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简介 ayuj)]b -1~bWRYq 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。 m6)8L?B C w`v\
9 模型 -U(T eW]K~SPd7 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。 }r6SV%]: :grJ}i-D Table 1. AZ眼睛模型的定义 }N1Z7G 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. INsc!xOQ GH![rK 光源 ";cWK29\f C$xU!9K[+ 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 *Y6BPFE*4 vW
0m% CEE`nn 图1. 光源和提示信息使用 H~1*`m 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 Aq}]{gfQ1 %<JjftNQ 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 67Z|=B!7 16[>af0<g 图2. 字母F光源的设定方法光 EUU9JnQhBJ ._"U{
f2V 图3. 字母F在视网膜上位置点列图 TGGeTtk= 视网膜的散射 [J0L7p*6 Funep[rA 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 K>9]I97g' 6|t4\' [nxjPx9- 图4. 视网膜朗伯散射设定 <*~vZT i( 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 -@-cG\{ r@0HqZx` s!``OyI/Z 图5. 视网膜重点采样规格设定 {n=)<w 脚本 a0Cf.[L cOthq87: 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: CE:TQzg B0NKav 图6. 用户对话框的创建与编辑 d>eVR 图7. 用户对话框编辑器 .R;HH_ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 7\'vSHIL 余下的脚本计算与屈光度有关的所有参数。 ` ZXX[&C Xz&Hfs"/J 分析 [s"3g\L'; at${^,& 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 }kdYR#{s G eN('0 图7. 字母F在视网膜上颜色分析 |S|0'C* 脚本代码 \zw0*;&U /Ou`$2H87 Option Explicit 'Remove this to enable non-dimensioned variables to be used. oJbD|m C2Fklp6 Dim entity As T_ENTITY #.UooFk+Y Dim op As T_OPERATION v-J*PB.0p Dim mat As T_MODELMATERIAL (m4`l_ Dim A As Double \@vR*E Dim pupilDiam As Double lwaxj7 Dim eID As Long 8i=J(5= Dim parID As Long *g]q~\b/; Dim count As Integer +^YXqOXU Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double t&^9o$ Dim tlens As Double, nlens As Double 3:7J@> Dim curv As Double, conic As Double mS5'q q;t Dim ok As Long -$J\BkI {$)zC*l Sub Main \dTX%<5D N_lQz(nG/2 '用户输入对话框 #ok1qT9_ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 M5s>;q) TextBox 220,21,40,21,.TextBox1 'default: 0 CTQF+Oe8O Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Lz's!b OKButton 40,91,90,21 o8.KakrPP CancelButton 190,91,90,21 `@q[&^ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 I?LJXo \O TextBox 220,49,40,21,.TextBox2 'default: 4 4eK!1|1 End Dialog xQ9P'ru Dim dlg As UserDialog \:9dt8(-U lfp[(Ph)9 ok = Dialog (dlg) i,1=5@rw5 O-y/K2MC* If ok=0 Then 'cancel button was pressed G?CaCleG Print "Execution cancelled." z %{Z End 'd 4I/ End If KWbnSL8 |1wfLJ4--l 'Assign accommodation and pupil diameter & use defaults if field left empty L|.q19b* If dlg.TextBox1 = "" Then A(G%9'T A = 0 'Default accommodation b<>GF-`w Else `&2~\o/ A = CDbl(dlg.TextBox1) 'g.9
goQ End If 5[}3j1 q&OF?z7H If dlg.TextBox2 = "" Then ["Mq pupilDiam = 4 'Default pupil diameter yoiKt;
S Else /|V!2dQs" pupilDiam = CDbl(dlg.TextBox2) 8+Sa$R End If nf=*KS\v Uyf<:8U\ Print " " JoeU J3N Print "Accommodation = " & A & " Diopters" ([SrIG> X Print "Pupil Diameter = " & pupilDiam & " mm" GSo&$T;B6 mW~t/$Y$ ' Calculate new parameters with accommodation 2u9O+]EP taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness &<hDl<E q)vdDdRe_ Rant = 12.0 - 0.4*A 'Radius of anterior lens HYm
| CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens /{@^h#4M1 z-};.!L^ Rpost = -5.224557 + 0.2*A 'Radius of posterior lens };;\&# CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens M &`ZF n${,r tlens = 3.767 + 0.04*A 'Lens thickness P7ktr?V0a W <.h@Rz+ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction C><]o OiBDI3,|+ 'Adjust parameters to account for accommodation ms9zp?M Tk~RT<\Ab+ '************************************************************************* b{Srd3 'Aqueous thickness (Position of Lens) ?4>uGaU\ '************************************************************************* Sc!]M 5 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) v`& GetCustomElement eID, entity 74f3a|vx/ lS1-e0,h1 parID = FindFullName( "Geometry.Arizona Eye" ) 6G2s^P1Dl@
qkQ_# ' Delete any shift(s) in z CUJP"u>8M count = 0 ~q0g7?}& While GetOperationCount(eID)>count )D_ZZPq_ GetOperation eID, count, op 1K(a=o[Ce If op.Type="ShiftZ" Then r*$$82s DeleteOperation eID,count Arvxl(R\4 count=count-1 <3?T^/8 End If 0LI:R'P+P[ count=count+1 0u0<)gdX Wend !
C}t)R]^ Ve/"9?Y_ 'Set new shift in b-Fv
vA op.Type = "ShiftZ" 5vxKkk&i4l op.val1 = taq :CH*~o op.parent = parID 'p0|wM_ AddOperation eID, op $xx5+A%, Print "Set aqueous humor thickness = " & taq-0.55 z3F ^OU 9iMQq40 '************************************************************************* ;VQFz&Q$u 'Radius and conic constant of anterior lens MYVUOd, '************************************************************************* >y
P`8Oq[ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 31BN ?q GetConic eID, entity, curv, conic "= H.$
+ 5<0d2bK$ SetConic eID, entity, 1/Rant, CCant P<+y%g(({ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant !: e0cV *7L*:g '************************************************************************* !AR$JUnX 'Radius and conic constant of posterior lens iQ[0d.(A '************************************************************************* TWv${m zE eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) m>po+7"b GetConic eID, entity, curv, conic 79.J`}# 8 I'1~d%$ SetConic eID, entity, 1/Rpost, CCpost o;#{N~4[$ Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost D+ki2UVt& Y~RZf /` '************************************************************************* HSt|Ua.c/h 'Lens thickness (Position of posterior lens surface) #
SmM5% '************************************************************************* +{%@kX<V_ %}z/_QZ parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6r"PtHr ,+p&ZpH ' Delete any z-shift(s) m wuFXu/ count = 0 kvU0$1 While GetOperationCount(eID)>count eYL7G-3 GetOperation eID, count, op uj.~/W1,! If op.Type="ShiftZ" Then K;2]c3T DeleteOperation eID,count pv;c<NQ'1 count=count-1 =k4yWC5- End If +uPN+CgQ@ count=count+1 /)80@ Wend ^q"wd?((h $s2-O!P? 'Set new z-shift l+'1>T.I op.Type = "ShiftZ" %iPu51+= op.val1 = tlens ?Az pb}# op.parent = parID Tb-`0^y&X1 AddOperation eID, op ]{9oB-;, Print "Set lens thickness = " & tlens 0/.#V*KM }9C5U>? '************************************************************************* -;$+`<% 'Lens index of refraction 39!o!_g '************************************************************************* %EPqJ(T eID = FindMaterial( "Lens" ) *$(=I6b GetModelMaterial eID, mat O$
i6r]j_ `w Sg/ mat.Nd = nlens m[^;HwJ SetModelMaterial eID, mat i_GE9A=h Print "Set lens index of refraction = " & nlens BfOG e!Si @C=, >+D '************************************************************************* oB[3?e 'Pupil diameter ;>=hQC{f> '************************************************************************* Q}jbk9gM5 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) hMJ \a [BhpfZNKRA 'Adjust pupil diameter (trimming volume inner hole) f5a%/1? gB3&AQ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ?Di,' 81a&99k# ' Adjust pupil location to just in front of the lens Y=G *[G# parID = FindFullName( "Geometry.Arizona Eye" ) w8%yX$< eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) m@JU).NKCS count = 0 o*n""m While GetOperationCount(eID)>count _}]o~ GetOperation eID, count, op ;J\{r$q If op.Type="ShiftZ" Then 8O{]ML DeleteOperation eID,count HZQ I | count=count-1 #)R;6" End If u2<:mu[|P count=count+1 HqgTu` Wend ^OG^%
x" op.Type = "ShiftZ" KHr8\qLH op.val1 = taq-0.01 $#4z>~0 op.parent = parID jn\\,n"6 AddOperation eID, op RA[` Cp" LWbWj ^ Print "Set pupil diameter = " & pupilDiam ?p5RSt 7k6rhf7H 'Update AZ Eye subassembly Description tBBN62^X eID = FindFullName( "Geometry.Arizona Eye" ) QBto$!}) GetEntity eID, entity =mqV&FgRo entity.Description = "Accommodation = " & A & "D" !xo@i XL SetEntity eID, entity U7crbj;c)d %o4d43uZ Update &P3B Print "DONE!" 8Z3+S)6 *MagicA End Sub Wc3!aLNx kq%`9,XE 如果屈光度是4,光瞳直径是4,则会输出如下数据: D3.sR\Hxf M/V
>25` Accommodation = 4 Diopters P>N\q Pupil Diameter = 4 mm `*oLEXYN Set aqueous humor thickness = 2.81 LR)is
Set anterior lens radius = 10.4 and conic constant = -2.375869 y6*i/3 Set posterior lens radius = -4.424557 and conic constant = -3.081019 62(WZX%b Set lens thickness = 3.927 nBiSc* Set lens index of refraction = 1.42672 ObM5v rEk| Set pupil diameter = 4 tDN-I5q DONE! 3C,e>zE} N_0&3PUSM #gN{8Yk> QQ:2987619807 XVv7W5/q]
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