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简介 23\RJpKb V$`Gwr]|n 人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 / |r' H}}$V7]^), 模型 d3Mva,bw< / ~%KVe 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。 */qtzt y046:@v( Table 1. AZ眼睛模型的定义 o{qr!*_3 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. }yn0IWVa hZXXBp 光源 =T?}Nt YY((#"o;l 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。 \Q?ip&R {7hLsK[]) y9H%
Xl 图1. 光源和提示信息使用 JuR"J1MY 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。 Vv.r8IGYm 1/+C5Bp* 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。 "I6P=]|b =WbOwI)u 图2. 字母F光源的设定方法光 tC?=E#3V 6RO(]5wX 图3. 字母F在视网膜上位置点列图 f"[J"j8 视网膜的散射 ~/pzxo$ r|Z3$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。 Qj{8?lew !^#jwRpeN 1@48BN8cm' 图4. 视网膜朗伯散射设定 z
/KK)u(q 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。 $,=6[T!z+e v4,h&JLt 5@IB39 图5. 视网膜重点采样规格设定 "xI" 脚本 GE;e]Jkjn ?liK\C2Z< 内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: <P[T!gST 9_s6l 图6. 用户对话框的创建与编辑 hd\gH^wk
图7. 用户对话框编辑器 H`bSYjgM! 如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 "I?Am&>' 余下的脚本计算与屈光度有关的所有参数。 n9w9JXp;! G@FI0\t 分析 6oaazB^L omO
S=d!o 屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ZRxZume<f
ptatzp]c# 图7. 字母F在视网膜上颜色分析 6=4wp? 脚本代码 ^'CPM6J jUv!9Y}F Option Explicit 'Remove this to enable non-dimensioned variables to be used. >^q7c8]~g f0<hE2 Dim entity As T_ENTITY ~CB[9D= Dim op As T_OPERATION F>tQn4 Dim mat As T_MODELMATERIAL 6R-&-4 Dim A As Double fbyQjvURnC Dim pupilDiam As Double e0@6Pd Dim eID As Long 'E/*d2CDM( Dim parID As Long 6:GTD$Uz. Dim count As Integer UDhG : Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double B]m@:|Q Dim tlens As Double, nlens As Double :q8b;*: Dim curv As Double, conic As Double B\J^=W+` Dim ok As Long
3G.5724, S)QAXjH Sub Main S6}@I ,Q U4m9e|/H;z '用户输入对话框 ]{"Br$ Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 F:*W5xX TextBox 220,21,40,21,.TextBox1 'default: 0 ZX ?yL>4 Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 }X x(^Zh OKButton 40,91,90,21 56^+;^f^` CancelButton 190,91,90,21 ;^*Unyt[4] Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 /9o!*K TextBox 220,49,40,21,.TextBox2 'default: 4 FX9F"42@ End Dialog CkJCi Dim dlg As UserDialog +!QJTn"3 u@ jX+\ ok = Dialog (dlg) lb'GXd % Hzrtlet If ok=0 Then 'cancel button was pressed 3qY K_M^[ Print "Execution cancelled." %6AW7q
t End f;/QJ End If h;=6VgXZ /R>nr" 'Assign accommodation and pupil diameter & use defaults if field left empty c/B'jPt If dlg.TextBox1 = "" Then jp $Z] A = 0 'Default accommodation :2njp% Else qwIa?!8o A = CDbl(dlg.TextBox1) gp$Ucfu' End If XU+<?%u}z LL|7rS|o If dlg.TextBox2 = "" Then PW3GL3+ pupilDiam = 4 'Default pupil diameter Lh.`C7] Else dt~YW pupilDiam = CDbl(dlg.TextBox2) nXjPx@ End If kId
n6 Wx, 5K|"\ Print " " -P&6L\V Print "Accommodation = " & A & " Diopters" mhW-J6u* Print "Pupil Diameter = " & pupilDiam & " mm" ##Z_QB(; 7'
S @3 ' Calculate new parameters with accommodation F)z;Z6{t4 taq = 0.55 + 2.97 - 0.04*A 'Aqueous thickness ,39aF*r1Q _fZZ_0\Q Rant = 12.0 - 0.4*A 'Radius of anterior lens =]-j;#'& CCant = -7.518749 + 1.285720*A 'Conic constant of anterior lens BTM),
w2 4t)%<4 Rpost = -5.224557 + 0.2*A 'Radius of posterior lens q>w)"Dd CCpost = -1.353971 - 0.431762*A 'Conic constant of posterior lens -hkQ2[Ew#
{EdH$l>94 tlens = 3.767 + 0.04*A 'Lens thickness #
O4gg Rq[ M29 nlens = 1.42 + 0.00256*A - 0.00022*A^2 'Lens index of refraction ID.n1i3 ?<6CFH] 'Adjust parameters to account for accommodation ~G27;Npy >DPB!XA3 '************************************************************************* 0flg=U9 'Aqueous thickness (Position of Lens) 'R&uD~Q '************************************************************************* ,;M4jc{ eID = FindFullName( "Geometry.Arizona Eye.Lens" ) xQw7 :18wQ GetCustomElement eID, entity O@?kT;B q5>v'ZSo parID = FindFullName( "Geometry.Arizona Eye" ) 8ssJ<LP PQ@L+],C ' Delete any shift(s) in z 31EyDU,W count = 0 P>9aI/d9 While GetOperationCount(eID)>count [!%![E GetOperation eID, count, op S$2b>#@UJ If op.Type="ShiftZ" Then [frq
'c DeleteOperation eID,count (%O@r!{ count=count-1 *Z_C4Tj End If KFa_ count=count+1 !?^b[
nC% Wend lC=~$c:
vSonkJ_ 'Set new shift in y^7}oH _ op.Type = "ShiftZ" <L&m4O#| op.val1 = taq %r4q8- op.parent = parID Tr^nkD{ AddOperation eID, op P,sjo u^ Print "Set aqueous humor thickness = " & taq-0.55 4nAa`(62 v:+~9w+ '************************************************************************* Z@Ae$ '9H 'Radius and conic constant of anterior lens t'm;:J1 '************************************************************************* ^[15&T5 eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) nNXgW GetConic eID, entity, curv, conic oA1a /[# #M A4 SetConic eID, entity, 1/Rant, CCant vky .^ Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ." $ ':R,53tjl '************************************************************************* JJRK7\~$ 'Radius and conic constant of posterior lens f{0F|w<gf '************************************************************************* .5!t:FPOv eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) t\$U`V) GetConic eID, entity, curv, conic "`asFg K!,<7[MBg SetConic eID, entity, 1/Rpost, CCpost /t-fjB{=G Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost I5h[%T 0EJ(.8hwm '************************************************************************* :rP#I#,7w
'Lens thickness (Position of posterior lens surface) Zf5`XslA. '************************************************************************* hVUP4 A cwV]!=RtO parID = FindFullName( "Geometry.Arizona Eye.Lens" ) BPr^D0P c)0amM ' Delete any z-shift(s) <LRey%{q count = 0 P9T5L<5 While GetOperationCount(eID)>count S>.F_Jl GetOperation eID, count, op ,C {*s$ If op.Type="ShiftZ" Then %7g:}O$ DeleteOperation eID,count >c-fI$] count=count-1 l]<L [Y,E- End If i_][PTH count=count+1 {647|j;e Wend }h 3K@R
}KhjlPhx 'Set new z-shift N N|u _ op.Type = "ShiftZ" =+w*gDr op.val1 = tlens 21RP=0Q: op.parent = parID %&
_V0R\k AddOperation eID, op T;L>P[hNn Print "Set lens thickness = " & tlens Vb
qto|X@ hp"L8w '************************************************************************* *-s,.
F+c 'Lens index of refraction Nm):9YQ/ '************************************************************************* [31p&FxM eID = FindMaterial( "Lens" ) ) _ I,KEe GetModelMaterial eID, mat e?bYjJq s( <uo{ mat.Nd = nlens LI)!4(WH SetModelMaterial eID, mat w:'dhr': Print "Set lens index of refraction = " & nlens %P;Q|v6/| -*2Mf Mh '************************************************************************* i@NqC;~; 'Pupil diameter m`6Yc:@E '************************************************************************* !EQ@#qW/ eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) L !4t[hhe= a^5^gId5l! 'Adjust pupil diameter (trimming volume inner hole) 0b91y3R+ ^TB>.c@ `* SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" PM":Vd/ L!_ZY ' Adjust pupil location to just in front of the lens q %A?V_ parID = FindFullName( "Geometry.Arizona Eye" ) . |*f!w}5 eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) P'MY[&|mM' count = 0 #E0t?:t5bk While GetOperationCount(eID)>count qNyzU@ GetOperation eID, count, op T!W~n
ZC If op.Type="ShiftZ" Then ^w~23g. DeleteOperation eID,count Nx#4W1B[`H count=count-1 ^[Cv26 End If 5BR5X\f0 count=count+1 qW 1V85FG Wend
x{}z ;yG op.Type = "ShiftZ" x ]5@>5 op.val1 = taq-0.01
wiX ~D
op.parent = parID FI8Oz, AddOperation eID, op 0tk#Gs[ 56hA]O29O Print "Set pupil diameter = " & pupilDiam M\b")Tu{0 Ch
)dLPz@ 'Update AZ Eye subassembly Description &4dz}zz90 eID = FindFullName( "Geometry.Arizona Eye" ) }Vu\(~ GetEntity eID, entity TST4Vy3 entity.Description = "Accommodation = " & A & "D" ~8`:7m? SetEntity eID, entity 9]$8MY -VDo[Zy Update uR6w|e` Print "DONE!" 6{d6s#|% @+U,Nzd End Sub
O?EB8RB /\mKY%kyh 如果屈光度是4,光瞳直径是4,则会输出如下数据: c':ezEaC :PbDU$x Accommodation = 4 Diopters #0b&^QL Pupil Diameter = 4 mm +a=
0\lpOy Set aqueous humor thickness = 2.81 {+zJI-XN/ Set anterior lens radius = 10.4 and conic constant = -2.375869 nA>sHy Set posterior lens radius = -4.424557 and conic constant = -3.081019 *p ? e.%nd Set lens thickness = 3.927 !\[+99F# Set lens index of refraction = 1.42672 I>h<b_y Set pupil diameter = 4 gJ2
H=#M DONE! 3-40'$lE RANPi\] `P+(&taT QQ:2987619807 D}Ilyk_uUw
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