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简介 5N/%v&1 ?4q4J8j 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。 Cjc6d4~ +^=8ge} 模型 l'/R&`-n kBD>-5Sn_T 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。 {>DEsO 0yuS3VY) Table 1. AZ眼睛模型的定义 A v2 08}Y 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. +@p%
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HK8jCa 光源 ]G5w6&d }:us:% 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。 n1ly
y0%u 7UVzp v OY;*zk 图1. 光源和提示信息使用 Xq_5Qv 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。 GP?M!C,/}k wr$M$i: 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。 ST:A<Da" wt!nMQ 图2. 字母F光源的设定方法光 !g5xq zgNc4B 图3. 字母F在视网膜上位置点列图 ew#B[[ 视网膜的散射 ?[g=F <r Jk7|{W\OA 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。 g;qx">xJ`o 6p?,( :N4t49i 图4. 视网膜朗伯散射设定 pWK(z[D 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。 &PYK8}pBk3 W6?pswQ S ?{#r 图5. 视网膜重点采样规格设定 * w?N{. 脚本 FbS|~Rp~ f&BY/ n, 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: x=b7': nQ /Z~<CbKKl 图6. 用户对话框的创建与编辑 'gC_)rK* 图7. 用户对话框编辑器 W+UfGk}A 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。 pGJ>O/% 余下的脚本计算与屈光度有关的所有参数。 D8Ykg >B;& #gz
M| 分析 n>ULRgiT:o DI:]GED"= 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 $c0h.t l_o@miG/ 图7. 字母F在视网膜上颜色分析 v|uAzM{73 脚本代码 a%kQl^I4 Al}6q{E9+8 Option Explicit 'Remove this to enable non-dimensioned variables to be used. /|tJ6T1LrB Jm xH"7hTE Dim entity As T_ENTITY }& cu/o4 Dim op As T_OPERATION 41`n1:-] Dim mat As T_MODELMATERIAL c~z82iXNO Dim A As Double a1C{(f) Dim pupilDiam As Double X:HacYqtC Dim eID As Long ?[@J8 Dim parID As Long /t+f{VX$ Dim count As Integer B"h#C!E Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double NQBpX Dim tlens As Double, nlens As Double D{GfLib"U Dim curv As Double, conic As Double K2TcOFQ Dim ok As Long B2>H_dmQ #|L8tuWW Sub Main z@!`:'ak U{2BVqM '用户输入对话框 zk$FkbX Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 b$N2z TextBox 220,21,40,21,.TextBox1 'default: 0 X{5vXT\/y Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Bt@^+vH ~ OKButton 40,91,90,21 01wX `"I CancelButton 190,91,90,21 cG[l!Z Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Of*Pw[vD TextBox 220,49,40,21,.TextBox2 'default: 4 .nrMfl_ End Dialog \UPjf]& Dim dlg As UserDialog VCV"S>aVf 6wBx;y
| ok = Dialog (dlg) ^uKwB;@ $ `ov4W If ok=0 Then 'cancel button was pressed C'9Cr}cZ. Print "Execution cancelled." SheM|I~de End KaPAa:Q End If J%u=Ucdh o}
J&E{Tk 'Assign accommodation and pupil diameter & use defaults if field left empty ,]bhy p If dlg.TextBox1 = "" Then Sdp&jZY A = 0 'Default accommodation )#?"Gjf~ Else `7c~mypx A = CDbl(dlg.TextBox1) &v56#lG End If '*K :
lx YmL06<Mh If dlg.TextBox2 = "" Then s2h@~y pupilDiam = 4 'Default pupil diameter `` ,fodA8 Else }JF13beU pupilDiam = CDbl(dlg.TextBox2) MLXN Zd End If 3x`| *:Y%HAy* Print " " ,f~J`3(& Print "Accommodation = " & A & " Diopters" ]] !VK Print "Pupil Diameter = " & pupilDiam & " mm" ,|3MG",@@h F^WP <0C ' Calculate new parameters with accommodation p2#)A" taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness PRx8I
. +9M^7/}H Rant = 12.0 - 0.4*A 'Radius of anterior lens K*%9)hq CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens caIL&G, @@R7p Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Xnt~]k\" CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens +[M6X}
TQ W<bGDh tlens = 3.767 + 0.04*A 'Lens thickness I4'5P}1yp DVG(Vw nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction #*D)Q/k MX$0Op 'Adjust parameters to account for accommodation ZT'`hK_up qU+t/C. '************************************************************************* 1#C4;3i, 'Aqueous thickness (Position of Lens) (SWYOMo" '************************************************************************* IoxgjUa eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 5yd MMb GetCustomElement eID, entity Bn^0^J- ! +a. Ei parID = FindFullName( "Geometry.Arizona Eye" ) rNrxaRQ CnU*Jb ' Delete any shift(s) in z Nkjza:f{ count = 0 #H)vK"hF While GetOperationCount(eID)>count \9cbI3rGz GetOperation eID, count, op :G [|CPm- If op.Type="ShiftZ" Then /$ w%Q-p DeleteOperation eID,count t#V!8EpBg count=count-1 &:;:"{t}Do End If hB"fhX count=count+1 AS!?q Wend &b.=M>\9Q {ME2ImD 'Set new shift in *M[?bk~~ op.Type = "ShiftZ" Cl5uS%g op.val1 = taq 2L:_rR#w op.parent = parID GOj-)i/_ AddOperation eID, op
DH[p\Wy' Print "Set aqueous humor thickness = " & taq-0.55 SbND
Y{5RO ?}Z1bH '************************************************************************* ed]=\Key 'Radius and conic constant of anterior lens GD&uQ`Y5 '************************************************************************* 6o!!=}'E[ eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) }QN1|mP2 GetConic eID, entity, curv, conic %oF}HF. @GPCwE1 SetConic eID, entity, 1/Rant, CCant spGb!Y`mR Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant }d[ kxo !Xh=k36 '************************************************************************* L(/e&J@>< 'Radius and conic constant of posterior lens Y4OPEo 5o '************************************************************************* qt"G[9; eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) NiNM{[3oS GetConic eID, entity, curv, conic =qoWCmg"& T%x}Y#U'` SetConic eID, entity, 1/Rpost, CCpost zE336 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost :I"2V h(<,fg1 '************************************************************************* Um} 'Lens thickness (Position of posterior lens surface) ob+b<HFv '************************************************************************* qPWP&k FGPB: parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ynmWW^dg 6}Vf\j~ ' Delete any z-shift(s) kj|6iG count = 0 rR$h* While GetOperationCount(eID)>count \(J8#V GetOperation eID, count, op $Ad{Z If op.Type="ShiftZ" Then jG6]A"pr DeleteOperation eID,count Z_PNI#h* count=count-1 CHdX;'`* End If 8&;UO{ count=count+1 Eou~P h*t Wend gMv.V{vD efSM`!%j 'Set new z-shift ZWii)0'PV op.Type = "ShiftZ" ~{*7"o/ op.val1 = tlens +ylTGSZS op.parent = parID -B>++r2A^ AddOperation eID, op /Y*WBTV' Print "Set lens thickness = " & tlens 1 da@3xaF JBD7h5|Lc '************************************************************************* ylUrLQ\ 'Lens index of refraction <z+t,<3D '************************************************************************* Okgv!Nt8)A eID = FindMaterial( "Lens" ) cO-7ke GetModelMaterial eID, mat R7]l{2V#^ zqd@EF6/bz mat.Nd = nlens :f Kl]XO SetModelMaterial eID, mat V
@rI`~$ Print "Set lens index of refraction = " & nlens ,4hJT B*qi_{Gp '************************************************************************* pb^i^tA+A 'Pupil diameter 2^XGGB0 '************************************************************************* Z<U6<{b eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) OHv[#xGuV? 9*$t!r{B@ 'Adjust pupil diameter (trimming volume inner hole) 3NZK*!@' M])ZK SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 3sc+3-TF (w&F/ynO: ' Adjust pupil location to just in front of the lens RFKtr parID = FindFullName( "Geometry.Arizona Eye" ) k2E0/ @f{k eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) JgG$?n\ count = 0 $v,dz_O*\ While GetOperationCount(eID)>count &6DMk- GetOperation eID, count, op hS_6 If op.Type="ShiftZ" Then QU#w%| DeleteOperation eID,count ;g8R4!J count=count-1 dCb`xR} End If TPVVck-T8 count=count+1 w'L\?pI Wend R{RwTN< op.Type = "ShiftZ" ;V@WtZv op.val1 = taq-0.01 xrlmKSPa op.parent = parID tM2)k+fg AddOperation eID, op $J4 *U J5*tJoCYS Print "Set pupil diameter = " & pupilDiam 8 m5p_\& Q)"C&)`l 'Update AZ Eye subassembly Description aGK?x1_ eID = FindFullName( "Geometry.Arizona Eye" ) SH3|sXH< GetEntity eID, entity n-5W*zk1 entity.Description = "Accommodation = " & A & "D" =b38(\ SetEntity eID, entity aHlcfh9| `/_o!(Z` Update Gn&-X]Rrl Print "DONE!" Z.d7U~_ )iq-yjO6 End Sub pqUCqo!m\ R=.4 如果屈光度是4,光瞳直径是4,则会输出如下数据: ?MXejEC `L:CA5sBud Accommodation = 4 Diopters "mX\&%i6\p Pupil Diameter = 4 mm *Kyw^DI Set aqueous humor thickness = 2.81 .b\$MZ"( Set anterior lens radius = 10.4 and conic constant = -2.375869 vesJEaw7 Set posterior lens radius = -4.424557 and conic constant = -3.081019 & +4gSr Set lens thickness = 3.927 ^?$WVB Set lens index of refraction = 1.42672 `IOs-%s Set pupil diameter = 4 lW<PoT DONE! m7&O9?X
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