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简介 pgz:F#>
K;<NBnH 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。 D rF iX8h2l 模型 '2Q.~6 u#a%( 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。 5 `4}A%@& 6)=](VmNL` Table 1. AZ眼睛模型的定义 avu*>SB 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. XPHQAo[(s %+AS0 JhB 光源 8BYIxHHz 2gQY8h8 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。 8Zcol$XS' wFK:Dp_^ i_|9<7a
图1. 光源和提示信息使用 c&E*KfOG 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 c8^+^.=pX B,~f " 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 Zw;$(=" dIoF ~8V 图2. 字母F光源的设定方法光 Gkdm7 SV mV6#!_" 图3. 字母F在视网膜上位置点列图 HBt|}uZ?6i 视网膜的散射 $Nj'OJSj% 3c01uObTL 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 j4E H2v Xtuhc dzu[ ??|d=4g\ 图4. 视网膜朗伯散射设定 ]*bAF^8i 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 mDb-=[W5 MC4284A5 9uA,
+ 图5. 视网膜重点采样规格设定 [:AB$l* 脚本 6!4';2Q >}-~rZ 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: \w{@u)h WuBmdjZ 图6. 用户对话框的创建与编辑 PYdIP\<V 图7. 用户对话框编辑器 J)-T:.i|0 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。 L@7Qs6G2u 余下的脚本计算与屈光度有关的所有参数。 ]WTf< W< *,E; 分析 4st~3,lR$ 9uuta4&uI 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 RxlszyE /uK)rG
F 图7. 字母F在视网膜上颜色分析 Gh2#-~|cB 脚本代码 ;l$9gD>R =hJfL}&O3 Option Explicit 'Remove this to enable non-dimensioned variables to be used. VT'0DQ!NIq 4O$ mR Dim entity As T_ENTITY Z+Kv+GmqH Dim op As T_OPERATION $8jaapNm@ Dim mat As T_MODELMATERIAL a`DWpc~ Dim A As Double P;j&kuW|zL Dim pupilDiam As Double u@AI&[Z Dim eID As Long N2ni3M5v Dim parID As Long -<8B, Dim count As Integer 3}08RU7[! Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double /rqqC(1 Dim tlens As Double, nlens As Double 3.(.*> Dim curv As Double, conic As Double E^7C
_JP Dim ok As Long 7 n\mj\ Y
[4vRzc Sub Main :aHcPc: `tX@8| '用户输入对话框 `GPQ((la Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 UMT\Q6p TextBox 220,21,40,21,.TextBox1 'default: 0 Cy`26[E$S Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 :*#rRQ>t OKButton 40,91,90,21 +e U`H[iu CancelButton 190,91,90,21 +yGY785b Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 kmIoJH5 TextBox 220,49,40,21,.TextBox2 'default: 4 R|-6o)$ End Dialog !IN@i:m Dim dlg As UserDialog oBb?"2 ~9 t
@;WgIp(& ok = Dialog (dlg) " <qEXX UIQQ\,3 If ok=0 Then 'cancel button was pressed +a #lofhv Print "Execution cancelled." ooY\t + End tzPC/? End If Rl1$?l6Rf e$HQuA~Q; 'Assign accommodation and pupil diameter & use defaults if field left empty 4b]_
#7Qm If dlg.TextBox1 = "" Then }X.>4\B5 A = 0 'Default accommodation `N$!s7M Else #^Ys{ A = CDbl(dlg.TextBox1) >jv\Qh End If "@4ghot t h!v/s=8c If dlg.TextBox2 = "" Then *_PPrx5 pupilDiam = 4 'Default pupil diameter 3&$Nd Else \9'!"-i pupilDiam = CDbl(dlg.TextBox2) -xz|ayn End If un6cD$cHr W+.{4K Print " " IJ0#iA. T Print "Accommodation = " & A & " Diopters" `YU=~xQ Print "Pupil Diameter = " & pupilDiam & " mm" wrabyRjK
fSjs?zd` ' Calculate new parameters with accommodation U~wjR"=' taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness :\mRtVH +ZclGchw Rant = 12.0 - 0.4*A 'Radius of anterior lens La9r CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens n08;
< zFywC-my@ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens '#A:.P CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens IfMpY;ow= x~EKGoz3 tlens = 3.767 + 0.04*A 'Lens thickness gJh}CrU- Pr`s0J%m nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction g,=^'D }"n7~| 'Adjust parameters to account for accommodation v77fQ0w3 'PpZ/ry$ '************************************************************************* N 'i,> 'Aqueous thickness (Position of Lens) '#W_boN '************************************************************************* wd wp9 r eID = FindFullName( "Geometry.Arizona Eye.Lens" ) lufeieW GetCustomElement eID, entity ;%WdvnW tFiR!f) parID = FindFullName( "Geometry.Arizona Eye" ) 1Cv#nhmp T9?54r ' Delete any shift(s) in z IC/Q count = 0 /&(1JqzlB While GetOperationCount(eID)>count &{ ZSE^ GetOperation eID, count, op pv&^D,H, If op.Type="ShiftZ" Then &\^rQi/tf DeleteOperation eID,count 3fp> 4;ym' count=count-1 HxIoA End If 3cixQzb}u count=count+1 nvt$F%+ Wend Xu#:Fe}: /zT`Y=1 'Set new shift in @1bH}QS op.Type = "ShiftZ" 8_a3'o%5 op.val1 = taq JDA]t&D!v op.parent = parID 2m" _z AddOperation eID, op W#{la`#Bu Print "Set aqueous humor thickness = " & taq-0.55 4,~tl~FD )xt4Wk/ '************************************************************************* EnJ!mr 'Radius and conic constant of anterior lens CT p!di| '************************************************************************* p411 `]Zf eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) +s~.A_7) GetConic eID, entity, curv, conic 3D_"yZ
ah+j!e SetConic eID, entity, 1/Rant, CCant LuS+_|]x Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant XYAmJ h e&V# # '************************************************************************* ,Sg33N? 'Radius and conic constant of posterior lens X#ZgS!Mn '************************************************************************* 3=-
})X; eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ARWZ; GX GetConic eID, entity, curv, conic 6Dst;: 8r^ ~0nm SetConic eID, entity, 1/Rpost, CCpost +EkW>$ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost !` 26\@1 B+"g2Y '************************************************************************* pbLGe' 'Lens thickness (Position of posterior lens surface) "U8S81' '************************************************************************* ; )llt
G &{z<kmc$6 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Uc&iZFid2K ;GOz>pg ' Delete any z-shift(s) &z@~B&O count = 0 iM5vrz`n While GetOperationCount(eID)>count *||d\peQ GetOperation eID, count, op KOSQQf
o If op.Type="ShiftZ" Then _| zBUrN DeleteOperation eID,count SaO3zz@L count=count-1 Lgi[u"Du End If CS@&^SEj count=count+1 XUSvhr$| Wend A5nO= F,T~\gO5, 'Set new z-shift Cq\I''~8 op.Type = "ShiftZ" !p[`IWZ op.val1 = tlens ROdK8*jL op.parent = parID A-uB\ L AddOperation eID, op n7l%gA* Print "Set lens thickness = " & tlens v(O=IUa 8l>CR#%@C '*************************************************************************
4["&O=:d 'Lens index of refraction Vmi{X b]< '************************************************************************* X?o(
b/F- eID = FindMaterial( "Lens" ) !'0S0a8 GetModelMaterial eID, mat Xy7Z38G D7?C mat.Nd = nlens qp~gP SetModelMaterial eID, mat k;Fh4Hv Print "Set lens index of refraction = " & nlens X_?97iXjx S$[k Q|Am '************************************************************************* b,<9 'Pupil diameter MGt]' } '************************************************************************* F
L=,YP eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) yL1CZ_ ~cqryr9
'Adjust pupil diameter (trimming volume inner hole) -]S.<8<$ 8;" *6vHZ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" '2nqHX
D Q8qz*v]{ ' Adjust pupil location to just in front of the lens :&w{\-0{ parID = FindFullName( "Geometry.Arizona Eye" ) '&yeQ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) =?
:@ count = 0 ga0'zo9K While GetOperationCount(eID)>count vkcRm`. GetOperation eID, count, op n(vDytrj; If op.Type="ShiftZ" Then \2kPq>hu
DeleteOperation eID,count B'weok count=count-1 !GK$[9 End If r\M9_s8 count=count+1 .EP6oKA Wend " I+p op.Type = "ShiftZ" =f 7r69I" op.val1 = taq-0.01 G|u3UhyB op.parent = parID -1r2 K AddOperation eID, op '0t-]NAc b ,^*mx= Print "Set pupil diameter = " & pupilDiam x?yD=Mq_ ,,<PVTd 'Update AZ Eye subassembly Description ^TFs;|.. eID = FindFullName( "Geometry.Arizona Eye" ) =o=1"o[ GetEntity eID, entity HOi C entity.Description = "Accommodation = " & A & "D" [=%YV# O SetEntity eID, entity =
+Xc4a BavO\{J#|0 Update \nvAa_, Print "DONE!" rOfK~g,X W WG /k17 End Sub q6q1\YB Y}STF 如果屈光度是4,光瞳直径是4,则会输出如下数据: f4('gl9 8im@4A+n` Accommodation = 4 Diopters wts:65~ Pupil Diameter = 4 mm 8v92Ng7 Set aqueous humor thickness = 2.81 ~H /2R Set anterior lens radius = 10.4 and conic constant = -2.375869 j 6)Y Set posterior lens radius = -4.424557 and conic constant = -3.081019 !~iGu\y Set lens thickness = 3.927 >_ \<E!j Set lens index of refraction = 1.42672 "$^0%- Set pupil diameter = 4 Ug"rJMZG DONE! (9RslvKL gn1(4
o -$a>f4] QQ:2987619807 i+vsp@d
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