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简介 GZ={G2@=I 5"Yw$DB9 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 7Tbk ti; DH^^$) 模型 9V&LJhDQ v^tKT& 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。 IFY!3^;zO :q=OW1^k^ Table 1. AZ眼睛模型的定义 QZlUUj\
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. ^wlep1D
U*@_T 3N 光源 v<wT`hiKW J\V(MN, 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。 m+g>s&1H
"DpQnhvbB [xPE?OD 图1. 光源和提示信息使用 UU/|s>F 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。 v4$,Vt:7 `9-Zg??8r 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 *C BCQp[$ 8'_Y=7b0Nw 图2. 字母F光源的设定方法光
T!PX? 9:>K!@ 图3. 字母F在视网膜上位置点列图 rx/6x(3 视网膜的散射 5glGlD6R F?B=:8,} 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。 brWt YLGLr@:q TTpF m~?( 图4. 视网膜朗伯散射设定 .Dm{mV@*T 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。 ]_?y[@ZP [_d*J/ X %u}sVRJ 图5. 视网膜重点采样规格设定 ;Y\,2b, xh 脚本 0^[6 #F@7>hd1 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: 1*h7L<#|mQ `t6L'%\ 图6. 用户对话框的创建与编辑 U4gJ![>5j 图7. 用户对话框编辑器 z3]U%y(, 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。 _=5ZB_I 余下的脚本计算与屈光度有关的所有参数。 F S:WbFmc k6BgY|0g C 分析 <.ky1aex7 *q{UipZbx 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 qgNK!(kWpr L ]c9 图7. 字母F在视网膜上颜色分析 ?sYjFiE 脚本代码 0
,-b %X ]6 wi Option Explicit 'Remove this to enable non-dimensioned variables to be used. W<"\hQI *\", qMp Dim entity As T_ENTITY e%6{P Dim op As T_OPERATION m12B:f Dim mat As T_MODELMATERIAL Phu|
hx< Dim A As Double -::%9D}P| Dim pupilDiam As Double "'Uk0>d=_I Dim eID As Long sdQv:nd'R Dim parID As Long (_ah~VnO Dim count As Integer h>0<@UP Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ,~(}lvqVH Dim tlens As Double, nlens As Double VsEAo Dim curv As Double, conic As Double Hw&M2a Dim ok As Long ^ {f^WL= E e>j7k.G. Sub Main Xf9%A2 iB _#mqg]W ' '用户输入对话框 #Ca's'j&f Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ;NE/!! TextBox 220,21,40,21,.TextBox1 'default: 0 om?CFl Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 _`>7
Q),7 OKButton 40,91,90,21 9'g{<(R] CancelButton 190,91,90,21 7"p s#)O Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 <z2mNq TextBox 220,49,40,21,.TextBox2 'default: 4 E2'e}RQ End Dialog %+a@|Z Dim dlg As UserDialog /
LM I?Fa ok = Dialog (dlg) 9X9zIh]JV **w~ If ok=0 Then 'cancel button was pressed 2-!Mao"^ Print "Execution cancelled." +|)1_NK End } <4[(N End If \N+Ta:U1P wS*CcIwj 'Assign accommodation and pupil diameter & use defaults if field left empty ?3,tG z) If dlg.TextBox1 = "" Then lFGxW 5 A = 0 'Default accommodation UMQW#$~C{g Else b.q"s6u A = CDbl(dlg.TextBox1) h\*rv5\M End If ,9wenr cjC6\.+l3 If dlg.TextBox2 = "" Then <<5 :zlb pupilDiam = 4 'Default pupil diameter ESjJHZoD( Else =^y{@[p`( pupilDiam = CDbl(dlg.TextBox2) (Zg'pSs) End If xWz;5=7a] h?3l Print " " Kx185Q'W Print "Accommodation = " & A & " Diopters" ^.kAZSgO Print "Pupil Diameter = " & pupilDiam & " mm" \}QuNwc 3(})uV ' Calculate new parameters with accommodation 'oZn<c` taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness vLFaZ^( LiD |4(3 Rant = 12.0 - 0.4*A 'Radius of anterior lens pkf OM"5' CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens emY5xZ@N I=
h4s( Rpost = -5.224557 + 0.2*A 'Radius of posterior lens #IhLpO CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens V/9"Xmv75 ,9tbu!Pvq tlens = 3.767 + 0.04*A 'Lens thickness 6Y_O^f *8X9lv.Z nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction `}8@[iB' 8<wuH#2<y 'Adjust parameters to account for accommodation d3=6MX[c #C;zS9(]B '************************************************************************* :Mu8W_ 'Aqueous thickness (Position of Lens) 4B8S e '************************************************************************* C:GHP$/} eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ?V)C9@bp GetCustomElement eID, entity MRg\FR2>1
2C33;?M parID = FindFullName( "Geometry.Arizona Eye" ) `TD%M`a 5*wApu{2A ' Delete any shift(s) in z a3dzok count = 0 7|M $W(P While GetOperationCount(eID)>count .1}rzh}8 GetOperation eID, count, op R-A'v&= If op.Type="ShiftZ" Then [zTYiNa DeleteOperation eID,count DPS1GO* count=count-1 RnA&-\|* End If OT}Yr9h4 count=count+1 _{*$>1q Wend K[LVT]3 n a j@C0 'Set new shift in ;;w6b:}-c op.Type = "ShiftZ" WW[`E op.val1 = taq N{V5 D op.parent = parID jQxPOl$- AddOperation eID, op T7lj39pJq Print "Set aqueous humor thickness = " & taq-0.55 N?=qEX|R x<*IF,o '************************************************************************* *pb:9JKi 'Radius and conic constant of anterior lens `b.o&t$L '************************************************************************* 8>VI$
eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) SGBVR ^ GetConic eID, entity, curv, conic }}``~ (U(/C5' SetConic eID, entity, 1/Rant, CCant pqH(
Tbjq Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant wj#J>C2] )+w/\~@ '************************************************************************* qb-2QPEB 'Radius and conic constant of posterior lens iFnOl*TC '************************************************************************* ~X~xE]1o|U eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Wd^lt7(j GetConic eID, entity, curv, conic X"TUe>cM T@Ss&eGT2 SetConic eID, entity, 1/Rpost, CCpost YHO;IQ5 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ovQS
ET18b 2;%#C!TG; '************************************************************************* OAW=Pozr9 'Lens thickness (Position of posterior lens surface) |C$:]MZx '************************************************************************* %
UW=: JtYYT/PB parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 95$pG/o SaR}\Up ' Delete any z-shift(s) |{7e#ww] count = 0 MK-a$~< While GetOperationCount(eID)>count RRS~ xOg GetOperation eID, count, op Dm|gSv8d, If op.Type="ShiftZ" Then ^e aRgNz DeleteOperation eID,count k1f3?l
vlU count=count-1 42Aje End If 8S.')<-f count=count+1 /FP ~jV!z Wend 9feD!0A J0?$v6S 'Set new z-shift 670J{b op.Type = "ShiftZ" B@cJ\ op.val1 = tlens IwTr'}XIw op.parent = parID m\*&2Na AddOperation eID, op 6P%<[Z Print "Set lens thickness = " & tlens lFiq<3Nk 0)A=+zSS1 '************************************************************************* -O~C m}e 'Lens index of refraction 3AdP^B< '************************************************************************* '^Pq(b~ eID = FindMaterial( "Lens" ) wUru1_zjO GetModelMaterial eID, mat
&7L~PZ $:f.Krj mat.Nd = nlens ov\Ct%] SetModelMaterial eID, mat jo,6Aog|u Print "Set lens index of refraction = " & nlens 9nng}em>. z3^RUoGU '************************************************************************* WdTbt 'Pupil diameter $"Y3mD}?L '************************************************************************* V.K70)] eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) n\Z^K n!UMU ^ 'Adjust pupil diameter (trimming volume inner hole) =gW"#ZjL){ 3
R5%N
~ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 9M1a*frxZ wD<vg3e[H ' Adjust pupil location to just in front of the lens ~8jThi
U parID = FindFullName( "Geometry.Arizona Eye" ) D-Bv(/Pz]$ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) -/M9 vS count = 0 JZ %`%rA While GetOperationCount(eID)>count PzIy">plm GetOperation eID, count, op ijvNmn1k If op.Type="ShiftZ" Then t*o7,
DeleteOperation eID,count \#
7@a74 count=count-1 -,R0IGS End If Qe2m8 count=count+1 pZu?V"R Wend IM[54_I op.Type = "ShiftZ" &[NVP&9&U op.val1 = taq-0.01 /t$rX3A op.parent = parID P-[fHCg~ AddOperation eID, op a;56k MPjr_yc] Print "Set pupil diameter = " & pupilDiam &\&'L|0F 6eD(dZ 'Update AZ Eye subassembly Description ?$<SCN= eID = FindFullName( "Geometry.Arizona Eye" ) hbVE;
9 GetEntity eID, entity IKvd!,0xf entity.Description = "Accommodation = " & A & "D" n)tU9@4Np SetEntity eID, entity Xf6fH O 53bM+ Update 86/. 8 Print "DONE!" +*n]tlk 6e,Apj 0 End Sub nARxn#<+ zs4>/9O 如果屈光度是4,光瞳直径是4,则会输出如下数据: ~@xT]D!BQ qO7fbql_ Accommodation = 4 Diopters l &}piC Pupil Diameter = 4 mm 0xN!DvCg>. Set aqueous humor thickness = 2.81 +z+F- Set anterior lens radius = 10.4 and conic constant = -2.375869 7Aqn[1{_O Set posterior lens radius = -4.424557 and conic constant = -3.081019 XxhsPFv Set lens thickness = 3.927 =\M)6"}y} Set lens index of refraction = 1.42672 :b"=KQ Set pupil diameter = 4 I9;xz ES DONE! "Lb fF
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