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简介 p( )LQT! Qsw.429t 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。 IwBO#HR~) Khl0 ~ 模型 r9*6=*J| f'bwtjO 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。 \GV'{W+o2 Q~/=p>=uu Table 1. AZ眼睛模型的定义 @+1AYVz(k 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. 4 L
5$=V _Fn`G.r< 光源 Z?d][zGw 8)MWC: 多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 6Eus_aP mN>(n+ly 4;@L#Pzt 图1. 光源和提示信息使用 r i)`e 除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 #
2FrP5rC ,B /b>i 在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 K"hnGYt? E^A!k=> 图2. 字母F光源的设定方法光 ktRGl>J G*,7pc 图3. 字母F在视网膜上位置点列图 3[m2F O,Z 视网膜的散射 U(Bmffn4Z 7G7"Zule*j 在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 ~]`U)Aw -PU.Uw] OOXP1L 图4. 视网膜朗伯散射设定 jP0TyhM 注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 o
q6^ K`j:F>b #3{{[i(;i 图5. 视网膜重点采样规格设定 JStEOQF4 脚本 O<$j}?2 ]g }5p4*& 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: o9yUJ@
:i lA;qFXaN> 图6. 用户对话框的创建与编辑 E$&bl 图7. 用户对话框编辑器 UI'fzlB 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 vP+qwvpGr 余下的脚本计算与屈光度有关的所有参数。 UR S=1+ .,U4 ATO 分析 "!fwIEG HuKOb4g 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 c.5u \I9" aR'~=t&;z1 图7. 字母F在视网膜上颜色分析 "zz b`T[8 脚本代码 'i: lV' .6I'V3:Kg Option Explicit 'Remove this to enable non-dimensioned variables to be used. 8J- ?bo SG1AYUs
V Dim entity As T_ENTITY =fdW H4 Dim op As T_OPERATION yq<W+b/ Dim mat As T_MODELMATERIAL #/8
Nav Dim A As Double ZR"qrCSw` Dim pupilDiam As Double e\f\CMb Dim eID As Long o*"Q{Xh#Qd Dim parID As Long M _lLP8W} Dim count As Integer !4<A|$mQ Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double XW\
3t tx Dim tlens As Double, nlens As Double k7L4~W Dim curv As Double, conic As Double ,H<nNBv3M Dim ok As Long c,M"a B@*!>R Sub Main }RY Pr Twr,O;*u= '用户输入对话框 yF_/.m I Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 {*r!oD!' TextBox 220,21,40,21,.TextBox1 'default: 0 \3%3=: Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 q_L. Sy|) OKButton 40,91,90,21 (H:A|Lw CancelButton 190,91,90,21 84i0h$ZZo Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 4L4u< TextBox 220,49,40,21,.TextBox2 'default: 4 =W2I0nr. End Dialog a<>cbP Dim dlg As UserDialog wlslG^^(! Dkh=(+> < ok = Dialog (dlg) w>}n1Nc$G \OWxf[ If ok=0 Then 'cancel button was pressed ,^<39ng Print "Execution cancelled." qV,x )y:V End zwP*7u$CH End If \q24E3zS& vq-;wdq?2 'Assign accommodation and pupil diameter & use defaults if field left empty qK~]au:C If dlg.TextBox1 = "" Then o]&P0 b A = 0 'Default accommodation "{3|(Qs Else HCe/!2Y/% A = CDbl(dlg.TextBox1) BQeg-M End If 5B8fz;l= B 8]O#L}" If dlg.TextBox2 = "" Then #e[r0f?U pupilDiam = 4 'Default pupil diameter aSJD'u4w.a Else _F^NX% pupilDiam = CDbl(dlg.TextBox2) 5lM 3In@ End If jHA(mU)b kGakdLl Print " " Qv;b$by3 Print "Accommodation = " & A & " Diopters" >?G!>kw Print "Pupil Diameter = " & pupilDiam & " mm" JS<w43/j &_j<!3* ' Calculate new parameters with accommodation A1z<2.R taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness QA)"3g
BJLeE}=H Rant = 12.0 - 0.4*A 'Radius of anterior lens r?^L/HGc CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens ~XvMiWuo FP0GE Rpost = -5.224557 + 0.2*A 'Radius of posterior lens /'_Yct= CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens Gc5mR9pV &NbSG+t tlens = 3.767 + 0.04*A 'Lens thickness CDr0QM4k:. /Bk`3~]E> nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction jMX|1b a"Ly9ovW 'Adjust parameters to account for accommodation 77 Z:!J| IF<T{/MA '************************************************************************* t#-4edB, 'Aqueous thickness (Position of Lens) u09D`QPP] '************************************************************************* MI.OOoP3a eID = FindFullName( "Geometry.Arizona Eye.Lens" ) AI,E9 GetCustomElement eID, entity beV+3HqB8 Eq=JmO'gHs parID = FindFullName( "Geometry.Arizona Eye" ) U^K8^an$ d`j<Bbf- ' Delete any shift(s) in z &Wk:>9]Jrb count = 0 f'qM?GlET While GetOperationCount(eID)>count yLl:G; GetOperation eID, count, op y`/:E<fVk If op.Type="ShiftZ" Then ,ZO?D|M1 DeleteOperation eID,count R+/kx#^ count=count-1 5a2;@}%V End If R4zOiBi'B count=count+1 `>lY$EBG@[ Wend A,7* 52U !2/o]_K@+ 'Set new shift in lACS^( op.Type = "ShiftZ" BgB0 op.val1 = taq gzlRK^5 op.parent = parID whGtVx|zR AddOperation eID, op 9PaV*S(\TR Print "Set aqueous humor thickness = " & taq-0.55 3J3wKw!` >rYMOC~ '************************************************************************* e#WASHZN 'Radius and conic constant of anterior lens li#ep?5h^ '************************************************************************* J$`5KbT3 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) o+- 0`!yj GetConic eID, entity, curv, conic SWT)M1O2 tCu.Fc@ SetConic eID, entity, 1/Rant, CCant |F qujZz Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant >]Dn,*R &7{yk$]* '************************************************************************* rV*Ri~Vx 'Radius and conic constant of posterior lens Oz"_KMz '************************************************************************* "od2i\ eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) <" 0b8 Z GetConic eID, entity, curv, conic j|[ >f \"Qa)1| SetConic eID, entity, 1/Rpost, CCpost f%q ? Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost $wl_ gTdr '************************************************************************* 3wPUP+)c7 'Lens thickness (Position of posterior lens surface) 2cZgG^ '************************************************************************* i7&ay\+@ [LV>z parID = FindFullName( "Geometry.Arizona Eye.Lens" ) [?XP[h gd iRV=I, ' Delete any z-shift(s) [<jU$93E count = 0 /8 "rCh|m- While GetOperationCount(eID)>count {GGP8 GetOperation eID, count, op 0])[\O`j If op.Type="ShiftZ" Then Pa?C-Xn^ DeleteOperation eID,count F U)=+m count=count-1 aeEio;G1 End If |>wGl count=count+1 @S&QxE^ Wend $Xs`'>," {?r5~T`2 'Set new z-shift J2$,'(!( op.Type = "ShiftZ" Kv ajk~ op.val1 = tlens yMpZ-b$*~ op.parent = parID =i},$"Bf*% AddOperation eID, op f7;<jj;w7 Print "Set lens thickness = " & tlens N]F}Z#h \AB)L{ '************************************************************************* cXb&Rm'L 'Lens index of refraction h1$75E?, '************************************************************************* J"XZnb)E= eID = FindMaterial( "Lens" ) mgb+HNH%q\ GetModelMaterial eID, mat c/l^;6O/!\ ss`Sl$ mat.Nd = nlens Sf2xI' SetModelMaterial eID, mat v]}\Ns/ Print "Set lens index of refraction = " & nlens _s}`ohKvD q RRvZhf '************************************************************************* TK0W=&6#A 'Pupil diameter k[y^7,r '************************************************************************* ;R$2+9 eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) |FSp`P 1-|aeJ 'Adjust pupil diameter (trimming volume inner hole) Mt@Ma ]! /<"ok;Pu7 SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" y~Mu~/s Q 87'zf ' Adjust pupil location to just in front of the lens K87yQOjPv parID = FindFullName( "Geometry.Arizona Eye" ) Zh`[A9I/ eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ,E"n 7*6mr count = 0 2q*wYuc While GetOperationCount(eID)>count Xv+,Z<>iQ GetOperation eID, count, op lAkg47i If op.Type="ShiftZ" Then /<Z3x
_c DeleteOperation eID,count e`Co =' count=count-1 Lb{.} End If }i^$
li@ count=count+1 1\g r
;b Wend r;+a%?P op.Type = "ShiftZ" (O&HCT| op.val1 = taq-0.01 8isQL op.parent = parID R*2F)e\| AddOperation eID, op [2!C^\t |7${E^u Print "Set pupil diameter = " & pupilDiam \u;`Lf AJ)&+H 'Update AZ Eye subassembly Description <,X=M6$0n eID = FindFullName( "Geometry.Arizona Eye" ) 7y_<BCx
h GetEntity eID, entity nYe:$t3F= entity.Description = "Accommodation = " & A & "D" }'K-1: SetEntity eID, entity -aV(6i*n 1MmEP Update *]nk{jo2 Print "DONE!" 9!.S9[[N ,H1K sN End Sub k=&n>P whm|"}x)u 如果屈光度是4,光瞳直径是4,则会输出如下数据: Wfy+9"-;s rinTB|5 Accommodation = 4 Diopters Ejnk\ 8: Pupil Diameter = 4 mm =|2F? Set aqueous humor thickness = 2.81 fK2r6D9 Set anterior lens radius = 10.4 and conic constant = -2.375869 A6 `a Set posterior lens radius = -4.424557 and conic constant = -3.081019
:6/$/`I0W Set lens thickness = 3.927 HJP~
lg Set lens index of refraction = 1.42672 T\bpeky~ Set pupil diameter = 4 =^ \?{oV DONE! "oyBF CW
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