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简介 fBv:
TC% `+>K)5hrR 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。 kLU-4W5t $60`Hh 4/ 模型 VfP\)Rl 9|v%bO 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。 uN>5Eh&=Pf vZ.<OD4 Table 1. AZ眼睛模型的定义 ACZK]~Y'N* 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. 0_MtmmL. 5$cjCjY 光源 '\xE56v)F RwOOe7mv 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 \x]\W#C 5s`r&2 w =+ >>l0=_v 图1. 光源和提示信息使用 xSSEDfq 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 v}d)uPl}; ctjQBWE 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 `M 'tuQ
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6ST(=X_C 图2. 字母F光源的设定方法光 U"+W)rUd x|G
:;{"+6 图3. 字母F在视网膜上位置点列图 *L$_80 视网膜的散射 72yJv=G f86Z #% 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。 .8!\6=iJB } e+`Kxy l!&ik9m 图4. 视网膜朗伯散射设定 ]W`?0VwF 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。 A8Fe@$<#8 Yv@n$W`: &r4|WM/ec 图5. 视网膜重点采样规格设定 #u8#<
,w 脚本 yGAFQ|+ Y68A+
B. 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: Xo/H+[;X vO~Tx 图6. 用户对话框的创建与编辑 (=Kv1
H aD 图7. 用户对话框编辑器 -eyF9++` 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。 &0-oi Y 余下的脚本计算与屈光度有关的所有参数。 "NGfT:HV >V27#L2:J 分析 /W BmR R !U m9ceK 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 6uFw+Ya#
83t/\x,Q 图7. 字母F在视网膜上颜色分析 /o 'lGvw 脚本代码 aK@
Y) Ju' *URT-+' Option Explicit 'Remove this to enable non-dimensioned variables to be used. m:[I$b6AY WGUw`sc\ Dim entity As T_ENTITY 9*ZlNZ
Dim op As T_OPERATION 9,`i[Dzp Dim mat As T_MODELMATERIAL a{hc{ Dim A As Double R)Arr77 Dim pupilDiam As Double /3~L#jS Dim eID As Long ~i>DF`w$ Dim parID As Long prz COw Dim count As Integer x"NQatdq Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double U{M3QOF Dim tlens As Double, nlens As Double ?{B5gaU9F Dim curv As Double, conic As Double nM2<u[{gF Dim ok As Long NGl
8*Af 52tc|j6~# Sub Main ~ a`[p\ 0r1GGEW`s '用户输入对话框 __.MS6"N Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 C:5-h(# TextBox 220,21,40,21,.TextBox1 'default: 0 qfE0J;e Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 u*)/e9C OKButton 40,91,90,21 i:0v6d CancelButton 190,91,90,21 K8X7IE Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 J~]@#=,v TextBox 220,49,40,21,.TextBox2 'default: 4 =N\; ?eF( End Dialog L4m Vk Dim dlg As UserDialog xS/W}-dPv -GPJ,S V> ok = Dialog (dlg) iiIns.V :QGo
-,6- If ok=0 Then 'cancel button was pressed +?o!"SJ Print "Execution cancelled." e!*]y&W End ?0qD(cfx< End If [-_{3qq<e EOrui:.B) 'Assign accommodation and pupil diameter & use defaults if field left empty 'QT~o-U If dlg.TextBox1 = "" Then Y|fD)zG_ A = 0 'Default accommodation K!&W} _@l Else BA2"GJvfIA A = CDbl(dlg.TextBox1) HdqB B End If {k_\1t(/ &`l\Q\_[@ If dlg.TextBox2 = "" Then [:cD pupilDiam = 4 'Default pupil diameter bt) C+|i Else :
"|/ pupilDiam = CDbl(dlg.TextBox2) *O~y6|U? End If <.n,:ir OA&'T*)-A6 Print " " F~
5,-atDM Print "Accommodation = " & A & " Diopters" )-)rL@s. Print "Pupil Diameter = " & pupilDiam & " mm" x:MwM? 5:IDl1f5 ' Calculate new parameters with accommodation F%|P#CaB taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness *zrGrk:l 8>eYM Rant = 12.0 - 0.4*A 'Radius of anterior lens HfVHjF) CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens @Z
==B%` mufGv%U2 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens -a)1L'R CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens
)Ri! ]{6/6jl tlens = 3.767 + 0.04*A 'Lens thickness f%o[eW# 6U*CR=4
nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 'cpm 4mT Q`9c/vPU 'Adjust parameters to account for accommodation MRt"#CO =m2_:&@0x '************************************************************************* sWr;%<K 'Aqueous thickness (Position of Lens) (NLw#)? '************************************************************************* `&D#P% eID = FindFullName( "Geometry.Arizona Eye.Lens" ) x!_5/ GetCustomElement eID, entity E,6|-V;? kFp^?+WI%H parID = FindFullName( "Geometry.Arizona Eye" ) >SDQ@63E? w/*G!o-< ' Delete any shift(s) in z T$D(Y`zdn count = 0 }9"''Z While GetOperationCount(eID)>count $\NqD:fgb GetOperation eID, count, op S=r0tao,!v If op.Type="ShiftZ" Then -n 9&W DeleteOperation eID,count x8@ 4lxj count=count-1 T-a>k.}y End If ?A|JKOst] count=count+1 00 x- Wend T5u71C_wmt wI|h9q1U 'Set new shift in t<` As6} op.Type = "ShiftZ" "KP]3EyPc op.val1 = taq <4Gy~? op.parent = parID RdPk1?}K AddOperation eID, op l%EvXdZuOy Print "Set aqueous humor thickness = " & taq-0.55 GFdbwn5B
d78 [(; '************************************************************************* _l7_!Il_ 'Radius and conic constant of anterior lens >*{k~Y-G '************************************************************************* 'd$RNqe eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ~-zIB=TyK GetConic eID, entity, curv, conic W\zZ&*8$ P'qBqx[ SetConic eID, entity, 1/Rant, CCant jV}8VK*`+ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant r"2lcNE Mm@G{J\\ '************************************************************************* m:h6J''<Z* 'Radius and conic constant of posterior lens BFW b0;+ '************************************************************************* ,kJ7c;:i eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) a|z-EKV GetConic eID, entity, curv, conic PN 93.G(W @KL&vm(F$ SetConic eID, entity, 1/Rpost, CCpost v%qOW)]. Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost y-3'qq'E jXeE]A" '************************************************************************* + kMj|()>\ 'Lens thickness (Position of posterior lens surface) )=Z;H"_ '************************************************************************* 7zH2dqrj G"?7 Z&+ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) C^"zU>W_ T$lV+[7 ' Delete any z-shift(s) ikc1,o count = 0 N-upNuv While GetOperationCount(eID)>count gFp3=s0~ GetOperation eID, count, op Yc]V+NxxQ If op.Type="ShiftZ" Then <ZSXOh,' DeleteOperation eID,count lq:q0>vyI count=count-1 3cghg._ End If @~$d4K
y< count=count+1 ] x)>q Wend R/v|ZvI M3-lL;!n 'Set new z-shift ;F258/J op.Type = "ShiftZ" &AJ bx op.val1 = tlens our
^J8 op.parent = parID QWOPCoUet AddOperation eID, op 3tf_\E+mIi Print "Set lens thickness = " & tlens u"qu!EY2 cIw X sx
'************************************************************************* sR9$=91` 'Lens index of refraction CBd%}il '************************************************************************* )<V!lsUx'- eID = FindMaterial( "Lens" ) {%3WHGr%L GetModelMaterial eID, mat Vx<{cHQQ p"hO6b%V mat.Nd = nlens s8,YQ5- SetModelMaterial eID, mat &5-1Cd E Print "Set lens index of refraction = " & nlens 73X*|g[O n0 l|7:Mk '************************************************************************* 5.5kH$;> 'Pupil diameter Hes!uy '************************************************************************* Ll=G+cw6P eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) .F7?}8>Z t}R!i-D|HB 'Adjust pupil diameter (trimming volume inner hole) # QwX|x{ z~h?"' SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ~}b0zL G06;x ' Adjust pupil location to just in front of the lens j:cu;6| parID = FindFullName( "Geometry.Arizona Eye" ) >;Hx<FKxP eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) }SWfP5D@ count = 0 A>gZl)c While GetOperationCount(eID)>count .fzyA5@l GetOperation eID, count, op F8?,}5j If op.Type="ShiftZ" Then =Lkn
DeleteOperation eID,count (m2%7f.I count=count-1 IB#
ua: End If ^4`x:6m count=count+1 TI3xt-/ Wend M%_*vD op.Type = "ShiftZ" /UunWZ u% op.val1 = taq-0.01 9!=4}:+ op.parent = parID A]m*~Vj] AddOperation eID, op N>3{!K>/Y: (DvPdOT+3 Print "Set pupil diameter = " & pupilDiam vx?KenO} PFpFqJ)Cs" 'Update AZ Eye subassembly Description %6(\Ki6I eID = FindFullName( "Geometry.Arizona Eye" ) {BlTLAKm GetEntity eID, entity <y?+xZM]#| entity.Description = "Accommodation = " & A & "D" \{<ml n SetEntity eID, entity
&5K3AL ]7<$1ta Update ?H8w;Csq- Print "DONE!" (QIU 3EN }BS
EK<W End Sub e-`9-U%6 $DH/ 如果屈光度是4,光瞳直径是4,则会输出如下数据: VJ-t#q" eHUyV@ Accommodation = 4 Diopters s@~3L Pupil Diameter = 4 mm "oxUKT Set aqueous humor thickness = 2.81 \
&|xMw[ Set anterior lens radius = 10.4 and conic constant = -2.375869 f
] *w1 Set posterior lens radius = -4.424557 and conic constant = -3.081019 b [HnhAI Set lens thickness = 3.927 vULDKJNHX Set lens index of refraction = 1.42672 l1zPL3"u_^ Set pupil diameter = 4 /
P@P1l|I DONE! xb[yy}>"L
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