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简介 pf107S EFljUT?& 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。 6
Bdxdx*zt SOOJq C 模型 q\x.e.@ tpC^68*F 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。 ^ =n7E O,|NOz Table 1. AZ眼睛模型的定义 fK+
5 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. R ZQH#+*t} 'vZIAnB8 光源 1}c'UEr%) z<mN-1PM7& 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。 ZQ+DAX*MS
7=9>yba)^ z fv@<' 图1. 光源和提示信息使用 kY'Wf`y( 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。 X-_VuM_p VQ|{Q} 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。 pCrm `hy( *jbPy?%oY 图2. 字母F光源的设定方法光 MTZCI} .pQ5lK(R 图3. 字母F在视网膜上位置点列图 !cYID \}S, 视网膜的散射 `D
|/g; pR93T+X 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。 p\&/m h!K"
;qw 8K-P]] 图4. 视网膜朗伯散射设定 'JJKnE zQ 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。 SFd_k9 f"P866@oWn aG^E^^Y 图5. 视网膜重点采样规格设定 1' U 脚本 ;Vat\,45pg vm_]X{80; 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: 1xd6p a-Y6ghs 图6. 用户对话框的创建与编辑 U364'O8_ 图7. 用户对话框编辑器 &Wcz~Gx3Q 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。 su%-b\8K 余下的脚本计算与屈光度有关的所有参数。 1:](=%oM&k h7q{i|5 分析 xS tsw5d n|&=6hiI 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 K+!e1
' g"5Kth 图7. 字母F在视网膜上颜色分析 ].kj-,5>f 脚本代码 7$Z_'GJ]1C W1X3ArP]m8 Option Explicit 'Remove this to enable non-dimensioned variables to be used. $j\>T@ .,xyE--;d Dim entity As T_ENTITY O}Pqbx& Dim op As T_OPERATION bRy(` Dim mat As T_MODELMATERIAL ~LpkA`Hn! Dim A As Double U|tacO5w` Dim pupilDiam As Double [znN'Fg:" Dim eID As Long go AV+V7 Dim parID As Long uK$ Xqo%L Dim count As Integer heou\;GI" Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double .ZF%$H Dim tlens As Double, nlens As Double k+-?b(z)$ Dim curv As Double, conic As Double
M-i3_H) Dim ok As Long ajk}&`Wj" h>D;QY Sub Main n'V{ Slg*[r# '用户输入对话框 JS^DyBXc Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 <hCO-r# TextBox 220,21,40,21,.TextBox1 'default: 0 ,4t6Cq! Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 *{#C;" OKButton 40,91,90,21 Y?J/KW3 CancelButton 190,91,90,21 GJcxqgk$ Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 1m"WrTen TextBox 220,49,40,21,.TextBox2 'default: 4 rIcgf1v70 End Dialog T^|k` Dim dlg As UserDialog eZ(ThA*2=t Dh2Cj-|
~ ok = Dialog (dlg) L}rZ1wV6 "[?DS If ok=0 Then 'cancel button was pressed -`XS2 Print "Execution cancelled." ]dNNw`1\V End $rcv@-l End If 02t({>` ["Ts7;q9[ 'Assign accommodation and pupil diameter & use defaults if field left empty >4luZnWMI If dlg.TextBox1 = "" Then SXqB<j$.; A = 0 'Default accommodation 7yyX8p> Else =hvPq@C% A = CDbl(dlg.TextBox1) J^jd@E End If mbkt7. ,P ~M^[ If dlg.TextBox2 = "" Then [%bGs1U pupilDiam = 4 'Default pupil diameter AH&RabH2 Else N
Nk pupilDiam = CDbl(dlg.TextBox2) qA!p7"m| End If g&y (- N? Jy Print " " ?V!5VHa Print "Accommodation = " & A & " Diopters" %P s.r{%{ Print "Pupil Diameter = " & pupilDiam & " mm" n46!H0mJ uOzoE_i ' Calculate new parameters with accommodation Qf^c}!I taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness rIFW1`N}i lH=|Qu Rant = 12.0 - 0.4*A 'Radius of anterior lens oFP8s[B CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens K9Mz4K_ C\5G43` Rpost = -5.224557 + 0.2*A 'Radius of posterior lens 6ScB:8M CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens } uS0N$4 ]m1p<*0I$ tlens = 3.767 + 0.04*A 'Lens thickness kR97)}Y $L0sBW& nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction 7BU7sQjs tWy.Gz\ 'Adjust parameters to account for accommodation X$6NJ(2G Rmmu#-{Y '************************************************************************* e&ysj:W5
" 'Aqueous thickness (Position of Lens) ]Pe>T& '************************************************************************* 7!cLTq eID = FindFullName( "Geometry.Arizona Eye.Lens" ) #&kj> GetCustomElement eID, entity wl]3g E} XmZxHV parID = FindFullName( "Geometry.Arizona Eye" ) .8s-)I 1!(lpp ' Delete any shift(s) in z Wj,s/Yr: count = 0 uT,i& While GetOperationCount(eID)>count B@M9oNWHu GetOperation eID, count, op ~)_Nh If op.Type="ShiftZ" Then Hh;lT DeleteOperation eID,count M]6+s`?r count=count-1 kQbZ!yl>[ End If O>pX(DS
L count=count+1 bC:sd2s Wend sPZwA0% ,on]Fts 'Set new shift in c|.te]!ds op.Type = "ShiftZ" ^,I2@OS op.val1 = taq @ U=y}vi8 op.parent = parID W>a}g[Ad AddOperation eID, op ~wuCa!!A Print "Set aqueous humor thickness = " & taq-0.55 \;N+PE %z@ Z^Jv '************************************************************************* J.h` 0$! 'Radius and conic constant of anterior lens FCNYfjB% '************************************************************************* o%~fJx:]y eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ?SgFD4<~P GetConic eID, entity, curv, conic &6OY^6< gNP1UH4m SetConic eID, entity, 1/Rant, CCant VnW6$W?g Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant <}[ !k< I[|Y
2i '************************************************************************* BkB_?^Nv8 'Radius and conic constant of posterior lens c6vJ;iz '************************************************************************* 8d5#vm eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) {rMf/ RAE GetConic eID, entity, curv, conic zGU MH7 M rd0Fd+t/ SetConic eID, entity, 1/Rpost, CCpost z9IW&f~~P Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 2o<*rH trrNu '************************************************************************* cJ$jU{} 'Lens thickness (Position of posterior lens surface) HI|egf@ '************************************************************************* THQ #zQ- H( .9tuA parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ek<B= F K!CVS7 ' Delete any z-shift(s) 7I w^ count = 0 TfZ M0Wz While GetOperationCount(eID)>count L^t%p1R GetOperation eID, count, op 3G4WKg.^ If op.Type="ShiftZ" Then x`7Le&4f DeleteOperation eID,count uxL+oP0 count=count-1 Uzvd*>mv End If j%`
C count=count+1 H][TH2H1 Wend 5lHt~hB\ IQ\!wWKmY 'Set new z-shift wry`2_c op.Type = "ShiftZ" s3A(`heoq op.val1 = tlens f91]0B`C op.parent = parID Td|,3
n AddOperation eID, op yWRIh*>nE Print "Set lens thickness = " & tlens 'L O3[G{ ?0X$ox '************************************************************************* Pq+|*Y<|& 'Lens index of refraction ]*a(^*}A% '************************************************************************* zu?112-v2 eID = FindMaterial( "Lens" ) *c4OhMU( GetModelMaterial eID, mat *3Lo[GE> <$?#P#A mat.Nd = nlens Cu%BU}( SetModelMaterial eID, mat ]g$ky.; Print "Set lens index of refraction = " & nlens v0)
%S N:3=G`Ws '************************************************************************* +$ djX=3 'Pupil diameter YC%xW* '************************************************************************* ]p+KN>1e eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 4ZUtK/i+r oO[eer_S- 'Adjust pupil diameter (trimming volume inner hole) tBzE(vW _"Y7}A\9 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" `/m]K~~ -]KgLgJ ' Adjust pupil location to just in front of the lens PYi<iSr parID = FindFullName( "Geometry.Arizona Eye" ) M)K!!Jqh eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) c(Y~5A{TXO count = 0 )OQm,5F1 While GetOperationCount(eID)>count f1SKOq GetOperation eID, count, op E^n!h06~G If op.Type="ShiftZ" Then 5KB Z-, DeleteOperation eID,count z<t2yh(DF count=count-1 9-j-nx
@) End If Nz{qu}dt count=count+1
'uz o[>p Wend FP{=b/ op.Type = "ShiftZ" Jityb}Z" op.val1 = taq-0.01 ,.{M1D6'R` op.parent = parID rJf{YUZe AddOperation eID, op > Q=e9L= p
Cx_[#DrP Print "Set pupil diameter = " & pupilDiam 2va[= >_ T@vE@D 'Update AZ Eye subassembly Description gF9GU5T: eID = FindFullName( "Geometry.Arizona Eye" ) s'tXb=!HO GetEntity eID, entity :twp95{R1 entity.Description = "Accommodation = " & A & "D" y /8iEs SetEntity eID, entity \l0!si h{HpI
0q4 Update G@D8[ Print "DONE!" |;V-;e* 8yI4=P"F, End Sub 0*P-/)o x s$f9?(,.Ay 如果屈光度是4,光瞳直径是4,则会输出如下数据: Ro$*bN6p KpG'E Accommodation = 4 Diopters e 0$m<5 Pupil Diameter = 4 mm =?Co<972Z Set aqueous humor thickness = 2.81 K
..Pn17t Set anterior lens radius = 10.4 and conic constant = -2.375869 \g]rOYW Set posterior lens radius = -4.424557 and conic constant = -3.081019 ~<IQe-Q5 Set lens thickness = 3.927 0 "@J*e# Set lens index of refraction = 1.42672 56c3tgVF Set pupil diameter = 4
nmL|v DONE! 7dB_q}< _,F\%} #.]W>hN8\ QQ:2987619807 WM$Z?CN%KB
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