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简介 h8)m2KrZ!.
A|90Ps 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。 :MF F*1 5dNM:1VoE 模型 o]jPG <|kS`y 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。 -yJ%G1R h't!1u Table 1. AZ眼睛模型的定义 -V_iv/fmM 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. F^/b!)4X ~TvKMW6/# 光源 v"I#.{LiH= {pR4+g 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。 O'L9 s>B 5X1z^( -H+<81"B# 图1. 光源和提示信息使用 6 *GR_sMm 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。 >[A7oH #JD:i% 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。 t~0!K;nn yOdh?:Imv 图2. 字母F光源的设定方法光 1!P\x=Nn_ P
=jRof$ 图3. 字母F在视网膜上位置点列图 AW')*{/(Ii 视网膜的散射 Mcfqo0T- =uil3:,[S 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。 4b/>ZHFOF; vWh]1G#'p[ "+{>"_KV 图4. 视网膜朗伯散射设定 2vLV1v$,q 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 ~_GW Kwmtt /qwl;_Jcf 图5. 视网膜重点采样规格设定 rQLl[a 脚本 nPRv.h n8RE 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: Q?xCb iU1yJ= 图6. 用户对话框的创建与编辑 \|f3\4;! 图7. 用户对话框编辑器 >&Ios<67g 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 gZ W(z 余下的脚本计算与屈光度有关的所有参数。 :+?w> l RM7s(^l 分析 |J^}BXW'^) D~T;z pS 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 :oeDksld /y-eVu6 图7. 字母F在视网膜上颜色分析 Q| _e= 脚本代码 qdQQt5Y'm =6Q\78b Option Explicit 'Remove this to enable non-dimensioned variables to be used. U'oFW@Y;h J`d_=C?J Dim entity As T_ENTITY Muay6b? Dim op As T_OPERATION : pkOZ+t Dim mat As T_MODELMATERIAL 4 >`2vb Dim A As Double u_ *DS- Dim pupilDiam As Double Vm]xV_FOd Dim eID As Long F~Sw-b kSf Dim parID As Long 9=5xt;mEs} Dim count As Integer (ptk!u6 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double *u ^m f~ Dim tlens As Double, nlens As Double O =gv2e Dim curv As Double, conic As Double MY w3+B+Jj Dim ok As Long 4m"6$ }v4T&/vt- Sub Main |x+g5~$ S-2@:E '用户输入对话框 ;^f ;< Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 )[np{eF.k TextBox 220,21,40,21,.TextBox1 'default: 0 EN-;@P9;C Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 B }t529Z OKButton 40,91,90,21 VtYrU>q CancelButton 190,91,90,21 jzb%?8ZJ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 g/(3D TextBox 220,49,40,21,.TextBox2 'default: 4 ESyb34T` End Dialog !4vepa}Y Dim dlg As UserDialog Q`)iy/1M UNF@%O4_T ok = Dialog (dlg) c_Lcsn von<I If ok=0 Then 'cancel button was pressed R|'ftFebB. Print "Execution cancelled." C-tkYP
End 59#o+qo4 End If <X"_S'O p?V@P6h 'Assign accommodation and pupil diameter & use defaults if field left empty aQHB If dlg.TextBox1 = "" Then pQCocy A = 0 'Default accommodation )N3XbbV Else Ux-i iH#s A = CDbl(dlg.TextBox1) vJ9IDc|[ End If q(\kCUy! 60--6n If dlg.TextBox2 = "" Then .X\9vVJ pupilDiam = 4 'Default pupil diameter ^Rh`XE Else vX}#wDNP pupilDiam = CDbl(dlg.TextBox2) 3XSfXS{lwP End If &HB!6T/ g@|2z Print " " &j?+%Y1n@ Print "Accommodation = " & A & " Diopters" a98J_^ n Print "Pupil Diameter = " & pupilDiam & " mm" oxNQNJ!X gaWJzK
Yc_ ' Calculate new parameters with accommodation Y6RbRcJw taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 0q o]nw :k Kdda<g# Rant = 12.0 - 0.4*A 'Radius of anterior lens !X4m6gRaP CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens e]*@|e4b ht_'GBS) Rpost = -5.224557 + 0.2*A 'Radius of posterior lens c>%%'c CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens `5
Iaz C;I:?4 tlens = 3.767 + 0.04*A 'Lens thickness ows3%
;[B-!F> nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction gTb%c84 1O2jvt7M 'Adjust parameters to account for accommodation ']U<R=5T$ u$<>8aMei '************************************************************************* PVaqKCj:6W 'Aqueous thickness (Position of Lens) DCKH^J '************************************************************************* )1gOO{T]h? eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Kh7C7[& GetCustomElement eID, entity uc
Ph*M "sYZ3 parID = FindFullName( "Geometry.Arizona Eye" ) W!V-m c Rv#aV ' Delete any shift(s) in z ?izl#? count = 0 R!rj:f!> While GetOperationCount(eID)>count c@Xb6 z_> GetOperation eID, count, op n;LjKE If op.Type="ShiftZ" Then (W
|;gQ DeleteOperation eID,count {ObUJ3 count=count-1 \Vx_$E End If Hm'aD2k count=count+1 v}TFM Wend AP+%T
6 IRa$h>H 'Set new shift in ^$s&bH'8 op.Type = "ShiftZ" &l0,q=T op.val1 = taq H'}6Mw%ra op.parent = parID INY?@in AddOperation eID, op ^s\T<; Print "Set aqueous humor thickness = " & taq-0.55 Nxr\Yey q!{>Nlk '************************************************************************* XD Q<28^ 'Radius and conic constant of anterior lens `L%<3/hF '************************************************************************* D2I|Z eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) dOVu D( GetConic eID, entity, curv, conic OMAvJzK . ZF@$3 SetConic eID, entity, 1/Rant, CCant sh*/wM Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 7Q9| P?&:z A<+1:@0 '************************************************************************* .Nk5W%7]= 'Radius and conic constant of posterior lens |nBs(>b '************************************************************************* o,RiAtdk eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) K[S)e!\. GetConic eID, entity, curv, conic
'Pxq>Os 1#9PE(!2 SetConic eID, entity, 1/Rpost, CCpost e~geBlLar Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost MzH'<`;BP u82 (`+B '************************************************************************* :LCyxLI 'Lens thickness (Position of posterior lens surface) OZEbs 7 '************************************************************************* $HCgawQ xnHB
<xrE} parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 3vdFO: j f)mOeD*u| ' Delete any z-shift(s) <H$!OPV count = 0 n=?wX#rEC# While GetOperationCount(eID)>count /=g/{&3[a> GetOperation eID, count, op nl~Z,Y$ If op.Type="ShiftZ" Then R_b4S%jhx DeleteOperation eID,count r7FJqd count=count-1 Bru] ;%Qg% End If `g<0FQA count=count+1 *c
9S. Wend V9jxmu F, a#lytp 'Set new z-shift Eu<f op.Type = "ShiftZ" MRg Ozg op.val1 = tlens ~n!&~ op.parent = parID K0D|p$v AddOperation eID, op }I1j #d0. Print "Set lens thickness = " & tlens iCCe8nK WNt':w^_ '************************************************************************* tEt46]{ 'Lens index of refraction 4o"?QV: '************************************************************************* 7 IJn9 b eID = FindMaterial( "Lens" ) : ^U>n{ GetModelMaterial eID, mat T2_iH=u p:W{c/tV mat.Nd = nlens vK`HgRQ(C SetModelMaterial eID, mat CM%;/[WBxy Print "Set lens index of refraction = " & nlens 97~>gFU77# O<#8R\v '************************************************************************* mX!*|$bs 'Pupil diameter o1"N{Eu '************************************************************************* .FV^hrJxI; eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) zl|
XZ pjl>ZoOM 'Adjust pupil diameter (trimming volume inner hole) )FPn_p#3] [4aw*M1z}. SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" __zHe-.m 9Ofls9]U ' Adjust pupil location to just in front of the lens 3SI0etVr parID = FindFullName( "Geometry.Arizona Eye" ) NCY2^ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 'sNiJ > count = 0 &n#yxv4 While GetOperationCount(eID)>count {> 8?6m- GetOperation eID, count, op K|OPtYeb If op.Type="ShiftZ" Then e]CoYuPr DeleteOperation eID,count D_1O4/ count=count-1 nA{yH}D4 End If a>rDJw: count=count+1 42p1P6d Wend UvM4-M%2JN op.Type = "ShiftZ" h&n1}W+ op.val1 = taq-0.01 xRdx`
YY u op.parent = parID _*n
`*" AddOperation eID, op H?!DcUg CC QleVW Print "Set pupil diameter = " & pupilDiam L[A?W }/h&`0z` 'Update AZ Eye subassembly Description :Ocw+X3 eID = FindFullName( "Geometry.Arizona Eye" ) t`{T:Tjc GetEntity eID, entity */_ 'pt entity.Description = "Accommodation = " & A & "D" 4T;<`{] SetEntity eID, entity WUo\jm[yr FvYciU! Update (xoYYO Print "DONE!" bar=^V) s$?LMfT End Sub SWY MB $aN': 如果屈光度是4,光瞳直径是4,则会输出如下数据: rGXUV`5Na Sk1t~ Accommodation = 4 Diopters "a}fwg9Y Pupil Diameter = 4 mm vC`SD] Set aqueous humor thickness = 2.81 ("r:L<xe& Set anterior lens radius = 10.4 and conic constant = -2.375869 ^Il*`&+?P Set posterior lens radius = -4.424557 and conic constant = -3.081019 ,G5[?H;ZN Set lens thickness = 3.927 $COjC!M Set lens index of refraction = 1.42672 7S&$M-k Set pupil diameter = 4 &"I csxG DONE! ^]'_Qbi]} ^jUw4Dj~-q GN9kCyPK QQ:2987619807 RPte[tq
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