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简介 IIPf5
Z}A 5(W9J j] 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。 +u#x[xO Q4x71*vy 模型 |(V3 .jKO 6f 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。 XVfQscZe fP|\1Y?CS Table 1. AZ眼睛模型的定义 usA!MMH4 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. DkIkiw{L u|ZO"t 光源 7jPmI 9+:Trc\%N 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。 phdN9<Z *"
)[Srbg :uEp7Y4 图1. 光源和提示信息使用 ?,NAihN] 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。 twn@~$
Ojs\2('u 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。 ?Y9?x,x [>0r'-kI 图2. 字母F光源的设定方法光 5"Yw$DB9 hD*?\bBs0 图3. 字母F在视网膜上位置点列图 vEsSqzc 视网膜的散射 u;!Rv E8N {
\ePJG# 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 */)gk=x8 h2>0#Vp3j :q=OW1^k^ 图4. 视网膜朗伯散射设定 QZlUUj\
注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 >W<5$ .G U*@_T 3N }dz(DPd 图5. 视网膜重点采样规格设定 J\V(MN, 脚本 #5D+XB T Jj " {r{ 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: A@ME7^w7 2?j1~ ]DvZ 图6. 用户对话框的创建与编辑 ?KN_J 图7. 用户对话框编辑器 Ce:ds% 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。 |>4 { 4 余下的脚本计算与屈光度有关的所有参数。 LPO" K"'w gm DC,"Y< 分析 tpN}9N 2. _cEY34 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 A=K1T]o (a?Ip)`I 图7. 字母F在视网膜上颜色分析 Ei-OuDM;) 脚本代码 q4{ t H A3_9MO
Option Explicit 'Remove this to enable non-dimensioned variables to be used. H~Cfni; m!_ghD{5h Dim entity As T_ENTITY Xhi?b| Dim op As T_OPERATION :X
f3wP= Dim mat As T_MODELMATERIAL [78
.%b' Dim A As Double wNZ7(W.U Dim pupilDiam As Double U:r2hqegd Dim eID As Long 5MJ'/Fy( Dim parID As Long %Qq)=J<H; Dim count As Integer ]Ho`*$dD Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double #4M0%rN Dim tlens As Double, nlens As Double P vwIO_W Dim curv As Double, conic As Double 1tdCzbEn+ Dim ok As Long 3iw9jhK!W #EUgb7 Sub Main :(Bi{cw ^%pwyY\t '用户输入对话框 Ks(U]G"V Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 5b p"dIe TextBox 220,21,40,21,.TextBox1 'default: 0 V-jL`(JF% Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Vi WgX. OKButton 40,91,90,21 Ziimz}WHF CancelButton 190,91,90,21 @k<~`S~| Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 03@|dN TextBox 220,49,40,21,.TextBox2 'default: 4 99K+7G\{ End Dialog R:N-y."La. Dim dlg As UserDialog _+iz?|U AHJ;>"] ok = Dialog (dlg) U.OX*-Cd Oy$BR
<\ If ok=0 Then 'cancel button was pressed W?-BT >#s Print "Execution cancelled." Ah{pidUx End ;4$C$r!t End If "6Uj:9 -QDgr`%5 'Assign accommodation and pupil diameter & use defaults if field left empty NCt sx /C If dlg.TextBox1 = "" Then yan[{h]EZ A = 0 'Default accommodation @~3c"q;i7 Else `gN68:B A = CDbl(dlg.TextBox1) 3:lp"C51 End If x35s6 tYZGf xj If dlg.TextBox2 = "" Then !U:s.^{ pupilDiam = 4 'Default pupil diameter "%*lE0Tx Else Ws)X5C=A pupilDiam = CDbl(dlg.TextBox2) W+e*(W|d6 End If twmJ /
LM Print " " I?Fa Print "Accommodation = " & A & " Diopters" 9X9zIh]JV Print "Pupil Diameter = " & pupilDiam & " mm" **w~ 9dtGqXX ' Calculate new parameters with accommodation `e>F<{
M6@ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness z/k~+-6O ok%!o+nk. Rant = 12.0 - 0.4*A 'Radius of anterior lens Q0Qm0B5eY CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ?^ezEpW {))S<_yN Rpost = -5.224557 + 0.2*A 'Radius of posterior lens o~_>p/7; CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens /(ju EZQ+HECpK tlens = 3.767 + 0.04*A 'Lens thickness 2%C5P0;QX oV>AFs6 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction |!5T+H{Sj cqL7dlhIl 'Adjust parameters to account for accommodation Z !25xqNCd y6jmn1K '************************************************************************* *jw$d8q2 'Aqueous thickness (Position of Lens) DPQGh`J '************************************************************************* F%Umau*1 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Tv,. GetCustomElement eID, entity H9Q7({v m:fouMS parID = FindFullName( "Geometry.Arizona Eye" ) 0k0c >ydb? ' Delete any shift(s) in z bSR+yr'? count = 0 )]?egw5l While GetOperationCount(eID)>count Jo aDX , GetOperation eID, count, op GL =XiBt If op.Type="ShiftZ" Then ^}/
E~Sg7\ DeleteOperation eID,count ZHD0u)ri=J count=count-1 D4O5@KfL End If eOPCYyN count=count+1 3p
1EScH Wend
G<-9U}~76 maUHjI
5A- 'Set new shift in ^x"c0R^ op.Type = "ShiftZ" NU&^7[!yl op.val1 = taq dFP-(dX# op.parent = parID u4,X.3V]A AddOperation eID, op ]VG84bFm Print "Set aqueous humor thickness = " & taq-0.55 ]RXtC* nR@,ouB-$ '************************************************************************* u~- fK'/!| 'Radius and conic constant of anterior lens JlDDM
% '************************************************************************* ?WQd eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) eIUuq&( GetConic eID, entity, curv, conic *- IlF] "ex~LB SetConic eID, entity, 1/Rant, CCant M`+e'vdw Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant r5!x,{E6 7hF,gl5 '************************************************************************* UK~B[=b9 'Radius and conic constant of posterior lens kV:FJx0xP '************************************************************************* r]JC~{ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) '
MS!ss=r GetConic eID, entity, curv, conic T5dUJR2k$ #ON#4WD? SetConic eID, entity, 1/Rpost, CCpost }]g95xT Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost L>~@9a\jO ()nKug`.@ '************************************************************************* VU`z|nBW@ 'Lens thickness (Position of posterior lens surface) 4)odFq: '************************************************************************* FJd8s* V3 _b! parID = FindFullName( "Geometry.Arizona Eye.Lens" ) >1a\%G H#|Z8^ *Ds ' Delete any z-shift(s) uH
ny ] count = 0 I`"-$99|t1 While GetOperationCount(eID)>count +\k9w.[:/ GetOperation eID, count, op 3Zaq#uA If op.Type="ShiftZ" Then >FY&-4+v DeleteOperation eID,count i{|lsd(+ count=count-1 AFINm%\/0 End If KcmDF4C2 count=count+1 4C,kA+P Wend Z[})40[M T\2) $ 'Set new z-shift <;z[+6T op.Type = "ShiftZ" Esz1uty op.val1 = tlens L_Y9+
e op.parent = parID !v-w6WG" AddOperation eID, op |6sT,/6 Print "Set lens thickness = " & tlens RP~vB#} H]tSb//qc '************************************************************************* --
i&" 'Lens index of refraction 'NT#(m% '************************************************************************* 7wiK.99 eID = FindMaterial( "Lens" ) %="~\1y GetModelMaterial eID, mat JNxW6 cK }>{ L#JW mat.Nd = nlens dysX SetModelMaterial eID, mat ^o $W Print "Set lens index of refraction = " & nlens a9D gy_!Y Y)Znb;`?a '************************************************************************* v:veV. y 'Pupil diameter u}-d7-= '************************************************************************* &*(n<5wt eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 670J{b B@cJ\ 'Adjust pupil diameter (trimming volume inner hole) 00`bL bK$/,,0=X/ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ^i{,z*vi '?{0z!! ' Adjust pupil location to just in front of the lens ;f".'9 l^ parID = FindFullName( "Geometry.Arizona Eye" ) < 72s7*Rv eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) DL'd&;6 count = 0 B#HnPUUK While GetOperationCount(eID)>count A+0T"2 GetOperation eID, count, op q4sl=`L5Sp If op.Type="ShiftZ" Then ",~ b2]ym DeleteOperation eID,count j}|N^A_ S count=count-1 y\F`B0#$ End If PoYr:=S? count=count+1 CDQJ bvx Wend _L*f8e8 op.Type = "ShiftZ" ^H5w41 op.val1 = taq-0.01 _-@ZOhw& op.parent = parID b:fxkQm AddOperation eID, op W$z#ssr -!XrwQyk Print "Set pupil diameter = " & pupilDiam /J1S@- H{j~ihq7 'Update AZ Eye subassembly Description :FoOQ[Q eID = FindFullName( "Geometry.Arizona Eye" ) H<V+d^qX\w GetEntity eID, entity %:"
RzHN entity.Description = "Accommodation = " & A & "D" =:4' SetEntity eID, entity hf_R\C(c R&NpdW N Update r@|R-Binz Print "DONE!" r> Fec E/:+@'(k End Sub !?BW_vY kjx> 如果屈光度是4,光瞳直径是4,则会输出如下数据: xh{mca>?G lP}o[Rd Accommodation = 4 Diopters hX0RET Pupil Diameter = 4 mm OfD@\;L Set aqueous humor thickness = 2.81 Vn)%C_-]A Set anterior lens radius = 10.4 and conic constant = -2.375869 V)2"l"Kt Set posterior lens radius = -4.424557 and conic constant = -3.081019 >oe4mW Set lens thickness = 3.927 5XzrS-I+X@ Set lens index of refraction = 1.42672 !IO&&\5 Set pupil diameter = 4 hbVE;
9 DONE! IKvd!,0xf <Cu'!h_nL :0B
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