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简介 +uWDP. pL1Q7&&c0 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。 8zLY6@ <H1` 模型 fP
tm0.r i&njqK!wS 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。 -LDCBc" |py6pek| Table 1. AZ眼睛模型的定义 7"7rmZ 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. _LAS~x7, W"{v2x i 光源 Q9d`zR] >{eCh$L 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 }pk#!N bWl5(S` Z l$K,#P<) 图1. 光源和提示信息使用 I/VxZ8T 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。 Uie?9&3 Z3k(P 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。 }?cGf-c `c/*H29 图2. 字母F光源的设定方法光 6.5T/D*TT dC=)^( 图3. 字母F在视网膜上位置点列图 *5zrZ]^ 视网膜的散射 !zPG?q]3 Lb{e,JH 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。 2j(h+?N7k nd;fy$<J\ hlu:=<B 图4. 视网膜朗伯散射设定 pA{ 5V9 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 vA$o~?a]/ K =.%$A r1ws1 rr= 图5. 视网膜重点采样规格设定 TI9UXa:V\ 脚本 Auy_K?he] h8\
T 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: [Q\GxX. r ]W 图6. 用户对话框的创建与编辑 n~g)I& 图7. 用户对话框编辑器 8 #ndFpu 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 6"c1;P!4 余下的脚本计算与屈光度有关的所有参数。 t+,4Ya|Xj 5TBp'7 /s~ 分析 AtR?J"3E }SI GPVM 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ^QuiH' X7,PEA 图7. 字母F在视网膜上颜色分析 =%zLh<3v 脚本代码 >5R<;#8 "<}&GcJbz Option Explicit 'Remove this to enable non-dimensioned variables to be used. e]=!"nJ+ GDYFU*0 Dim entity As T_ENTITY +(uYwdcN Dim op As T_OPERATION )BfT7{WN Dim mat As T_MODELMATERIAL 3E
f1bhi Dim A As Double y=Mq(c:'UN Dim pupilDiam As Double ZVeaTK4_
t Dim eID As Long 64-#}3zL Dim parID As Long 9h/>QLx Dim count As Integer x8;`i$ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double q1E:l!2al Dim tlens As Double, nlens As Double H
_Va"yTO6 Dim curv As Double, conic As Double o]IjK Dim ok As Long OMwsbp& mDh1>>K'~ Sub Main bCZ gcN 2,aPr:] '用户输入对话框 RE.r4uOJg Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 #YDr%>j TextBox 220,21,40,21,.TextBox1 'default: 0 *m%]zj0bo Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 TO2c"7td OKButton 40,91,90,21 ~2EH OO{ CancelButton 190,91,90,21 &C>/L; Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 DF6c| TextBox 220,49,40,21,.TextBox2 'default: 4 OT^%3:zg End Dialog $D31Q[p=+ Dim dlg As UserDialog fQLt=Lrp y8VpFa ok = Dialog (dlg) <o2r~E0r3 >;z<j$;F< If ok=0 Then 'cancel button was pressed iYnEwAoN; Print "Execution cancelled." KJE[+R H+z End ]pEV}@7 End If 3D9!M- yT{8d.Rh 'Assign accommodation and pupil diameter & use defaults if field left empty {brMqE>P# If dlg.TextBox1 = "" Then 7u\*_mrv A = 0 'Default accommodation ~)? Else LJX-AO.4 A = CDbl(dlg.TextBox1) `si#aU End If *&AfR8x_z ylKmj]A If dlg.TextBox2 = "" Then /v095H@ pupilDiam = 4 'Default pupil diameter 4/X/>Y1 Else Nr2 C@FU:0 pupilDiam = CDbl(dlg.TextBox2) :V)lbn\ End If E{HY!L[ ]a2W e` Print " " xoB},Xl$D Print "Accommodation = " & A & " Diopters" #S%Q*k<hw Print "Pupil Diameter = " & pupilDiam & " mm" (wc03,K^ Ld^GV ' Calculate new parameters with accommodation crO@?m1 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness _md=Q$9!m PNW \*;j Rant = 12.0 - 0.4*A 'Radius of anterior lens 4`#F^2r! CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens D71;&G]0 @v\*AYr'M Rpost = -5.224557 + 0.2*A 'Radius of posterior lens k7tYa;C CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens T^Ab!O Cw5%\K$= tlens = 3.767 + 0.04*A 'Lens thickness ,mPnQ? (BX83) nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction )hwV`2>l 3cj3u4y 'Adjust parameters to account for accommodation $ _8g8r} B*!WrB:s '************************************************************************* ~_9"3,~o5 'Aqueous thickness (Position of Lens) 93[DAs '************************************************************************* #6Xs.*b5C eID = FindFullName( "Geometry.Arizona Eye.Lens" ) PLM _#+R> GetCustomElement eID, entity HxK$ 4I` R`F,aIJ] parID = FindFullName( "Geometry.Arizona Eye" ) ]E3U
J!! TEUY3z[g ' Delete any shift(s) in z 1Xy]D count = 0 sqx`">R While GetOperationCount(eID)>count
2?Ye*- GetOperation eID, count, op 5>9Y|UU If op.Type="ShiftZ" Then DN4#H` DeleteOperation eID,count ,n2i@?NHZ count=count-1 0;,IKXK6X End If dQy>Nmfy count=count+1 66snC{gU Wend s!/TU{8J x0a.!
'Set new shift in r%Rs0)$yj op.Type = "ShiftZ" {|9}+
@5Q1 op.val1 = taq }~Q"s2 op.parent = parID y0v]N AddOperation eID, op lC97_T Print "Set aqueous humor thickness = " & taq-0.55 *cWmS\h| a:SQ16_? '************************************************************************* l2b{u
GE 'Radius and conic constant of anterior lens PXP`ZLF '************************************************************************* `n!viW|tB eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) [%HIbw J GetConic eID, entity, curv, conic 7#;vG>] ~;-9X| SetConic eID, entity, 1/Rant, CCant fbZibcQ%k Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant QzGV.Mt2 vUQFQ '************************************************************************* (7lBID4 'Radius and conic constant of posterior lens b syq* '************************************************************************* } :iBx eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 2k7bK6=nm GetConic eID, entity, curv, conic _BnTv$.P 9-*NW0 SetConic eID, entity, 1/Rpost, CCpost YHxbDf dA Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ]pTvMom$6 Hr;h4J '************************************************************************* S_J :&9L 'Lens thickness (Position of posterior lens surface) z?8~[h{i% '************************************************************************* ScnY3&rc (J:dK=O@Z parID = FindFullName( "Geometry.Arizona Eye.Lens" ) f<[jwhCWV jigs6# ' Delete any z-shift(s) OVoO6F] count = 0 HgJb4Fi While GetOperationCount(eID)>count !7H6i#g* GetOperation eID, count, op O^{1RV3:,T If op.Type="ShiftZ" Then V7CoZnz DeleteOperation eID,count (VHND%7P count=count-1 Uv?'m&_ End If x49!{} count=count+1 "#^MUQ!a Wend a,'Cyv"> 90 {tI X 'Set new z-shift T)u4S[
& op.Type = "ShiftZ" :x>T}C<Y op.val1 = tlens {'3D1#SK op.parent = parID kv|,b AddOperation eID, op ESQ!@G/n Print "Set lens thickness = " & tlens f%fa{ &TN2 HZ-bJ '************************************************************************* 4~?2wvz G4 'Lens index of refraction )@QJ '************************************************************************* 4-4?IwS eID = FindMaterial( "Lens" ) ;'kI/(;;C GetModelMaterial eID, mat kM*T$JqN Vk<k +=7 mat.Nd = nlens dBEIMn@ SetModelMaterial eID, mat c c G['7 Print "Set lens index of refraction = " & nlens Zy$L rr! c;!g '************************************************************************* ?A=b6Um 'Pupil diameter ;"7/@&M\m '************************************************************************* 4_Rdp`x#J eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ~@c-* U ^#?&u 'Adjust pupil diameter (trimming volume inner hole) IlZu~B9c bAhZ7;T~ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ;x[pM_ [STje8+V ' Adjust pupil location to just in front of the lens X\2_;zwf parID = FindFullName( "Geometry.Arizona Eye" ) ,7/
_T\d< eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) k&Jo"[i&WO count = 0 tP'GNsq+m While GetOperationCount(eID)>count >[K?fJ$+ GetOperation eID, count, op 2;(W-]V? If op.Type="ShiftZ" Then ;w6s<a@Zh DeleteOperation eID,count qe?Ggz3p. count=count-1 mZoD033H End If Z.jCera. count=count+1 wa?+qiWnrl Wend Z] { @H op.Type = "ShiftZ" jb@\i@- op.val1 = taq-0.01 vo;5f[>4i op.parent = parID v5Y@O|i# AddOperation eID, op sco
uO$K `!Ln|_,d Print "Set pupil diameter = " & pupilDiam Q_lu`F| Q]i[.ME 'Update AZ Eye subassembly Description U>3
>Ex
eID = FindFullName( "Geometry.Arizona Eye" ) wixD\t59X GetEntity eID, entity )1z4q` entity.Description = "Accommodation = " & A & "D" -N^=@Yx) SetEntity eID, entity [t}):}~F| m!!;/e?yx Update >\\5"Sf Print "DONE!" q!*MH/R rt;gC[3\ End Sub $MT}l
!$E~\uT 如果屈光度是4,光瞳直径是4,则会输出如下数据: W:B }u\)C ]L]T>~X` Accommodation = 4 Diopters 32KR--mn% Pupil Diameter = 4 mm .CmL7
5 Set aqueous humor thickness = 2.81 _W+Q3Jx-( Set anterior lens radius = 10.4 and conic constant = -2.375869 =tq7z =k Set posterior lens radius = -4.424557 and conic constant = -3.081019 7,su f }= Set lens thickness = 3.927 o[{&!t Set lens index of refraction = 1.42672 /$*; >4=>f Set pupil diameter = 4 t'Htx1#Zc[ DONE! &Q+]t"OA!
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