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简介 I0=_=aZO( y!e]bvN 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。 OI R5QH @nxo Bc !P 模型 i jI/z5 3JoY- 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。 bP,<^zA|X \?:L>-&h8 Table 1. AZ眼睛模型的定义 w7nt $L5 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. `h}eP[jA ?@V R%z 光源 e_BG%+;G, Iw1Y?Qia 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 ^}3^|jF ,m=F
H?5 *2X6;~ 图1. 光源和提示信息使用 TyxIlI4" 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 HN47/]"* WSThhI 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 4.6$m #kg`rrFr 图2. 字母F光源的设定方法光 St=nf\P&F ^({)t 图3. 字母F在视网膜上位置点列图 a"~o'W7 视网膜的散射 T.q2tC[bR >nSsbhAe 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。 KaIKb=4L| UuG%5 ZC a+h$u 图4. 视网膜朗伯散射设定 wNONh`b 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。 &K[*vyD B6XO&I1c @xG&K{j 图5. 视网膜重点采样规格设定 :}Jx 脚本 |9@,ri\'Rg PSrx! 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: _ %s#Cb W?7l-k=S 图6. 用户对话框的创建与编辑 "EW8ll7r 图7. 用户对话框编辑器 ~W'DEpq_ 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。 %zavSm" 余下的脚本计算与屈光度有关的所有参数。 $+gQnI3w s8j |>R|k 分析 `At.$3B n}p G&&;q 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 x"r0<RK yCX5
5: 图7. 字母F在视网膜上颜色分析 J,a&"eOZ 脚本代码 <y 4(!z" WR+j?Fcf Option Explicit 'Remove this to enable non-dimensioned variables to be used. u09Tlqh0 3 6#w>6g4V~R Dim entity As T_ENTITY zcpL[@B Dim op As T_OPERATION , 3R=8 Dim mat As T_MODELMATERIAL ; :e7Z^\/k Dim A As Double wG3L+[, Dim pupilDiam As Double E4#{&sRT Dim eID As Long aRd~T6I Dim parID As Long = XZU9df Dim count As Integer glAS$< Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double [i.@q}c~E Dim tlens As Double, nlens As Double #%,X),%- Dim curv As Double, conic As Double 1N5
E Dim ok As Long gt4GN`-k K5>3 Sub Main O[X*F2LC4 dT`nR" '用户输入对话框 ZbRRDXk! Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Za.}bR6?Y TextBox 220,21,40,21,.TextBox1 'default: 0 cIug~ x> Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 5-dt0I@< OKButton 40,91,90,21 =dm9+ff CancelButton 190,91,90,21 WC_.j^sW Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 pj'gTQ),0 TextBox 220,49,40,21,.TextBox2 'default: 4 ]#~J[uk End Dialog /Qgb t Dim dlg As UserDialog 8 Ku9;VEk !~^2Mu(X ok = Dialog (dlg) cGot0' mB z/Lb1ND8 If ok=0 Then 'cancel button was pressed +U
fw Print "Execution cancelled." >=k7#av End Q`CuZkP( End If Vjs2Yenx k|fM9E 'Assign accommodation and pupil diameter & use defaults if field left empty u5CSx'h] If dlg.TextBox1 = "" Then F6{g{
B A = 0 'Default accommodation ;NP-tA) Else <I,4Kc! A = CDbl(dlg.TextBox1) f,YORJ End If LP3#f{U W3i<Unq
If dlg.TextBox2 = "" Then 288mP]a(v_ pupilDiam = 4 'Default pupil diameter &Vj@){ Else CKw-HgXG pupilDiam = CDbl(dlg.TextBox2) 97c0bgI!+ End If qw+7.h#V l@Lk+-[D Print " " W83d$4\d Print "Accommodation = " & A & " Diopters" DLwlA!z Print "Pupil Diameter = " & pupilDiam & " mm" t!D'ZLw Q}#4Qz~n ' Calculate new parameters with accommodation tbQY&TO1 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness GEPWb[Oa [_N1
.}e Rant = 12.0 - 0.4*A 'Radius of anterior lens F'~r?D CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens kn#?+Q ?MDo. z3 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens d /jx8(0 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ?M90K)&g{ Uahh|>s tlens = 3.767 + 0.04*A 'Lens thickness >A )Sl'
\^1^|a" nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction zkt~[-jm} \ZnA%hC 'Adjust parameters to account for accommodation 51:5rN(_ TjpyU:R,&| '************************************************************************* $#^3>u 'Aqueous thickness (Position of Lens) G-CL \G\n '************************************************************************* .J.}}"+U eID = FindFullName( "Geometry.Arizona Eye.Lens" ) gd[muR ~ GetCustomElement eID, entity >$kFYb>~q H
Qj,0#J) parID = FindFullName( "Geometry.Arizona Eye" ) ->#wDL!6 2tU3p<[ ' Delete any shift(s) in z 'q}Ud10c count = 0 yCz"~c While GetOperationCount(eID)>count mI2Gs)SO GetOperation eID, count, op ZW M:Wj192 If op.Type="ShiftZ" Then h5{//0 y DeleteOperation eID,count P]"@3Z&w count=count-1 D[W`
q#W End If *b;)7lj0h count=count+1 *Y1s4FXu2 Wend 2k!uk6 ~vP_c(8f 'Set new shift in C,;?`3bH@ op.Type = "ShiftZ" D~inR3(} op.val1 = taq Gb2|e.z op.parent = parID aT/2rMKPF AddOperation eID, op zt2#K Print "Set aqueous humor thickness = " & taq-0.55 DN9x<%/- W'Gh:73'} '************************************************************************* @3eMvbI 'Radius and conic constant of anterior lens W}F~vx. '************************************************************************* [6@bsXiw eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) eDo4>k"5 GetConic eID, entity, curv, conic *K>2B99TXu F_u?.6e] SetConic eID, entity, 1/Rant, CCant bSM|" Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant W)`>'X` |yNyk7~ '************************************************************************* ; 8VZsh 'Radius and conic constant of posterior lens 7<kr|- '************************************************************************* !}A`6z eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) gy1kb,MO GetConic eID, entity, curv, conic 0"-H34M<D UB] tKn SetConic eID, entity, 1/Rpost, CCpost y;0Zk~R$ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 'bv(T2d~~
zCq6k7u '************************************************************************* 'Q'-7z-6 'Lens thickness (Position of posterior lens surface) W9Us I '************************************************************************* vU/sQt8 wV-N\5!r%H parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 2AqcabI9 3b?-83a ' Delete any z-shift(s) mGz'%?zj count = 0 WbFCj0 While GetOperationCount(eID)>count v&sp;%I6= GetOperation eID, count, op 4&]NC2I If op.Type="ShiftZ" Then YC{7;=Pf DeleteOperation eID,count C _W]3 count=count-1 j%vxCs> End If 48gpXcc@| count=count+1 U ;4;> Wend "{{@N4^ 7Aw <: 'Set new z-shift _#<l -R` op.Type = "ShiftZ" p<VW;1bt5 op.val1 = tlens <!u(_Bxw/ op.parent = parID B^1jd!m AddOperation eID, op 8Z@O%\1x6 Print "Set lens thickness = " & tlens Rlr[uU_ 3,+UsB% '************************************************************************* +SRM?av 'Lens index of refraction 4[0.M '************************************************************************* sx9[#6~{Y eID = FindMaterial( "Lens" ) j{5oXW GetModelMaterial eID, mat jaTCRn3|< a0FU[*q mat.Nd = nlens OUHd@up@n SetModelMaterial eID, mat GwD"j] Print "Set lens index of refraction = " & nlens ^w
RD| _i"[m(ABj1 '************************************************************************* {.,y v>% 'Pupil diameter =66,$~g{ '************************************************************************* )o_$AbPt eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) piUfvw Zfr?(y+3 'Adjust pupil diameter (trimming volume inner hole) "%t !+E>nr /Hc0~D4|x SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Lj3q?>D*^6 3TD!3p8 ' Adjust pupil location to just in front of the lens :n?}G0y parID = FindFullName( "Geometry.Arizona Eye" ) '$OLU[(Y eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Y0OVzp9 b count = 0 )ULxB'Dm While GetOperationCount(eID)>count PDh1*bf{u GetOperation eID, count, op PJcz] < If op.Type="ShiftZ" Then rNHV DeleteOperation eID,count 20uR? /|@ count=count-1 =>h~<88#5 End If @l2AL9z$m> count=count+1 jr5x!@rb Wend =HvLuVc op.Type = "ShiftZ" _bq2h%G=8 op.val1 = taq-0.01 @*LESN>T@t op.parent = parID xZ"kJ'C4} AddOperation eID, op Q ?W6 }oTac Print "Set pupil diameter = " & pupilDiam ">RDa<H] 'uOp?g' 7 'Update AZ Eye subassembly Description D#9W [6 eID = FindFullName( "Geometry.Arizona Eye" ) 0 g(hY: GetEntity eID, entity 4a~9?}V: entity.Description = "Accommodation = " & A & "D" QPa&kl SetEntity eID, entity 7"
cgj# <<![3&p# Update <tTn$<b Print "DONE!" mE]W#?
=M9Od7\J End Sub :U;ZBs3 .~
W^P>t 如果屈光度是4,光瞳直径是4,则会输出如下数据: WaWx5Fx+
5B(r[Ni
b Accommodation = 4 Diopters !$5U\"M Pupil Diameter = 4 mm #/1,Cv yj Set aqueous humor thickness = 2.81 hpym!G Set anterior lens radius = 10.4 and conic constant = -2.375869 SIRZ_lt$r Set posterior lens radius = -4.424557 and conic constant = -3.081019 CLD*\)QD\ Set lens thickness = 3.927 C31SXQ Set lens index of refraction = 1.42672 A]vQ1*pnk Set pupil diameter = 4 oZ~M`yOz. DONE! jKu"Vi|j> *Mqg_} 0Y ODM<$Yo:d QQ:2987619807 'bg%9}
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