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简介 1jQz%^~ ]xV7)/b5G 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。 bCc^)o/w e,8C}
2 模型 5a-8/.}cP 5Ss=z 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。 Qp%kX@Z' #2Mz.=#G Table 1. AZ眼睛模型的定义 t5[{ihv~: 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. 0Ac]&N d` 5Sk87o1E(d 光源 BxlpI[yWq fv#e 8y 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。 Zj!S('hSY 7?/ Fr(\ Ge|caiH1I 图1. 光源和提示信息使用 #^#N%_8 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。 =suj3.
%p@A8'b 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。 RIb<
7 &vd9\Pp 图2. 字母F光源的设定方法光 x@ (91f sd.:PE < 图3. 字母F在视网膜上位置点列图 =as ]>?< 视网膜的散射 j{S\X'?
D",ZrwyJ 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。 $UO7AHk ym8\q:N(R q<.^DO~$L 图4. 视网膜朗伯散射设定 q'd6\G0} 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)nBy)< d;H1B/ <-X)<k 图5. 视网膜重点采样规格设定 i%v^Zg&FU 脚本 Dy0cA| E qvhTc6oH 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: 7@|(z:uw o+q4Vg9& 图6. 用户对话框的创建与编辑 vQYd!DSh 图7. 用户对话框编辑器 xw]Zo<F 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。 `N
;!=7y7Y 余下的脚本计算与屈光度有关的所有参数。 >"N \ZC^ qEX59v 分析 _sJp"4? DJT)7l { 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 C5 ^_R {Km|SG[-q 图7. 字母F在视网膜上颜色分析 `L7 cS 脚本代码 bG;vl;C ,Ix7Yg[ Option Explicit 'Remove this to enable non-dimensioned variables to be used. *cq#>rN q$~S?X5\ Dim entity As T_ENTITY <`~]P$ Dim op As T_OPERATION )"=BbMfhu Dim mat As T_MODELMATERIAL Nr6YQH*[ Dim A As Double y @h^ Dim pupilDiam As Double boJQ3Xc Dim eID As Long `:?padZG Dim parID As Long ^L<1S/~) Dim count As Integer ^4c2}>f Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double "f3, w Dim tlens As Double, nlens As Double N{L ]H_= Dim curv As Double, conic As Double %[&cy' Dim ok As Long nS]/=xP{ Uw<Lt"ls. Sub Main >LwAG:Ud -L</,>p '用户输入对话框 /$]dVvhX% Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ir3iW*5k TextBox 220,21,40,21,.TextBox1 'default: 0 a}El!7RO0 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ^kt#[N OKButton 40,91,90,21 VS1gg4tCv CancelButton 190,91,90,21 C} Ewi- Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 wF$8#= TextBox 220,49,40,21,.TextBox2 'default: 4 NJLU+byU End Dialog qA
Jgz7=c Dim dlg As UserDialog E':y3T@." C
`k^So) ok = Dialog (dlg) ukzXQe;l1 h&;\ If ok=0 Then 'cancel button was pressed _dIv{L! Print "Execution cancelled." S'B7C>i`#N End *.n9D End If 80c\O-{ e8--qV#< 'Assign accommodation and pupil diameter & use defaults if field left empty VL7zU->
If dlg.TextBox1 = "" Then oRmN|d ~4 A = 0 'Default accommodation *`=V"nXw$| Else P=(\3ok A = CDbl(dlg.TextBox1) }7wQFKME End If !@p@u;djJ @1^iWM j If dlg.TextBox2 = "" Then /'!F \ kz pupilDiam = 4 'Default pupil diameter &*T57tE Else xa5I{<<U pupilDiam = CDbl(dlg.TextBox2) UTHGjE End If ^mkplp
a d=Q0/sI& Print " " '~<D[](/F Print "Accommodation = " & A & " Diopters" w3fi2B&q Print "Pupil Diameter = " & pupilDiam & " mm" i*nNu-g 'FO^VJ;ha ' Calculate new parameters with accommodation V:2|l!l* taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness 6*tI~ y~]>J^ Rant = 12.0 - 0.4*A 'Radius of anterior lens pc:~_6S CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens $NT{ssh +wS?Z5%mU Rpost = -5.224557 + 0.2*A 'Radius of posterior lens Y[
a$~n^:n CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens k%VV(P]sT oypX.nye_ tlens = 3.767 + 0.04*A 'Lens thickness Wd3/Y/MD !E4YUEY6 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction L&. 9.Ll 7o'kdYJzo 'Adjust parameters to account for accommodation 87r#;ND `:R8~>p '************************************************************************* $
[0 'Aqueous thickness (Position of Lens) v>;6pcp[F '************************************************************************* xpRQ"6 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6psK2d0 GetCustomElement eID, entity Jd7+~isu~ BQ2DQ7q parID = FindFullName( "Geometry.Arizona Eye" ) P)7SK&]r;= j@&F[ r ' Delete any shift(s) in z cQA;Y!Q# count = 0 Ro$l/lXl8t While GetOperationCount(eID)>count cK1r9ED| GetOperation eID, count, op ikw_t? If op.Type="ShiftZ" Then ?2aglj*"v, DeleteOperation eID,count _ ?xORzO count=count-1 [?.k 8;k End If 65)/|j+ count=count+1 !J3g, p* Wend 3tA6r Jx.Jx~ 'Set new shift in E}b"
qOV op.Type = "ShiftZ" p*8=($j4 op.val1 = taq F
MHpa op.parent = parID /MosE,7l AddOperation eID, op 6L}$R`s5H Print "Set aqueous humor thickness = " & taq-0.55 a>ZV'~zTf |Q@4F&k '************************************************************************* ]wc'h>w 'Radius and conic constant of anterior lens ~Yb5FYE '************************************************************************* J)"2^?!&B eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) s%1 O}X$c GetConic eID, entity, curv, conic OT+=H)/ 9!NL<}]{ SetConic eID, entity, 1/Rant, CCant H"=%|/1M0 Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant AD_")_B|i nxS|] '************************************************************************* N>/!e787OU 'Radius and conic constant of posterior lens ;%0$3a '************************************************************************* sC(IeGbX eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) K7 -AVMY GetConic eID, entity, curv, conic |Rd?s0u ; $i{>mDT SetConic eID, entity, 1/Rpost, CCpost qRZv[T%*Q Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost wDVKp[' {P&{+`sov '************************************************************************* V|13%aE_v 'Lens thickness (Position of posterior lens surface) "jb`KBH%" '************************************************************************* TWZ**S- "v@Y[QI parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Ub2t7MU m(i8 4~ ' Delete any z-shift(s) 1hp`.!3]H count = 0 2!Yq9,` While GetOperationCount(eID)>count ]w`)"{j5m GetOperation eID, count, op WYSqnmi If op.Type="ShiftZ" Then ywTt<;
DeleteOperation eID,count Z-z^0QO count=count-1 -K eoq End If dWqKt0uh! count=count+1 mvgsf(a*' Wend d,8L-pT$FM I$7|?8 'Set new z-shift #s>AiD op.Type = "ShiftZ" e=Ko4Ao2y op.val1 = tlens JZI)jIh op.parent = parID
kw{dvE\K AddOperation eID, op ~"|MwR!0 Print "Set lens thickness = " & tlens 6
<XQ'tM]N `@TWZ%f6 '************************************************************************* )O\w'|$G 'Lens index of refraction "jV:L '************************************************************************* 7^)8DwAl eID = FindMaterial( "Lens" ) S52'!WTq GetModelMaterial eID, mat .8e]-^Z QOiPDu=8z mat.Nd = nlens {*mf Is SetModelMaterial eID, mat KCP$i@Pjv Print "Set lens index of refraction = " & nlens G5*"P!@6 ]8@s+N '************************************************************************* jV{?.0/h| 'Pupil diameter D+#OB|&Dn '************************************************************************* C2}n &{T eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) xB-\yWDZe
:j^IXZW 'Adjust pupil diameter (trimming volume inner hole) M^IEu} K|L&mL&8 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ;>hRj! 8u8-:c%{ ' Adjust pupil location to just in front of the lens m.F}9HI%hN parID = FindFullName( "Geometry.Arizona Eye" ) xmVW6 ,<? eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) P* X^)R count = 0 u00w'=pe) While GetOperationCount(eID)>count 0JT"Pv_ GetOperation eID, count, op ^_\S)P2c If op.Type="ShiftZ" Then TOT#l6yqdd DeleteOperation eID,count u,RR|/@ count=count-1 90wGS_P04 End If 21k,{FB'? count=count+1 W&~\@j]!D Wend ycq+C8J+Ep op.Type = "ShiftZ" 4Jn+Ot.,d op.val1 = taq-0.01 >Nam@,hm op.parent = parID r4 $<,~ AddOperation eID, op o|G'vMph 1.0: Print "Set pupil diameter = " & pupilDiam bG)EZ ?e{hidg 'Update AZ Eye subassembly Description *@I/TX'\rY eID = FindFullName( "Geometry.Arizona Eye" ) ~3&*>H^U GetEntity eID, entity vh"wXu entity.Description = "Accommodation = " & A & "D" aT4I sPA?_ SetEntity eID, entity >sjvE4s n'To: Update #<K'RJn Print "DONE!" >P+oNY ' !2NSv End Sub buldA5*!o Wr3z%1 如果屈光度是4,光瞳直径是4,则会输出如下数据: =;"e Z D\^mh{q( Accommodation = 4 Diopters H Y~[/H+: Pupil Diameter = 4 mm /HH_Zi0?N| Set aqueous humor thickness = 2.81 9Y:Iha`$w Set anterior lens radius = 10.4 and conic constant = -2.375869 ?[]jJ Set posterior lens radius = -4.424557 and conic constant = -3.081019 i>7]9gBm1q Set lens thickness = 3.927 %Rt
5$+dNT Set lens index of refraction = 1.42672 wRdN(`;v Set pupil diameter = 4 I5*<J n DONE! ( Sjlm^bca m*wDJEKo 2]y Hxo/6 QQ:2987619807 ?bH`
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