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简介 ehEXC dbGW`_zQ4 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。
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W=P 模型 [T', ZLR| ;czMsHu0X 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。 >b;fhdd:4 >LxYP7M Table 1. AZ眼睛模型的定义 )%8oE3O# 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. ~:ddTv?F W(9fCDO; 光源 VHXvm* gP.Q_/V 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。 ?4=8z8((! 5,!,mor$] | ]`gps 图1. 光源和提示信息使用 +~J?/ 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 0 1[LPN [X:mmM0gd 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 R}4o{l6 hd1H 图2. 字母F光源的设定方法光 "HFS5Bj' Ak%M,``(L 图3. 字母F在视网膜上位置点列图 lpkg(J#& 视网膜的散射 ~1YL <Ft6d 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 =tl[?6 MP, l*wVd Iw~3y{\ 图4. 视网膜朗伯散射设定 VY8p[` 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 +]Of f^s zcItZP |E-0P=h 图5. 视网膜重点采样规格设定 Ltpd:c 脚本 ~,yHE3B\G UwY <3ul 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: &9\z!r6mc J=>?D@K 图6. 用户对话框的创建与编辑 qWe1`.o 图7. 用户对话框编辑器 J)
v~ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 !o &+ 余下的脚本计算与屈光度有关的所有参数。 VP=(",` KC o<% 分析 BR\%aU$u 70&v`" 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 vOsd>3" sd\>|N?' 图7. 字母F在视网膜上颜色分析 c+AZ(6O?\ 脚本代码 94%gg0azp [.B)W); Option Explicit 'Remove this to enable non-dimensioned variables to be used. CFqoD l hu\HK81m Dim entity As T_ENTITY (r`+q[ Dim op As T_OPERATION 49}yw3- Dim mat As T_MODELMATERIAL OlhfBu)~ Dim A As Double A|tee@H*0 Dim pupilDiam As Double ` =dD6r Dim eID As Long !*u5HVn Dim parID As Long )F&@ M;2p' Dim count As Integer ?*E Y~'I Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double exV6&bdu Dim tlens As Double, nlens As Double i0,{*LD%^ Dim curv As Double, conic As Double ?UQVmE& Dim ok As Long W^0F(9~!( 8rXq-V_u Sub Main W5(t+$L. lDV8< '用户输入对话框 j11 \t Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 mp0p#8txi TextBox 220,21,40,21,.TextBox1 'default: 0 JU:!lyd Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 zB\g'F/ OKButton 40,91,90,21 KgVit+4u/ CancelButton 190,91,90,21 ]>/YU*\ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 [y}/QPR TextBox 220,49,40,21,.TextBox2 'default: 4 ]R}#3(]1 End Dialog y#HD1SZ Dim dlg As UserDialog j>eL&.d v83uGEq( ok = Dialog (dlg) WM: ~P$%cx _`/0/69 If ok=0 Then 'cancel button was pressed a*CP1@O Print "Execution cancelled." 9:A>a3KOH End ?+GbPG~ End If 93x.b]]" ?1 r@r 'Assign accommodation and pupil diameter & use defaults if field left empty ,oIZ5u{#, If dlg.TextBox1 = "" Then |`s}PcV A = 0 'Default accommodation MTb}um.($ Else Ol9U^ A = CDbl(dlg.TextBox1) FFbMG:>: End If "Na9Xea D[7K2G+ If dlg.TextBox2 = "" Then VbM5]UT/ pupilDiam = 4 'Default pupil diameter V-A^9AAPm Else yNc>s/ pupilDiam = CDbl(dlg.TextBox2) tzi+A;>c(v End If m<8j' [+ nen6!bw4 Print " " KU-z;}9s Print "Accommodation = " & A & " Diopters" cAyR)Y!I Print "Pupil Diameter = " & pupilDiam & " mm" ro@Zbm;P @5
kKMz ' Calculate new parameters with accommodation (&PamsV*8 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness i0-!! pPo?5s Rant = 12.0 - 0.4*A 'Radius of anterior lens |{PQ0DS CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens >1pD'UZIy7 90sM S]a Rpost = -5.224557 + 0.2*A 'Radius of posterior lens B_hob CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Qu!\Cx@ |rdG+> tlens = 3.767 + 0.04*A 'Lens thickness *Vfas|3hZI au"HIyi?k nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction P)1@HDN== kjaz{&P 'Adjust parameters to account for accommodation H4l:L(!D \2_>$:UoV '************************************************************************* "x\3`Qk 'Aqueous thickness (Position of Lens) =e$
#m; '************************************************************************* T~"tex] eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 0#K@^a GetCustomElement eID, entity (n" ) @kvp2P+O parID = FindFullName( "Geometry.Arizona Eye" ) OOl{ vR,HCI ' Delete any shift(s) in z t)cG_+rJ count = 0 CSr{MF`]e While GetOperationCount(eID)>count cnLC> _hY GetOperation eID, count, op v^@L?{"}8 If op.Type="ShiftZ" Then 1"/V?ArfL DeleteOperation eID,count <$?:| count=count-1 h4?+/jk7 End If <g*rTqT' count=count+1 fEVuH] Wend )V@qH] ++&F5'?g 'Set new shift in 'Dat.@j op.Type = "ShiftZ" > 7;JZuVo op.val1 = taq
n:wn(BC3 op.parent = parID "3\RJ?eW:S AddOperation eID, op C{!Czz.N Print "Set aqueous humor thickness = " & taq-0.55 <(f4#BP 1/cb;:h> '************************************************************************* '')G6-c/ 'Radius and conic constant of anterior lens cYbO)?mC_ '************************************************************************* .z[+sy_ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) YvYav d GetConic eID, entity, curv, conic uXhp+q\
A:D\!5= SetConic eID, entity, 1/Rant, CCant 7PQedZ<\ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant e. [+xOu` dH`a|SVW9 '************************************************************************* ;euWpE;E\# 'Radius and conic constant of posterior lens nn=JM7e\9 '************************************************************************* hA@X;Mh^w eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) _I8-0DnOM GetConic eID, entity, curv, conic A%GJ|h,i 4U6{E# SetConic eID, entity, 1/Rpost, CCpost piId5Gx7 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost wZC'BLD s]I],>}RU '************************************************************************* PN'8"8`{ 'Lens thickness (Position of posterior lens surface) }2\"(_ '************************************************************************* <5X@r#Lz -"cN9RF parID = FindFullName( "Geometry.Arizona Eye.Lens" ) [=9R5.)c $<aBawLZO ' Delete any z-shift(s) CD[7h count = 0 ^#=L?e While GetOperationCount(eID)>count 7q\c\qL GetOperation eID, count, op p0tv@8C> If op.Type="ShiftZ" Then .H>Rqikj DeleteOperation eID,count K&X'^|en count=count-1 I}q-J~s End If Gt1Up~\s count=count+1 AH7k|6ku<* Wend )a}5\V 9.@(& 'Set new z-shift 3jI.!xD` op.Type = "ShiftZ" g@U#Y#b@" op.val1 = tlens H 0h op.parent = parID =CVw0'yZ AddOperation eID, op asF-mf;D Print "Set lens thickness = " & tlens :rj78_e9 Q0--.Q=:Y '************************************************************************* t/$xzsoJZr 'Lens index of refraction O<E0L&4-& '************************************************************************* u qyf3bK eID = FindMaterial( "Lens" ) O-B3@qQ. h GetModelMaterial eID, mat Wp]EaYt2D OM.^>= mat.Nd = nlens e56#Qb@$\ SetModelMaterial eID, mat jG2w(h/" Print "Set lens index of refraction = " & nlens Cn55%: U;nC)'~YW9 '************************************************************************* g}D$`Nx: 'Pupil diameter J)G3Kq5>:b '************************************************************************* g\l;> eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) x L BG}C %b?Pasf. 'Adjust pupil diameter (trimming volume inner hole) }ot _k- $W?XxgkB? SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" <oO,CXF (LfVa`<1 ' Adjust pupil location to just in front of the lens ep?0@5D}] parID = FindFullName( "Geometry.Arizona Eye" ) m7"f6zSo( eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) }-vBRY count = 0 gfYB|VyWo While GetOperationCount(eID)>count Wk|z\OR( GetOperation eID, count, op Zb
2 If op.Type="ShiftZ" Then IBqY$K+l DeleteOperation eID,count H6I #Xj count=count-1 | rvr Sab) End If LnDj count=count+1 ]Rye AJ3 Wend ^55?VQB op.Type = "ShiftZ" /kz&9FM op.val1 = taq-0.01 m\f_u* op.parent = parID A|J\X=5 AddOperation eID, op OeYLL4H )
b10%n^ Print "Set pupil diameter = " & pupilDiam R
u5&xIQ W,~1KUTc 'Update AZ Eye subassembly Description @"!SU'* eID = FindFullName( "Geometry.Arizona Eye" ) G|lI=Q3f GetEntity eID, entity K5>:WiY entity.Description = "Accommodation = " & A & "D" `$H SetEntity eID, entity zl\#n:| j 7URg>i0 Update [S:)UvB Print "DONE!" &w0=/G/T=~ Elp!,(+&6 End Sub fYy.>m+P1 dmz3O(]$ 如果屈光度是4,光瞳直径是4,则会输出如下数据: }L!`K"^O& CiI:
uU Accommodation = 4 Diopters zRu`[b3u< Pupil Diameter = 4 mm |esjhf}H>v Set aqueous humor thickness = 2.81 G 7]wg>* Set anterior lens radius = 10.4 and conic constant = -2.375869 )^H9C"7T Set posterior lens radius = -4.424557 and conic constant = -3.081019 W~3tQ! Set lens thickness = 3.927 6t:c]G'J Set lens index of refraction = 1.42672 MuGg
z>CV[ Set pupil diameter = 4 14!J\`rI DONE! >e;STU
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