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简介 i8F^ N= sD|P*ir 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。 f^P:eBgpx Lci SQ
R! 模型 uSeRn@ SLzxF uV 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。 ?#OGH`ZvkI 6qW/Td|g Table 1. AZ眼睛模型的定义 ?;s}GpEY: 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. zYCrfr }ze,6T*z 光源 Ck71N3~W f`zH#{u 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。 Q&zEa0^rG6 Q9-o$4#R[ ^hG
Y,\K9 图1. 光源和提示信息使用 AS 5\X.%L* 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。 S7{L-"D=y f}jo18z% 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。 C$9+p@G6 { o2pCH 图2. 字母F光源的设定方法光 n|t?MoUP Pm2T!0 图3. 字母F在视网膜上位置点列图 F\' ^DtB 视网膜的散射 $$UMc-Pq ~hubh!d= 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。 z:RclDm I!
s&m%s h5+qP"n!?q 图4. 视网膜朗伯散射设定 wzLR]<6G 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。 :)!X%2_ t`PA85.|d eBZa9X$ 图5. 视网膜重点采样规格设定 hD~P)@^ 脚本 aBo8?VV]8 ?\_N*NEtK 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: $~h\8 Y^zL}@ 图6. 用户对话框的创建与编辑 ,XD'f 图7. 用户对话框编辑器 h8IjTd]z{$ 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。 d>ltL`xn 余下的脚本计算与屈光度有关的所有参数。 [;bZQ6JR 1J}i :i& 分析 (C<~:Y?% ye -o'%{ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 PQla- 68m (%%E@ 图7. 字母F在视网膜上颜色分析 A=Au>"nAA 脚本代码 Gp=X1 F HOWm""IkB Option Explicit 'Remove this to enable non-dimensioned variables to be used. h/h`?vWu X!+#1NPM Dim entity As T_ENTITY 5O.dRp7dJ Dim op As T_OPERATION Ql1HaC/5)- Dim mat As T_MODELMATERIAL E)eRi"a46 Dim A As Double {@T8i^EI Dim pupilDiam As Double RX-qL,dc Dim eID As Long SU0K#: Dim parID As Long W)3IS&;P Dim count As Integer ~ vD7BO` Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 44H#8kV Dim tlens As Double, nlens As Double Qr`WPTQr" Dim curv As Double, conic As Double T6s~f$G Dim ok As Long [emUyF vn n4 Sub Main &^ECQ #;Yn8'a~ '用户输入对话框 GA19=gow Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 5):2;h k TextBox 220,21,40,21,.TextBox1 'default: 0 %
K$om|]p Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 wRgh`Hc\} OKButton 40,91,90,21 sOc<'):TK CancelButton 190,91,90,21 _pu G?p Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 y %dUry%> TextBox 220,49,40,21,.TextBox2 'default: 4 OrXx0Hn End Dialog "%O,*t Dim dlg As UserDialog Lod$&k@@ EleK*l ok = Dialog (dlg) DKV^c'
FA 1E`AdU If ok=0 Then 'cancel button was pressed ,vBi)H Print "Execution cancelled." 9>qc 1z End M8Y\1#~ End If P0m;AqS#R +PC<# 'Assign accommodation and pupil diameter & use defaults if field left empty rbP"
n)0= If dlg.TextBox1 = "" Then qaBjV6loy A = 0 'Default accommodation &1hJ?uM01 Else b .9]b A = CDbl(dlg.TextBox1) c5_?jKpl End If ;6N@raP7 Nrl&"IK|J If dlg.TextBox2 = "" Then 8l|v#^v pupilDiam = 4 'Default pupil diameter )A]E:]2 Else "hRw_< pupilDiam = CDbl(dlg.TextBox2) zx7*Bnu0 End If {7^7)^@ .e2qa Print " " ?#@JH Print "Accommodation = " & A & " Diopters" H-%)r&"vn Print "Pupil Diameter = " & pupilDiam & " mm" *&X. {p-b,J9~a ' Calculate new parameters with accommodation Y21,!$4gb taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness vt`hY4 .Z=D|&! Rant = 12.0 - 0.4*A 'Radius of anterior lens fo])=KM CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens 1gp3A 7p""5hw Rpost = -5.224557 + 0.2*A 'Radius of posterior lens EK:!.Fl CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens w yO@oi
Vn 5m")GWQaP@ tlens = 3.767 + 0.04*A 'Lens thickness ]Xcqf9k -Z&6PT7 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction \LB =_W$ M 7j0&>NTG 'Adjust parameters to account for accommodation ^6v ob [ V`j@dV '************************************************************************* ^n5[pF}Gw 'Aqueous thickness (Position of Lens) >'#G$f '************************************************************************* {.9phW4Vr? eID = FindFullName( "Geometry.Arizona Eye.Lens" ) |xaJv:96% GetCustomElement eID, entity 84[T!cDk eWO^n>Y parID = FindFullName( "Geometry.Arizona Eye" ) se](hu~w pfW0)V1t ' Delete any shift(s) in z E^S[8= count = 0 }S6Sz&) While GetOperationCount(eID)>count IC}?oXs5G GetOperation eID, count, op P>%\pCJ]) If op.Type="ShiftZ" Then .?b2Bd!MC DeleteOperation eID,count c@:L7#8 count=count-1 y|!%C-P End If 0;'kv| count=count+1 v%3mhk# Wend po_||NIY Z~o*$tF/ 'Set new shift in c_xtwdkL9 op.Type = "ShiftZ" &)L2a) op.val1 = taq }~dXz?{p8 op.parent = parID IWN:GFH( AddOperation eID, op HBYqqEO Print "Set aqueous humor thickness = " & taq-0.55 10dVV[= oo7&.HWf '************************************************************************* !]Z> T5$ 'Radius and conic constant of anterior lens a#W:SgE?Y '************************************************************************* '2=u<a B eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 06 gE;iT GetConic eID, entity, curv, conic ,YFuMek W#|]m=2W SetConic eID, entity, 1/Rant, CCant QLo^6S5! Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ?iG}Qj@5 W?{:HV '************************************************************************* b3e:F{n
^ 'Radius and conic constant of posterior lens Ltpd:c '************************************************************************* ~,yHE3B\G eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) UwY <3ul GetConic eID, entity, curv, conic B M{GSX PPT"?lt*& SetConic eID, entity, 1/Rpost, CCpost qWe1`.o Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost J)
v~ aR.1&3fE '************************************************************************* VP=(",` 'Lens thickness (Position of posterior lens surface) KC o<% '************************************************************************* BR\%aU$u w\=zTHo88 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) i](,s. OxX{[|!` ' Delete any z-shift(s) u814ZN} count = 0 R3F>"(P@tS While GetOperationCount(eID)>count a_I!2w<I GetOperation eID, count, op Q^/5hA If op.Type="ShiftZ" Then hu\HK81m DeleteOperation eID,count S{j|("W"[ count=count-1 *Id$%O End If 2}]6~i count=count+1 WZ5[tZf Wend ~\/>b}^uf' ?RvXO'm l 'Set new z-shift Z$0r+phQk= op.Type = "ShiftZ" (6z^m?t? op.val1 = tlens hNc;,13 op.parent = parID 1Nw&Z0MI AddOperation eID, op FCQoz"M Print "Set lens thickness = " & tlens ,5'LbO- #/@U|g '************************************************************************* l?(nkg["nY 'Lens index of refraction dv-yZRU: '************************************************************************* B{a:cz>0< eID = FindMaterial( "Lens" ) G;V@oT GetModelMaterial eID, mat @B
~![l _~_04p mat.Nd = nlens ;_K+b, SetModelMaterial eID, mat #})Oz| c Print "Set lens index of refraction = " & nlens \v]} 7CUu:6% '************************************************************************* Ri4_zb 'Pupil diameter !^!<Xz; '************************************************************************* QL}5vSl eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) &d`Umm] ADA%$NhJ! 'Adjust pupil diameter (trimming volume inner hole) O;f^'N F}0QocD SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ;|w &n m(nlu ' Adjust pupil location to just in front of the lens !$AVlMnJ parID = FindFullName( "Geometry.Arizona Eye" ) x+|Fw d eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) t*<vc]D count = 0 jd l1Q<Z While GetOperationCount(eID)>count /V~L:0% GetOperation eID, count, op (U2G" If op.Type="ShiftZ" Then n0U^gsD4J DeleteOperation eID,count f1=BBQY
> count=count-1 8_>\A=
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End If =b32E^z, count=count+1 CB_(9T72H Wend lZ0+:DaP2 op.Type = "ShiftZ" BQSA;;n] op.val1 = taq-0.01 J=*y>Zt-b op.parent = parID T =3te|fv AddOperation eID, op )&+_T+\ o}v #Df Print "Set pupil diameter = " & pupilDiam 9Q]v#&1 aen(Mcd3bg 'Update AZ Eye subassembly Description zA&0H eID = FindFullName( "Geometry.Arizona Eye" ) <Xp
F GetEntity eID, entity I.R3?+tZ
entity.Description = "Accommodation = " & A & "D" 5|m|R"I*Y SetEntity eID, entity qS&PMQ"$ .`Z{ptt> Update >1pD'UZIy7 Print "DONE!" 90sM S]a B_hob End Sub Qu!\Cx@ |rdG+> 如果屈光度是4,光瞳直径是4,则会输出如下数据: z(.$>O&6H G&D N'bp Accommodation = 4 Diopters aZ@4Z=LK Pupil Diameter = 4 mm ||`w MWq Set aqueous humor thickness = 2.81 dwrc"GK!o Set anterior lens radius = 10.4 and conic constant = -2.375869 FPaj
p Set posterior lens radius = -4.424557 and conic constant = -3.081019 1GOa'bxm Set lens thickness = 3.927 qqw6p j Set lens index of refraction = 1.42672 Hxb{bF Set pupil diameter = 4 l]WV?^* DONE! 6$ IXER ~(aq3ngo. ?[RG8,B QQ:2987619807 ^+`vh0TPQ
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