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简介 @Y*ONnl 5#+!|S[PK 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。 swuW6p yWu80C8q 模型 EP7L5GZ-a ZVE q{x1Zc 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。 SZH,I&8 T<~NB5&f Table 1. AZ眼睛模型的定义 I(ds]E
;_E 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. $+zev$f erYpeq. 光源 )Z0pU\ n_sCZ6uXEQ 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。 k61Ot3 Ix !O&_6s s$J0^8Q~i 图1. 光源和提示信息使用 PMjqcdBzm 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。 TIlcdpwXf f$9V_j-K+ 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 K[PIw}V$?: py9(z`} 图2. 字母F光源的设定方法光 ;OTD1= Z.<OtsQN 图3. 字母F在视网膜上位置点列图 h djv/ 视网膜的散射 3,e^;{w #rqLuqw 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。 i1ur>4Ns dGf{d7 D zn&NLsA 图4. 视网膜朗伯散射设定 6",1JH,;p 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。 {e0cc1Up} Jj_E/c" 6<.Ma7)lA 图5. 视网膜重点采样规格设定 4 StiYfae 脚本 ,95Nj h _/MHi-]/. 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: `] ;*k2 ^tIs57! 图6. 用户对话框的创建与编辑 Vq2d+
,fb 图7. 用户对话框编辑器 6:i{_YX(.S 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。 xq-R5(k
余下的脚本计算与屈光度有关的所有参数。 fmY=SqQG- nJY#d; 分析 ihBlP\C BV"7Wp; 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 (S* T{OgO %fnL 图7. 字母F在视网膜上颜色分析 IQf:aX 脚本代码 i]a 5cn M%5qx,JQY Option Explicit 'Remove this to enable non-dimensioned variables to be used. &]3_ .C ?<bByxa Dim entity As T_ENTITY TZT i:\nS Dim op As T_OPERATION b=horvs/! Dim mat As T_MODELMATERIAL Hly2{hokq Dim A As Double ='a[(C&Y Dim pupilDiam As Double yt}Ve6 m Dim eID As Long L,M=ogdb Dim parID As Long pca `nN! Dim count As Integer Vb az#I Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ZH;VEX Dim tlens As Double, nlens As Double sxinA8 Dim curv As Double, conic As Double zs:OHEZw Dim ok As Long ET;YAa* O{SP4|0JV Sub Main .(^KA{ 1p=^I'# '用户输入对话框 .w/w]
Eq Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 3&:Us|} TextBox 220,21,40,21,.TextBox1 'default: 0 n*{aN}auJ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 q}p&<k OKButton 40,91,90,21 A-x; ai] CancelButton 190,91,90,21 | s%--W Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 S#_g/3w TextBox 220,49,40,21,.TextBox2 'default: 4 ad1 I2 End Dialog m1H_kJ Dim dlg As UserDialog L|pMq!@J #N9^C@ ok = Dialog (dlg) W{:^P0l o|O730"2F If ok=0 Then 'cancel button was pressed _rt+OzZ*L Print "Execution cancelled." zrVw l\& End
2%P{fJbwd End If r0t4\d_&
KK$t3e) 'Assign accommodation and pupil diameter & use defaults if field left empty AGu#*,K If dlg.TextBox1 = "" Then $X<O\Kna A = 0 'Default accommodation "`HkAW4GZa Else 'Dw+k;RH A = CDbl(dlg.TextBox1) qM78s>\-h End If (37dD! @i2"+_}* If dlg.TextBox2 = "" Then kT)[<`p pupilDiam = 4 'Default pupil diameter NV\t%/ ? Else l7#5.%A pupilDiam = CDbl(dlg.TextBox2) 1oU/gm$7\q End If xe?!UCUb@ Rr#Zcs!G Print " " 0x BO5[w,Y Print "Accommodation = " & A & " Diopters" %PA#x36 Print "Pupil Diameter = " & pupilDiam & " mm" !2L?8oP-z X.}i9a
6 ' Calculate new parameters with accommodation ^f6pw! taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 1.Kun !w E,IeW {6s Rant = 12.0 - 0.4*A 'Radius of anterior lens `%S 35x9 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 3
UUOB. NzS(,F Rpost = -5.224557 + 0.2*A 'Radius of posterior lens oP>+2.i CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens (~S=DFsP #<h//< tlens = 3.767 + 0.04*A 'Lens thickness x -;tV=E} +/O3L=QyJ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 9u[^9tL+D |ppG*ee 'Adjust parameters to account for accommodation .cks){\ 1N\/61+aA '************************************************************************* U]Y</>xGI
'Aqueous thickness (Position of Lens) *G rYB6MT '************************************************************************* $?P 5A E eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 7:/gO~gI GetCustomElement eID, entity |k.%e4 CcCcuxtR parID = FindFullName( "Geometry.Arizona Eye" ) Ymvd3> _ #hMS?F| ' Delete any shift(s) in z + /+> : count = 0 p~Wy`g- While GetOperationCount(eID)>count 2WO5Af% GetOperation eID, count, op lKdd3W"o If op.Type="ShiftZ" Then +H{TV#+r DeleteOperation eID,count 4og/y0n,l" count=count-1 XrUc` End If d#8 n<NM count=count+1 >U\1*F,Om, Wend ^sVr#T :+ZLKm 'Set new shift in l+nT$IPF op.Type = "ShiftZ" VW`SqUl op.val1 = taq _DouVv> op.parent = parID RCqd2$K"J+ AddOperation eID, op J?#Xy9dz Print "Set aqueous humor thickness = " & taq-0.55 5Z@0XI y5{Vx{V"Q '************************************************************************* AZ.$g?3w 'Radius and conic constant of anterior lens 2A=q{7s '************************************************************************* 3N[Rrxe2 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) *fCmZ$U:{ GetConic eID, entity, curv, conic Gf=3h4 O!G!Gq& SetConic eID, entity, 1/Rant, CCant (b;Kl1Ql] Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant @}\i`H1s xyD2<?dGUb '************************************************************************* %?hvN 'Radius and conic constant of posterior lens H)k V8wU '************************************************************************* $GR
rT C! eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ID:
tTltcc GetConic eID, entity, curv, conic +OI <0 w,i?e\5 SetConic eID, entity, 1/Rpost, CCpost $\+x7"pI Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost s*Nb=v.e9 !,|-{": '************************************************************************* YP
Qix 'Lens thickness (Position of posterior lens surface) 1}_4C0h\' '************************************************************************* W{%X1::q$ h% eGtd$n parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ,!40\"A 1xEFMHjy ' Delete any z-shift(s) p#%*z~ui count = 0 OdbXna While GetOperationCount(eID)>count |}? H$d GetOperation eID, count, op %M3L<2 If op.Type="ShiftZ" Then &,P; 7 R DeleteOperation eID,count .07"I7 count=count-1 = GyABK End If G@KDRv count=count+1 G^sx/H76J Wend C*}PL Uc,MZV4 'Set new z-shift k;B[wEW@ op.Type = "ShiftZ" ;W T<] op.val1 = tlens qSGM6kb op.parent = parID Pr:\zI AddOperation eID, op hVz] wKP Print "Set lens thickness = " & tlens H:|.e)$i 0l3[?YtXc '************************************************************************* %AN,cE* 'Lens index of refraction iZLy#5(St '************************************************************************* t`="2$NO eID = FindMaterial( "Lens" ) P!"{-m' GetModelMaterial eID, mat A%2B3@1'q gnGh ) mat.Nd = nlens X}xf_3N
" SetModelMaterial eID, mat 5E]iv^q% Print "Set lens index of refraction = " & nlens h% KEg667 *u-$$@|y '************************************************************************* zYP6m3n 'Pupil diameter $KQ q~| '************************************************************************* `KtP;nG eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) \WBO(,]V Dw/vXyZ 'Adjust pupil diameter (trimming volume inner hole) ?=LT
^Zp` Wsgp#W+ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Zf1
uK(6X pSb tm74 ' Adjust pupil location to just in front of the lens x|yJCs> parID = FindFullName( "Geometry.Arizona Eye" ) < =~=IZ) eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) j^5YFUwsQg count = 0 eKy!Pai While GetOperationCount(eID)>count z{|0W!nHJ GetOperation eID, count, op B~E">}=! If op.Type="ShiftZ" Then }S8aR:' DeleteOperation eID,count \gA<yz-;N count=count-1 L}CU" End If 8R%<~fq r count=count+1 0TaI"/ai Wend %g:'6%26 op.Type = "ShiftZ" dOKp:|9G op.val1 = taq-0.01 KJV8y"^=Q op.parent = parID IA<>+NS AddOperation eID, op Lu{/"&) \I:27:iAL Print "Set pupil diameter = " & pupilDiam ^8EW/$k g5y`XFY 'Update AZ Eye subassembly Description pbEWnx_ eID = FindFullName( "Geometry.Arizona Eye" ) :o'|%JE GetEntity eID, entity Ea&NJ]& g entity.Description = "Accommodation = " & A & "D" 6`7tTn?n SetEntity eID, entity .CnZMw{' Ovc9x\N Update 9DJ&J{2W Print "DONE!" *1Bq>h: z]r'8Jc End Sub *~g*J^R} -Uy)=]Zae 如果屈光度是4,光瞳直径是4,则会输出如下数据: \wD/TLS} n<bU' n Accommodation = 4 Diopters bS;_xDXd Pupil Diameter = 4 mm %-yzU/`JF Set aqueous humor thickness = 2.81 *ma
w`1 Set anterior lens radius = 10.4 and conic constant = -2.375869 ]}PXN1( Set posterior lens radius = -4.424557 and conic constant = -3.081019 X5YOxMq Set lens thickness = 3.927 >zqaV@T Set lens index of refraction = 1.42672 4P[MkMoC Set pupil diameter = 4 W M` 3QJb DONE! sBB[u'h!
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