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简介 _+z5~6> ]DcQ8D 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。 Dg]( ?^ (~t/8!7N 模型 s UX%{|T_ G&FA~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。 \yeo-uN8 F6 ?4E"d Table 1. AZ眼睛模型的定义 S`ms[^-q* 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. GY9CU=- 'Dl31w%: 光源 67zCil w+<`> 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。 871taL= D&KD5_Sw *G|w#-\.c 图1. 光源和提示信息使用 e-vwve 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。 4f+R}Ee7 9Tbi_6[ 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。 \
UCOe 6{/HNEI*1 图2. 字母F光源的设定方法光 rap`[O|l= "0al"? 图3. 字母F在视网膜上位置点列图 P~Cx#`#(V 视网膜的散射 Q)}_S@v|% 9Yg=4>#$ 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。 3LKL,z 83io@*D uH'n.d"WG 图4. 视网膜朗伯散射设定 at_~b Ox6X 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。 XI#1) O=c^Ak 7;H!F!K] 图5. 视网膜重点采样规格设定 ,U9gg-.Lp 脚本 Q9v
OY8 |fYr*8rH 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: %hcn|-"F =?Y%w%2 图6. 用户对话框的创建与编辑 </,RS5ukn 图7. 用户对话框编辑器 E3X6-J| 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。 ^,`;x 余下的脚本计算与屈光度有关的所有参数。 FM\yf]' 59eq"08 分析 )@"iWQ3K (<RZZ{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。
%W!C ]F:5-[V# 图7. 字母F在视网膜上颜色分析 ~@8r-[ 脚本代码 t#pF.!9= ,'~8{,h5 Option Explicit 'Remove this to enable non-dimensioned variables to be used. C(( 7 Er; @nOyD Dim entity As T_ENTITY tBSHMz Dim op As T_OPERATION y_bb//IAG Dim mat As T_MODELMATERIAL {<f_,Nlc Dim A As Double # fvt:iE Dim pupilDiam As Double *`
}Rt Dim eID As Long N5$IVz} Dim parID As Long {Vy2uow0 Dim count As Integer Gt9(@USK Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ~y@,d Dim tlens As Double, nlens As Double !?t#QDo Dim curv As Double, conic As Double bDh,r!I Dim ok As Long e
C\;n f=0U&~ Sub Main Eg&oAY.U KjK.Sv{N '用户输入对话框 \4;}S&` k Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 )TNAgTmqK TextBox 220,21,40,21,.TextBox1 'default: 0 $]eU'!2) Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 u,]?_bK) OKButton 40,91,90,21 2)O-EAn CancelButton 190,91,90,21 ySyA!Z Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Oj6PmUK4 TextBox 220,49,40,21,.TextBox2 'default: 4 yht|0mZV End Dialog yb)!jLnH Dim dlg As UserDialog oqu; D'8 6I,^4U ok = Dialog (dlg) fQZ,kl y7)s0g>%H If ok=0 Then 'cancel button was pressed rGPFPsMQ] Print "Execution cancelled." 1A>>#M=A End s d-5AE End If +&t`"lRl& GEJEhwO;H 'Assign accommodation and pupil diameter & use defaults if field left empty >lZ9Y{Y4v If dlg.TextBox1 = "" Then @9yY`\"ed A = 0 'Default accommodation p#['CqP8 Else Bismd21F6= A = CDbl(dlg.TextBox1) zT;F4_p3G- End If pDW4DF:`( ,MH9e! If dlg.TextBox2 = "" Then 6pyLb3[e pupilDiam = 4 'Default pupil diameter !3]}3jZ. Else |7
.WP; 1 pupilDiam = CDbl(dlg.TextBox2) ,yZvT7 End If KW&5&~)2 XJ\j0 Print " " \EP<r Print "Accommodation = " & A & " Diopters" 51:NL[[6 Print "Pupil Diameter = " & pupilDiam & " mm" \\\%pBT7]\ {5<3./5O ' Calculate new parameters with accommodation } v#Tm taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness sA(
e Tyc`U& Rant = 12.0 - 0.4*A 'Radius of anterior lens &<Gs@UX~w CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 8Ja't8 6rBXC <Z Rpost = -5.224557 + 0.2*A 'Radius of posterior lens (]*otVJ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens u ##.t e -sZ_<GH tlens = 3.767 + 0.04*A 'Lens thickness @@&([f &y164xn'h nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 9eA2v{!S 2m$\]\kCUv 'Adjust parameters to account for accommodation zUw=e}?: Vn4y^_H '************************************************************************* W{z7h[?5, 'Aqueous thickness (Position of Lens) lwY2zX&%)/ '************************************************************************* ^o`;C\ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) I-=H;6w7 GetCustomElement eID, entity "YUh4uZ~P .fZ*N/ parID = FindFullName( "Geometry.Arizona Eye" ) =3~u.iq$ #!a}ZhIt ' Delete any shift(s) in z VR/*h% count = 0 }ioHSkCD While GetOperationCount(eID)>count h[%t7qo= GetOperation eID, count, op ;@I4[4ph} If op.Type="ShiftZ" Then I2U/\ DeleteOperation eID,count z?9vbx count=count-1 jJ(()EJ End If {w,g~ew
` count=count+1 /hNZ7\|P Wend ENmfbJ4d~ Sqt'} 'Set new shift in rKK{*%n op.Type = "ShiftZ" B~[}E]WEK op.val1 = taq 1Wz -Z op.parent = parID Rds_Cd C AddOperation eID, op 0N" VOEvG Print "Set aqueous humor thickness = " & taq-0.55 nPAVrDg
O 9_~[ '************************************************************************* >= G{.H 'Radius and conic constant of anterior lens -d|Q|zF^x '************************************************************************* X4- _l$j eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) d[cqs9=\ GetConic eID, entity, curv, conic %fv;C O.ce"5Y^ SetConic eID, entity, 1/Rant, CCant C(RZ09,.S Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant @raw8w\Zj+ st|;]q9? '************************************************************************* |oYqkP| 'Radius and conic constant of posterior lens e@Cv')]B '************************************************************************* _8-iO.T+2 eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) S 54N GetConic eID, entity, curv, conic LF2@qv w D k|Xxr SetConic eID, entity, 1/Rpost, CCpost V>8)1)dF Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Y,?!" fV 6$YCf '************************************************************************* LjE@[@d 'Lens thickness (Position of posterior lens surface) e 58 '************************************************************************* {iz,iv/U u]D>O$_ s parID = FindFullName( "Geometry.Arizona Eye.Lens" ) \R m2c8Z2 v#HaZT]u ' Delete any z-shift(s) Awip qDAu count = 0 H[cHF While GetOperationCount(eID)>count M;14s*g GetOperation eID, count, op mKsTA; If op.Type="ShiftZ" Then a!_vd B DeleteOperation eID,count "*ot:;I count=count-1 *%{ End If HQpw2bdy count=count+1 Qh3V[br Wend `|Ll R(i2TAaaU 'Set new z-shift 0<,Q7onDD: op.Type = "ShiftZ" pPC_ub op.val1 = tlens 't3@dz_dG op.parent = parID =nq9)4o AddOperation eID, op
R%(ww Print "Set lens thickness = " & tlens n@hf{hA[a _fVC\18T '************************************************************************* S%+$ 'Lens index of refraction 01/? '************************************************************************* %XpYiW#AK eID = FindMaterial( "Lens" ) (Wj2%*NT GetModelMaterial eID, mat N@o Ng}D&: 8Wa&&YTB mat.Nd = nlens GN7\p) SetModelMaterial eID, mat vlHE\%{ Print "Set lens index of refraction = " & nlens s+=JT+g !7m
) QNV '************************************************************************* /7bIE!Cn 'Pupil diameter [P,/J$v^~ '************************************************************************* kpe7\nd=> eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) fnZa IV=H #4?(A[]>H 'Adjust pupil diameter (trimming volume inner hole) eX+FtN 75O-%9lFF SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" |o:[*2- _$W</8< ' Adjust pupil location to just in front of the lens 3\=iB&Gf| parID = FindFullName( "Geometry.Arizona Eye" ) <])w@QOA# eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) AADvk_R count = 0 2'R&K While GetOperationCount(eID)>count "8bxb GetOperation eID, count, op ]h
Dy] If op.Type="ShiftZ" Then c:a5pd7T DeleteOperation eID,count Esc*+}ck count=count-1 6Y#V;/gK!5 End If Is87
9_Z count=count+1 ~7N>tjB Wend D^E+#a 1 op.Type = "ShiftZ" ,O9rL :? op.val1 = taq-0.01 LPg1 G+e op.parent = parID jslfq@5v AddOperation eID, op 5`ma#_zk|f QQd%V#M? Print "Set pupil diameter = " & pupilDiam [n53eC aS7[s6 'Update AZ Eye subassembly Description L@ b8, eID = FindFullName( "Geometry.Arizona Eye" ) .] S{T GetEntity eID, entity bt$+l[U^J entity.Description = "Accommodation = " & A & "D" STC'j1U SetEntity eID, entity _` %z rKP;T"?; Update l
)hg!( Print "DONE!" w% Ug9 n..9F$a End Sub ..ig jc#UF %H-(-v^T* 如果屈光度是4,光瞳直径是4,则会输出如下数据: ~(TS>ck@ Qi_De
'@ Accommodation = 4 Diopters b,?@_*qv+ Pupil Diameter = 4 mm H:~41f[ Set aqueous humor thickness = 2.81 (I bT5 Set anterior lens radius = 10.4 and conic constant = -2.375869 uW.)(l Set posterior lens radius = -4.424557 and conic constant = -3.081019 ^,Sl^ 9K Set lens thickness = 3.927 =xs{Ov= Set lens index of refraction = 1.42672 a;Nj'M~U Set pupil diameter = 4 ,{@,dw`lUz DONE! a\wpJ|3{=T
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