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简介 wX$:NOO e[S`Dm"i)' 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。 8.E"[QktZ .KsR48g8 模型 nwRltK c OYDN[k 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。 :6^7l/p +6m.f,14q Table 1. AZ眼睛模型的定义 I[\~pi, 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. Q?{%c[s /7Q|D sa 光源 =OVDJ0ozZ eL!41_QI 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。 !3ggQG!e '%)R}wgV .6B\fr.za 图1. 光源和提示信息使用 6_LeP9s ) 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。 iCt.rr~;V
{pzj@b 1S 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。 ^)VwxH:s 7*/{m K) 图2. 字母F光源的设定方法光 {h<D/:^v 3r\8v`^> 图3. 字母F在视网膜上位置点列图 x-^6U 视网膜的散射 gT+/nSrLV xNP_>Qa~ 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。 ITu19WG #el27"QP0 '6KvB 图4. 视网膜朗伯散射设定 1+o]+Jz| 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。 x 3@-E f)I5=Ijy( E+td~&x 图5. 视网膜重点采样规格设定 k3\N.@\ 脚本 N^^0j, #cbgp;,M{I 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: |(7}0]BP0 OWd'z1Yl 图6. 用户对话框的创建与编辑 8;PkuJR_] 图7. 用户对话框编辑器
B.z$0=b 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 {Gxe%gu6K 余下的脚本计算与屈光度有关的所有参数。 R>Ra~b s-i|P 分析 \-<BUG]=
%H{p&ms 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Bd>~F7VWs yDWIflP0; 图7. 字母F在视网膜上颜色分析 E?m~DYnU 脚本代码 %!|w(Povq cHFi(K]|1 Option Explicit 'Remove this to enable non-dimensioned variables to be used. "S#FI S_}`'Z ) Dim entity As T_ENTITY <LX\s*M) Dim op As T_OPERATION =x~I'|%3 Dim mat As T_MODELMATERIAL >rG>Bz^Pu Dim A As Double 5dBftTv? Dim pupilDiam As Double GW2\YU^{ Dim eID As Long 18g_v"6o Dim parID As Long _03?XUKV Dim count As Integer d@%"B($nR Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double >J"IN I Dim tlens As Double, nlens As Double r8k (L{W Dim curv As Double, conic As Double
+2uSMr Dim ok As Long 3"fDFR A~ya{^} Sub Main
~zp8%lEe xm'9n? '用户输入对话框 >mGH4{H Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Ts iJK TextBox 220,21,40,21,.TextBox1 'default: 0 ez4!5&TzRm Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 _ _O f0< OKButton 40,91,90,21 1/_g36\l$ CancelButton 190,91,90,21 bMH~vR Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ZsGvv]P TextBox 220,49,40,21,.TextBox2 'default: 4 .6?"<zdPU End Dialog 5=>1>HYM Dim dlg As UserDialog Lp`.fn8Ln lH-VqkR\ ok = Dialog (dlg) s.3"2waZ=T !oLn= If ok=0 Then 'cancel button was pressed {I#_0Q,i Print "Execution cancelled." A^U84kV= End &|>@K#V8-; End If ,0l
Od< \Lx=iKs< 'Assign accommodation and pupil diameter & use defaults if field left empty 4vhf!!1 If dlg.TextBox1 = "" Then 'K[ml ?_ A = 0 'Default accommodation n.%QWhUB Else 7*:zN A = CDbl(dlg.TextBox1) AGhenDNV End If 7vRtTP ]>3Y~KH( If dlg.TextBox2 = "" Then % "RJi? pupilDiam = 4 'Default pupil diameter )ycI.[C Else N['DqS = pupilDiam = CDbl(dlg.TextBox2) L G}{ibB End If k
%I83,+ j,n:%5P\v Print " " iO L$| Z( Print "Accommodation = " & A & " Diopters" &AiAd6 Print "Pupil Diameter = " & pupilDiam & " mm" 1\hLwG6Jj (m]l -Re ' Calculate new parameters with accommodation /ViY:-8s taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness LF|0lAr zAgX{$/Fg Rant = 12.0 - 0.4*A 'Radius of anterior lens *A-_*A CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens w[~G^x& (
eV,f Rpost = -5.224557 + 0.2*A 'Radius of posterior lens =NB[jQ :( CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens -jH|L{Iyq} %9-^,og tlens = 3.767 + 0.04*A 'Lens thickness F^UtZG+
Y@,iDQ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction E'iE#He 0R
x#Fm 'Adjust parameters to account for accommodation vPkLG*d8 !gh8 Qs '************************************************************************* {3Inj8a=?A 'Aqueous thickness (Position of Lens) yT^x0?U '*************************************************************************
(s8b?Ol/ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) T(|'.&a GetCustomElement eID, entity 2mLZ4r>WE AD?zBg Zu parID = FindFullName( "Geometry.Arizona Eye" ) %m&6'Rpfk ~nZcA^b#DQ ' Delete any shift(s) in z c*KE3: count = 0 *s6x While GetOperationCount(eID)>count Y6{^cZ!= GetOperation eID, count, op <q63?Ms' If op.Type="ShiftZ" Then 7QO/; zL DeleteOperation eID,count <G})$f'x2 count=count-1 Yf0 KG End If =v2|QuS$ count=count+1 ^PG" Wend +!lDAkW0 k
9i
W1 'Set new shift in =<]`'15"V op.Type = "ShiftZ" OqtGKda op.val1 = taq J4bP(=w! op.parent = parID vh,(]t AddOperation eID, op D4%J!L<P Print "Set aqueous humor thickness = " & taq-0.55 4m*)("H )uqzu%T '************************************************************************* N'{[BA(eE 'Radius and conic constant of anterior lens jY6GWsh:9 '************************************************************************* y2W+YV* eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) t]K20(FSN GetConic eID, entity, curv, conic "'4 !Asncc G SetConic eID, entity, 1/Rant, CCant U[C>Aoze Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 20Zxv! /HIyQW\Ki- '************************************************************************* MQ,K%_m8 'Radius and conic constant of posterior lens @*%3+9`yq '************************************************************************* $6Ma{r C| eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) G'|ql5Zw GetConic eID, entity, curv, conic >u= .W]k8N E SetConic eID, entity, 1/Rpost, CCpost CR4O#f8\ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 6_mi9_w a (U52dO, '************************************************************************* x`E<]z*w} 'Lens thickness (Position of posterior lens surface) ERPg TZT '************************************************************************* (%_X{R' 6Bq_<3P_ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) TV{GHB!p" yD"]:ts3 ' Delete any z-shift(s) } c G)$E count = 0 bEcs(Mc~ While GetOperationCount(eID)>count 9'MGv*Ho GetOperation eID, count, op 2u.0AG If op.Type="ShiftZ" Then @i ~ A7L0/ DeleteOperation eID,count kf@JEcKV count=count-1 dD,}i$ End If nJI2IPZ count=count+1 rrL.Y&DTK Wend e!6yxL*[@[ s|%R 'Set new z-shift UJO3Yn op.Type = "ShiftZ" bM?gAY]mB8 op.val1 = tlens U["0B8 op.parent = parID uV:R3#^ AddOperation eID, op n/KO{: Print "Set lens thickness = " & tlens E#!N8fQ tW/k '************************************************************************* tz;3 'Lens index of refraction l'I:0a
4T '************************************************************************* >XtfT' eID = FindMaterial( "Lens" ) q,Gymh; GetModelMaterial eID, mat B[8bkFS>] >/ay'EyY;> mat.Nd = nlens *RkUF!)( SetModelMaterial eID, mat k;\gYb%L Print "Set lens index of refraction = " & nlens ^E^`" _}R9!R0O '************************************************************************* >YI Vi4'' 'Pupil diameter
3\W/VBJJ '************************************************************************* [9
MH"\ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 5W)ST&YPL* $udhTI#, 'Adjust pupil diameter (trimming volume inner hole) aL1%BGlmZ< V'9.l6l SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 40?RiwwD L-+g` ' Adjust pupil location to just in front of the lens +/[M
Ex= parID = FindFullName( "Geometry.Arizona Eye" ) +q&Hj|;8r eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) I|rb"bG count = 0 ?tYZ/ While GetOperationCount(eID)>count cWAw-E5 GetOperation eID, count, op R;DU68R If op.Type="ShiftZ" Then =}Tm8b0 DeleteOperation eID,count 8 m"k3:e^ count=count-1 k6C XuU End If k[@P526 count=count+1 1<ag=D`F_" Wend JP8}+ op.Type = "ShiftZ" -rO34l op.val1 = taq-0.01 G _cJI op.parent = parID @v2<T1UC AddOperation eID, op f$dPDbZQ )JzY%a SP Print "Set pupil diameter = " & pupilDiam gGMfy]]R z>W:+W"o 'Update AZ Eye subassembly Description >._d2.Q' eID = FindFullName( "Geometry.Arizona Eye" ) n^nE&'[?0g GetEntity eID, entity krfXvQJwJ entity.Description = "Accommodation = " & A & "D" oz&`3` SetEntity eID, entity 9JFN8Gf*) BpIyw
Update 'dwW~4|B Print "DONE!" ~
*&\5rPb `n$Ak5f End Sub }xsO^K {<yapBMw 如果屈光度是4,光瞳直径是4,则会输出如下数据: CY o
m HAn{^8"@ Accommodation = 4 Diopters Vg'R=+Wb Pupil Diameter = 4 mm LwB1~fF Set aqueous humor thickness = 2.81 WJq>%<# Set anterior lens radius = 10.4 and conic constant = -2.375869 u+V*U5v Set posterior lens radius = -4.424557 and conic constant = -3.081019 g, d_ Set lens thickness = 3.927 u=0O3-\h Set lens index of refraction = 1.42672 j !*,( Set pupil diameter = 4 zA5nr` DONE! F;Q,cg M
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