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简介 Ud_0{%@ > .K 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。 ))6YOc $U"pdf 模型 J;N\q L0qL\>#ejr 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 Q[9W{l+
= Atyy Table 1. AZ眼睛模型的定义 mZ g' 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. pp+z5 47)\\n_\z 光源 6$t+Q~2G! XrJLlH>R4 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。 C[CNJ66 De\Ocxx QTU$mC] 图1. 光源和提示信息使用 M4e8PRlI 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 1sq1{|NW~ :464~tHI[` 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 a&Me#H{ "}b/[U@> 图2. 字母F光源的设定方法光 ;pqS|ayl jxZ_-1 图3. 字母F在视网膜上位置点列图 F.AP)`6+* 视网膜的散射 4veXg/l G[]h1f! 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 ~<"{u-q#K @2sr/gX^ XdE|7=+s 图4. 视网膜朗伯散射设定 or(P?Ro 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 v!#koqd1y. SmV}Wf (8(P12l 图5. 视网膜重点采样规格设定 `We?j7O 脚本 2+yti,s+/ f.:0T&%G 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: NYeL1h)l j07b!j:"\} 图6. 用户对话框的创建与编辑 ^xq)Q?[{ 图7. 用户对话框编辑器 Y8/&1s_ 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 }^`5$HEi 余下的脚本计算与屈光度有关的所有参数。 - H`,`#{ Ki(0s 分析 /}S1e P6 wq]vcY9^ 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ^2nH6,LPS R#Z
m[S 图7. 字母F在视网膜上颜色分析 ufN`=IJ% 脚本代码 `82^!7 ! h5lngw Option Explicit 'Remove this to enable non-dimensioned variables to be used. A",R2d (R!`Z% Dim entity As T_ENTITY
AIw~@*T Dim op As T_OPERATION @DlN;r?Cv Dim mat As T_MODELMATERIAL D 1(9/;9 Dim A As Double [ub)`-6 u Dim pupilDiam As Double ^39?@xc@ Dim eID As Long 1%7zCM0s Dim parID As Long c
LfPSA Dim count As Integer 7TA&u' Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double mzcxq:uZ5 Dim tlens As Double, nlens As Double L"}2Y3 Dim curv As Double, conic As Double yS4nB04`= Dim ok As Long T!|-dYYI ygxaT"3"= Sub Main )jMk~;'r 3m"9q '用户输入对话框 twp~#s:\z Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 uExYgI`<%& TextBox 220,21,40,21,.TextBox1 'default: 0 Ju_(,M-Vgr Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 \7Fp@ .S3 OKButton 40,91,90,21 lN7YU-ygz CancelButton 190,91,90,21 \j0016; Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 zS `>65}e TextBox 220,49,40,21,.TextBox2 'default: 4 'E cd\p End Dialog wdRk+ Dim dlg As UserDialog uP1]EA A6#v6 iT ok = Dialog (dlg) JR|P]} Agwl2AM5k If ok=0 Then 'cancel button was pressed ]C>h_,EZc Print "Execution cancelled." tw<}7l_>Au End oSH]TL2@Cd End If vZIx>
WDh*8!) 'Assign accommodation and pupil diameter & use defaults if field left empty Sv[+~co<l If dlg.TextBox1 = "" Then
QLZ%m $Z A = 0 'Default accommodation Q'rX ]kk_ Else =64Ju Wvo A = CDbl(dlg.TextBox1) V QbKrnX End If ki]i[cdk _
Uv3glK If dlg.TextBox2 = "" Then IDp2#qg_ pupilDiam = 4 'Default pupil diameter VKy3tW/_& Else _:G>bU/^ pupilDiam = CDbl(dlg.TextBox2) z*WQ=l2 End If ]F4|@+\9 <4*)J9V^s= Print " " sfC/Q"Zs Print "Accommodation = " & A & " Diopters" ]u%Y8kBe Print "Pupil Diameter = " & pupilDiam & " mm" 'L2[^iF9 JgB"N/Oz ' Calculate new parameters with accommodation h[gKyxZ/t taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ":L d}~> OJs
s Rant = 12.0 - 0.4*A 'Radius of anterior lens yXro6u?rC CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ,772$7x A~8-{F 31 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens #G("Oh CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens j`-9. sDXQ{*6a tlens = 3.767 + 0.04*A 'Lens thickness .;37 e =]-D_$S~ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction }nWW`:t kx ?DC;Hk< 'Adjust parameters to account for accommodation cB7'>L (E \lLlN '************************************************************************* ~.Cu,>fV 'Aqueous thickness (Position of Lens) !3Q^oR '************************************************************************* Edl .R}&1 eID = FindFullName( "Geometry.Arizona Eye.Lens" ) y{QF#&lW GetCustomElement eID, entity *YWk. 4M>E QF& parID = FindFullName( "Geometry.Arizona Eye" ) 0lpUn74F yu=(m~KX
' Delete any shift(s) in z n)rSgzI count = 0 trL8oZ6 While GetOperationCount(eID)>count kj!mgu#T GetOperation eID, count, op Wq*W+7=. If op.Type="ShiftZ" Then :SVWi}:Co1 DeleteOperation eID,count UvVq# <- count=count-1 0zXF{5Up End If Z|zT%8.8N count=count+1 0[fqF^HEN Wend TuzH'F V Rz9;=m 'Set new shift in 4"Pf0PD: op.Type = "ShiftZ" 2$?j'i! op.val1 = taq ]}BT'fky# op.parent = parID r'& 6P-Vm AddOperation eID, op F vHd` Print "Set aqueous humor thickness = " & taq-0.55 r~T3Ieb ]D|Hq4ug '************************************************************************* $(;0;!t. 'Radius and conic constant of anterior lens L_}F.nbS5 '************************************************************************* axdRV1+s eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) KgEfhO$W GetConic eID, entity, curv, conic jLreN#:9 %o#|zaK SetConic eID, entity, 1/Rant, CCant /7Ft1f Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant cy#N(S[ 1 Z_[jah '************************************************************************* K?acRi 'Radius and conic constant of posterior lens n }4L q^$ '************************************************************************* 4$8\IJ7G eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ,98`tB0 GetConic eID, entity, curv, conic %ysfFE IsP!ZcV; SetConic eID, entity, 1/Rpost, CCpost D2Dk7//82Y Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost >y
iE} *\F,?yU '************************************************************************* ;.b^A 'Lens thickness (Position of posterior lens surface) $Z4IPs '************************************************************************* -LEpT$v| IP l]$j>N parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 3(>NS ?lX JbEQ35r ' Delete any z-shift(s) gq an]b_ count = 0 O_y?5 3X While GetOperationCount(eID)>count bGa"r GetOperation eID, count, op #BX^"J{~ If op.Type="ShiftZ" Then 6O'6,%# DeleteOperation eID,count a1#
'uS9W count=count-1 R%^AW2 End If [;hCwj# count=count+1 FK.Qj P: Wend -O?&+xIK& dE|luN~ 'Set new z-shift {A MoE+U op.Type = "ShiftZ" -K%~2M< op.val1 = tlens 6T{SRN{ op.parent = parID UvM_~qo AddOperation eID, op (T Fo]c Print "Set lens thickness = " & tlens 9>HCt*|_8 TeWpdUCO '************************************************************************* Gu@Znh-D 'Lens index of refraction ]*JH~.p '************************************************************************* UqZ#mK i eID = FindMaterial( "Lens" ) !0
-[}vvU GetModelMaterial eID, mat yaKw/vV iZDZ/hohv mat.Nd = nlens 3eP7vy SetModelMaterial eID, mat Z7Xic5PI{4 Print "Set lens index of refraction = " & nlens )m[dfeqd + 1#
X*kF '************************************************************************* ?br 4 wl 'Pupil diameter R
SqO$~ '************************************************************************* zV"oB9\9O eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) UV8K$n< 'ai!6[|SD 'Adjust pupil diameter (trimming volume inner hole) F_C_K"[s ;m cu(J SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" vQIN#;m4 2rJeON ' Adjust pupil location to just in front of the lens , 1`-u$ parID = FindFullName( "Geometry.Arizona Eye" ) I`8jJpGA eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 26<Wg7/, count = 0 O)Mf/P' While GetOperationCount(eID)>count Wx-vWWx*Q GetOperation eID, count, op @%sr#YqY If op.Type="ShiftZ" Then _F9O4Q4 DeleteOperation eID,count "[BDa}Il count=count-1 JOm6Zc End If ?\$\YX%/p count=count+1 8}(ul Wend K JX@?1" op.Type = "ShiftZ" Z-B b,8 op.val1 = taq-0.01 y:3d`E4Xw op.parent = parID v9R"dc]0h AddOperation eID, op DR w;.it2 37QXML Print "Set pupil diameter = " & pupilDiam nfbq J '{(/C?T 'Update AZ Eye subassembly Description {IpIQ-@l eID = FindFullName( "Geometry.Arizona Eye" ) Ee?+IZ H7| GetEntity eID, entity dn)pVti_ entity.Description = "Accommodation = " & A & "D" ZT'Sw%U: SetEntity eID, entity =ap6IVR --9Z Update x3++JG Print "DONE!" 78i"3Tm)w
#RA3 T[A End Sub /P3s.-sL @lnM% 如果屈光度是4,光瞳直径是4,则会输出如下数据: +\ O[)\ `bF]O" Accommodation = 4 Diopters >&3ATH;&( Pupil Diameter = 4 mm k;9"L90 Set aqueous humor thickness = 2.81 s"solPw Set anterior lens radius = 10.4 and conic constant = -2.375869 )"o+wSI1 Set posterior lens radius = -4.424557 and conic constant = -3.081019 >)IXc<"wq Set lens thickness = 3.927 f YuM`O Set lens index of refraction = 1.42672 +#d}3^_] Set pupil diameter = 4
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C DONE! @~l?hf _7M! b9oA m*^|9*dIC QQ:2987619807 k-LT'>CWl
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