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GjBt 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。 |;(P+Q4lB uVhzJu. 模型 |"KdW#.x YMNLn9 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。 FIAmAZH}_ htrtiJ1 Table 1. AZ眼睛模型的定义 ^*UtF9~%n 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. (RrC<5" wpC.!T 光源 !B#lZjW# J4j:nd 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。 c;(Fz^&_ {,6J*v"o 0|K<$e6IH 图1. 光源和提示信息使用 @p/"]zf 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 9An\uH)mL Uc,.. 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 FqGMHM\J )K::WqR%w) 图2. 字母F光源的设定方法光 7@e}rh?N-| kef%5B 图3. 字母F在视网膜上位置点列图 z0a`*3 -2 视网膜的散射 I`jG xQzW6H| 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 Y}q~Km S=`$w {[/A?AV;F 图4. 视网膜朗伯散射设定 yA*U^:% 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。 2?:OsA} :yi} CM4 "Y5 :{Kj 图5. 视网膜重点采样规格设定 8KkN
"4' 脚本 v+trHdSBYE YwZx{%f 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: =TzJgx 5! +{JTXa 图6. 用户对话框的创建与编辑 $\1M"a}F 图7. 用户对话框编辑器 a+ O?bO 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 u#y)+A2&! 余下的脚本计算与屈光度有关的所有参数。 r}Gku0Hu_E m J$[X 分析 {%P2.: ]mNsG0r6 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 #4"eQ*.*" x;} 25A| 图7. 字母F在视网膜上颜色分析 o
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}f 脚本代码 1gt 7My xC0y2+)| Option Explicit 'Remove this to enable non-dimensioned variables to be used. 8:*ZuR|~ 2
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0$ Dim entity As T_ENTITY vpdPW %B Dim op As T_OPERATION 9`VY)"rJ Dim mat As T_MODELMATERIAL QuI!`/N)z Dim A As Double rFm?Bu Dim pupilDiam As Double ^'Rs`e Dim eID As Long >\J<` Dim parID As Long ![vy{U.:` Dim count As Integer $nIE;idk Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double &m9= q|;m Dim tlens As Double, nlens As Double \h0+`
;Q Dim curv As Double, conic As Double q@VIFmqY! Dim ok As Long ;p<BiC$b oOubqx Sub Main Vu4LC&q =,qY\@fq '用户输入对话框 E KN<KnU% Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ]-a/)8 TextBox 220,21,40,21,.TextBox1 'default: 0 'gD./|Z0 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ,VUOsNN4\ OKButton 40,91,90,21 ni )G CancelButton 190,91,90,21 >f-RzQ k Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 d|~'#:y@ TextBox 220,49,40,21,.TextBox2 'default: 4 on5\rY<I:@ End Dialog gXn`! Dim dlg As UserDialog k$#1T +(G @7Ln1v ok = Dialog (dlg) M)wNu IkA~+6UY If ok=0 Then 'cancel button was pressed k!$$ *a* Print "Execution cancelled." E(1G!uu< End |DVFi2 End If Ic&YiATj U%#Vz-r 'Assign accommodation and pupil diameter & use defaults if field left empty -y3[\zNe If dlg.TextBox1 = "" Then };Df >< A = 0 'Default accommodation Pd
`~#! Else ,qV 7$u A = CDbl(dlg.TextBox1) fT?m~W^ End If >lek@euqw _ogN
If dlg.TextBox2 = "" Then oz|+{b}% pupilDiam = 4 'Default pupil diameter 9q&~!>lt Else WHLTJ]OB pupilDiam = CDbl(dlg.TextBox2) %=s2>vv9 End If .>_%12> >>y\idg&: Print " " ]ERAt^$0 Print "Accommodation = " & A & " Diopters" M9~'dS'XI Print "Pupil Diameter = " & pupilDiam & " mm" d]sg9` '%TD#!a ' Calculate new parameters with accommodation Dd,
&a taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness NQiu>Sg N693eN! Rant = 12.0 - 0.4*A 'Radius of anterior lens P~x4h{~Gd CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens XC}2GHO< *Csxf[O Rpost = -5.224557 + 0.2*A 'Radius of posterior lens z`u$C+Ov CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens wk^$DM/KJ) : ?Z9 tlens = 3.767 + 0.04*A 'Lens thickness =t~]@?]1D [IHG9Xg nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 5dX0C w=ufJRj 'Adjust parameters to account for accommodation *`Ge8?qC hX-^h2eV '************************************************************************* K>\v<!%a 'Aqueous thickness (Position of Lens) j!0-3YKv '************************************************************************* GQjU="+ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) I.SMn,N GetCustomElement eID, entity q!h'rX=_- lD#
yXLaC\ parID = FindFullName( "Geometry.Arizona Eye" ) rV-Xsf7Z Aaz:C5dtU ' Delete any shift(s) in z /:,}hy+U count = 0 p"*xyex While GetOperationCount(eID)>count 3lS1WA GetOperation eID, count, op =dWqB& If op.Type="ShiftZ" Then )!
kl: DeleteOperation eID,count `bLJwJ7 count=count-1 ;vk>k0S End If XN3'k[ count=count+1 XF@34b5( Wend 0juP"v$C> |gT8 QP 'Set new shift in 9El{>&Fs4 op.Type = "ShiftZ" ]&='E.f op.val1 = taq T/hz23nH op.parent = parID F"23vG>3 AddOperation eID, op eG.s|0` Print "Set aqueous humor thickness = " & taq-0.55 I}}>M# Cw5B
p9 '************************************************************************* 4:s,e<Tc4v 'Radius and conic constant of anterior lens 85A7YraL '************************************************************************* a:1$i dj eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 8@FgvWC GetConic eID, entity, curv, conic CRNt5T>qH [l~G7u.d SetConic eID, entity, 1/Rant, CCant _0iV6Bj Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ArT@BqWd =C7<I '************************************************************************* \34:]NM 'Radius and conic constant of posterior lens *A0d0M]cg '************************************************************************* [BEQ ~A_I eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) cCG!X%9 GetConic eID, entity, curv, conic ow'CwOj$ idjk uB(6 SetConic eID, entity, 1/Rpost, CCpost Juk'eH2^s Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost sM9utR ?MSV3uODb '************************************************************************* @$~;vS 'Lens thickness (Position of posterior lens surface) 0R-W9qP '************************************************************************* Zb<D%9 d^5x@E_Td parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Y44[2 :m Dh68=F0 ' Delete any z-shift(s) yy`XtJBWWs count = 0 m`tX&K#- While GetOperationCount(eID)>count {]4Zpev GetOperation eID, count, op 8rLhOA If op.Type="ShiftZ" Then u!FF{~5cs DeleteOperation eID,count JI&.d: count=count-1 /3;]e3x End If q{xF7}i count=count+1 `2M*?.vk Wend +Ur75YPh c?Mbyay 'Set new z-shift ]na$n[T/I op.Type = "ShiftZ" mPo.Z"uy7 op.val1 = tlens Jpn= ^f[rm op.parent = parID j@/p: fk AddOperation eID, op Z~;rp`P Print "Set lens thickness = " & tlens P<LmCYm 59X XmVg '************************************************************************* vm=d?*cR 'Lens index of refraction wZ_"@j< '************************************************************************* LMLrH. eID = FindMaterial( "Lens" ) UC.kI&A GetModelMaterial eID, mat ehZ/J5 ?kF?
~\c mat.Nd = nlens 2g5jGe*0 SetModelMaterial eID, mat @=BApuer+ Print "Set lens index of refraction = " & nlens xiqeKoAD ]VS:5kOj` '************************************************************************* &_\;p-1: 'Pupil diameter C;_0 0EQ= '************************************************************************* Zlrbd eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) m!3D5z]n9 1'1>B 'Adjust pupil diameter (trimming volume inner hole) 0y2zjXM;3 u>*qDr*d SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" n8i: /ypB equi26jhr ' Adjust pupil location to just in front of the lens b&RsxW7 parID = FindFullName( "Geometry.Arizona Eye" ) 02-% B~oP eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) @h/-P'Lc=7 count = 0 z]2lT
IWg While GetOperationCount(eID)>count XR$i:kL,, GetOperation eID, count, op i\x@s>@x} If op.Type="ShiftZ" Then BQ B<+o' DeleteOperation eID,count C(M ?$s` count=count-1 (&X/n=UI End If #L&/o9| count=count+1 G?Za/G Wend % pAbkb3m op.Type = "ShiftZ" 35:RsL op.val1 = taq-0.01 z|zEsDh; op.parent = parID 4E+8kz' AddOperation eID, op
{~XAg~ _v++NyZXx Print "Set pupil diameter = " & pupilDiam |\94a 0IBQE 'Update AZ Eye subassembly Description &}\{qFD; eID = FindFullName( "Geometry.Arizona Eye" ) +x<OyjY5?] GetEntity eID, entity pwV~[+SS_ entity.Description = "Accommodation = " & A & "D" s|X_:3\x SetEntity eID, entity _9?v?mL5; FU;a
{irB Update 'lOQb) Print "DONE!" n Q{~D5y,, bH!_0+$P End Sub
^mN`!+ b1%w+* d<z 如果屈光度是4,光瞳直径是4,则会输出如下数据: \[%_ :9eq q_[`PYT Accommodation = 4 Diopters [Mj5o<k;I Pupil Diameter = 4 mm 8~g~XUl Set aqueous humor thickness = 2.81 U~dqxR"Q Set anterior lens radius = 10.4 and conic constant = -2.375869 FtlJ3fB@ Set posterior lens radius = -4.424557 and conic constant = -3.081019 N,:G5WxW Set lens thickness = 3.927 nswhYSX Set lens index of refraction = 1.42672 1K'cT\aFm Set pupil diameter = 4 nGur2}>n DONE! ;Zn&Nc7
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