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简介 3,S5>~R= V?0|#=_mE 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。 3Akb|r ;'p X1T 模型 d+[hB4!l2 nke[}Hqf 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。 ~Se/uL;* F~)xZN3= Table 1. AZ眼睛模型的定义 *`=V"nXw$| 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. ZWh:&e( A!W(> 光源 //_v"dqP{) vEW;~FLd 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 )I$_wB!UV xH; 4lw By:A9s 图1. 光源和提示信息使用 Q0Dw2>~_K 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。 (B7M*e +8mfq\Y1 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。 &yp_wW- qwiM.b5 图2. 字母F光源的设定方法光 zA\DI]:+ _ N.ZpKVu 图3. 字母F在视网膜上位置点列图 V:2|l!l* 视网膜的散射 57%:0loW +c+#InsY 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。 p`T7Y\\#! h9 [ov) uRxo,.}c 图4. 视网膜朗伯散射设定 . m@Sk`s 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。 !!DHfAV] mWfzL'* .y#@~H($ 图5. 视网膜重点采样规格设定 '!b1~+PV 脚本 7z5AI!s_ Ym2![FC1 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: E{(7]Wri G0xk @SE 图6. 用户对话框的创建与编辑 nhiCV>@y 图7. 用户对话框编辑器 &5~bJ]P 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。 +p>tO\mo 余下的脚本计算与屈光度有关的所有参数。 n;/yo~RR
AQ'~EbH( 分析 }gGcYRT ,M5zhp$ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 -jFvDf,M,D cOxF.(L 图7. 字母F在视网膜上颜色分析 D}&U3?g= 脚本代码 k`'^e/ e#<%`\qH Option Explicit 'Remove this to enable non-dimensioned variables to be used. j^Bo0{{ 5O]ph[7 Dim entity As T_ENTITY 118A6qyi Dim op As T_OPERATION ROW8YTYb Dim mat As T_MODELMATERIAL !%_}Rv!JT Dim A As Double _@ev(B Dim pupilDiam As Double !QSL8v@c Dim eID As Long =M*31>"I0 Dim parID As Long "!+q0l1]@ Dim count As Integer /!P,o}l7 Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double i%:oO
KI Dim tlens As Double, nlens As Double N0vr>e` Dim curv As Double, conic As Double Zb^0EbV Dim ok As Long Kj;Q;Ii DrC4oxS 1 Sub Main MOJKz!% ~]O~a}]g( '用户输入对话框 L^Fni~ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ~Yb5FYE TextBox 220,21,40,21,.TextBox1 'default: 0 qa.nm4"6+ Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ;S7MP`o@ OKButton 40,91,90,21 4`7N}$j#, CancelButton 190,91,90,21 <V5(5gx Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 u$X[= TextBox 220,49,40,21,.TextBox2 'default: 4 +>M^p2l*& End Dialog [?Cv^t${+ Dim dlg As UserDialog %7xx"$P:R 2ed$5.D ok = Dialog (dlg) AD_")_B|i nxS|] If ok=0 Then 'cancel button was pressed N>/!e787OU Print "Execution cancelled." I~-W4{ End sC(IeGbX End If K7 -AVMY |Rd?s0u 'Assign accommodation and pupil diameter & use defaults if field left empty ; $i{>mDT If dlg.TextBox1 = "" Then qRZv[T%*Q A = 0 'Default accommodation -Wd2FD^x Else .D!0$W mOZ A = CDbl(dlg.TextBox1) nQy.?*X End If sf<S#;aYqn ?\"GT] 5D If dlg.TextBox2 = "" Then J<'[P$D pupilDiam = 4 'Default pupil diameter ]bLI!2Kr Else %JF^@\E!| pupilDiam = CDbl(dlg.TextBox2) 4>-'w MW") End If :PE{2* 'y[74?1 Print " " ePv3M&\J Print "Accommodation = " & A & " Diopters" |r>+\" X Print "Pupil Diameter = " & pupilDiam & " mm" _~/F- zo6|1xq ' Calculate new parameters with accommodation * ?x$q/a taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness Kkcb'aDR K|,P Rant = 12.0 - 0.4*A 'Radius of anterior lens =PYfk6j9 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens Y3=5J\d!a H=RzY-\a% Rpost = -5.224557 + 0.2*A 'Radius of posterior lens |;sL*Vr CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens iO 9.SF0:
zisf8x7^W tlens = 3.767 + 0.04*A 'Lens thickness &W+lwEu ]9qY(m nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction +O"!* 6B`XHdCq 'Adjust parameters to account for accommodation 'K&^y%~py, ndg1E;> '************************************************************************* !xk`oW 'Aqueous thickness (Position of Lens) Oy
EOb> '************************************************************************* v=5H,4UMA eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 7+
+Fak GetCustomElement eID, entity C# zYZ JZ |ecK~+ parID = FindFullName( "Geometry.Arizona Eye" ) &n$kVNE -UY5T@as ' Delete any shift(s) in z Cm@rXA/ count = 0 _|+}4 ap While GetOperationCount(eID)>count m';j#j)w GetOperation eID, count, op bpP-wA^Hd If op.Type="ShiftZ" Then
IR JN DeleteOperation eID,count -&q@|h' count=count-1 ;>hRj! End If gxnIur) count=count+1 # dA9v7 Wend {=K);z Ey|{yUmU+ 'Set new shift in eJbZA&: op.Type = "ShiftZ" 43wm_4C!H op.val1 = taq gy5 ^JL op.parent = parID 1.24ZX AddOperation eID, op T*o!#E. Print "Set aqueous humor thickness = " & taq-0.55 ~:FF"T> t57MKDn '************************************************************************* L a>fvm 'Radius and conic constant of anterior lens ^_\S)P2c '************************************************************************* TOT#l6yqdd eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) u,RR|/@ GetConic eID, entity, curv, conic tJBj9{ '+EtnWHs SetConic eID, entity, 1/Rant, CCant f \ E9u} Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ='A VI-go5 H!'Ek[s+ '************************************************************************* 3d>8~ANi=% 'Radius and conic constant of posterior lens wqxChTbs '************************************************************************* [>$?/DM eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 1X5MknA GetConic eID, entity, curv, conic 3vXa#f>P< IA%|OVAfF SetConic eID, entity, 1/Rpost, CCpost -7Bg5{FA Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 1.0: joz0D!-"# '*************************************************************************
&x?m5%^l 'Lens thickness (Position of posterior lens surface) :6gRoMb] '************************************************************************* m!5MGq~ gmqA 5W~y parID = FindFullName( "Geometry.Arizona Eye.Lens" ) V15/~ ;!S i_b2 ' Delete any z-shift(s) &|-jU+r}B count = 0 ZH)Jq^^RI While GetOperationCount(eID)>count ~6A;H$dr GetOperation eID, count, op FuC#w 9_ If op.Type="ShiftZ" Then .oS[ DTn5S DeleteOperation eID,count ?;]Xc~ count=count-1 r2%Qk End If F MX^k count=count+1 >,x&L[3 Wend l{I.l jl>jy6T 'Set new z-shift K
0e*K=UM op.Type = "ShiftZ" 1%$t;R op.val1 = tlens E4$y|Ni" op.parent = parID qTrM*/m:]L AddOperation eID, op 5BJn_< Print "Set lens thickness = " & tlens CKnPMvmz 1B#iJZ} '************************************************************************* VS\| f'E 'Lens index of refraction s
!IvUc7' '************************************************************************* :}UjX|D eID = FindMaterial( "Lens" ) wP7
E8' GetModelMaterial eID, mat )[ QT?; DH7]TRCMZ) mat.Nd = nlens {[4.<|26 SetModelMaterial eID, mat u4tv=+jh Print "Set lens index of refraction = " & nlens 1Ep7CV-n} \kZ@2.pN '************************************************************************* j#~ S"t 'Pupil diameter 2KlVj]!7 '************************************************************************* 2:RFPK eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) T[evh]koB d]USk&8 'Adjust pupil diameter (trimming volume inner hole) u9{SG^ C|V5@O?;&
SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" mBxMDnh jR9;<qT/ ' Adjust pupil location to just in front of the lens d\R "?Sg parID = FindFullName( "Geometry.Arizona Eye" ) -_xTs(;|8 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) JXV#V7 count = 0 Z;z,dw While GetOperationCount(eID)>count :IX,mDO GetOperation eID, count, op l,6' S8= If op.Type="ShiftZ" Then L&KL]n DeleteOperation eID,count (}5};v count=count-1 e(?1`1 End If *k,{[b count=count+1 ~W-l|-eogz Wend `z`=!1 op.Type = "ShiftZ" K8/jfm op.val1 = taq-0.01 'C=(?H)M op.parent = parID ![!,i\x AddOperation eID, op 1LaJ
hrp? w`EC6ZN Print "Set pupil diameter = " & pupilDiam _%3p&1ld c'XSs 'Update AZ Eye subassembly Description i%GiWanG eID = FindFullName( "Geometry.Arizona Eye" ) 2%v6h GetEntity eID, entity guVuO entity.Description = "Accommodation = " & A & "D" 1Vkb}A,' SetEntity eID, entity )gz]F_ D^xg2D Update :]4s;q:m Print "DONE!" r:PYAb=g aTfc>A; End Sub 2c51kG77E /eT9W[a 如果屈光度是4,光瞳直径是4,则会输出如下数据: )6BySk (0l>P]"n Accommodation = 4 Diopters qo}yEl1 Pupil Diameter = 4 mm ~$ Po3]{s Set aqueous humor thickness = 2.81 D-D8La?0p Set anterior lens radius = 10.4 and conic constant = -2.375869 AQtOTT$ Set posterior lens radius = -4.424557 and conic constant = -3.081019 3s?ZyQy Set lens thickness = 3.927 P^ht$)Y Set lens index of refraction = 1.42672 uP$i2Cy Set pupil diameter = 4 @NiLKcL# DONE! 1cx%+-
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