-
UID:317649
-
- 注册时间2020-06-19
- 最后登录2025-11-19
- 在线时间1888小时
-
-
访问TA的空间加好友用道具
|
简介 Bg}l$?S x~=Mn%Ew0 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 Qq'e#nI@ 1OV] W
f 模型 YRMe<upo tEt46]{ 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 nw_s: .PV(MV Table 1. AZ眼睛模型的定义 qOIVuzi* 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. Uq~b4 X$ 3D^cPkX 光源 5 D=r7 ;WAa4r> 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。 Q @[gj:w zszmG^W{ }9glr]= 图1. 光源和提示信息使用 jo3(\Bq 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。 ZH*h1?\X sVGQSJJ5 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。 sPVE_n \hn$-'=4 图2. 字母F光源的设定方法光 =:!>0~ XE&h&v=> 图3. 字母F在视网膜上位置点列图 1z0|uc
视网膜的散射 /DP0K
@% g*`xEb=' 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 5W$Jxuyqj i+pQ 7wx BO7XN; 图4. 视网膜朗伯散射设定 Z/!awf> 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。 tCm]1ZgRW ,p /{!BX ,LP^v'[V7 图5. 视网膜重点采样规格设定 _!!Fg%a5"R 脚本 &W c$VDC KV8<'g +2? 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: W-gu*iZ6& *A4eYHn@ 图6. 用户对话框的创建与编辑 X;2LK!x;y 图7. 用户对话框编辑器 /h{Rf,H 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 QleVW 余下的脚本计算与屈光度有关的所有参数。 e /1x/v' #ti%hm 分析 k{=dV <=D
a 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 7!h>
< sx GNEPb?+T 图7. 字母F在视网膜上颜色分析 3Pgokj
脚本代码 m(d|TwG{ ;<thEWH;Y Option Explicit 'Remove this to enable non-dimensioned variables to be used. wW/q#kc }S3 oX$ Dim entity As T_ENTITY F3]VSI6^E, Dim op As T_OPERATION 6/?onEL9_ Dim mat As T_MODELMATERIAL pT3icy!A= Dim A As Double 1r_V$o$ Dim pupilDiam As Double zx,9x*g Dim eID As Long 'TuaP`]< Dim parID As Long A0U9,M Dim count As Integer Pr(@&:v: Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double )J0h\ky Dim tlens As Double, nlens As Double awvP;F?q| Dim curv As Double, conic As Double h_+ Dim ok As Long nxx/26{
E`V\/`5D Sub Main %[s%H)e) yN0`JI '用户输入对话框 Ej
5_d Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1
-{8K/! TextBox 220,21,40,21,.TextBox1 'default: 0 XPD1HN!,LT Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 EApbaS}Up OKButton 40,91,90,21 {j;` wN CancelButton 190,91,90,21 K1BBCe Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 '21gUYm TextBox 220,49,40,21,.TextBox2 'default: 4 S4[#[w`= End Dialog k4hk*
0Jq Dim dlg As UserDialog 3Jt#
Mp (_<,Oj#*S ok = Dialog (dlg) FMI1[|:; '
|B3@9< If ok=0 Then 'cancel button was pressed s.Bb@Jq Print "Execution cancelled." vNrn]v=|}7 End i}P{{kMJ End If %Nvw`H `]XI Q\ * 'Assign accommodation and pupil diameter & use defaults if field left empty X<Z(,B If dlg.TextBox1 = "" Then fByf~iv, A = 0 'Default accommodation X?wZ7*'1 Else l
v hJ A = CDbl(dlg.TextBox1) s</qT6@ End If z F.@rXl M}# DX=NZc If dlg.TextBox2 = "" Then ^r(My} pupilDiam = 4 'Default pupil diameter _8
|X820 Else kaB4[u pupilDiam = CDbl(dlg.TextBox2) X~c?C-fV End If 3Cc#{X-+ :S_]!'H Print " " %dg[ho Print "Accommodation = " & A & " Diopters" 25-h5$s Print "Pupil Diameter = " & pupilDiam & " mm"
w:QO@ matna ' Calculate new parameters with accommodation -X~|jF taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ~'KqiUY RK &>!^ Rant = 12.0 - 0.4*A 'Radius of anterior lens /*,_\ ; CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens .6azUD4 @`:X,]{ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens o!KDeY CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens L*[3rqER ->{-yh]jv tlens = 3.767 + 0.04*A 'Lens thickness @x+2b0 b @r/~Y]0Ye5 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction M?%x=q\< uHSnZ"# 'Adjust parameters to account for accommodation ?X6}+ -Z$u[L [c '************************************************************************* ]kTxVe 'Aqueous thickness (Position of Lens) QO(F%&v++ '************************************************************************* A8*zB=C eID = FindFullName( "Geometry.Arizona Eye.Lens" ) &4S2fWx GetCustomElement eID, entity `>)Ge](oN :vG0 l\ parID = FindFullName( "Geometry.Arizona Eye" ) D\-\U
E/ {DQ%fneN4 ' Delete any shift(s) in z k-=LD count = 0 ~8u *sy While GetOperationCount(eID)>count z77>W}d GetOperation eID, count, op .E}lAd.Mn If op.Type="ShiftZ" Then Gb\PubJ DeleteOperation eID,count qz>R"pj0g count=count-1 .Lna\Bv End If /~ {`!30 count=count+1 ~BmA!BZV` Wend M
lR~`B}m {XmCG%%L 'Set new shift in 71{jedT op.Type = "ShiftZ" |50sGJE( op.val1 = taq !EhKg)y= op.parent = parID c Pf_B= AddOperation eID, op 4v hz`1 Print "Set aqueous humor thickness = " & taq-0.55 Pa{ src+z# '************************************************************************* >9dD7FH 'Radius and conic constant of anterior lens `IUn{I '************************************************************************* Jq'8" eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 1d<Uwb> GetConic eID, entity, curv, conic 4>>=TJ!M d/&>
`[i SetConic eID, entity, 1/Rant, CCant '6 F-% Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant i9DD)Y< }Pg}"fb^ '************************************************************************* l\*9rs:! 'Radius and conic constant of posterior lens aLGq<6Ja '************************************************************************* o6k#neB>=. eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ~(QfVpRnV= GetConic eID, entity, curv, conic jRS{7rx%MH T+F]hv' SetConic eID, entity, 1/Rpost, CCpost vyIH<@@p7 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 2+
cs^M3 wgS,U}/i '************************************************************************* M}V!;o<t^ 'Lens thickness (Position of posterior lens surface) 5dj@N3ZX7; '************************************************************************* ?1SsF>| y(p_Unm parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ^Fco'nlM Y#ZgrziYM ' Delete any z-shift(s) Zp9.
~&4o- count = 0 %'=*utOxy While GetOperationCount(eID)>count i.vH$ GetOperation eID, count, op S=(O6+U If op.Type="ShiftZ" Then 00QJ596 DeleteOperation eID,count P9
<U+\z count=count-1 \xkKgI/ End If bx8](cT_ count=count+1 TJO$r6& Wend h^yqrDyJ pa[/6( 'Set new z-shift 27e!KG[& op.Type = "ShiftZ" N7+L@CC6T op.val1 = tlens _5jT}I<k op.parent = parID _F;v3|`D@< AddOperation eID, op 0Ds3wNz Print "Set lens thickness = " & tlens ) CP Rqh5FzB> '************************************************************************* KhHFJo[8sf 'Lens index of refraction "La;$7ds '************************************************************************* "]+g5G eID = FindMaterial( "Lens" ) YA4 D?' GetModelMaterial eID, mat o8bd L< ;Y?MbD mat.Nd = nlens
}X&rJV SetModelMaterial eID, mat U#` e~d t< Print "Set lens index of refraction = " & nlens 'dLw8&T+W 0@
Y#P|QF '************************************************************************* @%]A,\ 'Pupil diameter m+TAaK '************************************************************************* 'r?ULft1 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) -zR<m \HfAKBT 'Adjust pupil diameter (trimming volume inner hole) Iux3f+H ')y2W1 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" FE~D:)Xj'? 6p9fq3~7Y ' Adjust pupil location to just in front of the lens &|/_"*uM parID = FindFullName( "Geometry.Arizona Eye" ) zR" cj eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ANM#Kx+ count = 0 1@F-t94I While GetOperationCount(eID)>count 6>a6;[ GetOperation eID, count, op BzzC| If op.Type="ShiftZ" Then VfX^iG r DeleteOperation eID,count 4<y count=count-1 =RQF::[h End If `^bP9X_a count=count+1 O$,Fga Wend )kpEcMlR op.Type = "ShiftZ" qO#3{kW op.val1 = taq-0.01 uE-(^u op.parent = parID )6OD@<r{ AddOperation eID, op u "[f\l S
/hx\TzC Print "Set pupil diameter = " & pupilDiam {M]_]L{&7 sdFHr4 'Update AZ Eye subassembly Description x< A-Ws{^V eID = FindFullName( "Geometry.Arizona Eye" ) uoS:-v}/Y~ GetEntity eID, entity +V3mF_s|z entity.Description = "Accommodation = " & A & "D" .H" ?&Mf SetEntity eID, entity o*cu-j3 (Xd8'-G$m Update aZOn01v;!& Print "DONE!" X?5{2ulrI Ar`+x5
End Sub A3jxjQ fF@w:;u 如果屈光度是4,光瞳直径是4,则会输出如下数据: (8duV i}-uK,^ Accommodation = 4 Diopters (jT)o,IW& Pupil Diameter = 4 mm 5 ~Wg=u<6 Set aqueous humor thickness = 2.81 uzYB`H< Set anterior lens radius = 10.4 and conic constant = -2.375869 sy: xA w Set posterior lens radius = -4.424557 and conic constant = -3.081019 nBh+UT} Set lens thickness = 3.927 Q_5l.M/9] Set lens index of refraction = 1.42672 z$~x 2< Set pupil diameter = 4 LOh2eZ"n DONE! <DF3!r '!HTE`Aj I'/3_AX QQ:2987619807 bJ~H
|