameter = " & pupilDiam & " mm" Yi?bY r'jUB^E ' Calculate new parameters with accommodation SMD*9&, taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness :`zO%h xi(1H1KN5B Rant = 12.0 - 0.4*A 'Radius of anterior lens Lv]%P.=[G CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 3 a.!9R> zmGHI!tP Rpost = -5.224557 + 0.2*A 'Radius of posterior lens F5RL+rU(h CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Gmi?xGn Y&j`HO8f tlens = 3.767 + 0.04*A 'Lens thickness XQ9W
y D$K'Qk nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction #WSqh + ioD8- 'Adjust parameters to account for accommodation T2S_>
#."l _*6]4\; '************************************************************************* myR{}G 'Aqueous thickness (Position of Lens) O^`EuaL '************************************************************************* A~PR eID = FindFullName( "Geometry.Arizona Eye.Lens" ) G9^`cTvv'8 GetCustomElement eID, entity t&?{+?p:
9 zP%s] >hH parID = FindFullName( "Geometry.Arizona Eye" ) !i~(h&z 17Cb{Q ' Delete any shift(s) in z HTT&T9] count = 0 :vb5J33U While GetOperationCount(eID)>count 6!"wiM"] GetOperation eID, count, op o& FOp' If op.Type="ShiftZ" Then "H[K3 DeleteOperation eID,count yiQ ?p:DM count=count-1 @6yc^DAA End If ZI!: count=count+1 T,/rC{ Wend (T#$0RFq Cjr]l! 'Set new shift in ;,[0 bmL op.Type = "ShiftZ" B#S8j18M op.val1 = taq P M [_0b op.parent = parID 'G l~P><e AddOperation eID, op W+!UVUpW Print "Set aqueous humor thickness = " & taq-0.55 XqmB%g( ,~naKd.ZY '************************************************************************* 8xO 'Radius and conic constant of anterior lens 1 ;$XX#7o '************************************************************************* 9)1Ye eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ]##aAh-P4& GetConic eID, entity, curv, conic uVn"L:_ EcB
!bf SetConic eID, entity, 1/Rant, CCant d-_V*rYU Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant nUP, Yd ML905n u '************************************************************************* ~r.R|f]IQ 'Radius and conic constant of posterior lens &|Duc} t '************************************************************************* Jx.fDVJ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) !{.CGpS ] GetConic eID, entity, curv, conic Dm)B? H" P 0.cF]<m SetConic eID, entity, 1/Rpost, CCpost ^<OYW|q?\r Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost G^W0!u,@ '%rT]u3U '************************************************************************* 5U~KYy^v 'Lens thickness (Position of posterior lens surface) %42a>piev '************************************************************************* r&E gP |&= -Nm parID = FindFullName( "Geometry.Arizona Eye.Lens" ) tr<fii3< k)n
b<JW|r ' Delete any z-shift(s) ~-zTY&c_ count = 0 skcyLIb While GetOperationCount(eID)>count 2xLtJR4L GetOperation eID, count, op 2L](4Q[M If op.Type="ShiftZ" Then 5j`xSG DeleteOperation eID,count _U^[h ! count=count-1 \ZLi Y End If U*r54AyP count=count+1 031"D*W'i Wend eK:?~BI! q~R8<G%YK 'Set new z-shift ?@G s7' op.Type = "ShiftZ" Z0L($ op.val1 = tlens <==uK>pET op.parent = parID TWp w/osW AddOperation eID, op Czjb.c:a.Y Print "Set lens thickness = " & tlens TRm#H$ 4{uQ}ea '************************************************************************* @Ul3J )=m 'Lens index of refraction <YU?1y?V '************************************************************************* G JRl{Y eID = FindMaterial( "Lens" ) :8)Jnh\5 GetModelMaterial eID, mat ?wB_fDb} a* cWj}u mat.Nd = nlens .|O T#"LP SetModelMaterial eID, mat wb.yGfJ Print "Set lens index of refraction = " & nlens E#KZZ lbx eC!=4_lx) '************************************************************************* 64?HqO
6( 'Pupil diameter zo ?RFn '************************************************************************* 0*XsAz1,9 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) s>J5.Z7"'j E5^\]`9P 'Adjust pupil diameter (trimming volume inner hole) OvX&5Q5 MI`qzC*% SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" h< r(:.%!} /yG7!k]Eg ' Adjust pupil location to just in front of the lens y47N(;vy parID = FindFullName( "Geometry.Arizona Eye" ) ;A,X,f eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) *K|~]r(F? count = 0 3*h"B$g! While GetOperationCount(eID)>count <,)R`90_X6 GetOperation eID, count, op qk<jvha If op.Type="ShiftZ" Then K KB+o)*W DeleteOperation eID,count [q?RJmB] count=count-1 w#b@6d End If hBX*02p count=count+1 `>
%QCc\ Wend _;k<=ns(= op.Type = "ShiftZ" Ur])*# op.val1 = taq-0.01 kGV:=h op.parent = parID ?62Im^1/ AddOperation eID, op !.6n=r8d ;?/5Mr Print "Set pupil diameter = " & pupilDiam 5pJe`}O4 n2K1X!E$ 'Update AZ Eye subassembly Description ,\6Vb*G|E> eID = FindFullName( "Geometry.Arizona Eye" ) 'f6H#V*C
GetEntity eID, entity r84^/+"T entity.Description = "Accommodation = " & A & "D" BY~Tc5 SetEntity eID, entity Y%?S:&GH '[WL8,.Q Update lOt7ij(,L Print "DONE!" w0~%,S VM%g QOo< End Sub INA3^p'w BH0m[9nU; 如果屈光度是4,光瞳直径是4,则会输出如下数据: T01Iu -P}A26qB Accommodation = 4 Diopters 1Vu#:6% Pupil Diameter = 4 mm xF[%R{Mn' Set aqueous humor thickness = 2.81 5GM-*Ak @ Set anterior lens radius = 10.4 and conic constant = -2.375869 uHKEt[PS$ Set posterior lens radius = -4.424557 and conic constant = -3.081019 @5^&&4>N Set lens thickness = 3.927 9O 'j+?(`@ Set lens index of refraction = 1.42672 #s{^fUN6 Set pupil diameter = 4 ,ucRQ&P DONE! G[>NP#P inaO{ny y n<C]
6H QQ:2987619807 ["D!IqI:
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