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简介 bslrqUk_`= 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。 Ax oD8| 5unG#szq 模型 2cu#lMq Y-ux7F{=z 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。 QZ
`tNq :/ iVB^,KQ@ Table 1. AZ眼睛模型的定义 W&h[p_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. D71;&G]0 @v\*AYr'M 光源 k7tYa;C w@2Vts 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。 Cw5%\K$= ,mPnQ? (BX83) 图1. 光源和提示信息使用 y {q*s8NY 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 `ovtHl3Q lq.Te,Y%w 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 yV)m"j ,wwZI`>- 图2. 字母F光源的设定方法光 (2?G:+C 7 k
{- 图3. 字母F在视网膜上位置点列图 &iN--~}!$ 视网膜的散射 >]'yK!a? `"vZ);i< 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。 ]E3U
J!! TEUY3z[g 1Xy]D 图4. 视网膜朗伯散射设定 w",?
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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。 'H9=J*9oG '2hbJk 3CTX -#)vS 图5. 视网膜重点采样规格设定 fIoIW&iy 脚本 zr76_~B1u >k']T/% 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: F2(q>#<_ ]IJRnVp% 图6. 用户对话框的创建与编辑 A5#y?Aq 图7. 用户对话框编辑器 &PcyKpyd 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。 ujW1+Oj=~ 余下的脚本计算与屈光度有关的所有参数。 2EQ6J ~Lfcg* 分析 +.[\g|G 3*DXE9gA9 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 g|P C$p-z+ Y^$HrI(vq 图7. 字母F在视网膜上颜色分析 `n!viW|tB 脚本代码 [%HIbw J jc_\'Gr+[ Option Explicit 'Remove this to enable non-dimensioned variables to be used. b7C
e%Br O`FqD{@V Dim entity As T_ENTITY $#o1MX Dim op As T_OPERATION ps1YQ3Ep& Dim mat As T_MODELMATERIAL yh;Y,;4 Dim A As Double eX&Gw{U-f Dim pupilDiam As Double g1DmV,W-Q Dim eID As Long ?_6YtR,{ Dim parID As Long "$p#&W69"J Dim count As Integer K0+;bu Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double l QPqcZd Dim tlens As Double, nlens As Double YHxbDf dA Dim curv As Double, conic As Double ]pTvMom$6 Dim ok As Long Hr;h4J S_J :&9L Sub Main z?8~[h{i% .uZ7 -l '用户输入对话框 }{7e7tW6 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 jigs6# TextBox 220,21,40,21,.TextBox1 'default: 0 OVoO6F] Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 !J>A,D"- OKButton 40,91,90,21 Ru%|}sfd CancelButton 190,91,90,21 ed~R>F> Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 g;F"7
^sg TextBox 220,49,40,21,.TextBox2 'default: 4 \Z)1 ?fq End Dialog Qqs"?Z,P Dim dlg As UserDialog g: %9jf l_FGZ!7 ok = Dialog (dlg) _rQUE^9 kL{;.WsB If ok=0 Then 'cancel button was pressed 6DS43AQs Print "Execution cancelled." V:K;] h*! End y<r}"TAf- End If u7]<=*V] X\GM/A 'Assign accommodation and pupil diameter & use defaults if field left empty \,W.0#D8v4 If dlg.TextBox1 = "" Then $B\E.ml. A = 0 'Default accommodation _pDjg%A>n Else I{.HO<$7D} A = CDbl(dlg.TextBox1) 4-4?IwS End If ;'kI/(;;C H~+xB1 If dlg.TextBox2 = "" Then Hw_o
w? pupilDiam = 4 'Default pupil diameter B<
;==| Else SPy3~Db-o pupilDiam = CDbl(dlg.TextBox2) ?#[)C=p]z End If :uCdq`SaQl p,#6
@* Print " " T`L}[?w Print "Accommodation = " & A & " Diopters" T nxKR$Hoh Print "Pupil Diameter = " & pupilDiam & " mm" 9{J?HFw*; Cyk s ' Calculate new parameters with accommodation _\AUQ{ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness Ygj6(2 l)}t,!M6 Rant = 12.0 - 0.4*A 'Radius of anterior lens /5a;_ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens _x\m|SF_g q(9%^cV6 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens a|x8=H CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens F?*k}]Gi =:K@zlO: tlens = 3.767 + 0.04*A 'Lens thickness N=fz/CD)I d.}}s$Q nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction mUwUs~PjA
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'Adjust parameters to account for accommodation 3ut_Bt\ mCk5B*Jy '************************************************************************* !RMS+Mm? 'Aqueous thickness (Position of Lens) rc~Y=m '************************************************************************* zGs|DB eID = FindFullName( "Geometry.Arizona Eye.Lens" ) >}]H;&
l GetCustomElement eID, entity y_%&]/% b.Su@ay@(^ parID = FindFullName( "Geometry.Arizona Eye" ) K`+vfqX Q]i[.ME ' Delete any shift(s) in z U>3
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count = 0 wixD\t59X While GetOperationCount(eID)>count 5Bj77?Z GetOperation eID, count, op Ru7L>(Njs If op.Type="ShiftZ" Then i7v/A&Rc DeleteOperation eID,count "Z9^} count=count-1 &q>h*w4O End If &wGg6$ count=count+1 lZ a?Y@ Wend pGk"3.ce mVrK z 'Set new shift in @^HwrwRA op.Type = "ShiftZ" [f(uqLdeM op.val1 = taq E!YmcpCl op.parent = parID bw;iz,Z AddOperation eID, op BD4"pcr Print "Set aqueous humor thickness = " & taq-0.55 onh?/3l /'`6
;
uRN '************************************************************************* W9jNUZVXE# 'Radius and conic constant of anterior lens @ V5S4E '************************************************************************* yA0Y
14\* eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) vK'9{q|g GetConic eID, entity, curv, conic |0DP}
`~ z (#Xca SetConic eID, entity, 1/Rant, CCant }wG|%Y#+r Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 'Aet{A=9 hLn&5jYHvt '************************************************************************* hs,5LV)|y 'Radius and conic constant of posterior lens FLEg0/m0 '************************************************************************* JOgmF_(>Z eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) a[JZ5D GetConic eID, entity, curv, conic }{#7Z8 s#`cX0L) SetConic eID, entity, 1/Rpost, CCpost @2|G|C/]O} Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ]nHe$x!2] q|/!0MU" '*************************************************************************
3:"AFV 'Lens thickness (Position of posterior lens surface) lk~dgky@ '************************************************************************* |WUA1g a(g$ d2H parID = FindFullName( "Geometry.Arizona Eye.Lens" ) (A|B@a!Y> .yG8B:7N2 ' Delete any z-shift(s) :(RL8 count = 0 FcY$k%;'Q While GetOperationCount(eID)>count M +\rX1T GetOperation eID, count, op TA<hj[-8 If op.Type="ShiftZ" Then @u<0_r
t DeleteOperation eID,count FqL`Kt count=count-1 myffYK, End If UzN8G$92qF count=count+1 =^ gvZ|] Wend J;7s/YH^ mnQal>0~ 'Set new z-shift ?<g|.HY/ op.Type = "ShiftZ" '|J) ds op.val1 = tlens f};!m=b op.parent = parID Y9/{0TArG AddOperation eID, op *di&%&f Print "Set lens thickness = " & tlens N.k+AQb (PyTq
5:F '************************************************************************* {W]bU{%. 'Lens index of refraction TIKEg10I '************************************************************************* ~ }Kp eID = FindMaterial( "Lens" ) *C
tsFS~ GetModelMaterial eID, mat ,d3Q+9/ _Eszr(zJ mat.Nd = nlens '"'D.,[W2 SetModelMaterial eID, mat m]Hb+Y=;h Print "Set lens index of refraction = " & nlens aGdpecv Ixyvn#ux) '************************************************************************* Bi$
0{V Z8 'Pupil diameter q.U*X5 '************************************************************************* nmTm(?yE eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) G%y>:$rw[O .Gjr`6R 'Adjust pupil diameter (trimming volume inner hole) +.XZK3 C+ZQB)gn SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" m
j'"Z75 +"TI_tK,S ' Adjust pupil location to just in front of the lens ?r^
hmu"a parID = FindFullName( "Geometry.Arizona Eye" ) z(c@(UD-_ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) &?}kL=
h count = 0 3(cU) While GetOperationCount(eID)>count
yBJ/>SAcG GetOperation eID, count, op jdV .{8@ If op.Type="ShiftZ" Then ocb%&m;i DeleteOperation eID,count A73V6" count=count-1 G5y]^P End If @>qx:jx(-S count=count+1 Dlqn~ Wend *#ob5TBq[ op.Type = "ShiftZ" -lJx%9> op.val1 = taq-0.01
rTWh(8T op.parent = parID z }FiU[Hs AddOperation eID, op :w?:WH?2L qAS70XjOF Print "Set pupil diameter = " & pupilDiam 6R$F =MB >C*?17\ 'Update AZ Eye subassembly Description chvrHvByS eID = FindFullName( "Geometry.Arizona Eye" ) ~%cSckE GetEntity eID, entity krEH`f entity.Description = "Accommodation = " & A & "D" 1 2%z3/i SetEntity eID, entity +0oyt? yv6Zo0s<J Update F[o+p|nF Print "DONE!" s0~05{ _mIa8K; End Sub q\\8b{~ ~#HH;q_7m 如果屈光度是4,光瞳直径是4,则会输出如下数据: kxr6sO~ XwHu:v'= Accommodation = 4 Diopters !0>!tW Pupil Diameter = 4 mm Fy4< Set aqueous humor thickness = 2.81 [[/ }1% Set anterior lens radius = 10.4 and conic constant = -2.375869 (`q6G d Set posterior lens radius = -4.424557 and conic constant = -3.081019 m<X#W W)N Set lens thickness = 3.927 GY0XWUlC Set lens index of refraction = 1.42672 i5L+8kx4 Set pupil diameter = 4 rzYobOKd# DONE! Z=e[
!c p[af[! (文章来源:讯技光电)
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