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简介 ;8XRs?xyd I;"pPJ3G 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。 0sU*3 r? C{m%]jKH 模型 9s_^?q zMA;1Na 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。 2?
yo e(/F:ZEh Table 1. AZ眼睛模型的定义 ^?H|RAp 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. Dfzj/spFV @%x2d1FS 光源 +@^);b6 1xEOYM) 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。 MhCU;
! mj$Ucql /;(ji?wN 图1. 光源和提示信息使用 C`t@tgT 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 uarfH]T{ L~t<
0\r 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 -_Z 4)"k b9X*2pnWJ 图2. 字母F光源的设定方法光 1N(1h
D YX-~?Pl 图3. 字母F在视网膜上位置点列图 k*)sz 视网膜的散射 8 5ET$YV BZ:tVfg. 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。 \\\8{jq LWJ ?p-X -c]AS[( 图4. 视网膜朗伯散射设定 <skqq+ 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。 Jf?6y~X>Y e^\e;>Dh> hm73Zy 图5. 视网膜重点采样规格设定 V($V8P/ 脚本 Godrz*" #PD6LO 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: gm)Uyr$ LE<J<~2Z 图6. 用户对话框的创建与编辑 YS^!'IyG/B 图7. 用户对话框编辑器 T8A(W 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。 GqR XNs! 余下的脚本计算与屈光度有关的所有参数。 A`Dx]y w1"+HJd 分析 L_Gw:"-+Q 0pMN@Cz6 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 Oq.ss!/z [-$
Do 图7. 字母F在视网膜上颜色分析 %a~/q0o> 脚本代码 e9[72V iWD|F- Option Explicit 'Remove this to enable non-dimensioned variables to be used. u5A?; a =|P
&G~] Dim entity As T_ENTITY ;B=aK"\ Dim op As T_OPERATION DO80HS3ZD Dim mat As T_MODELMATERIAL *
HKu%g Dim A As Double l{Df{1b. Dim pupilDiam As Double b&F9<XLqq Dim eID As Long RJ3oI+gI Dim parID As Long ;`#R9\C=h Dim count As Integer A!bG 2{r Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double /dYv@OU? Dim tlens As Double, nlens As Double VdK%m`;2 Dim curv As Double, conic As Double 3>1^$0iq Dim ok As Long W\kli';jyC Y'|,vG Sub Main xW`y7Q }p z/{X{+Z '用户输入对话框 D|9+:Y Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1
Bx#i?=*W TextBox 220,21,40,21,.TextBox1 'default: 0 DRQx5fgL Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 N;|^C{uz OKButton 40,91,90,21 ~'_cBJ
'XD CancelButton 190,91,90,21 S\TXx79PhC Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 en< $.aY TextBox 220,49,40,21,.TextBox2 'default: 4 06pvI} End Dialog bGWfMu=n Dim dlg As UserDialog l\s!A&L a<G&}|6 ok = Dialog (dlg) U7s$';y"% 4qie&:4j If ok=0 Then 'cancel button was pressed _!',%+ Print "Execution cancelled." -)}s{[]d6m End =hKAwk/^ End If Z0Z6aZeb @yuiNj.T 'Assign accommodation and pupil diameter & use defaults if field left empty y>a?<*Y+e If dlg.TextBox1 = "" Then &-ropY A = 0 'Default accommodation 9wWBE<}>u Else "@UQSf, A = CDbl(dlg.TextBox1) 3%Y:+%VE End If &$
h~Q B3#G If dlg.TextBox2 = "" Then k]@]a pupilDiam = 4 'Default pupil diameter Uq
.6h Else )Z/"P\qo pupilDiam = CDbl(dlg.TextBox2) "bo0O7InOV End If P"w\hF \]9)%3I Print " " >pU9}2fpT Print "Accommodation = " & A & " Diopters" Op'a=4x] Print "Pupil Diameter = " & pupilDiam & " mm" [%P#ieD4 w"^h<]b ' Calculate new parameters with accommodation ^LMgOA(7 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness cl~Yx4 e,U:H~+] Rant = 12.0 - 0.4*A 'Radius of anterior lens ote,`h CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens (GSP3KKo*G zK<af Rpost = -5.224557 + 0.2*A 'Radius of posterior lens x)::^'74 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens M5^Y
W#e A'|!O:s
tlens = 3.767 + 0.04*A 'Lens thickness W7>2&$ 9@
tp# nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction Zl9@E;|= w_(3{P[Iz 'Adjust parameters to account for accommodation HxG8'G isZ5s\ '************************************************************************* YT\@fgBt 'Aqueous thickness (Position of Lens) ":Wq<Z' '************************************************************************* bNea5u## eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Y?0/f[Ax,y GetCustomElement eID, entity JVE\{ e) GShxPH{_j parID = FindFullName( "Geometry.Arizona Eye" ) -#|D> :?t~|7O: ' Delete any shift(s) in z HK@ij,px count = 0 @]=40Yj~w While GetOperationCount(eID)>count }s}g}t8v- GetOperation eID, count, op [?!I*=*b If op.Type="ShiftZ" Then 1+x"
5<(W DeleteOperation eID,count q-F
K=r 5 count=count-1 pO`KtagL End If 8|a./%gixs count=count+1 (`tRJWbdz Wend ScPVjqG2{ #oUNF0L@6 'Set new shift in 2{OR#v~ op.Type = "ShiftZ" %Y^J'' op.val1 = taq [{x}# oRSE op.parent = parID AYts
&+ AddOperation eID, op J+6zV m Print "Set aqueous humor thickness = " & taq-0.55 Rr)+M3' @YJI'Hf67 '************************************************************************* 4U}qrN~= 'Radius and conic constant of anterior lens 3N7H7(IR '************************************************************************* TktH28tK eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) K+B978XD GetConic eID, entity, curv, conic UiFH*HT .|UQ)J?s SetConic eID, entity, 1/Rant, CCant u^80NR Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant G-aR%]7$g $<}c[Nm '************************************************************************* Zi!Ta"}8 'Radius and conic constant of posterior lens $NXP)Lic) '************************************************************************* F@w; .e! eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) xs$$fPAQ GetConic eID, entity, curv, conic iGN\ >m} HgI!q<) SetConic eID, entity, 1/Rpost, CCpost }lJ;|kx$
Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost bzgC+yT zG!nqSDG '************************************************************************* }U_
'7_JT 'Lens thickness (Position of posterior lens surface) "t@p9> '************************************************************************* 8%?y)K^
D {@Mr7*u parID = FindFullName( "Geometry.Arizona Eye.Lens" ) [Kgb#L'{ uV/5f#) ' Delete any z-shift(s) &p0e)o~Ux count = 0 UO/sv2CN While GetOperationCount(eID)>count VtreOJ+ GetOperation eID, count, op wp[Ug2;G If op.Type="ShiftZ" Then ,"(L2+Yp DeleteOperation eID,count @f!X%)\;x count=count-1 okNo-\Dh! End If sp9gz~Kq count=count+1 d0cL9&~qW Wend NFK`, $6hPTc<C 'Set new z-shift 1<@SMcj> op.Type = "ShiftZ" I.2J-pu} op.val1 = tlens x&}]8S) op.parent = parID 3a/n/_D AddOperation eID, op r~w.J+W Print "Set lens thickness = " & tlens '%)R}wgV VJh8`PVX '************************************************************************* 4zug9kFK 'Lens index of refraction 9>""xt '************************************************************************* Yo-}uTkw eID = FindMaterial( "Lens" ) Cs,H#L GetModelMaterial eID, mat )G? qX.D wb-yAQ8 mat.Nd = nlens vW63j't_ SetModelMaterial eID, mat IgT`on3Y Print "Set lens index of refraction = " & nlens B5e9'X^
[ D28`?B9( '************************************************************************* +/:tap|V 'Pupil diameter ?GhyVXS y. '************************************************************************* 5En6f`nR{ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 1v o)]ff K%(y<%Xp 'Adjust pupil diameter (trimming volume inner hole) *Ak .KBg +^)v"@,VP SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" P T"}2sR) _KT!OYH ' Adjust pupil location to just in front of the lens jYsAL=oh,* parID = FindFullName( "Geometry.Arizona Eye" ) R[WiW RfD eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) }`"`VLh count = 0 4
1_gak; While GetOperationCount(eID)>count jm_-f GetOperation eID, count, op 7>JYwU{ If op.Type="ShiftZ" Then
B.z$0=b DeleteOperation eID,count +)]YvZ6%[, count=count-1 p!.~hw9 End If g(7-3q8eq count=count+1 @=J|%NO Wend |HazM9= op.Type = "ShiftZ" @Mk`Tl op.val1 = taq-0.01 ]B8
A op.parent = parID q76POytV| AddOperation eID, op }d$-:l,w 0X$mT:=9 Print "Set pupil diameter = " & pupilDiam h}b:-a VYyija: 'Update AZ Eye subassembly Description O*yxOb* eID = FindFullName( "Geometry.Arizona Eye" ) Iv`IJQH> GetEntity eID, entity w~'xZ?
entity.Description = "Accommodation = " & A & "D" *Cy54Z# SetEntity eID, entity u\R?(G& ^xo<$zn Update UA[`{rf Print "DONE!" dZM^?rq ,'#TdLe End Sub qsj{0 Go m 2H4V+M+ 如果屈光度是4,光瞳直径是4,则会输出如下数据: qTO6I5u k.T=&0J_1 Accommodation = 4 Diopters ul{x|R Pupil Diameter = 4 mm _vQ52H, Set aqueous humor thickness = 2.81 ZbnAAbfKH Set anterior lens radius = 10.4 and conic constant = -2.375869 qY_qS=H^ Set posterior lens radius = -4.424557 and conic constant = -3.081019 J0G@]H Set lens thickness = 3.927 TS<d?: Set lens index of refraction = 1.42672 j0=6B Set pupil diameter = 4 $-4](br| DONE! +X?ErQm
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