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简介 \EW<;xq :N64FR# 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。 KZGy&u
>` Y+ !z]S/x 模型 1"f)\FPGe 3gs!ojG 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。 xTf|u RX?y}BDo0 Table 1. AZ眼睛模型的定义 vbEO pYCS 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. =XFyEt _&e$?hY 光源 nd~O*-uYg 7f>~P_ 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。 *AJYSa,z "P a y2 kK/([! 图1. 光源和提示信息使用 ?,w9e| 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。 T\w{&3ONm QC6:ZxP 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)W:@,* d~#:t~
$, 图2. 字母F光源的设定方法光 *K;s*-|U `X%Qt~ 图3. 字母F在视网膜上位置点列图 L~E|c/ 视网膜的散射 _*++xF1 ou=33}uO 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 6cXZ3;a ZoR6f\2M D[dI_|59a 图4. 视网膜朗伯散射设定 m1Xc3=Y 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 h^'+y1 T
3<2ds !md1~g$rN 图5. 视网膜重点采样规格设定 $S/EIN c 脚本 1*?L>@Wdy ),XDY_9K 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: BHt9$$Z| `JcWH_[ 图6. 用户对话框的创建与编辑 (BGflb 图7. 用户对话框编辑器 <Aqo['] 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。 MH/bJtNq 余下的脚本计算与屈光度有关的所有参数。 $l_\9J913 X*t2h3"} 分析 mD7kOOMY
lBLL45%BIN 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 bMGXx>x ~z'Y(qG 图7. 字母F在视网膜上颜色分析 \m#{{SGm 脚本代码 m8Rt>DY S3^(L Option Explicit 'Remove this to enable non-dimensioned variables to be used. *iJ>@vew >[S\NAE> Dim entity As T_ENTITY :@~mN7O* Dim op As T_OPERATION Qn}M Dim mat As T_MODELMATERIAL 814cCrr,o Dim A As Double #9t3 <H[ Dim pupilDiam As Double VjJ}q*/3e Dim eID As Long EzU3'x Dim parID As Long %*OQH?pyx} Dim count As Integer -'T^gEd)c Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Z6#(83G4 Dim tlens As Double, nlens As Double a1z*Z/!5 Dim curv As Double, conic As Double 8aTo
TA7JA Dim ok As Long "Ug+#;}p$ ,6aF~p;wI| Sub Main wZt2%+$6m x{S2 '用户输入对话框 "
f.9u Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7GRPPh<4 TextBox 220,21,40,21,.TextBox1 'default: 0 d(C5i8d Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 '^(qlCI
OKButton 40,91,90,21 ]{18-= CancelButton 190,91,90,21 x5b .^75p$ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 3*N0oc^m TextBox 220,49,40,21,.TextBox2 'default: 4 (#nB90E{* End Dialog W!JEl|] Dim dlg As UserDialog Lc0=5]D @_
Tq>tOr& ok = Dialog (dlg) 0qL.Rnt n@J>,K_B If ok=0 Then 'cancel button was pressed ,3W,M=j) Print "Execution cancelled." j:U6q,f] End xXCsJ9] End If .@psW0T% EPU3Jban
'Assign accommodation and pupil diameter & use defaults if field left empty \lK ` If dlg.TextBox1 = "" Then gdS@NUM A = 0 'Default accommodation yeA]j[ # Else ut.tf \c A = CDbl(dlg.TextBox1) [X ]XH End If l_pf9!z YwZ]J If dlg.TextBox2 = "" Then ~-'-<- pupilDiam = 4 'Default pupil diameter 4jC7>mE Else uCc5) pupilDiam = CDbl(dlg.TextBox2) oo|Nu+ End If
czH# ~ Px&)kEQ Print " " fzUG1|$e Print "Accommodation = " & A & " Diopters" NMESGNa)z Print "Pupil Diameter = " & pupilDiam & " mm" eQ<GNvm luJNdA:t& ' Calculate new parameters with accommodation G-'CjiMu taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness @#yl_r% 63kZ#5g(Dw Rant = 12.0 - 0.4*A 'Radius of anterior lens S7j U:CLJ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens MJU*Sq !{vZvy" Rpost = -5.224557 + 0.2*A 'Radius of posterior lens 1z_1Hl CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens U5[r&Y
D @>+`1C tlens = 3.767 + 0.04*A 'Lens thickness ysFp$!9Ux l7U<]i GL nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction =.qPjp_Qd TWdhl9Ot 'Adjust parameters to account for accommodation zm#%]p80f <DhuY/o '************************************************************************* cCcJOhk|d 'Aqueous thickness (Position of Lens) (&M,rW~Qxs '************************************************************************* l@`n4U.Gwl eID = FindFullName( "Geometry.Arizona Eye.Lens" ) B?ipo,2~{ GetCustomElement eID, entity '
?a d (O/W`qo parID = FindFullName( "Geometry.Arizona Eye" ) vd/ BO YD#L@:&gv ' Delete any shift(s) in z q NUd "%S count = 0 seb/rxb While GetOperationCount(eID)>count \mqrDaB GetOperation eID, count, op t-Ble If op.Type="ShiftZ" Then 6n
H'NNS:J DeleteOperation eID,count 3&R1C>JS ] count=count-1 Nx!7sE*b$1 End If ~;uU{TT count=count+1 X$eR RSW Wend CIz_v.&: df/7u}>9 'Set new shift in rd,!-w5 op.Type = "ShiftZ" HC"yC;_ op.val1 = taq >RrG&Wv59 op.parent = parID xPJ@!ks9 AddOperation eID, op Wr+1e1[ Print "Set aqueous humor thickness = " & taq-0.55 uJa.]J~L= ;aH3{TS '************************************************************************* =FQH5iSd 'Radius and conic constant of anterior lens xu@xP5GB^ '************************************************************************* ?y,KN}s_ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ktM7L{Nz GetConic eID, entity, curv, conic #;h>
x fsWPU]\) SetConic eID, entity, 1/Rant, CCant 3bHB$n Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant hJ?PV@xy 67U6`9d '************************************************************************* ;8b!T
-K 'Radius and conic constant of posterior lens hLT?aQLx '************************************************************************* O2/_$i[F eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ~6{U^3 GetConic eID, entity, curv, conic }/jWa|)f /&l4 sF1 SetConic eID, entity, 1/Rpost, CCpost )ib$*dmUP Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost }4?z<. V ak{XLzn '************************************************************************* #Vy:6O 'Lens thickness (Position of posterior lens surface) fM"&=X '************************************************************************* eKRE1DK !PgwFJ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) <VhD>4f{] ),2|TlQ ' Delete any z-shift(s) {D8yqO A} count = 0 N9~'\O$'7 While GetOperationCount(eID)>count bd2QQ1[1vh GetOperation eID, count, op *]c~[&x5& If op.Type="ShiftZ" Then SQ<{X/5 DeleteOperation eID,count K1p. { count=count-1 Z7k ku:9 End If Lzx2An@R count=count+1 s%G%s,d Wend s0DT1s& 9xeg,#1 'Set new z-shift 8YQ7XB op.Type = "ShiftZ" 9)uJ\NMy op.val1 = tlens GtKSA#oYZB op.parent = parID cI-@nV AddOperation eID, op 5>hXqNjP2 Print "Set lens thickness = " & tlens {:=]J4] B &3sV+ '************************************************************************* T/:6Z 'Lens index of refraction NHe[,nIV '************************************************************************* a'O-0]g, eID = FindMaterial( "Lens" ) 0qW"b`9R GetModelMaterial eID, mat arvKJmD dV
/Es mat.Nd = nlens V;hO1xfR3& SetModelMaterial eID, mat N$u: ! Print "Set lens index of refraction = " & nlens fh`}~ aQ D'#,%4P,e\ '************************************************************************* t_+owiF)M 'Pupil diameter 9U3 .=J '************************************************************************* f/"IC;<~t> eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) -?-yeJP2 iu2O/l#r 'Adjust pupil diameter (trimming volume inner hole) .vd*~U" ]l`V#Rd SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" +^%)QH>9 )|W6Z ' Adjust pupil location to just in front of the lens U|aEyMU parID = FindFullName( "Geometry.Arizona Eye" ) 'Z)#Sz Y eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) H|/"'t
OZ count = 0 /v.<h*hxWy While GetOperationCount(eID)>count V6B[eV$D GetOperation eID, count, op a%`L+b5-$ If op.Type="ShiftZ" Then ! vuun | DeleteOperation eID,count fS p count=count-1 ""IPaNHQ End If ;@O8y\@ count=count+1
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Wend ]ZH6
.@| op.Type = "ShiftZ" ,rOh*ebF op.val1 = taq-0.01 l~[
K.p& op.parent = parID W{1l?Wo AddOperation eID, op =%|f-x ~*`wRiUhis Print "Set pupil diameter = " & pupilDiam #TcX5 AdbTI#eY 'Update AZ Eye subassembly Description 3ouo4tf$H. eID = FindFullName( "Geometry.Arizona Eye" ) Swgvj(y;!A GetEntity eID, entity @c}Gw;e entity.Description = "Accommodation = " & A & "D" ZgmK~iJ SetEntity eID, entity Q |hBGH9:B b#n Update Z%
]LZ/O8 Print "DONE!" {mLv?"M] %VE FruM End Sub lB7/oa1]> 3@* ~>H 如果屈光度是4,光瞳直径是4,则会输出如下数据: b,47
EJ} Sg13Dp@x Accommodation = 4 Diopters
&a6-+r Pupil Diameter = 4 mm nYO$ |/e Set aqueous humor thickness = 2.81 Fxn=+Xgg Set anterior lens radius = 10.4 and conic constant = -2.375869 pP%+@; Set posterior lens radius = -4.424557 and conic constant = -3.081019 5f75r Set lens thickness = 3.927 rEWuWv$ Set lens index of refraction = 1.42672 I*pFX0+ Set pupil diameter = 4 u3DFgl3-7 DONE! [hqat'Vj, ebLt:gGo 4$4Tx9C QQ:2987619807 Psm9hP :m
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