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简介 $+Vp> G'
a{;3 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 *lws7R M}b[;/~ 模型 d"hW45L m}>#s3KPA 模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 r4FGz!U H+2m Table 1. AZ眼睛模型的定义 '6W|, 在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. N\WEp?%~ o+.LG($+U 光源 w%Tjn^ d *we*IhIP 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。 DAt Zp% C%\. 9 54O=9PQ 图1. 光源和提示信息使用 zz~AoX7V6 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。 Dwp-*QK^G Hwm]l`E] 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。 ~xaPq=AH #99fFs`w 图2. 字母F光源的设定方法光 G^=C#9c.m {Kkut?5 图3. 字母F在视网膜上位置点列图 A5LTgGzaW 视网膜的散射 R#i{eE*WF W|aFEY 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。 h
TY7`m"> {E+o+2L l^*'W(% 图4. 视网膜朗伯散射设定 [N4#R 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。 Y$ To)qo z7'C;I ?* %JGz_ 图5. 视网膜重点采样规格设定 lYt|C^ 脚本 n_X)6 s {[%kn rRJ 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: Q(J6;s#b |Q)c{9sD 图6. 用户对话框的创建与编辑 Tf1G827 图7. 用户对话框编辑器 /^T XGc. 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。 bF
X0UE> 余下的脚本计算与屈光度有关的所有参数。 bzt(;>_8 Z_qOQ%l 分析 W~e/3#R\= 5D#Mhgun 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 c8cPGm#i jRCG}' 图7. 字母F在视网膜上颜色分析 ui\yY3? 脚本代码 2!+saf^-, `"* ]C Option Explicit 'Remove this to enable non-dimensioned variables to be used. aV9QIH~ ?onTW2cG; Dim entity As T_ENTITY Vo2{aK; Dim op As T_OPERATION
1:+f@# Dim mat As T_MODELMATERIAL %kRQ9I". Dim A As Double KPcOW#.T Dim pupilDiam As Double AQH\ ;L Dim eID As Long 7"c^$fj Dim parID As Long a*4l!-7 Dim count As Integer ~jDG&L Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double [h
GS* Dim tlens As Double, nlens As Double ^+m6lsuA Dim curv As Double, conic As Double 7;T6hKWV[ Dim ok As Long L(bYG0ZI5C G(~
s(r{%I Sub Main T3W?-, /Dl{I7W '用户输入对话框 ~RRp5x _ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ?'dsiA[ TextBox 220,21,40,21,.TextBox1 'default: 0 9J0JSy Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Y%B:IeF} OKButton 40,91,90,21 ?pF7g$>q CancelButton 190,91,90,21 y)B>g/Hoh Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ?Thh7#7LM TextBox 220,49,40,21,.TextBox2 'default: 4 mjwh40x.o End Dialog 6/Pw'4H9$ Dim dlg As UserDialog iksd^\]f lLb"><8a ok = Dialog (dlg) G{ 9p.Q tTzPT< If ok=0 Then 'cancel button was pressed sKvz<7pag Print "Execution cancelled." k_^|%xJ End srbU}u3VZ End If ;c!}'2>vM g=T
!fF= 'Assign accommodation and pupil diameter & use defaults if field left empty tS2Orzc>, If dlg.TextBox1 = "" Then U{+<c [ A = 0 'Default accommodation w[bhm$SX]B Else rX-V0 A = CDbl(dlg.TextBox1) gg-4ce/ End If ,'KQF C t=IpVl! If dlg.TextBox2 = "" Then V@QWJZ" pupilDiam = 4 'Default pupil diameter am$-1+iX Else HFr#Ql>g pupilDiam = CDbl(dlg.TextBox2) U=<d;2N# End If YhVV~bvz* iL%Q@!ka Print " " ?G48GxJ Print "Accommodation = " & A & " Diopters" Xlw8>.\ Print "Pupil Diameter = " & pupilDiam & " mm" ? ^EB"{ &K1\" ' Calculate new parameters with accommodation .fQ/a`AsU taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness &g{b5x{iD -t<8)9q( Rant = 12.0 - 0.4*A 'Radius of anterior lens E7_)P>aS5 CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens Dd(# JwkMRO Rpost = -5.224557 + 0.2*A 'Radius of posterior lens ww_gG5Fc$ CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens ]7*Z'E \5]${vs&s tlens = 3.767 + 0.04*A 'Lens thickness NaR/IsN8% dFu<h nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction qB`-[A9HPe C;u8qVI 'Adjust parameters to account for accommodation L=7U#Q/DE F)W7,^=X>- '************************************************************************* J73B$0FP 'Aqueous thickness (Position of Lens) .3{PgrZ '************************************************************************* v-V#?+# eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 63J_u-o GetCustomElement eID, entity 5eZ8$-&([ E5#Dn.!~ parID = FindFullName( "Geometry.Arizona Eye" ) Z#+{ksU S690Y]:h$v ' Delete any shift(s) in z @+gr>a1K# count = 0 RjII(4Et While GetOperationCount(eID)>count n^svRM]eQ GetOperation eID, count, op syEWc(5 If op.Type="ShiftZ" Then sd@JQ%O DeleteOperation eID,count k63]Qf=5?N count=count-1 Q:
H`TSR] End If y?ps+ce93 count=count+1 F~NmLm Wend }`O_ \m>mE/N 'Set new shift in r[>=iim op.Type = "ShiftZ" e~Oge op.val1 = taq Y7|R vLWoP op.parent = parID kl0!*j AddOperation eID, op ,?OV39h Print "Set aqueous humor thickness = " & taq-0.55 Ca SoR | :'L^zGf '************************************************************************* -QUr|:SK: 'Radius and conic constant of anterior lens (&25 8i, '************************************************************************* 6D[m}/?Uy eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) _K4Igq GetConic eID, entity, curv, conic #~&SkIhBE -,M*j| SetConic eID, entity, 1/Rant, CCant tWs ]Zd Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant /M:R|91:_ H nKO '************************************************************************* E3pnu.;U:_ 'Radius and conic constant of posterior lens 2:31J4t-< '************************************************************************* NTnjVU
} eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) >)/,5VSE GetConic eID, entity, curv, conic C^}2::Qu "T*Sg SetConic eID, entity, 1/Rpost, CCpost C q/936`O Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost YLr<^G-v IoEITKd '************************************************************************* &"D * 'Lens thickness (Position of posterior lens surface) ]h(}%fk_ '************************************************************************* w]4=uL6 (*.t~6c?5 parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ?2Q9z-$ e <Hbm ' Delete any z-shift(s) C~16Jj:v count = 0 6Un61s While GetOperationCount(eID)>count \#(3r1( GetOperation eID, count, op `Qf$]Eoft If op.Type="ShiftZ" Then uXs.7+f DeleteOperation eID,count }y<p_dZI count=count-1 dQ4VpR9|; End If
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%OA count=count+1 J&64tQl* Wend ~16QdwK #6XN_< 'Set new z-shift N5 BC<pu op.Type = "ShiftZ"
ohK_~ op.val1 = tlens 2v
^bd^]u: op.parent = parID zJp}JO AddOperation eID, op W`baD!* Print "Set lens thickness = " & tlens jv:!vi: '@Zau\xC '************************************************************************* k4|9'V&1*6 'Lens index of refraction Yx- 2ux '************************************************************************* Cu5fp.OS7 eID = FindMaterial( "Lens" ) a[<'%S#3x GetModelMaterial eID, mat k7rFbrLZ %M=[h2SN mat.Nd = nlens zEG6T * SetModelMaterial eID, mat s>=DfE-;" Print "Set lens index of refraction = " & nlens (1~d/u?2\ w2-:!,X '************************************************************************* 8p4J7 - 'Pupil diameter tb^8jC '************************************************************************* %9,: eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) %LeQpbyOR l(-We.:( 'Adjust pupil diameter (trimming volume inner hole) #) eI] #cB=](N SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" wVSM\ Z(fXN$ ' Adjust pupil location to just in front of the lens dP>~ExYtm parID = FindFullName( "Geometry.Arizona Eye" ) m `"^d # eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) \Tf$i(0q count = 0 pmm?Fq!s= While GetOperationCount(eID)>count :%[=v(G[ GetOperation eID, count, op iV
h^; If op.Type="ShiftZ" Then XLEEd?Vct9 DeleteOperation eID,count ~r<@`[-L count=count-1 yc4?'k! End If wul$lJ?tE count=count+1 n#jBqr&!M Wend 3\x@G)1 op.Type = "ShiftZ" [E9V#J89 op.val1 = taq-0.01 ?gknJ: op.parent = parID W[pOLc- AddOperation eID, op |Ai/q6u K gN=b Print "Set pupil diameter = " & pupilDiam 'r&az BO \!!qzrq 'Update AZ Eye subassembly Description XJx$HM&0M eID = FindFullName( "Geometry.Arizona Eye" ) .YV{w L@cB GetEntity eID, entity xvP=i/SO entity.Description = "Accommodation = " & A & "D" $]V,H" SetEntity eID, entity 4&r5M bve_*7CEM Update RJpH1XQ
j Print "DONE!" _?j66-(
Q |u r/6{Oj1 End Sub 9q
+I vrRbUwL! 如果屈光度是4,光瞳直径是4,则会输出如下数据: 8*nv+ U
GA_^?4 Accommodation = 4 Diopters L1'PQV Pupil Diameter = 4 mm r[doN{% Set aqueous humor thickness = 2.81 4LG[i}u.N Set anterior lens radius = 10.4 and conic constant = -2.375869 j@N z Set posterior lens radius = -4.424557 and conic constant = -3.081019 -^1}J Set lens thickness = 3.927 F52%og~N Set lens index of refraction = 1.42672 9((BOq Set pupil diameter = 4 5yOIwzr&Uu DONE! 1NHiW
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