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简介 _D,f4.R E816YS=' 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。 m&0BbyE.z A-C)w/7 模型 Q1\k`J HmB[oH"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。 +xBK^5/x >fA@tUQB Table 1. AZ眼睛模型的定义 T_tDpq_| 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. BI.k On= GKujDx+h 光源 OK?3,<x nf.:5I. 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。 Y\Qxdq 8w8I:* ^ lc}FN 图1. 光源和提示信息使用 jvc?hUcLKT 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。 $<
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j} 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。 kbp(
a+5 avt>saR 图2. 字母F光源的设定方法光 &*]{"^ _[vdY|_ 图3. 字母F在视网膜上位置点列图 Tb0;Mbr 视网膜的散射 H(G^O&ppdB oD#<?h)( 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。 +fP/|A8P @Gn?8Ur% 8Z4?X% 图4. 视网膜朗伯散射设定 ZG/8 Ds 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">vaa q]i(CaKh <V:<x 图5. 视网膜重点采样规格设定 AXh3LA 脚本 f5yux}A{ yg+IkQDf4U 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: }EedHS >4|c7z4 图6. 用户对话框的创建与编辑 =yTa,PY 图7. 用户对话框编辑器 X=p3KzzX 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。 XHZ:
mLf 余下的脚本计算与屈光度有关的所有参数。 a?,[w'7FU $D/bU lFx 分析 MB8SB ,bVS.A'o 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ~6-"i0k
:e&n.i^ 图7. 字母F在视网膜上颜色分析 iIGI=EwZ 脚本代码 x>^3]m 5&?KW)6 Rz Option Explicit 'Remove this to enable non-dimensioned variables to be used.
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y(] Dim entity As T_ENTITY 5qd_>UHp Dim op As T_OPERATION {7=WU4$ Dim mat As T_MODELMATERIAL G !1~i*P$u Dim A As Double hEv=T'*,K) Dim pupilDiam As Double ~3'RW0 Dim eID As Long 9QH9gdiw Dim parID As Long gv#c~cX] Dim count As Integer pFsCd"zv Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 8Q^6ibE Dim tlens As Double, nlens As Double 5oU`[&=Ob Dim curv As Double, conic As Double bB:r]*_
s] Dim ok As Long -Wlp=#9 crJ7pe9 Sub Main #*Yi4Cn< U/X|i / '用户输入对话框 M[YTk=IM# Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 JO2ZS6k[ TextBox 220,21,40,21,.TextBox1 'default: 0 =f4[=C$&` Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1
':4}O# OKButton 40,91,90,21 r=~WMDCz@ CancelButton 190,91,90,21 ceFsGdS Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 [lNqT1%] TextBox 220,49,40,21,.TextBox2 'default: 4 K\IYx|Hm a End Dialog &Y54QE". Dim dlg As UserDialog ]6t]m2~\ Uvjdx(fY[a ok = Dialog (dlg) %RQ C9! K\{b!Cfr^ If ok=0 Then 'cancel button was pressed \7Gg2;TA6o Print "Execution cancelled." .M9d*qp`S End bJQ5- *F End If $J QWfGwR 7P<r`,~k- 'Assign accommodation and pupil diameter & use defaults if field left empty 8K\'Z If dlg.TextBox1 = "" Then r}/yi A = 0 'Default accommodation f^W[;w Else ,vPe}OKj A = CDbl(dlg.TextBox1) [3O^0-:6E End If @br@[RpB _0'm4?" If dlg.TextBox2 = "" Then }>MP{67Dm pupilDiam = 4 'Default pupil diameter hLb;5u&!kW Else B{7Kzwh; pupilDiam = CDbl(dlg.TextBox2) ]y3pE}R End If p91`<>Iw T4OguP= Print " " 4. 1rJa Print "Accommodation = " & A & " Diopters" $[Tt#CJw Print "Pupil Diameter = " & pupilDiam & " mm" I
jZ]_*^! Lw*;tL<, ' Calculate new parameters with accommodation H>60D|v[ taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness .6> hD1' C%giv9a Rant = 12.0 - 0.4*A 'Radius of anterior lens L|&'jH) CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens PX;Vo~6 tIq>Oojdx Rpost = -5.224557 + 0.2*A 'Radius of posterior lens SArfczoB CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens M]}l^m>L 3`8dii tlens = 3.767 + 0.04*A 'Lens thickness >qR7'Q wP 8g\wVKkTQp nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction OnZF6yfN=3 _i5mC,OffN 'Adjust parameters to account for accommodation a%Uw;6|{ ]JOephX2R '************************************************************************* kmryu= 'Aqueous thickness (Position of Lens) HbcOTd)=5 '************************************************************************* !7}IqSs eID = FindFullName( "Geometry.Arizona Eye.Lens" ) !X^Hi=aV GetCustomElement eID, entity {vs 4vS6 c\At0.QCA parID = FindFullName( "Geometry.Arizona Eye" ) w{pUUo:< XC=%H'p ' Delete any shift(s) in z )FRM_$t count = 0 <"W?<VjO While GetOperationCount(eID)>count l
:/&E 6 9 GetOperation eID, count, op ~A6 "sb= If op.Type="ShiftZ" Then fX_#S|DlSG DeleteOperation eID,count W+_ R hJ count=count-1 OFA{
KZga End If VZ$=6CavH count=count+1 7W"/N#G Wend [r(Qs| #O" 'Set new shift in BT]ua]T+ op.Type = "ShiftZ" |'tW= op.val1 = taq F!JJ6d53y op.parent = parID rz6uDJ" AddOperation eID, op ['z!{Ez Print "Set aqueous humor thickness = " & taq-0.55 %%>_B2vc U[R@x` '************************************************************************* Wt^|BjbB4 'Radius and conic constant of anterior lens QdQd(4/1 '************************************************************************* 6SVqRD<` eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Ir5WN_EaS GetConic eID, entity, curv, conic ~4\,&HH -T7xK/ SetConic eID, entity, 1/Rant, CCant 9}5K6aQ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 1~J5uB 4 ZPHXzi3j '************************************************************************* )t:7_M3 'Radius and conic constant of posterior lens n 6{2]&sd '************************************************************************* h>alGLN> eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) -?<4Og[^ GetConic eID, entity, curv, conic 9GgA 6# @wp4 |G SetConic eID, entity, 1/Rpost, CCpost \?D R
s Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 9I`Y-D ahJ1n< '************************************************************************* k;I &.H 'Lens thickness (Position of posterior lens surface) n-o3 '************************************************************************* eWvo,4 =p@8z
/u parID = FindFullName( "Geometry.Arizona Eye.Lens" ) :~zv t _n"Ae?TP ' Delete any z-shift(s) Q$ri=uB;+ count = 0 F2 ~%zNe While GetOperationCount(eID)>count {fV}gR2 GetOperation eID, count, op O oSb>Y/4 If op.Type="ShiftZ" Then r[_4Lo@G DeleteOperation eID,count e8}Ezy"^ count=count-1 ~9=aT1S| End If N
j4IQ<OV count=count+1 0:&ZnE}## Wend b.F^vv"]] G^wtE90 'Set new z-shift v>A=2i*j op.Type = "ShiftZ" &<5+!cV= op.val1 = tlens >^$2f&z op.parent = parID 8i}<
k$S AddOperation eID, op TZRcd~ 5$ Print "Set lens thickness = " & tlens iWLa> z|, la
<npX '************************************************************************* }P9Ap3? 'Lens index of refraction `zpbnxOL$T '************************************************************************* ]"~51HQZ eID = FindMaterial( "Lens" ) 8FkFM^\1L GetModelMaterial eID, mat (k`{*!:1a N]N4^A' mat.Nd = nlens B*1W`f SetModelMaterial eID, mat q
o 1lj"P Print "Set lens index of refraction = " & nlens _:`!DIz~9} ;AJTytE>% '************************************************************************* 7=XL!:P 'Pupil diameter %XTcP2pRJ '************************************************************************* E7zm{BX] eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) WO</Mw bEV<iZDq% 'Adjust pupil diameter (trimming volume inner hole) !yOeW0/2[ \5)h tL1F SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" BxK^?b[E8 1"#*)MF ' Adjust pupil location to just in front of the lens "
=]
-%B parID = FindFullName( "Geometry.Arizona Eye" ) up'
eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) =PHIpFIuk count = 0 o4b~4h{% While GetOperationCount(eID)>count X"fh@. GetOperation eID, count, op 6\jf|:h If op.Type="ShiftZ" Then 8>WVodv DeleteOperation eID,count -fI@])$9J count=count-1 76cG90!Z End If 4Kwh?8. count=count+1 ^! 8P<y Wend 1xE]6he4{T op.Type = "ShiftZ" 4*.K'(S5fx op.val1 = taq-0.01 -62'}%?A<C op.parent = parID JPn$FQD AddOperation eID, op
Ez~'^s@ 6$fYt&1 Print "Set pupil diameter = " & pupilDiam 41a.#o gb=/#G0R 'Update AZ Eye subassembly Description `(6r3f~XJ eID = FindFullName( "Geometry.Arizona Eye" ) 6]zd.W GetEntity eID, entity '})0!g<Y entity.Description = "Accommodation = " & A & "D" NcPgq?3p SetEntity eID, entity [+m?G4[ G`fC/Le Update l1U=f] Print "DONE!" 5}$b0<em~ u]+~VT1C,3 End Sub K_?W\Yg |t
iUej 如果屈光度是4,光瞳直径是4,则会输出如下数据: ~ 9)"! ps
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Accommodation = 4 Diopters ^.k
|SK`U Pupil Diameter = 4 mm p!O(Y6QM Set aqueous humor thickness = 2.81 {j5e9pg1L| Set anterior lens radius = 10.4 and conic constant = -2.375869
~=<}\a~ Set posterior lens radius = -4.424557 and conic constant = -3.081019 l
{jmlT Set lens thickness = 3.927 R" )bDy? Set lens index of refraction = 1.42672 7@lS.w\#- Set pupil diameter = 4 G0u LmW70 DONE! $N:Vo(*
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