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简介 iX4?5yz~< 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。 .Bxv|dji 'J(rIH3U 模型 2LS03 27 T:$ a
x 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。 -0[?6.(s" G3O`r8oZcJ Table 1. AZ眼睛模型的定义 pC<~\RR 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. V<&x+?>S Ce 3{KGBw 光源 B3 f Kb#T :t?Z 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。 :u$nH9kwv S8-3Nv' M*ZR+pq, 图1. 光源和提示信息使用 nn'a`N 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 t[$C r; )BI6nU 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。 '
lt5| v%gkQa 图2. 字母F光源的设定方法光 cm`Jr#kl{ hKa<9>MI` 图3. 字母F在视网膜上位置点列图 Mrpz (}) 视网膜的散射 .W4P/Pw' !EO*xxQ 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。 h"h3SD~ (bpO>4(S &/XRiK1"0 图4. 视网膜朗伯散射设定 37C'knW 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。 Wp7lDx }G8gk"st 1+wmR4o 图5. 视网膜重点采样规格设定 kg0X2^#b 脚本 Sg#$
B#g OP:i;%@c 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: p5RnFe l -*`7Q'}% 图6. 用户对话框的创建与编辑 lG[@s 'j 图7. 用户对话框编辑器 &<??,R14 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。 L'1!vu *Rg 余下的脚本计算与屈光度有关的所有参数。 T!-*; yu 25e*W>SLw 分析 b$7p`Ay c~1+5& 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 )Z4ilpU, ^qB
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图7. 字母F在视网膜上颜色分析 clhmpu 脚本代码 n1yIQ8 F {owXyQ2mK Option Explicit 'Remove this to enable non-dimensioned variables to be used. 2bu,_<K. `<Ry_}V Dim entity As T_ENTITY 6}z-X* Dim op As T_OPERATION .|XG0 M Dim mat As T_MODELMATERIAL S($8_u$U Dim A As Double (^_j,4 Dim pupilDiam As Double =@e3I)D#?i Dim eID As Long !{u`}:\ Dim parID As Long dWc'R wL Dim count As Integer nZ tMF%j' Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double &TgS$c5k Dim tlens As Double, nlens As Double .wH`9aq;5@ Dim curv As Double, conic As Double 6&8uLM(z Dim ok As Long D*T*of G 3?%?J^/a Sub Main uU$YN- {J&[JA\ '用户输入对话框 -BV8,1 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 0H9UM*O TextBox 220,21,40,21,.TextBox1 'default: 0 dG8_3T}i Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 *'i9 OKButton 40,91,90,21 RpmOg
CancelButton 190,91,90,21 nYFM^56>_ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 {l0[`"EF TextBox 220,49,40,21,.TextBox2 'default: 4 8]@$7hy8 End Dialog [SKN}:D Dim dlg As UserDialog `[)!4Jb Zk:Kux[7 ok = Dialog (dlg) gT-"=AsxZQ ?)-#\z=6G If ok=0 Then 'cancel button was pressed ]z77hcjB1 Print "Execution cancelled." ID_#a9N End `erKHZ]S End If mz>GbImVD~ ur$=%3vM 'Assign accommodation and pupil diameter & use defaults if field left empty 5^5hhm4 If dlg.TextBox1 = "" Then m;4qs#qCg? A = 0 'Default accommodation -~_[2u^3 Else 0s$;3qE A = CDbl(dlg.TextBox1) `=Z3X(Kc End If GQH15_ [d?tf If dlg.TextBox2 = "" Then 7 /6Zp? pupilDiam = 4 'Default pupil diameter zJ*(G_H Else 5:yRFzhqd pupilDiam = CDbl(dlg.TextBox2) '.B5CQ End If ieap {j8M78 }3 Print " " H`bS::JI- Print "Accommodation = " & A & " Diopters"
g)mjw Print "Pupil Diameter = " & pupilDiam & " mm" \=qZ),bU@ +HT?>k ' Calculate new parameters with accommodation p![UO I"W taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness (Q?@LzCjy ,,c+R?D Rant = 12.0 - 0.4*A 'Radius of anterior lens :.P{}\/ CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens JP,yRb\ d-cW47 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens *'cyFu$ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens T
-p~8=I oTN:Q"oK7? tlens = 3.767 + 0.04*A 'Lens thickness k>)Uyw$! yz<$?Gblz nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction &[z<p fZiwuq!_ 'Adjust parameters to account for accommodation XW.k%H4@ *djVOC '************************************************************************* G]n_RP$G 'Aqueous thickness (Position of Lens) -pHUC't '************************************************************************* yvWM]A eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 8F
K%7\V GetCustomElement eID, entity -A,UqEt oZ_,WwnE parID = FindFullName( "Geometry.Arizona Eye" ) g#q7~#9 /!'Png0! ' Delete any shift(s) in z 8ZF!}kb0F count = 0 wEF"'T While GetOperationCount(eID)>count Ih HKRb[ GetOperation eID, count, op 6rMXv0) If op.Type="ShiftZ" Then M%YxhuT0 DeleteOperation eID,count ,4j^lgJ count=count-1 D(WdI End If 2~l +2.. count=count+1 (?xR<]~g* Wend Z*+y?5+L"P t52KF#+> 'Set new shift in ^4Uk'T7V op.Type = "ShiftZ" #p<(2wN op.val1 = taq >a;LBQ0 op.parent = parID t)5.m} AddOperation eID, op j+PLtE Print "Set aqueous humor thickness = " & taq-0.55 C]Q`!e JM7FVB '************************************************************************* t*J?#r 'Radius and conic constant of anterior lens VHi'~B#'* '************************************************************************* X%$1%)C9 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) +G6 Ge; GetConic eID, entity, curv, conic . H}R}^ 29^(weT"] SetConic eID, entity, 1/Rant, CCant rJ{k1H > Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant I7\T :Q[ }9 ]7V < '************************************************************************* |\Q2L;4C 'Radius and conic constant of posterior lens {"2Hv;x '************************************************************************* <TTBIXV eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) AyNpY_B0c GetConic eID, entity, curv, conic >`l^
C 'ka}x~EF SetConic eID, entity, 1/Rpost, CCpost <G0Ut6J> Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ,9M2'6= "(iDUl '************************************************************************* 9^&B.6! 6 'Lens thickness (Position of posterior lens surface) g~2=he\C '************************************************************************* }G "EdhSl W!"Oho' parID = FindFullName( "Geometry.Arizona Eye.Lens" ) <J>k%,:B B@@tKn_CQ ' Delete any z-shift(s) (-],VB
(+ count = 0 ,vo]WIQ\: While GetOperationCount(eID)>count v cUGBGX_& GetOperation eID, count, op 86e aX+F If op.Type="ShiftZ" Then iL!4r]~H DeleteOperation eID,count DS9-i2 count=count-1 6HPuCP End If GO.7IL{{ count=count+1 Z^BZH/I? Wend :*/g~y(fE .mNw^>:cq 'Set new z-shift liqVfB% op.Type = "ShiftZ"
YCVT0d op.val1 = tlens xLb=^Xjec op.parent = parID 3<l}gB'S[ AddOperation eID, op x:Q$1&3N Print "Set lens thickness = " & tlens >xA(*7 ,:#h;4!VRF '************************************************************************* 7[mP@ { 'Lens index of refraction P#MUS_x '************************************************************************* mHAfK B eID = FindMaterial( "Lens" ) YS@TQ? GetModelMaterial eID, mat H )>3c1 t>OEzUd9 mat.Nd = nlens {>PEl;,- SetModelMaterial eID, mat N]14~r= Print "Set lens index of refraction = " & nlens `e`DSl D> R)4,f~@" '************************************************************************* +*Fe 'Pupil diameter L&rtN@5; '************************************************************************* pN_%>v"o eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ll[&O4.F itE/QB 'Adjust pupil diameter (trimming volume inner hole) Wsp c;]& y\4/M6 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" w ~"%&SNN :yE0DS<_ ' Adjust pupil location to just in front of the lens \3]O?' parID = FindFullName( "Geometry.Arizona Eye" ) 86 9sS eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Jamt@= count = 0 EiaP1o While GetOperationCount(eID)>count "Bwmq9Jq GetOperation eID, count, op LitdO>%#2 If op.Type="ShiftZ" Then W'=}2Y$]u DeleteOperation eID,count jse!EtB: count=count-1 a\~118 ! End If )#1!%aQ count=count+1 {;th~[ Wend $iMLT8U op.Type = "ShiftZ" ~{);Ab.9+ op.val1 = taq-0.01 #qUGc` op.parent = parID ?Ok&,\F@E AddOperation eID, op T@`Al(' f& \Bs8la Print "Set pupil diameter = " & pupilDiam DajN1}] bo@
?`5 'Update AZ Eye subassembly Description ZR-64G=L, eID = FindFullName( "Geometry.Arizona Eye" ) X h}D_c GetEntity eID, entity #0Uz1[ entity.Description = "Accommodation = " & A & "D" y"ss<`Cn SetEntity eID, entity ?Z4%u8Krvz +V9xKhR;x Update @/ nGc9h Print "DONE!" Ml;` *; yGSZ;BDW:K End Sub @$t\yBSK ]zCD1*) 如果屈光度是4,光瞳直径是4,则会输出如下数据: pq\N2d D%LYQ
Accommodation = 4 Diopters wr=KAsH< Pupil Diameter = 4 mm wf1p/bpf Set aqueous humor thickness = 2.81 C(h Td% Set anterior lens radius = 10.4 and conic constant = -2.375869 Rjlp< Set posterior lens radius = -4.424557 and conic constant = -3.081019 {IvA 5^ Set lens thickness = 3.927 F |R7hqf Set lens index of refraction = 1.42672 cH4PrMm& Set pupil diameter = 4 KZ%us 6 DONE! 5W&L cBB lN8l71N^ (文章来源:讯技光电)
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