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简介 9l2,:EQ* *6~ODiB 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。 )xiiTkJd5 _^Lv8a3(O 模型 <A&mc,kj pN/)$6= 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 4g]Er<-P I%^Ks$<" Table 1. AZ眼睛模型的定义 e2Sm.H ' 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. Ed9ynJ~)X e{8z1t20: 光源 }f np}L J&}/Xw) 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。 \o9-[V#Gm ]Mi
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q oK&LYlU 图1. 光源和提示信息使用 v5l)T}Nb 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。 fk4s19;?
O[f* ! 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。 p+U}oC O{a<f7 W 图2. 字母F光源的设定方法光 / <WB%O <b>@'\w9 图3. 字母F在视网膜上位置点列图 A_1cM#4 视网膜的散射 7PO3{I cVJ"^wgBt 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。 |cStN[97% emOd<C1A Yu-e|: 图4. 视网膜朗伯散射设定 C4],7"Sw 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。 9tsI1]1[m _x 'R8/ Mit,X 图5. 视网膜重点采样规格设定 $u_0"sUV 脚本 b'Qia'a% B
PTQm4TN 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: C%d\DuJ5'~ [hA%VF.9 图6. 用户对话框的创建与编辑 NR-d|`P; 图7. 用户对话框编辑器 y0cHs|8 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 m\`dLrPX4j 余下的脚本计算与屈光度有关的所有参数。 <uUQ-]QOIh 84^'^nd 分析 k@U8K(:x Mg;%];2Nt 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 <l]P
<N8^ W)3?T&` 图7. 字母F在视网膜上颜色分析 ia
1Sf3 脚本代码 e*p7(b- G%w.Z< qy Option Explicit 'Remove this to enable non-dimensioned variables to be used. tAFKq>\ Gm;)Om_ Dim entity As T_ENTITY '_,/N!-V Dim op As T_OPERATION T%~w~stW Dim mat As T_MODELMATERIAL 3ny>5A!;2 Dim A As Double >c%OnA,3 Dim pupilDiam As Double exw~SvT3 Dim eID As Long [G2@[CtY1 Dim parID As Long 6nh!g Dim count As Integer 1>P[3Y@} Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 4Gs#_|! Dim tlens As Double, nlens As Double b/'{6zn Dim curv As Double, conic As Double hc
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Dim ok As Long AE`X4 q `s5<PCq Sub Main d4KTwn5g D/)wg$MI '用户输入对话框 P'.MwS Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 XWN
ra TextBox 220,21,40,21,.TextBox1 'default: 0 f =@'F= Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Fb=(FQ2Y? OKButton 40,91,90,21 stuj,8 CancelButton 190,91,90,21 koOkm:(, Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 OE' ?3S TextBox 220,49,40,21,.TextBox2 'default: 4 jGpSECs End Dialog c} )U:?6 Dim dlg As UserDialog hw! l{yv |{W4JFKJ ok = Dialog (dlg) ~_opU(;f .GcIwP'aU- If ok=0 Then 'cancel button was pressed q1ybJii Print "Execution cancelled." ,5oe8\uz End Yt&Isi
+ End If zQ3m@x 68Po`_/s 'Assign accommodation and pupil diameter & use defaults if field left empty s}Phw2`1U If dlg.TextBox1 = "" Then Y~\71QE> A = 0 'Default accommodation n^aSio6 Else z~&uLu A = CDbl(dlg.TextBox1) uQh dg4 End If wZ6D\I d 90 If dlg.TextBox2 = "" Then 6.
N?=R pupilDiam = 4 'Default pupil diameter xC N6? Else '%Og9Bgd+ pupilDiam = CDbl(dlg.TextBox2) e RY2.! End If _8t5rF 9U[Gh97Sf Print " " rR`'l=,t Print "Accommodation = " & A & " Diopters" *D`]7I~} Print "Pupil Diameter = " & pupilDiam & " mm" a&:1W83 :})(@.H ' Calculate new parameters with accommodation J{>9ctN taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness =k.:XblEe[ >[t0a"
Rant = 12.0 - 0.4*A 'Radius of anterior lens ?bFP'. CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens cUW>`F(S ?LJ$:u Rpost = -5.224557 + 0.2*A 'Radius of posterior lens vJZ0G:1 CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ?88k`T'EI TdGda'C tlens = 3.767 + 0.04*A 'Lens thickness :QKxpHi &Tz@lvOv% nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction GX2aV6} *u
L Ooq 'Adjust parameters to account for accommodation V{!fag m(0sG(A~ '************************************************************************* 1B}q?8n 'Aqueous thickness (Position of Lens) _N8Tu~lqV '************************************************************************* F`!B!uY eID = FindFullName( "Geometry.Arizona Eye.Lens" ) (al.7VA;9 GetCustomElement eID, entity Vb{5 -v
;a 3a9%djGq parID = FindFullName( "Geometry.Arizona Eye" ) yx5F]Z<M2 ++ O
L&n ' Delete any shift(s) in z =^liong0 count = 0 :`u?pc27Sm While GetOperationCount(eID)>count
V|6PKED GetOperation eID, count, op tW<i;2 l If op.Type="ShiftZ" Then GMk\
l DeleteOperation eID,count 5x$/.U
count=count-1 9Z?P/
o End If )m8ve)l count=count+1 R Lnsy, Wend {
'A`ram Z_b^K^4 'Set new shift in /zt9;^e op.Type = "ShiftZ" C]@v60I
op.val1 = taq j^4KczJl op.parent = parID lKVy{X3]* AddOperation eID, op IZ){xI Print "Set aqueous humor thickness = " & taq-0.55 a[e&O&Z +Dvdv<+ '************************************************************************* yf|,/{S 'Radius and conic constant of anterior lens G.j R '************************************************************************* P9d%80(b4 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) m/{HZKh GetConic eID, entity, curv, conic 6d4e~F |E{tS,{OhJ SetConic eID, entity, 1/Rant, CCant 1zo0/<dk Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Lj]I7ICNh OGl>i '************************************************************************* rw CFt6;v 'Radius and conic constant of posterior lens Y!3Mm* '************************************************************************* a#i85su eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 0 QzUcr)3+ GetConic eID, entity, curv, conic z@70{* Tbf@qid e SetConic eID, entity, 1/Rpost, CCpost hMcSB8 ? Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost O
&/9wi>!q j@w+>h '************************************************************************* =1!,A 'Lens thickness (Position of posterior lens surface) Vgh;w-a '************************************************************************* OO7sj@ 8`\^wG$W parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 25bbuhss "o| f ' Delete any z-shift(s) 8S8^sP count = 0 ?nVwT[ While GetOperationCount(eID)>count =O~ J GetOperation eID, count, op t=-t xnlr< If op.Type="ShiftZ" Then $ 12mS DeleteOperation eID,count |3Fo4K%+ count=count-1 N }$$<i2o End If P4\{be>e count=count+1 8LI
aN} Wend 7g* "AEk EnM }H9A 'Set new z-shift @Feusprs op.Type = "ShiftZ" 8vk*", op.val1 = tlens 9+z5$ op.parent = parID >DFpL$oP AddOperation eID, op DGs=.U-=e Print "Set lens thickness = " & tlens rNi]|)-ET >e
g8zN '************************************************************************* /J0YF
'Lens index of refraction (31ia"i% '************************************************************************* z;c~(o@4 eID = FindMaterial( "Lens" ) ^)JUl!5j]C GetModelMaterial eID, mat gY\g+df- sIM^e mat.Nd = nlens .Mn_T*F SetModelMaterial eID, mat 8fG$><@ Print "Set lens index of refraction = " & nlens BLepCF38 )aV\=a |A '************************************************************************* 5s5GBJ? 'Pupil diameter g6s&nH`Z2 '************************************************************************* Q|gw\.]$&[ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) _f"HUKGN BzVF!<! 'Adjust pupil diameter (trimming volume inner hole) +t9$*i9`L /Zzb7bHLK SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" v$WH#;(\ ].TAZ-4s ' Adjust pupil location to just in front of the lens bNH72gX2Yh parID = FindFullName( "Geometry.Arizona Eye" ) +vDEDOS1 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 46yq F count = 0 `Kt]i5[ " While GetOperationCount(eID)>count slQxz;t GetOperation eID, count, op ""Ub^:ucD If op.Type="ShiftZ" Then t PJW|wo DeleteOperation eID,count n?UFFi+a count=count-1 D2,2Yy5y End If JU6PBY~C' count=count+1 )=k8W9i8b Wend n#US4&uT4A op.Type = "ShiftZ" b0PQ;?R#V op.val1 = taq-0.01 l[,RA?i
{ op.parent = parID j O-H1@; AddOperation eID, op a?d)lnk +zl2|' Print "Set pupil diameter = " & pupilDiam C;m,{MD Gz_[|,i 'Update AZ Eye subassembly Description !1X^lFf;~ eID = FindFullName( "Geometry.Arizona Eye" ) x;F^7c1 GetEntity eID, entity j;BMuLTm1 entity.Description = "Accommodation = " & A & "D" q2$-U& SetEntity eID, entity V[Z^Z Tc3~~ X Update k2-:!IE Print "DONE!" rnkq. UI?AM 34 End Sub ,GU|3 dj;Zzt3 如果屈光度是4,光瞳直径是4,则会输出如下数据: z#j)uD >u-6,[(5X* Accommodation = 4 Diopters +,g"8&> Pupil Diameter = 4 mm FX
yyY-(O Set aqueous humor thickness = 2.81 hx5oTJR Set anterior lens radius = 10.4 and conic constant = -2.375869 I,nW~;OV0 Set posterior lens radius = -4.424557 and conic constant = -3.081019 nt5x[xa Set lens thickness = 3.927 %k"qpu Set lens index of refraction = 1.42672 pA%Sybw+ Set pupil diameter = 4 1DTA Dh0 DONE! 5PRS|R7
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