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简介 ?~:4O}5Ax ez-jVi-Fi 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。 V+$^4Ht {V^|9j:\K 模型 o#Viz: u*S-Pji,x 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 cr`NHl/XF @ *<`*W Table 1. AZ眼睛模型的定义 +^ cjdH* 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. 5%jy7)8C {y%|Io`P 光源 u~~H'*EM c;B: o 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 ?8/T#ox BO,xA -+ ?u4t; 图1. 光源和提示信息使用 dJ9v/k_ 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 W]oILL"d Yh["IhjR 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 lD#S:HX "(YfvO+ 图2. 字母F光源的设定方法光 1wg#4h43l ,Dy9-o 图3. 字母F在视网膜上位置点列图 8~}~d}wW 视网膜的散射 eyzXHS*s;L VZ]}9k 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 j0~dJ# 0JXXJ:d B 7$JOIsM 图4. 视网膜朗伯散射设定 -y'tz,En. 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。 }3/|;0j$ 9 >"}||)) O9P4r*prA 图5. 视网膜重点采样规格设定 5|A"YzY# 脚本 XE$;Z'Qhjm lyzM?lK- 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: +&4@HHU{G rM`z2*7%d 图6. 用户对话框的创建与编辑 Rr0]~2R 图7. 用户对话框编辑器 1l s 8 h 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 pHzl/b8 余下的脚本计算与屈光度有关的所有参数。 wD92Ava
(,R\6 分析 ?BRZ){) .1f!w!ltVR 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ?P;=_~X 8I7JsCj 图7. 字母F在视网膜上颜色分析 bHg 0,N 脚本代码 ()ww9L2 pD]2.O Option Explicit 'Remove this to enable non-dimensioned variables to be used. 4xF}rm [M2xF<r6t Dim entity As T_ENTITY OyQ[}w3o| Dim op As T_OPERATION KP_7h/e Dim mat As T_MODELMATERIAL 6Z5$cR_vC7 Dim A As Double sitgz)Ki^ Dim pupilDiam As Double d~KTUgH'< Dim eID As Long RREl($$p Dim parID As Long }Xb|Ur43 Dim count As Integer XPLm`Q|1#t Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double : cPV08i Dim tlens As Double, nlens As Double 7[1VFc#tf Dim curv As Double, conic As Double >@EwfM4[e Dim ok As Long 63'L58O 8:U0M'}u> Sub Main bsc#Oq] U45-R- '用户输入对话框 .M s$)1 Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 @QDUz>_y TextBox 220,21,40,21,.TextBox1 'default: 0 mr,GHx Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 #n+sbx5~7 OKButton 40,91,90,21 ;?Q0mXr CancelButton 190,91,90,21 {<zE}7/2- Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 1
J[z ![Tf TextBox 220,49,40,21,.TextBox2 'default: 4 >:OP+Vc End Dialog I5E5,{ Dim dlg As UserDialog uT
Y G/O I7C+XUQkQ ok = Dialog (dlg) |M EJ)LE7 9t7 e~&R If ok=0 Then 'cancel button was pressed gX(8V*os^ Print "Execution cancelled." -|P7e End c^R "g)gr End If 212 =+k P0rdGf 5T 'Assign accommodation and pupil diameter & use defaults if field left empty (L!u[e0[# If dlg.TextBox1 = "" Then /U>8vV+C A = 0 'Default accommodation #fFD|q Else eGUe#(I / A = CDbl(dlg.TextBox1) \}Kad\) End If m|[cEZxHB r#d]"3tH If dlg.TextBox2 = "" Then <)+;Bg pupilDiam = 4 'Default pupil diameter ;1k_J~Qei Else OA7=kH@3c pupilDiam = CDbl(dlg.TextBox2) 2|`~3B)# End If sA
}X)aP qz 29f Print " " akQb%Wq Print "Accommodation = " & A & " Diopters" \\/
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Print "Pupil Diameter = " & pupilDiam & " mm" hP/uS%X R=W$3Ue~, ' Calculate new parameters with accommodation E8o9ufj3 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness s%?<:9 3ep
L'My$ Rant = 12.0 - 0.4*A 'Radius of anterior lens we?t/YB= CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens x!onan th=45y"C Rpost = -5.224557 + 0.2*A 'Radius of posterior lens UHDcheeRD CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens '=IuwCB|; efh 1-3f tlens = 3.767 + 0.04*A 'Lens thickness "?YpF2pD V.[b${ nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction DE?@8k QYWl`Yqf 'Adjust parameters to account for accommodation [{J1b }80n5X<9 '************************************************************************* !p)cP"fa 'Aqueous thickness (Position of Lens) * =O@D2g0 '************************************************************************* t;[Q&Jl eID = FindFullName( "Geometry.Arizona Eye.Lens" ) hy:K) _
GetCustomElement eID, entity 73M;-qnU _"'-fl98* parID = FindFullName( "Geometry.Arizona Eye" ) 1xwq:vFC. [92bGR{ ' Delete any shift(s) in z .gI9jRdKw count = 0 gOk^("@ While GetOperationCount(eID)>count gwYTOs^ GetOperation eID, count, op ,]?l(H $x' If op.Type="ShiftZ" Then @HXXhYH DeleteOperation eID,count taOsC!Bp count=count-1 8\Eq(o}7 End If OZh+x`' # count=count+1 dGc>EZSdj Wend $w<~W1\: W/;qMP1"- 'Set new shift in p|w;StLy op.Type = "ShiftZ" WTh|7& op.val1 = taq o6
[i0S op.parent = parID yM34G S=,J AddOperation eID, op /XW,H0pR Print "Set aqueous humor thickness = " & taq-0.55 KL*UU,qU vGPaW YV '************************************************************************* z~a]dMs"(P 'Radius and conic constant of anterior lens ]%%cc '************************************************************************* O4 Y; eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 6d/b*,4[ GetConic eID, entity, curv, conic 3!B3C(g BcoE&I?[m| SetConic eID, entity, 1/Rant, CCant dzMI5fA<_ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ts0K"xmY\c /h%MWCZWm^ '************************************************************************* cl-i6[F 'Radius and conic constant of posterior lens S[M\com' '************************************************************************* Jh:-<xy) eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 5*>3(U GetConic eID, entity, curv, conic %25_ & ~[%N
O SetConic eID, entity, 1/Rpost, CCpost AuYi$?8|5 Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost [G|2m_ h Tn^:%( '************************************************************************* `o*g2fW! 'Lens thickness (Position of posterior lens surface) Dy^4^ J5+ '************************************************************************* 3/@'tLtN z95V 7E parID = FindFullName( "Geometry.Arizona Eye.Lens" ) _mL 9G5~r Z_Ma|V?6 ' Delete any z-shift(s) {1YT a:evl count = 0 +=@Z5eu While GetOperationCount(eID)>count z:R2Wksg GetOperation eID, count, op &f qmO>M If op.Type="ShiftZ" Then _.06^5o DeleteOperation eID,count fhn0^Qc"+ count=count-1 o6KBJx End If U>x2'B v count=count+1 z_l3=7R Wend z(orA} [ JnY3] 'Set new z-shift JT^E`<nn op.Type = "ShiftZ" )x|BY> op.val1 = tlens 7<^D7 op.parent = parID n7q-)Dv_U AddOperation eID, op PvT8XSlTx! Print "Set lens thickness = " & tlens M7Hk54U+t p r0V) C6 '************************************************************************* ;+b}@e 'Lens index of refraction @7^#_772 '************************************************************************* khv! \^&DD eID = FindMaterial( "Lens" ) }\DQxHG GetModelMaterial eID, mat v,i:vT\~ nLfnikw& mat.Nd = nlens YJ16vb9 SetModelMaterial eID, mat '/
&" Print "Set lens index of refraction = " & nlens fF[ g%?w f|^f^Hu:{ '************************************************************************* A^p $~e\) 'Pupil diameter
B?%D '************************************************************************* D[#\Y+N eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ^:)&KV8D| Xp?Z;$r$ 'Adjust pupil diameter (trimming volume inner hole) c\b>4 &n %<muVRkB\ SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" iRVLo~ 1aT$07G0 ' Adjust pupil location to just in front of the lens gq@."wHU parID = FindFullName( "Geometry.Arizona Eye" ) 6~/H#8Kdn eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) QF>[cdl?8 count = 0 t@HE.h While GetOperationCount(eID)>count v/haUPWF\ GetOperation eID, count, op Hf-F-~E If op.Type="ShiftZ" Then h B+ t
pa DeleteOperation eID,count TnaIRJ\B count=count-1 Elq8WtS End If )nk>*oE count=count+1 ~3YNHm6V Wend K/,lw~> op.Type = "ShiftZ" N_DgnZ7* op.val1 = taq-0.01 &4[iC/} op.parent = parID A{o{o++ AddOperation eID, op M#>GU<4" "}EbA3 Print "Set pupil diameter = " & pupilDiam '~cEdGD9H HY:@=%R 'Update AZ Eye subassembly Description g0U
?s eID = FindFullName( "Geometry.Arizona Eye" ) TatyD**( GetEntity eID, entity I(CI')Q entity.Description = "Accommodation = " & A & "D" #?=cg]v_ SetEntity eID, entity Jr9}'l8 <XagkD Update MnI $% Print "DONE!" .2P?1HpK Vwqfn4sx?i End Sub ^Bb_NcU !!86Sv 如果屈光度是4,光瞳直径是4,则会输出如下数据: >g2B5KY Vel;t<1 Accommodation = 4 Diopters 7GUJ&U)J Pupil Diameter = 4 mm !tdfTf$ Set aqueous humor thickness = 2.81 xVyUUzXs Set anterior lens radius = 10.4 and conic constant = -2.375869 %E\%nTV Set posterior lens radius = -4.424557 and conic constant = -3.081019 yBj)#m5! Set lens thickness = 3.927 B# fzMaC Set lens index of refraction = 1.42672 z)~!G~J] Set pupil diameter = 4 3$cF)5V f DONE! a=FRJQ8S zOOX>3^ f tPw6 QQ:2987619807 lRr-S%
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