|
|
简介 x+? 9C 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。 fkfZ>D^1 y<W8Q<9 模型 nGZX7Fx5 < V\Y@Ei+ 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。 @#+jMV$g :/YO ni1h Table 1. AZ眼睛模型的定义 \8uo{#cL8 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. >1L=,M n9LGP2#! 光源 $
E1Tb{' Ocg"M Gb 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。 _\5~>g_ +5<k-0v sfp,Lq` 图1. 光源和提示信息使用 fbrp#G71y 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。 BOlAm*tFt @mw "W{ 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。 ir>]r<Zl nR
\'[~+ 图2. 字母F光源的设定方法光 RR1A65B Hyk'c't_O 图3. 字母F在视网膜上位置点列图 ^jdL@#k00 视网膜的散射 q)u2Y] ;sdN-mb 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。 ,reJ(s 'iSAAwT2aj p?(L'q"WK 图4. 视网膜朗伯散射设定 }pNX@C#De 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。 R U"/2i .W\ve>; $*MCUnl 图5. 视网膜重点采样规格设定 4FeEGySow 脚本 >hMUr*j !&kL9A). 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: R5Yl 1 AWr}"r?s 图6. 用户对话框的创建与编辑 H{ M)- 图7. 用户对话框编辑器 L6:h.1 U$ 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。 <T,A&`/ 余下的脚本计算与屈光度有关的所有参数。 ?4t-caK^u 2f, B$-# 分析 8"'x)y UP1?5Q=H]Q 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 d<p 2/aA hP?fMW$V 图7. 字母F在视网膜上颜色分析 F:FMeg 脚本代码 ;Kxbg>U i`U:gw Option Explicit 'Remove this to enable non-dimensioned variables to be used. c|p,/L09L uq7T{7~< Dim entity As T_ENTITY }amU[U, Dim op As T_OPERATION #5CI)4x0! Dim mat As T_MODELMATERIAL eBB:~,C^q. Dim A As Double _]#klL Dim pupilDiam As Double =fLL| Dim eID As Long wJ"ev.A) Dim parID As Long *DeTqO65 Dim count As Integer ,krS-. Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Dk)}|GJ()" Dim tlens As Double, nlens As Double B:oF;~d/, Dim curv As Double, conic As Double `_AM` >_ Dim ok As Long vS;'}N c,5n,i Sub Main ,\ldz(D?+ <HoAj"xf '用户输入对话框 2=*=^)FNI Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Bt~s*{3$8 TextBox 220,21,40,21,.TextBox1 'default: 0 pu;3nUH Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 _g|acBF OKButton 40,91,90,21 WO</Q6+ CancelButton 190,91,90,21 )@7DsV/M Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 M]_E TextBox 220,49,40,21,.TextBox2 'default: 4 ksI>IW End Dialog "e62/Ejg% Dim dlg As UserDialog zhEo(kU!
0Oxz3r%}r ok = Dialog (dlg) ~t/JCxa ?X_V#8JK If ok=0 Then 'cancel button was pressed ym%slg Print "Execution cancelled." $C_M&O} End Y(i?M~3\t End If rg&+ pG yRX_; 'Assign accommodation and pupil diameter & use defaults if field left empty 3B9nP._ If dlg.TextBox1 = "" Then av' *u A = 0 'Default accommodation 5{l1A(b Else (aKZ5>>cN A = CDbl(dlg.TextBox1) ZlR!s!vv End If S ~|.&0"\ T%I&txl If dlg.TextBox2 = "" Then M []OHw pupilDiam = 4 'Default pupil diameter |O (G nsZ Else d79N-O- pupilDiam = CDbl(dlg.TextBox2) LpWI>sNv End If l1-HO k/`i6%F#m Print " " 960qvz! Print "Accommodation = " & A & " Diopters" !wh=dQgMe Print "Pupil Diameter = " & pupilDiam & " mm"
(K
#A EF;,Gjh5p ' Calculate new parameters with accommodation J+2R&3;_O taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness `SOhG?Zo ^
}#f() Rant = 12.0 - 0.4*A 'Radius of anterior lens b=LF%P CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens vjTwv+B" 6E+=Xi Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Dd/}Ya(Gi CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens 4
X`^{~ Zoow*`b|$U tlens = 3.767 + 0.04*A 'Lens thickness 9~Xg#{ T
T"3^@ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction .cR*P<3O XiG88Kwv 'Adjust parameters to account for accommodation N$Hqa^!'T `^%GN8d}nm '************************************************************************* 1g i}H) 'Aqueous thickness (Position of Lens) raQYn?[ '************************************************************************* |h,FUj<r eID = FindFullName( "Geometry.Arizona Eye.Lens" ) L?f qcW{ GetCustomElement eID, entity 3wNN<R qJMp1DC parID = FindFullName( "Geometry.Arizona Eye" ) b\L)m ( "jGe^+9uT ' Delete any shift(s) in z ,k%8yK count = 0 \X opU" While GetOperationCount(eID)>count l$`G:%qHj GetOperation eID, count, op VRhRwdC If op.Type="ShiftZ" Then @Z2/9K%1' DeleteOperation eID,count vs*I7< count=count-1 <4NQL*|> End If b-b;7a\N count=count+1 w:R]!e_6\9 Wend SRk7gfP*q AzX(~Qc 'Set new shift in ,CW%JIM op.Type = "ShiftZ"
* D3 op.val1 = taq riEqW}{ op.parent = parID q_58Lw AddOperation eID, op gT7I9 (x!W Print "Set aqueous humor thickness = " & taq-0.55 ]}_,U!`8 =0Y'f](2eW '************************************************************************* zf")|9j 'Radius and conic constant of anterior lens QQ|9>QP '************************************************************************* qq>44 k\|) eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) KqY>4tb GetConic eID, entity, curv, conic Px#4pmz -(ER4# SetConic eID, entity, 1/Rant, CCant G[B*TM6$ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant m-#d8sD2C %J3lK]bv( '************************************************************************* -CZ-l;5 'Radius and conic constant of posterior lens L`bo#,eg6 '************************************************************************* fa.f(c eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) h!;MBn`8 GetConic eID, entity, curv, conic CY\mU_.b t9n'! SetConic eID, entity, 1/Rpost, CCpost "p2u+ 8? Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost .Px,=56$X otZ JY) '************************************************************************* {kv4g\a; 'Lens thickness (Position of posterior lens surface) /3;=xZq '************************************************************************* 5[ hlg(eb {.%0@{Y parID = FindFullName( "Geometry.Arizona Eye.Lens" ) GYTbeY CTh1;U20 ' Delete any z-shift(s) n/:Z{ count = 0 }8X:?S
% While GetOperationCount(eID)>count uof0Oc. GetOperation eID, count, op -kt1t@O If op.Type="ShiftZ" Then ob)D{4B' DeleteOperation eID,count nFSG<#x\ count=count-1 uFa-QG^Y{ End If %k~C-+ count=count+1 |O'Hh7 Wend l$qmn$Uc aw;{<?* 'Set new z-shift <kk'v'GW@ op.Type = "ShiftZ" `jt(DKB+J op.val1 = tlens !WDn7j'A op.parent = parID j=p|'` AddOperation eID, op +._f.BRmX. Print "Set lens thickness = " & tlens J78Qj[v "otr+.{`* '************************************************************************* yzODF>KJ 'Lens index of refraction puk4D '************************************************************************* 3<yCe%I: eID = FindMaterial( "Lens" ) 4_Tb)?L+: GetModelMaterial eID, mat Gf!t< =T _y.mpX& mat.Nd = nlens 1"N/ZKF-x SetModelMaterial eID, mat DB!uv[c Print "Set lens index of refraction = " & nlens .kz(V5 h6K!|-Gq. '************************************************************************* Hd96[Uo 'Pupil diameter $=X!nQ& Z| '************************************************************************* NO%|c|B| eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 9iiU,}M`j ~r7DEy|+ 'Adjust pupil diameter (trimming volume inner hole) 1j_aH#Fz: %!1@aL]pQ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 1KNkl,E @D( KuF ' Adjust pupil location to just in front of the lens C8O7i[uc parID = FindFullName( "Geometry.Arizona Eye" ) gogl[gHO eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) EVby 9! count = 0 @*AYm-k While GetOperationCount(eID)>count +;{rU& GetOperation eID, count, op 'lSnyW{ If op.Type="ShiftZ" Then *=r@vQ DeleteOperation eID,count pRb+'v&_k count=count-1 $u(M 4(} End If j58Dki->. count=count+1 [0(
E>vm Wend +sV# Z, op.Type = "ShiftZ" il 8A&`% op.val1 = taq-0.01 x|P<F 2L op.parent = parID !c3Qcva AddOperation eID, op Phk`=:xh .je~qo) Print "Set pupil diameter = " & pupilDiam hv_pb#1Ks 0Te)s3X 'Update AZ Eye subassembly Description S.?\>iH[ eID = FindFullName( "Geometry.Arizona Eye" ) l#<}|b GetEntity eID, entity I3F6-gH entity.Description = "Accommodation = " & A & "D" :d:|7hlNQ SetEntity eID, entity &z1| N
P0Hgd Update ;RTrRh0v Print "DONE!" "m<eHz]D R
oF End Sub /;]B1T7 Gff[c%I 如果屈光度是4,光瞳直径是4,则会输出如下数据: I=3B
5u bHlD m~5 Accommodation = 4 Diopters )U3 H15 Pupil Diameter = 4 mm ?3KR(6D Set aqueous humor thickness = 2.81 3 z{5c Set anterior lens radius = 10.4 and conic constant = -2.375869 jQw`*Y/, Set posterior lens radius = -4.424557 and conic constant = -3.081019 8kn]_6:3i Set lens thickness = 3.927 s|rZ>SLL Set lens index of refraction = 1.42672 : Oz7R: Set pupil diameter = 4 A(_^_p.| DONE! f"OA Zji d%[`=fs]|m (文章来源:讯技光电)
|