Moire fringe measurements of corneal analogue

Edwards, James A

English

CommonKnowledge

Pacific University 
CommonKnowledge 
College of Optometry Theses, Dissertations and Capstone Projects 
10-2-1979 
Moire fringe measurements of corneal analogues 
James A. Edwards 
Pacific University 
Recommended Citation 
Edwards, James A., "Moire fringe measurements of corneal analogues" (1979). College of Optometry. 
511. 
https://commons.pacificu.edu/opt/511 
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Moire fringe measurements of corneal analogues 
Abstract 
Moire fringe measurements of corneal analogues 
Degree Type 
Thesis 
Degree Name 
Master of Science in Vision Science 
Committee Chair 
Jurgen R. Meyer-Arendt 
Subject Categories 
Optometry 
This thesis is available at CommonKnowledge: https://commons.pacificu.edu/opt/511 
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,, MOIRE F'RTNGE }!e .. �iSUREMF;WTS �OF CORNEAL ANAIOOUES 
by, .James A. Edwards 
tJni \•ersi tv Collep;e · or Optometry October 2�·1979 
· jt\'es ""··.:'> . ·  
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' .j,, ,:i· �) .•• 'b . .  ,�:/ ., f' . ./!' • ' ' . a.sses�.�wI;nvs 9,,l'h.i,  J .VJ s1 :L.l ':Y: o ;.r:inges. 
jrytere�t i.n t:;_e st:.:<:'�.J� of' "�1'.Y:i;T:'rl O.r3"J�.:i:.catttms? Wh�ri:·tlft��e ��otor,S Pir'f,: 1'c:J.t.iM1zl?· j·�<."-�.·;.:" 
!)O!'h.e;�l. 4�0-pocr�phy seems pr9mts'i��· . . , Tn tl1is \$,¥� ·�.<�ave �Pli�$der�t,:i. some �:€.the 
basic design r�atures ·qr .motre'·��ch�qu�� ;as,.�i��a9,to.measm_:e!nent� on th¢ 
co:t""nea� 
' . ; 
. ,' ' '·, 
. The t:i'?e ()J' moir; }>;rodu�f.'±�n.useti in. thi� stlidy':i� ()t tl';i.e sllr.wiJ9.t,-;:e;µ �las� 6.r 
To 0btatn the nec���ar:y :,��s�on and ��Q�wbination 'of: ·thf3 ·i�tens�ty 
.i� ···tfje ·nonchi. �:i.�.u�f,q, ,as.··a �ar�et,,. ·a cutw: :h�mJi spi:ttter is• u�md� .• •· 
. 
. F:tgure ··1·
•. illust!'at�s. £1;ie·•·prqgres�.ion· .�t lign.l;tr� $��t 'to n�lrb th��µgh ;th,e· <>ptical 
e1em�pts.•· when·the' corne� (a 'conve�· mroi).·· is'.e�n��r�d tQ�ha�e· �;�5Q.,()() 
' ' \_�/ 
of figure l.t the �ersence of'·.ngh.:t�;}ri df9ptei-e�>:as' it �a���s. 
Below, th'e• power �f .e aeh qPifc!il· et>Jn!)orl�i�t, J.tj . �'.��t�rs,.. ��; · · 
'.in. \nm, a.re g:i,ven. The index di' r�rrs.3�1qi1,.of 't.h� eu�e 
·h-1)·" "!,}�e·�·)"'"'"1P.:.t' • t• (T • .·.t. •.; ··. •• n .....: > · ···• "';tt· · .< .,. · " •, · · ;;.'• .· . · · ·• "'·f'.'·''/.J"' . .,. ; " ·J.; : . '"�-· ,, . • • .. r�,�r�. · .. ,ng, .
. 
1.,... '.1�am S:Q.Ll. . · · · er1 
.
. lioo' ·,:1,;.e.rt�� �CQ:r�e-a., 

back v·erte.x rowers oJ' . the 
trarif1pat'ent<riller w�s .. ·:�sed. t,o 
1'ensee,�y autu�ol�inmt;�� {! •• •. 5 
th� C0nta*}:C,; le.nses Wer� !l!P�.�'ll.���'.W'f;tfl a. �h�:t(}flle'��r'. 
" ' ., . , . 
Jocat,:i:'0rt n:t' th.c� lehs 01· 1'.!-0n$ta.11t ®�i'.t:ron:(-t��t le:ft�} 1r{f.{S me�sl.:rr� d �i�i�:�' tt· 
'!'h0 J,;)t�at5.on o.f f.he, lens :bf 'V!¢5:;able �psit�.to:n -\re:f�l'�n,�e J��). JoT,11.S �e��r�tl· . - . . 
-� t:-ans�tirent t·u1��r :ln cor,i:O:ina:tio11 wt th a. &;ti1"e�1 typ�; C�"'.'ir'i;i:i::;e 
,+ ,-
.· :,, .. ,· · .  ·.·" 
t-:'.pl:ttt,e'f': >,:,nd ·th� g.r-)tlt�,pal ' . .  ·· -:./. . ··, - . 
·.; ...... .:..\-�-- : ·� +-·:_:: - . · . - ,,,.:.,.·<.-.':.::· __ __ --� - :.· ·rt· 
.. · .•.<::u u. Ufl'lt:n ···t th� · ., E::-f�re.?.'h.� l�ri�: 
b 1 n{;:ki'i 15,gl'i;t i'�:d��ted !hti;� 
ln'Q1H';ht .ft'l::ml t�r- the·r�,��r��ce�l�ns 
.':. - ' :_.· . . �"" '-· /"·.. - . . . > 
has .. 1'o }re:e�.i. th� tj!t:i� le in fo6us< while adj1J:�"t.i.txg the ;leti�es,. 
:U!!t1'.l .an . ev�nly p,J.urit'l nate<J. :J!fJBif�e 6!: 
�eticle. �e �ar�:tk,ge � .. s 
ll11'1 tios:ft.:i:on. and' the . 1.s f1:no ... fpt'!J;l;EEl'l by fll6Vi,)lg.:tn�� an�'Jqg:tie' P):'�m J',s.'.!" 
;)1�,yJ;1,�ed front bot;b . P().sj,tlon� t\lt1st he ce�t��ed 1.r! the r�.t'l�le. seal�· 
'f1Y>red .t�r'-· hJ:O.ck · thf' ref'l��ttons fl'.'Qlt! the r.e!Jf:!renee lens .. ·· 
"'"""1· .. . · .. · ·fs th. • :N· .... 6· � ... ,.,.,.,.,,,�·,.,,, ,..,,.:: .;.,._,,.;+·e�,,,,.� · •-=i!"<· ()f\Je• .... :. · . en ...... ,_,� .. �:1."''�-i., .. ,,, .. :1- .... . ... . . \·,'-""" ·"""'.i. 
. .  
·tis the . . :refe�et;.ce �al0g1Je :i 8 
'/ .moire fringes .s,:re fieen,. Tf'. the 
arl/iust�i 'Until the fr.inge pr:'.tj.ern is 
· . .  
adj1istme.fi� £nclnd�$ rote:tlo.rr of:. the te0t .. ' 
;
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,, 
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: 
. 
:. '· . ·. 
. .. ·' 
te� .. •o't · :r-etie1'.� ; ·���fe 
-
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. 
' 
made in the central iegi� <.>.f the sp,ale to. mini;iirl.z·� t.;l:le 
position of'. the referend'0··1ens. is• .varied w}li,::1,e;#i..�e�:t'QcUSing· ·· w:i.uh £he r.e.ferenee .,, _. :. _ . " "�· ' .. . • . • . 
.· 
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. 
-· ·.-,. " ' ,:. 
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'· ><;,_." -- _-: -- .. > .  ', - - -· - .- '.;\- ' , ; . -
�lfo�. r>o�;i.tion of! t�e I'E!fei'ence len.s '(•whe,n.<'t,he fring�•:$epatl��ion is 10 unit's) 
,-/.>' -;:" --, _ .. . ::- / 
drawn wi.th t1le positfon of the �e,t'�re�ce leµi(pJ:o$ted ar{ the ordi..n\9;te and the, .rad.J.,u.s 
curvat1J.re of the·· ti=�st anat,'l�:tl.� as the• abkcissa. ··.·The �teH�or •r�dius o!' curYA£ure: 
; ·- . • .  _
· ': .. • .-'_.,··.,_. ·::· ' - ---·,"' ::-:: .,, .. -· _ _  .- -� ',, -: ;:- - ·.-.· ... - - · �«:._-:..,:·- �.: .• - ·< --�-'. _'. ;.'"�- - : · '"-"J 
tf:;t?. ttn1<:n�Y,JD surface ·cap·'t,h�n: l'.lt'.1 ext,kapp��ed' . .er�'.gil,}le gr�p}i) :ot)ee :���f pa$i.i>:J.�zf Of 
the. refe.rence.·len.s•· c.�rreE;pon�ingJ�()··•·S.• �t�ng�;���th)�I'<Jo·
··
units .ts a�i�rrnin�d.
·
· 
• 
' ,. 
' ' ' " . ' 
' '. 
. -- "· ' - , ' ' .... ,� - ,,;< . .- - \ . - ' ,, - >: �-' • • ' . ' '" . 
'?he rrioi:re' £):'inges r;��o:iuc�d;irr the 
or the tiyo images • .  • Ttiis ���i'en4� i;{)·e��'�;; 
.
. �ed bi: th�.·. 
•. -I•\ •' .� 
�af@�fiC'a�i.cm: of: . e .ach 9f the gre;t�lig images r���tl.�� to· �hf):·��ti.�le�·�eale., 
ref'erene"• lens and t�1e �·�¥-dgge are'p¢sxti¢�ed. s:tict/tnat tb£J:"l.1n'�:·.spacing· 14;thtn • '<; ·, " -_. , _, �-- � : «· 
", - ' 
-:.-,_..; ) /·--- ,"· ,' ,-- .__. ,
; 
' " ; ·' ' �--- : • - --- --
re si.rl:t ailt imas:re :rs �qar;i) t·Q. on� r�.tioie �0,�e 
.,.' ·,� 
': '. :\. ,. '·-'-:.. � 
as the poslt�pri o:e·5r11.t �l�gntf,'ic�t�qn �rJ\fo�� 
geometrical optics: .·!�he totS:J .. . tr.a,gp.ifJ.c$.tion'• �f'.t�hi� i�e. with ;.;esl)t;lct to the · 
Horichi j!11 } ng is �iveri b;'· �'.·h�. yer£>;en�k ;atit>S, at· e��h; Qf. t�e. int�ttt?.C:e·s of thci 
.const�·.nt (•,,-J:th respect ,tn r"t,he b�a,m�· f;Plit:ter surf��"' hy·iiaj.-iit�Jrtil'lg i/;�gristant 
te'tescii}pe .ma.�ni�l�ation �.'-�1d t,ar�et grating ��i,ti��,..>t.he orJ.; re�i,ni11g; 
· th9 ·Ustance, x,, bet1veerr the te:te�etic� an�..l;()gµ� �d�'t)f� prifa�s.�al r:·lar1e 
• ' <• ' 
f;l; €' re ]:;2,t,j_ Vt'> fft�gni f:i r;,;17;,j Orl xranger q.f . the irlstrjl.nl�lltj the tot.a1. .·!J18.f;r:�,r:i.6at ion. 
. 
. 
,.. .,., ,.. ,l·1i>['or .;:- ., ..,. "'i=>.fe...,"'n"e· 1en· "' .,e';.t��'flP-S. ·o·-".76· 'l ·'1:;)/:..,...,d· 10, ........,. 'T'h .. e ... , P.e +., ,o+,"'.l m ... ,.r>.·."··"}·'r.i . .  r:... · . �.":.-1,i . . ·o .. r:.:·.: .  1.· ., <"•-·'·�\ ...... ;.� • ' ".1.C • .1 •. , ..: • .  _,,l <'': ; ·� . . ·.�. .;·;:; •> '�;,..,_,:::, ·, . .J.· . . ;"!.-' j :L+.,i' .:r ;�A;, ,' • .' . ""''"" • • I'> - r::> - .. - • .  ;· '' V 
C<:Yrr(�f;�ond to' a.TJ: #3;!1.t�r"i.l':ir ra�i.1tf'l of c��.rvatilr� 
re:fe!'er>�e lens :power' o:P +LJ�'?6t D;... Tben X ts· 
f;igu:r� J A B;%°�tlh js sh�� T'1"hich demO:O.S!tl°'ates th� :!'e1�tfve 
',: :, 
. ' 
·'' 
�:, 
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' 
'.�:· 
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' ·  ' . 
th .respec:f. J,o the b�ua.TTI '.S:01:i tt·e.� 
/�Q, 
'.!:'he brr:i5:nate 'is r�rr: "'�s��t:�t-i_yp oi 
>' ', ' ' . · � . _,., 
th� pbsit:i.or: 
· _:,io -'tO: "" . 3D .. 'It> SI) 'D Rf3i'erenca<x.ens Pos±t�oli d.(mrriJ 
c:'.'':''.�,·1<:'.'!r"hiv tht:i :r>Al�tianship be.t�en ' ' ·, '.: . . . ' 
Qf .C ·:rrvat11/•e Of thej',fjgtJ $ltrfaee, 8i1YJ;\t;jon . z···. ·<i·� . .  B.ga;i n· be· .n sed. to 
��e1 in. eqiJation 2, y!e:fding 't;he :tota1 mag:i;l1;f'it:�atlon 
Th'?se values arB . .  col)�;teu :to r�t:icle> sca;te 
have .dorie i.n ta.b1'3 1�<t 
}··.
-�··, 
t.�st s11rf'a0es wer.e .'1sed in. .t!ds stu4y.. LW� :•ra.d.�i,. of' c�arya-t,tlre< w�re 
pJ ott.er:l i� 
of 


. . 1 ) • . ·4: arc , · s:1ze aJ1u 
test lens 
' ,':,',,·1,",: ; '»:' 
.f:'le�ing � . .  sto:p>in the �1a.'1f.i 9,f-f.ne eti\ pont. of''ttj� moir�.ap:p�..rat:l.'l:s. ·. 
. . 
· ··. • t. i 
· d.·:t.a:i_ .. m. }.�.·•,· .. te .. :r_.··.·.s ... ·.·· ar .. . ·· .. e. n . . sea.
• ..
. 
·. \ .. h . . e . .. e .. ·.n. • f>r>_·,.0rt' .or." 2�p10��::D:PY.�.0 ,�e ·"''�:r:s . . . ., . __ _ . 
'2 c:bncave .len,s sh6t� i.i:l ±'±giJ.f� 6 ari":l a. 40. .mm···· area 
one .t.�me ! The. sta,'nd:ard .d,evj;at!l<m pf f1r:dings wo1ild perhe;ps. 
thls .study,. Uoweve:r, the .relationshi9 b$tween re�eren��. 
achraritages of•. this · methdd of· mcitre cor�a1 asse.ssrnent .are the 
aon�rtrtv:-:V.cri, t.h€" �u"'ect ;:-eadahiJity pf the ;find.i�gs,, and ;£he acq�1!,'Mj� ?btain?-d. with 
One st�ndard deyi ation 
be. ·olitrti.�e·:l i:11ickl�r a.nd a�c1J,-ratelyc, <)the 1m�triliit¢nt::does note: require mn�h ', . ' · . .  '. ' . .  . . 
&4d. ""h,at�ent ±1:�com:f01•t.is �1egll;gib:i;e.· Jn �,-fihe method pre8-����d in.this 
eas? ly · aqapted .-to :� 'biol!dcroscop�· utllizirig .·. t.he JtLi.�rosc�'.9�. system: 
''.:· �· ;. 
•, · 
&'1d the $1it l�mp �ystem fo:r i11.Ul1li1'ia;tf<)p. of the target'.1ig)fatine. 
ll.�t�-�1.p�ted thif!( moil·� ·me't��ds�r.i:I1-eve!i,turu.J�re!'iaee··
·
pre$�nt nt$tho��,-of· .•d�tel'mini�g .. 
corneal topogra.phy byprovi�.ing 
easi}.y :l.n_cludcfd in anY eye �xa"Tlinatief1 .. 

Test Ir.ms; diroensions-
Back focB.1: 1er1Kth ! there.fore 't-52•632_ )J· 
. Front ·f'Gcal length =. 19 �. -· �5 mpi, .i;n�i;e.ro\t>e +52(q32 n .. � Cente�'.. tr:iekness "" j mm ... · .. 'l mm .. 
' < +: . Etige th"ickness =;: 2.J mm � .• 1 mm 
lli$t.an�e.mea.sux:ed b;.t:1v;e.;'en fi'orit, et:l;ge of te�t:l,�ns and cube !��$ 
DJ �•""'Ce oet�,.,e'en .... · c· u1;� 
.
fa· 'c·· e "'nd .. ·\. D, "'1' �c'. ± 
.. '.:.P. • .... ·,. ..
. ·i.
'
··�.· ..•. J..''··.•a·.\ ...... :e.
·
··. ·.'.O.� ... ·· �ff.:.·.:r .. ·.·•··.32 .•.  ·.·=·  J, .. ..... -1::lt;�!�:�-�� ... - , _. ·�iv.
_
, « · �· :' - � · , '. \ '� - ·:._ . » t;\; -"': ' - · - ' � !:':, ,4-� J;: ....,...._. .......... 
Reference le:ns · q.iJ'riem;f()J.1:s .;; . . .· · .. 
Back ft>cal ltirigt}"i ""\19 mm ! .S mm; thefef��� ·�S2.q.�2 + · ' ' ' ' ' ' •  •/ ' : ' ':· . ; ' .·., Fl:'orrb focal length "' 19 ·fum ;.. �5 th�'r'ef(}l'.e +5?.632 O 
... · .+ Gente:i' tn:iclmess = t0 .. 8 mm> .. ·,.1 
--, -
,,. _
4
_
;
:
· ;_ '_,-\ '·+ Edge thickne§$ ll:i , • 1 mm ... , 1 mm 
Ass1trnptir:m - SA.rne . as for te �t · lens 
. +.52�632 .. p ---- ·-c�0"1pa--�· + P ' th,us P-. +23i9Q7.D/�1lri'ace 
�· Py:S2J 
F�quiv"IJ.Elnt power = ?(?J.907) - {.00709)'(23.967}2. =+h3.7�t D · · . . · .,· . . . · .. ·· ·;;· ·· .·,, ,� ...   
uif>t.!:!nce between rof;,e:r.erice l�ns .ed�e and, 61tbe f>ace � r! ' . . . . 
D1.st,a.11G0 be.tween �\i.l:\::; i.a.c.e a;nd reference . . l*ns pp:i.ri.cipal. th\·, " · . : .' .. " �. • . . ·. '\ • .:e�e�cop9 . .. ... ::imens:i. om;-
· the� _t,e1ef1cor;;;; ""· 61.i.S :ri:.m - 1 mm 
TJ:l·�.;:,;,,.,,, "mo ·.,,,r·d b't···· .p.;_ . t � · t . 1 · · ".·"" 
..
. "' 
... 
·;;i
.
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·. ·"-· ··" ·· · ·.i::. ··t· -·.·· 1•  ··· .L,"''·""J''"'.' ,,,,�a..,.,. e : .. ev�'fBP..U .�J:.0}'1 0.L.• .e �SOO,P� o.o,.l<l Q:lh1E' :i .. ace. i'IHen. 8K1hg 
+ h?.,.0 ?!mt -�· .5 mm 
crc.f'.lm flnlit,t<:>r d:i:T?'J';nstonf:>­
'l'h:i.ckne:'>s. of GUbe "" 
tl.Cft�: Rn1'1;chi r'�.;tini:c 
'rest 
r 1 
Reference 


Moire fringe measurements of corneal analogues

https://commons.pacificu.edu/cgi/viewcontent.cgi?article=2118&amp;context=opt

Moire fringe measurements of corneal analogues

Abstract

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