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简介 f0aKlhEC E`k@{*Hn& 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。 0k(a VkZ I |qZ1| 模型 (/*]?Ehd +XYE {E5 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。 `I5wV/%ib [=^3n#WW Table 1. AZ眼睛模型的定义 )Iq <+IJ 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. Nl(3Xqov !1Cy$}w 光源 <nK?L cP qc~iQSI 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 Clb@$, r_;Nt we?76t:- 图1. 光源和提示信息使用 0tB0@Wj 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。 \A6B,|@ VEw" 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。 ^UhBH@ti k/gZ, 图2. 字母F光源的设定方法光 3fJc
9| Z@@K[$ 图3. 字母F在视网膜上位置点列图 ~PahoRS 视网膜的散射
{ Z5nGG 2oRg 2R} 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。 [o5Hl^ ~B(4qK1G ""QP% 图4. 视网膜朗伯散射设定 %lGfAYEM= 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。 WPG(@zD PO7Lf#9] @\P;W(m.i 图5. 视网膜重点采样规格设定 *lw_=MXSK 脚本 #7YY<)
xt} tWa)_y 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: xDoC( x&T [*i 图6. 用户对话框的创建与编辑 'V=P*#|SR 图7. 用户对话框编辑器 pWsDzb6?% 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。 E6gI,f/p0X 余下的脚本计算与屈光度有关的所有参数。 K$_0`>[ BC<^a )D= 分析 B[-v[K2 z}ddqZ27G$ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Um-[~- tX %5BTv 图7. 字母F在视网膜上颜色分析 =k0_eX0 脚本代码 M|`U"vO MsGM5(r:b Option Explicit 'Remove this to enable non-dimensioned variables to be used.
|CZ@te)> }\:NuTf Dim entity As T_ENTITY qd)/9*|Jl Dim op As T_OPERATION Hi1JLW, Dim mat As T_MODELMATERIAL zSja/yq Dim A As Double }YNR"X9*)/ Dim pupilDiam As Double qC:raH_: Dim eID As Long ,+{LYF Dim parID As Long :Ab%g- Dim count As Integer 5VAK:eB Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double '>0fWBs Dim tlens As Double, nlens As Double ],a 5)kV Dim curv As Double, conic As Double 1@1U/ss1 Dim ok As Long Rt!FPoN,y (/j/>9iro Sub Main aV|hCN~ 91g2A| '用户输入对话框 wlk4*4dKn Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 |O9O )o TextBox 220,21,40,21,.TextBox1 'default: 0 j<@lX^ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 '*w00 OKButton 40,91,90,21 EYEnN CancelButton 190,91,90,21 ?D*/*Gk{ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ~%=MpQ3 TextBox 220,49,40,21,.TextBox2 'default: 4 v`zJb00DT End Dialog o`P%& Dim dlg As UserDialog R$TB1w9] "4+WZR] ok = Dialog (dlg) Slher0.Y -pGE]nwDL If ok=0 Then 'cancel button was pressed ]d0tE?9 Print "Execution cancelled." kDN:ep{/ End SO(NVJh End If 1Z~)RJ<D OFv%B/O 'Assign accommodation and pupil diameter & use defaults if field left empty ^_u kLzP9 If dlg.TextBox1 = "" Then 8b-Q F
A = 0 'Default accommodation N<|Nwq:NN Else DB:+E|vSD A = CDbl(dlg.TextBox1) S` ;?z End If C=It* j55 Z99>5\k If dlg.TextBox2 = "" Then ^T$|J;I pupilDiam = 4 'Default pupil diameter Dg?70v<a Else J)~L pupilDiam = CDbl(dlg.TextBox2) <55g3>X End If DhT>']Z 0#&5.Gr) Print " " fb8g7H| Print "Accommodation = " & A & " Diopters" Ry K\uv Print "Pupil Diameter = " & pupilDiam & " mm" (>GK\=:< I@%t.%O Jp ' Calculate new parameters with accommodation L>%o[tS taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness r{ef .^&: %_L\z*+ Rant = 12.0 - 0.4*A 'Radius of anterior lens % !>I*H CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens "a"]o pDcjwlA% Rpost = -5.224557 + 0.2*A 'Radius of posterior lens 9Hu/u=vB< CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens V=V:SlS9| Nkl_Ho, tlens = 3.767 + 0.04*A 'Lens thickness ^Z#W_R\l U,q\emR nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction yo)%J NchXt6$i9 'Adjust parameters to account for accommodation Boz@bl mCB A"D,Kg
S '************************************************************************* .!,z:l$Kh 'Aqueous thickness (Position of Lens) :Q_<Z@2Y{ '************************************************************************* [uls8
"^/j eID = FindFullName( "Geometry.Arizona Eye.Lens" )
Mo @C9Y0 GetCustomElement eID, entity *"n vX2iz Q|L9gz[? parID = FindFullName( "Geometry.Arizona Eye" ) BT"42#7_ [YT>*BH ? ' Delete any shift(s) in z 9Z'8!$LYg count = 0 ``e$AS While GetOperationCount(eID)>count Pgus42f% GetOperation eID, count, op qt
2d\f If op.Type="ShiftZ" Then D]~MC DeleteOperation eID,count r*_ZJ*h[ count=count-1 Z%Zd2
v End If #x3ujJ count=count+1 '-b*EZU8t Wend ?Poq2 #ap9Yoyk\ 'Set new shift in Yf~{I-|`q op.Type = "ShiftZ" .?e\I`Kk^' op.val1 = taq pV,P|>YTf op.parent = parID +d!v}aJ AddOperation eID, op Za8#$`zq Print "Set aqueous humor thickness = " & taq-0.55 J8)#PY[i4 09kt[
'************************************************************************* Fa_VKAq 'Radius and conic constant of anterior lens jR#~I@q^ '************************************************************************* /2Bi@syxK eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) wqW0v\ GetConic eID, entity, curv, conic _}VloiY ^=SD9V SetConic eID, entity, 1/Rant, CCant *@)O7vB Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant s)2fG\1 mL`5 uf '************************************************************************* 0,rTdjH7 'Radius and conic constant of posterior lens
\qR %%S '************************************************************************* H0R&2#YD eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) VZ](uF BY GetConic eID, entity, curv, conic 0}xFD6{X BQ2wnGc SetConic eID, entity, 1/Rpost, CCpost e^Ky<*Y Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ]&{ ci tP%{P"g3^ '************************************************************************* GSQ/NYK 'Lens thickness (Position of posterior lens surface) zC:wNz@zK '************************************************************************* j>/ ,$H `TPOCxM Mo parID = FindFullName( "Geometry.Arizona Eye.Lens" ) fH?ha ee#):
-p ' Delete any z-shift(s) JiU9CeD3 count = 0 { F}; n?' While GetOperationCount(eID)>count ^~HQC* GetOperation eID, count, op C2w2252T If op.Type="ShiftZ" Then &0 BdUU+:< DeleteOperation eID,count .eO?Z^ count=count-1 wL^%w9q- End If NwR}yb6 count=count+1 $4T2z- Wend W|,V50K &"mzwQX 'Set new z-shift tpTAeQ*:d op.Type = "ShiftZ" TSsKfexQ op.val1 = tlens @b3#X@e} op.parent = parID cl*PFQp9j AddOperation eID, op NAzX". g Print "Set lens thickness = " & tlens |s)?cpb A?T<",bO '************************************************************************* \S)2 'Lens index of refraction ii0Ce}8d~ '************************************************************************* h<\_XJJ eID = FindMaterial( "Lens" ) zn@N'R/ GetModelMaterial eID, mat 3u\;j; Td! k%op>
& mat.Nd = nlens ;eZ#b jw-d SetModelMaterial eID, mat ZB[Qs Print "Set lens index of refraction = " & nlens +EM_TTf4 UYtuED '************************************************************************* :g\rQazxO 'Pupil diameter oq_6L\
~ '************************************************************************* 35x 0T/8 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) leiW4Fj %&\ jOq~ 'Adjust pupil diameter (trimming volume inner hole) =0'q!}._! 5Fm=/o1 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" A;u" <KG? 9cv]y# ' Adjust pupil location to just in front of the lens M#@aB"@J> parID = FindFullName( "Geometry.Arizona Eye" ) .\qj;20W eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 9ElCg" count = 0 VNtPKtx\ While GetOperationCount(eID)>count HOp-P8z GetOperation eID, count, op 1Fi86 If op.Type="ShiftZ" Then g3%t8O/M DeleteOperation eID,count Ij'NC C count=count-1 JkA|Qdj~Mr End If .M4IGOvOS count=count+1 m2Uc>S Wend N|2y"5 op.Type = "ShiftZ" 2`=6 %s
op.val1 = taq-0.01 D=)f
)-u' op.parent = parID '?yCq$& AddOperation eID, op t=#Pya 5ZAb]F90 Print "Set pupil diameter = " & pupilDiam ARfRsPxr AP\ofLmq 'Update AZ Eye subassembly Description 0X(]7b&~R eID = FindFullName( "Geometry.Arizona Eye" ) bxXiQa GetEntity eID, entity XO
F1c3'H entity.Description = "Accommodation = " & A & "D" s2v(=
SetEntity eID, entity *V;3~x! Q:|w%L*E
Update hD<f3_k Print "DONE!" s-VSH mi2o1"Jd$` End Sub ~-F?Mc ~L+]n0* 如果屈光度是4,光瞳直径是4,则会输出如下数据: e^$j5jV 7XyOB+aQO Accommodation = 4 Diopters cUDg M Pupil Diameter = 4 mm $'[q4 wo< Set aqueous humor thickness = 2.81 rFL$QC2 Set anterior lens radius = 10.4 and conic constant = -2.375869 cVq}c? Set posterior lens radius = -4.424557 and conic constant = -3.081019 9''p[V.3 Set lens thickness = 3.927 u&TdWZe Set lens index of refraction = 1.42672 3An(jt$%Q Set pupil diameter = 4 9F+ P@Kp DONE! e"+dTq8W 1ZKzumF q3'o|pp QQ:2987619807 |&hU=J
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