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简介 |Y-{)5/5} rY?]p Mp 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。 NUO#[7OK+x ys/U.e|)! 模型 kAV4V;ydh qjr:(x / 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。 Lm-f0\( Rb/|ae Table 1. AZ眼睛模型的定义 8SZZ_tS3r 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. ^;8dl.; Z= +Tw!wR> 光源 *x!j:/S`n i C)+5L#' 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。 ]F{F+r XY`{F.2h C.|.0^5 图1. 光源和提示信息使用 tZXq<k9 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。 "lVbla4b
:Bh7mF-1 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。 iFOa9!_0n R@df~ 图2. 字母F光源的设定方法光 ZGw6Bd_I lRANXM 图3. 字母F在视网膜上位置点列图 !U7}?i&H 视网膜的散射 9GX'+$R] Hg~8Td** 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。 aCRiW;+' @?n~v^ cy64xR BB 图4. 视网膜朗伯散射设定 x%yzhIRR 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。 $jg~a lyS`X 1rIL[(r4 图5. 视网膜重点采样规格设定 ^/ff)'.J 脚本 t`-
[ 7](aPm8 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: mIe 5{.m# z8dBfA<z 图6. 用户对话框的创建与编辑 C14"lB. 图7. 用户对话框编辑器 {^.q6,l 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。 8 \"A-+_Q 余下的脚本计算与屈光度有关的所有参数。 (j(hr'f % !>@m6JK 分析 e +Ikw1y"f |;(>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。 a"{b}UP j;<s!A#
图7. 字母F在视网膜上颜色分析 Ub{7 Xk
n 脚本代码 )GfL?'Z
6`@6k2] Option Explicit 'Remove this to enable non-dimensioned variables to be used. mKLWz1GZ v]'\]U^ Dim entity As T_ENTITY m f\tMik< Dim op As T_OPERATION k5|GN Y6a Dim mat As T_MODELMATERIAL qL?$u07<9' Dim A As Double gg.lajX Dim pupilDiam As Double BZa`:ah~x Dim eID As Long -bgj<4R$p Dim parID As Long ]*X z~Ox2 Dim count As Integer J^=Xy(3e Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ?@^gpVK{ Dim tlens As Double, nlens As Double :(K JLa] Dim curv As Double, conic As Double w!b;.l Dim ok As Long RNopx3 Us\Nmso
z Sub Main v\g1w&PN /&E]qc*-p '用户输入对话框 oT!i}TW?o Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 !TN)6e7`
TextBox 220,21,40,21,.TextBox1 'default: 0 Ekn3ODz, Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 "[sr0'g: OKButton 40,91,90,21 sVH
w\_F$ CancelButton 190,91,90,21 6H!l>@a7v Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 6n\){dkZ~ TextBox 220,49,40,21,.TextBox2 'default: 4 F9>"1 End Dialog xS; tmc Dim dlg As UserDialog y~z&8XrH ^e]h\G ok = Dialog (dlg) ^SbxClUfw! ~"Su2{"8B If ok=0 Then 'cancel button was pressed E;YD5^B Print "Execution cancelled." wjTW{Bg~G End RSx{Gbd4X End If 4j(*%da FjW%M;H 'Assign accommodation and pupil diameter & use defaults if field left empty mln%Rd6u/ If dlg.TextBox1 = "" Then B}@CtVWFz A = 0 'Default accommodation R ^"*ut Else #+
{%>f A = CDbl(dlg.TextBox1) Knp}88DR^j End If Q6p75$SVq YXg^t$ If dlg.TextBox2 = "" Then EL6<%~,V"I pupilDiam = 4 'Default pupil diameter #dFE}!"#` Else t1p[!53( pupilDiam = CDbl(dlg.TextBox2) 2gW+&5;4 End If id)J;!^;J D 77$aCt Print " " [7l5p(= Print "Accommodation = " & A & " Diopters" k;<F33v;Mh Print "Pupil Diameter = " & pupilDiam & " mm" ;+n25_9 ^Yo2 R ' Calculate new parameters with accommodation )o;n2T#O taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 6?-,@e a
fB?js6 Rant = 12.0 - 0.4*A 'Radius of anterior lens XcKyrh;i CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ,w,)n^ p+;x&h)[l Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ;(s.G-9S CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 3=_to7] kZQ$Iv+^( tlens = 3.767 + 0.04*A 'Lens thickness rUmnv%qTS ,%KMi-w]q, nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction R7Ns5s3X 9abn6S(XpJ 'Adjust parameters to account for accommodation _<jccQ XRn+6fn| '************************************************************************* nz`"f, 'Aqueous thickness (Position of Lens) Y|<1|wGG '************************************************************************* h=_h,?_ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 2'WdH1UrBc GetCustomElement eID, entity tp b(.`G wtQ (R4 parID = FindFullName( "Geometry.Arizona Eye" ) BgwZZ<B GEAVc9V ' Delete any shift(s) in z #Y>d@ count = 0 S4%MnT6Uy While GetOperationCount(eID)>count BtP*R,> GetOperation eID, count, op cKAZWON8;v If op.Type="ShiftZ" Then 9R|B 5. DeleteOperation eID,count 0.!Q4bhD count=count-1 (d-j/v*4 End If SFa^$w count=count+1 "Oy&6rrr Wend "#`c\JuR] 7@i2Mz/eV 'Set new shift in |y2cI,& op.Type = "ShiftZ" .w)T2( op.val1 = taq B'D4]EB op.parent = parID
\4&FW|mx AddOperation eID, op EB>rY Print "Set aqueous humor thickness = " & taq-0.55 %suXp,j fpvzx{2 '************************************************************************* |p+ xM 'Radius and conic constant of anterior lens ,_yf5 a '************************************************************************* Jx= v6==7 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) wB W]w GetConic eID, entity, curv, conic V~qlg1h \JEI+A PY* SetConic eID, entity, 1/Rant, CCant pi?U|&.1z Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant <S
M%M? mH09*
Z '************************************************************************* XWFuAE 'Radius and conic constant of posterior lens W>]=0u4 '************************************************************************* &:*|K xX eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) [KjL` GetConic eID, entity, curv, conic Oo95\Yf$N }!g^}BWWp SetConic eID, entity, 1/Rpost, CCpost eEkbD"Q Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost -* ;`~5 oGi{d5 '************************************************************************* @Y2&v956 'Lens thickness (Position of posterior lens surface) ni x1_Wo; '************************************************************************* \muC_9ke >P\/\xL= parID = FindFullName( "Geometry.Arizona Eye.Lens" ) EJ3R{^ 9}6^5f?| ' Delete any z-shift(s) .% EEly count = 0 t Sf` While GetOperationCount(eID)>count B%Spmx8 GetOperation eID, count, op (eAh8^) If op.Type="ShiftZ" Then gRdg3qvU DeleteOperation eID,count .4wp count=count-1 ROHr%'owgL End If Wc)f:]7 count=count+1 8o;9=.<<~u Wend nfMQ3KP .v:K`y;f\( 'Set new z-shift K
r&HT,>B op.Type = "ShiftZ" H A(e op.val1 = tlens X pd^^ op.parent = parID =1"8ua AddOperation eID, op Y-WYQ{ Print "Set lens thickness = " & tlens l`R/WC 0oi
=}lV '************************************************************************* xFY;aK 'Lens index of refraction A@0%7xm '************************************************************************* V/G'{ q eID = FindMaterial( "Lens" ) lS(?x|dO GetModelMaterial eID, mat }9xEA[@; DN@T4!
mat.Nd = nlens :d<;h:^_ SetModelMaterial eID, mat `MtPua\_ Print "Set lens index of refraction = " & nlens }X3SjNd q ToN$x^M
w '************************************************************************* 2|)3Ly9 'Pupil diameter Osdw\NNH~M '************************************************************************* aMFUJrXo eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) D`lTP(] y 5Qik{cWxBq 'Adjust pupil diameter (trimming volume inner hole) lc=C mq?5|` SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ~Cj55S+ 8eSIY17 ' Adjust pupil location to just in front of the lens gHC -Y 0_ parID = FindFullName( "Geometry.Arizona Eye" ) |Y!#` eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Fr)G
h> count = 0 MX?K3=j @> While GetOperationCount(eID)>count s45Y8!c GetOperation eID, count, op
P.RlozF5; If op.Type="ShiftZ" Then }xHoitOD DeleteOperation eID,count _{o=I?+] count=count-1 B8_w3;x End If *Ri?mEv
hF count=count+1 .Mw'P\GtM Wend p
IXBJk op.Type = "ShiftZ" 9LGJ -gL op.val1 = taq-0.01 k|,pj^ op.parent = parID OedL?4 AddOperation eID, op DA@YjebP' 85l 1 Print "Set pupil diameter = " & pupilDiam 4?X#d)L( AyKaazm]9 'Update AZ Eye subassembly Description Te~"\`omJ3 eID = FindFullName( "Geometry.Arizona Eye" ) {hX.R GetEntity eID, entity Pn5@7~ entity.Description = "Accommodation = " & A & "D" X|H%jdta SetEntity eID, entity gO?+:}! `/<KDd:_t Update d+%1q Print "DONE!" j[yGfDb 8f% @ End Sub SHPaSq'&N 'z2}qJJ) 如果屈光度是4,光瞳直径是4,则会输出如下数据: -3X#$k8 (j+C&*u Accommodation = 4 Diopters wYhWRgP Pupil Diameter = 4 mm *~fZ9EkD Set aqueous humor thickness = 2.81 %FQMB Set anterior lens radius = 10.4 and conic constant = -2.375869 >/EmC3?b! Set posterior lens radius = -4.424557 and conic constant = -3.081019 /g712\?M4 Set lens thickness = 3.927 'bkecC Set lens index of refraction = 1.42672 ,-t3gc1~X Set pupil diameter = 4 Y*O7lZuF% DONE! XZA3TZ
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