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简介 @pz2}Hd| }S4Fy3) 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。 |Gi/=[Tp ?K"]XXsI 模型 2]wh1) {`> x"Y5 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。 %94"e7Hy LTHS&3%2 Table 1. AZ眼睛模型的定义 i%2K%5{)$D 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. =Ju}{ bX Pc<ZfO # 光源 9Wn0YIc RP$A"<goP 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。 [cq>QMW uwJkqlUOz <U*d
图1. 光源和提示信息使用 Y/gCtSF 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。 )U`
c9*. UpbzH(?# 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。 (WC<X Kf 7w|s8B 图2. 字母F光源的设定方法光 ux=@"!PJ ~7v^7;tT 图3. 字母F在视网膜上位置点列图 "$_ypgRrSR 视网膜的散射 w&H7S{ 9]iDNa/D 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 tq[C"| dH `XQ5> c O?_'6T 图4. 视网膜朗伯散射设定 cP,jC(<N 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 23PSv8;EM u|E,Wy1 EifYK 图5. 视网膜重点采样规格设定 TocqoYX{{ 脚本 RN0Rk 8AC {ib`mC^ 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: s*;~CH-[ D c^d$gh 图6. 用户对话框的创建与编辑 h!MT5B)r. 图7. 用户对话框编辑器 2mRso.Ah 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。 v|e>zm< 余下的脚本计算与屈光度有关的所有参数。 b\?`721BG ^VQiq7 xm 分析 u4Sa4o iZUBw 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 S$Wd}2> 8^T' a^Wt 图7. 字母F在视网膜上颜色分析 h W-[omr0 脚本代码 G} p~VLf wBf
bpoE7 Option Explicit 'Remove this to enable non-dimensioned variables to be used. *+G K?Ga /cg!Ap5 Dim entity As T_ENTITY tU(6%zvR Dim op As T_OPERATION D4G{= Y}G Dim mat As T_MODELMATERIAL m$kmoY/ Dim A As Double WrV|<%EQh Dim pupilDiam As Double Rj8l]m6U9 Dim eID As Long V1+IqOXAIp Dim parID As Long =J:~AD# Dim count As Integer TS-[p d Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double :=/DF Dim tlens As Double, nlens As Double `f(!i mN Dim curv As Double, conic As Double @{bf]Oc Dim ok As Long F>&8b^v bn %Z.!Bm: Sub Main It4F;Ah vO\CPb
%/ '用户输入对话框 f~53:;L/ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 KS%,N _F< TextBox 220,21,40,21,.TextBox1 'default: 0 Uc/%4Gx Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 |i|O9^*% OKButton 40,91,90,21 __a9}m4i7x CancelButton 190,91,90,21 @?t) UE Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 =[P || TextBox 220,49,40,21,.TextBox2 'default: 4 GK)hK-
End Dialog hfY2pG9N Dim dlg As UserDialog ;;2s{{(R AojX)_"z ok = Dialog (dlg) p4/D%*G^` /rquI y^ If ok=0 Then 'cancel button was pressed J[^-k!9M Print "Execution cancelled." CkOd>Kn End \X(.%5xC End If m$U2|5un& p}h)WjC 'Assign accommodation and pupil diameter & use defaults if field left empty RSp=If+4 If dlg.TextBox1 = "" Then S -im
o A = 0 'Default accommodation gG#M-2P Else DCHU=r A = CDbl(dlg.TextBox1) \=w|Zeu{l End If V%"aU}
CrK}mbe If dlg.TextBox2 = "" Then AH ;h#dT pupilDiam = 4 'Default pupil diameter [z/OY&kF Else ,Q^.SHP8 pupilDiam = CDbl(dlg.TextBox2) i`X/d= End If -?j'<g0 Mq-;sPsFP Print " " $[H3O(B0* Print "Accommodation = " & A & " Diopters" R+P1 +5 Print "Pupil Diameter = " & pupilDiam & " mm" 0PZpE
"$X xw`Pq6 ' Calculate new parameters with accommodation Qv#]T, taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness gVb;sk^ aK'BC>uFI Rant = 12.0 - 0.4*A 'Radius of anterior lens p2\@E}
z CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ?v6xaVg: SDZ/rC!C Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ,XR1N$LN8_ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens f`T#=6C4| Y\s@'UoVN tlens = 3.767 + 0.04*A 'Lens thickness iOw'NxmY :Oxrw5`= nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 4v Ug:'DM ?8pR RzV$ 'Adjust parameters to account for accommodation J#MUtpPdQ $vx]\`
^ '************************************************************************* uq'T:d 'Aqueous thickness (Position of Lens) H}`}qu #~V '************************************************************************* qEE
V& eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6,| !zaeS GetCustomElement eID, entity Z!DGCw |pA3ZWm parID = FindFullName( "Geometry.Arizona Eye" ) X$)<>e]!> )ui]vS:> ' Delete any shift(s) in z 2{(_{9<>z count = 0 h<JV6h :8 While GetOperationCount(eID)>count x= X"4Mj0) GetOperation eID, count, op "|`euxYV If op.Type="ShiftZ" Then ogtl
UCUD DeleteOperation eID,count 'Y`or14E count=count-1 w6aq/m"' End If bu$YW' count=count+1 E&9BeU
a# Wend yJNQO'wcv E0G"B'x 'Set new shift in "&W80,O3 op.Type = "ShiftZ" l]C#bL>i op.val1 = taq 0w)Gb}o$ op.parent = parID },+ &y^ AddOperation eID, op b"iPuN!p Print "Set aqueous humor thickness = " & taq-0.55 ^zn&"@ E+)3n[G '************************************************************************* R.^
Y'TLyc 'Radius and conic constant of anterior lens Qq+$ea?> '************************************************************************* ~lib~Y'- eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) bi~1d"j GetConic eID, entity, curv, conic opqY@>Vh& gaV>WF SetConic eID, entity, 1/Rant, CCant 05hjC Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant X;'H@GU0 Ce_k&[AJF '************************************************************************* pr-=<[ d 'Radius and conic constant of posterior lens 9X/]O<i,Es '************************************************************************* t\S=u y eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) -aPRLHR GetConic eID, entity, curv, conic K,j'!VQA4g $\Oc]% SetConic eID, entity, 1/Rpost, CCpost owQSy9Az Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost *!NxtB!LC /F@CrNFb( '************************************************************************* <<w*_GM 'Lens thickness (Position of posterior lens surface) _xY
dnTEl '************************************************************************* }ff+RGxLIG 5Q7Z$A1a
9 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) [3 D*DyQt M47t(9krV ' Delete any z-shift(s) 4]G J+a count = 0 l$Y*ii While GetOperationCount(eID)>count p?-qlPl GetOperation eID, count, op _TntZv.? If op.Type="ShiftZ" Then zCji]: DeleteOperation eID,count N2 4J!L count=count-1 y~Z7sx0 End If WIKSz
{"=/ count=count+1 \?tE,\Ln Wend i+90##4<? +9exap27 'Set new z-shift WYJH+"@%j op.Type = "ShiftZ" )s N}ClgJ op.val1 = tlens V9Pw\K!w#\ op.parent = parID WA((>Daf] AddOperation eID, op g286
P_a`* Print "Set lens thickness = " & tlens DrK@y8 CFXr=.yz '************************************************************************* ;&c9!LfP 'Lens index of refraction (h"-#q8$ '************************************************************************* UMUG~P&@ eID = FindMaterial( "Lens" ) ?k`UQi]Q GetModelMaterial eID, mat .fAHP
5- Z\r?>2 mat.Nd = nlens F1*xY%Jv^M SetModelMaterial eID, mat #$X _,+<HZ Print "Set lens index of refraction = " & nlens U0=: `G2l S-5O$EnD '************************************************************************* R0~w F> 'Pupil diameter mor[AJ '************************************************************************* &yRR!1n)H eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) BdrYc^?JL] _9yW; i- 'Adjust pupil diameter (trimming volume inner hole) J4%"38l `ztp u
~? SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" `{%ImXQF @4G{L8Q} ' Adjust pupil location to just in front of the lens ;;S9kNp^v parID = FindFullName( "Geometry.Arizona Eye" ) V3Ep&<=/ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ,Cd4Q7T count = 0 ?{L5=X@$$ While GetOperationCount(eID)>count 9zl-C*9vj GetOperation eID, count, op ' ""s%C+ If op.Type="ShiftZ" Then L"RE[" m DeleteOperation eID,count 1}R\L" count=count-1 6zIK%< End If V%'' GF count=count+1 h<G7ocu ! Wend 9^7z"*@# op.Type = "ShiftZ" B[~Q0lPih op.val1 = taq-0.01 G/ H>M%M op.parent = parID 2y IDyo AddOperation eID, op 5,|of{8 </pt($ Print "Set pupil diameter = " & pupilDiam iD.p KG (&-I-#i 'Update AZ Eye subassembly Description 97dF eID = FindFullName( "Geometry.Arizona Eye" ) }{}?mQ GetEntity eID, entity WMS~Bk+! entity.Description = "Accommodation = " & A & "D" z))rk vL% SetEntity eID, entity %Z8wUG uS JLIb Update F. I\?b Print "DONE!" BCO (,k 7^;-[?l
End Sub BoXPX2: oT|:gih5 如果屈光度是4,光瞳直径是4,则会输出如下数据: YZAQt*x drvz
[
9; Accommodation = 4 Diopters \!"3yd Pupil Diameter = 4 mm &oE'|^G Set aqueous humor thickness = 2.81 \E6 0 Set anterior lens radius = 10.4 and conic constant = -2.375869 Y.q$"lm7k Set posterior lens radius = -4.424557 and conic constant = -3.081019 *x_e] /} Set lens thickness = 3.927 #r,!-;^'p Set lens index of refraction = 1.42672 fZ(k"*\MZ Set pupil diameter = 4 7Y)i>[u3 DONE! MO?
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