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简介 N6=cqUM wt lSC3m=4g 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。 Y=sRVypJ ca*USM 模型 T9jp* Wxkk^J9F3 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。 s<5q%5ix3 ?/9]"HFHN Table 1. AZ眼睛模型的定义 eft-]c+*0 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. S,fMGKcq .*:SZ3v 光源 "Y}f"X| c!T^JZBb 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。 daE/v.a4| 5(q\x(N PvBx<i}A 图1. 光源和提示信息使用 Ij(S"P@ 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。 -20o%t I7r{&X) D 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。 "B*a|
'n! n9]^v-]K 图2. 字母F光源的设定方法光
B]ul~FX A3*ti!X<6 图3. 字母F在视网膜上位置点列图 =xQ7:TB 视网膜的散射 Gg|'T}0X Z2)f$ c 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。 qe4hNFq #B8`qFpQC 0{F"b'h 图4. 视网膜朗伯散射设定 e
&^BPzg 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。 }X$vriW fO[X<|9 h?j;*|o- 图5. 视网膜重点采样规格设定 lyI
rO"o 脚本 Vo+d3 N~{0QewMI' 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: 0aQtJ0e16 F')T:;,s 图6. 用户对话框的创建与编辑 7{RI`Er` 图7. 用户对话框编辑器 zwR@^ 5^6 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 NLyvi,svS 余下的脚本计算与屈光度有关的所有参数。 fKOm\R47 `~UCWK 分析 I+D`\OSL -b~MQ/,2 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 jV\M`=4IC B}X
C 图7. 字母F在视网膜上颜色分析 ~'dnrhdme 脚本代码 [6V'UI6 (9';zw
Option Explicit 'Remove this to enable non-dimensioned variables to be used. )wP0U{7?v @I\Z2-J Dim entity As T_ENTITY t!c8c^HR Dim op As T_OPERATION JmrQDO_( Dim mat As T_MODELMATERIAL 8xj4N%PA Dim A As Double }U7>_b2 Dim pupilDiam As Double S+ymdZ)xZ` Dim eID As Long -))>7skc Dim parID As Long IE$x2==) Dim count As Integer EAF<PMb Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double j8zh^q Dim tlens As Double, nlens As Double daWmF Dim curv As Double, conic As Double |(}uagfrd Dim ok As Long Yk(OVl T ' :g8a=L Sub Main (6u<w#u [
w '用户输入对话框 7
tF1g=\ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _S8]W
!c TextBox 220,21,40,21,.TextBox1 'default: 0 reM%GU Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 |O\(<n S OKButton 40,91,90,21 BT
98WR"\ CancelButton 190,91,90,21 UL;d H Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 fdho`juFa TextBox 220,49,40,21,.TextBox2 'default: 4 =ADAMP End Dialog zF;}b3oIo Dim dlg As UserDialog y
97QqQ^ Z@
h<xo*r ok = Dialog (dlg) b6bmvHD ll1?I8}5| If ok=0 Then 'cancel button was pressed hOfd<k\A Print "Execution cancelled." NTXT0: End HGWwGd End If Xu3^tH-b< g0rdF 'Assign accommodation and pupil diameter & use defaults if field left empty < t>N(e If dlg.TextBox1 = "" Then PHDKx+$ A = 0 'Default accommodation '0H+ 2 Else _ H$Cm A = CDbl(dlg.TextBox1) i.cSD%* End If ~S|Vd GuM-H$, If dlg.TextBox2 = "" Then <2A4}+p: pupilDiam = 4 'Default pupil diameter s7FqE>#c0 Else s=q\BmG pupilDiam = CDbl(dlg.TextBox2) q5lRc=.b[ End If hx)Ed .w$v<y6C Print " " t@}<&{zk Print "Accommodation = " & A & " Diopters" *2MUG
h Print "Pupil Diameter = " & pupilDiam & " mm" \5s!lv*& F__DPEAc_ ' Calculate new parameters with accommodation s<:"rw` taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness Fj 1/B0acS F`Q,pBl1p6 Rant = 12.0 - 0.4*A 'Radius of anterior lens
H.Jcp|k[; CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ^%go\ C ; p*Q"<@n Rpost = -5.224557 + 0.2*A 'Radius of posterior lens k]R O=/ ?M CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens H1\~T &JfyXM[] tlens = 3.767 + 0.04*A 'Lens thickness Pl1:d{"d )/
s9ty nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 5uDQ*nJ| O(&EnNm[2 'Adjust parameters to account for accommodation YI%7#L7C JFYeOmR+l '************************************************************************* ~p'/Z@Atu 'Aqueous thickness (Position of Lens) %*|XN*i XC '************************************************************************* M_9|YjwS eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ^o,@9GTs GetCustomElement eID, entity C,tlp D3XQ>T [*q parID = FindFullName( "Geometry.Arizona Eye" ) XHN?pVZ7 ,wX/cUyZ
' Delete any shift(s) in z m?[F)<~a count = 0 y;<jE.7>
While GetOperationCount(eID)>count ,j&o H$mW GetOperation eID, count, op H7l[5ib If op.Type="ShiftZ" Then =i:?4pIZ DeleteOperation eID,count "DRp4; count=count-1 q".l:T%|C} End If "Jv&=zJ count=count+1 [c>X Q Wend [W^6=7EO '7Te{^<FQ$ 'Set new shift in dR$P-V\y`% op.Type = "ShiftZ" -MB,]m op.val1 = taq v+Mt/8 op.parent = parID +pf 7 AddOperation eID, op {tWfLfzU Print "Set aqueous humor thickness = " & taq-0.55 w'L;`k;Q )}paQmy# '************************************************************************* /8Vh G|Wb 'Radius and conic constant of anterior lens YJ3970c/M '************************************************************************* uidE/7 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) u=ENf1{ $> GetConic eID, entity, curv, conic jRgv
8n <Xl G :nmY SetConic eID, entity, 1/Rant, CCant =faV,o&{` Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Qz<v. _ N4H nW0 '************************************************************************* yP-.8[; 'Radius and conic constant of posterior lens &<!I]:Y '************************************************************************* ia?8Z"&lK eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) _Z8zD[l GetConic eID, entity, curv, conic "h:xdaIE/p r-'j#|^tz SetConic eID, entity, 1/Rpost, CCpost ~hM4({/QN Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost VK$+Nm) qPzgGbmD9 '************************************************************************* !sR`]0 'Lens thickness (Position of posterior lens surface) Q>sq:R+' '************************************************************************* DM>j@(uWF NEJ
Nu_Z parID = FindFullName( "Geometry.Arizona Eye.Lens" ) O"Xjv`j: T[<9Ty'^ ' Delete any z-shift(s) u 4)i7 count = 0 lW>bXC While GetOperationCount(eID)>count o ue;$8 GetOperation eID, count, op ZYL]|/"J9 If op.Type="ShiftZ" Then RYvS,hf6z DeleteOperation eID,count Dk[[f<H_{ count=count-1 \&W~nYXq" End If hg\$>W~2 count=count+1 q$H'u[KQ06 Wend le8n!Dk( eb+[=nmP 'Set new z-shift (wbG0lu op.Type = "ShiftZ" (<3'LhFII op.val1 = tlens 9nd'"$ op.parent = parID 'f5,%e2# AddOperation eID, op AZtZa'hbkQ Print "Set lens thickness = " & tlens ~Jq<FVK D+"5R5J", '************************************************************************* )8LCmvQ 'Lens index of refraction ot,<iE#za '************************************************************************* *+Q,b ^N eID = FindMaterial( "Lens" ) vsES` GetModelMaterial eID, mat xT=|Uc0 Fdvex$r& mat.Nd = nlens 5$zC,g*# SetModelMaterial eID, mat B23R9.FK Print "Set lens index of refraction = " & nlens nc l-VN #x"pG '************************************************************************* zXMIDrq 'Pupil diameter m2VF}%
EIr '************************************************************************* IURi90Ir eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) rF
7EO%, }HXNhv-K 'Adjust pupil diameter (trimming volume inner hole) L!/USh:IP ,hX03P-X SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" t
ZFG`'/ WXXLD:gxI ' Adjust pupil location to just in front of the lens J^1w& 40 parID = FindFullName( "Geometry.Arizona Eye" ) {) jQbAr(G eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) oIbd+6>f count = 0 i' N While GetOperationCount(eID)>count CXJ0N GetOperation eID, count, op )zen"](cze If op.Type="ShiftZ" Then tS`fG; DeleteOperation eID,count HiVF<tN count=count-1 cH"M8gP# End If ly6?jVJ count=count+1 uKtrG,/ p Wend dkRJ^~ op.Type = "ShiftZ" xOD;pRZQ
op.val1 = taq-0.01 0UlaB
sv op.parent = parID
KqaeRs.u AddOperation eID, op `EV[uj&1S 7uxy<#Ar Print "Set pupil diameter = " & pupilDiam GQ)h Zt0 q6/ o.j 'Update AZ Eye subassembly Description lusINILc eID = FindFullName( "Geometry.Arizona Eye" ) Z/56JYt!~ GetEntity eID, entity Bz!ddAvlK entity.Description = "Accommodation = " & A & "D" #p*OLQ3~ SetEntity eID, entity '{U56^b] j3z&0sc2(0 Update 2{**bArV Print "DONE!" `^(6{p ? TZPWMCN4 End Sub I@ }:} 8t Z]oa+W+ 如果屈光度是4,光瞳直径是4,则会输出如下数据: 0B1*N_.L@ QT\S>} Accommodation = 4 Diopters l0[jepmpiT Pupil Diameter = 4 mm &bnF{~<\ Set aqueous humor thickness = 2.81 a*74FVZo.; Set anterior lens radius = 10.4 and conic constant = -2.375869 q^Oq:l$s Set posterior lens radius = -4.424557 and conic constant = -3.081019 Vx-HW;, Set lens thickness = 3.927 In=3#u
,M Set lens index of refraction = 1.42672 CI$F#j Set pupil diameter = 4 g:e| DONE! A3yVT8
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