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简介 :ye)%UU"|: 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。 HkrNh>^= q*'hSt@+D 模型 75^-93 E]ZM`bex& 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。 zIdQ^vm8Q W^yF5 Table 1. AZ眼睛模型的定义 - MBK/ 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. ~t#'X8.) yK}#|b'cM 光源 +mF}j=k rylllJz|L: 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。 <(^-o4Cl 5dL-v&W ? 4.W
_ 图1. 光源和提示信息使用 4|XE
f, 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。 @aj"12 2;kab^iv' 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。 m6IZGl7% FPcgQ
v;p 图2. 字母F光源的设定方法光 KDn`XCnk, 7Y!^88,f. 图3. 字母F在视网膜上位置点列图 <-lz_ 视网膜的散射 b!`:|!7r' 'z!I#Y!Y 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。 u 6%56 %^f y XS/3_A{ { !FrI@ 图4. 视网膜朗伯散射设定 8fDnDA.e 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。 S++}kR);
(:hPT-1 q.g!WLiI 图5. 视网膜重点采样规格设定 NtA}I)'SWU 脚本 0~FX!1; SS H/q/ 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: UO!OO&l! <:%Iq13D 图6. 用户对话框的创建与编辑 d<Z`)hI{K 图7. 用户对话框编辑器
NghQ#c 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。 *Qyw
_Q 余下的脚本计算与屈光度有关的所有参数。 3Um\?fj>}( wuh$=fya 分析 dXdU4YJX .Q?AzU,2D 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 40 :YJ_n
4uTYuaCNs 图7. 字母F在视网膜上颜色分析 Yq2mVo 脚本代码 jh=:Q P/ %n-LDn Option Explicit 'Remove this to enable non-dimensioned variables to be used. S:t7U% 778L[wYe Dim entity As T_ENTITY /,B"H@J Dim op As T_OPERATION bu$5gGWVf Dim mat As T_MODELMATERIAL uQ&xoDCB Dim A As Double !E$S&zVMQ Dim pupilDiam As Double ['sIR+c%'O Dim eID As Long Bp4QHv9xqL Dim parID As Long `N|WCiBV. Dim count As Integer
xXHz)w Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double CBO8^M<K Dim tlens As Double, nlens As Double JBg",2w |C Dim curv As Double, conic As Double MiRMjQ2 Dim ok As Long -@i2]o :v&GAs6H Sub Main x9@%L{* 4RdpROK '用户输入对话框 u}u2{pO! Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 7dW9i7Aj TextBox 220,21,40,21,.TextBox1 'default: 0 h~F uuL Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Q<78<#I OKButton 40,91,90,21 H:0-.a^ZS CancelButton 190,91,90,21 <'s1+^LC Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 VT+GmS TextBox 220,49,40,21,.TextBox2 'default: 4 g *^"x& End Dialog Gb8LW,$IT- Dim dlg As UserDialog V{a 7@_y Z\@vN[[ ok = Dialog (dlg) 4; j#7 hDz_BvE If ok=0 Then 'cancel button was pressed |e+I5 Print "Execution cancelled." KiCZEA
End eo,m ^& End If N|Rlb5\ ;9;.!4g/T 'Assign accommodation and pupil diameter & use defaults if field left empty 5bMVDw/ If dlg.TextBox1 = "" Then "qwRcuHY A = 0 'Default accommodation iVmf/N@A| Else 9hLPo A = CDbl(dlg.TextBox1) gS"@P:wYzs End If (/FPGYu3h ko ~iDT If dlg.TextBox2 = "" Then La3f{;|u5M pupilDiam = 4 'Default pupil diameter /V3*[ Else `~*qjA pupilDiam = CDbl(dlg.TextBox2) m6g+ B > End If J7mT&U&Ru lOZ.{0{f, Print " " Tm`QZh3 Print "Accommodation = " & A & " Diopters" VEz&TPu Print "Pupil Diameter = " & pupilDiam & " mm" *Z{W,8h*s Ue-HO ' Calculate new parameters with accommodation X'iki4 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness >.M
`Fz. ts)0+x Rant = 12.0 - 0.4*A 'Radius of anterior lens t6js@Ih CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens \r<&7x#j "jAV7lP Rpost = -5.224557 + 0.2*A 'Radius of posterior lens "7gS*v,r CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens '3|OgV |=GRPvvi tlens = 3.767 + 0.04*A 'Lens thickness o#w6]Fmc xazh8X0P nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction &Vl,x/ ' OJXllGi 'Adjust parameters to account for accommodation Nz$OD_] m#8KCZS '************************************************************************* if_e$,dh~> 'Aqueous thickness (Position of Lens) 5t0i/&zX '************************************************************************* Gb~q:&IUr eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 62Jn8DwAT GetCustomElement eID, entity IO,kP`Wcx i?|K+"=D parID = FindFullName( "Geometry.Arizona Eye" ) mflI> J=g o@;w!' ' Delete any shift(s) in z Zwq
uS9 count = 0 G#lzB`i While GetOperationCount(eID)>count d8Upr1_ GetOperation eID, count, op 1eT| If op.Type="ShiftZ" Then d(fgv DeleteOperation eID,count S%Ja:0=}? count=count-1 5X~ko> End If a^sR?.+3 count=count+1 TTqOAo[-Z Wend b6NttY!3 f+/^1~^ 'Set new shift in /:%^Vh3XF op.Type = "ShiftZ" Jr1^qY`0+ op.val1 = taq ,PIdPaV-- op.parent = parID 9Z#37) AddOperation eID, op !3T x\a`?/ Print "Set aqueous humor thickness = " & taq-0.55 0.+iVOz+Y faJ5f. '************************************************************************* 2RM1-j
($ 'Radius and conic constant of anterior lens Ro%S_! '************************************************************************* crvWAsm eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 5[*MT%ms GetConic eID, entity, curv, conic |y=CmNG, MjG.Ili$m SetConic eID, entity, 1/Rant, CCant ;1eu8N8 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant H ) (K wmoOp;C '************************************************************************* sIELkF?. 'Radius and conic constant of posterior lens E}a3. 6)p '************************************************************************* gc(1,hv eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) .h*&$c/l GetConic eID, entity, curv, conic I>P</TE7 e3[QM SetConic eID, entity, 1/Rpost, CCpost g%\e80~1 ( Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 8zpK;+ "@ox= '************************************************************************* ^?juY}rZ=| 'Lens thickness (Position of posterior lens surface) k$+& '************************************************************************* <F!:dyl Ex*g>~e parID = FindFullName( "Geometry.Arizona Eye.Lens" ) s)To# [NKWudq ' Delete any z-shift(s) iP_rEi*-J count = 0 ,*C^ixNE While GetOperationCount(eID)>count i[YYR,X| GetOperation eID, count, op t zV"|s=o If op.Type="ShiftZ" Then !C/`"JeYL DeleteOperation eID,count -7+Fb^"L count=count-1 -<<!eH End If B3yn:=80 count=count+1 :F<a~_k Wend E8-p
,e, r[\47cG 'Set new z-shift ME |"pJ op.Type = "ShiftZ" JP@UvDE| op.val1 = tlens B1p9pr op.parent = parID 1 9)78kV{ AddOperation eID, op C8{CKrVE Print "Set lens thickness = " & tlens C6,Bqlio _VM J q9. '************************************************************************* zR5D)`Ph 'Lens index of refraction vhUuf+P* '************************************************************************* B!-W765Y eID = FindMaterial( "Lens" ) Sa<R8X'J GetModelMaterial eID, mat LLU>c]a LpF6e9V\Wp mat.Nd = nlens 1yE~#KpH SetModelMaterial eID, mat $~9U-B\ Print "Set lens index of refraction = " & nlens I5D\Z rhUZ9Fdv '************************************************************************* 9GQTe1[t4 'Pupil diameter P089Mh9 '************************************************************************* XBeHyQp eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Dic(G[ L~;_R*Th 'Adjust pupil diameter (trimming volume inner hole) 2OZdj JUXK}0d%eN SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" t71 0sWh{ M.l;!U!} ' Adjust pupil location to just in front of the lens I]$kVa1iN parID = FindFullName( "Geometry.Arizona Eye" )
N.2rF eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ^7_<rs count = 0 u(lq9; ;Th While GetOperationCount(eID)>count Yhx~5p GetOperation eID, count, op x,1&ml5 If op.Type="ShiftZ" Then 6: M DeleteOperation eID,count 0u0Hl% nl count=count-1 pFG~XW End If JEAqSZak# count=count+1 R.RCa$ Wend 55[K[K op.Type = "ShiftZ" v/m6(z op.val1 = taq-0.01 QR,i
b op.parent = parID }wUF# AddOperation eID, op mqE&phF, 2xjS;lpw Print "Set pupil diameter = " & pupilDiam z#-&M J 9wAP%xh 'Update AZ Eye subassembly Description S5uV\Y/A eID = FindFullName( "Geometry.Arizona Eye" ) c[;I\g GetEntity eID, entity XCt}>/"s\h entity.Description = "Accommodation = " & A & "D" !WIL|\jbh SetEntity eID, entity }ShZ4 xMz U 26Iz Update Y${ $7+@ Print "DONE!" JY_' d,O QX8N p{g- End Sub )@sz\yI%U eH6#'M4+\ 如果屈光度是4,光瞳直径是4,则会输出如下数据: 4sva%Up `@:^(sMo Accommodation = 4 Diopters G.BqT\ o' Pupil Diameter = 4 mm /Db~-$K Set aqueous humor thickness = 2.81
4f/8APA Set anterior lens radius = 10.4 and conic constant = -2.375869 LOOv8'%O8 Set posterior lens radius = -4.424557 and conic constant = -3.081019 yX)2
hj:s Set lens thickness = 3.927 ?vk&k(FT Set lens index of refraction = 1.42672 uH7u4f1Q Set pupil diameter = 4 au#IA DONE! gFW1Nm_DJ :oZ30} (文章来源:讯技光电)
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