Acquired Cupping

8/3/2019 Acquired Cupping

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B r i t . J. O p h t h a l . ( I 9 7 5 ) 5 9 , 2 I 6

A c q u i r e d c u p p i n g o f t h e o p t i c nerve h e a di n n o r m o t e n s i v e eyesJ . THEODORE SCHWARTZ,t FRANK H. REULINGt, AND ROBERT J . GARRISON*F r o m t h e N a t i o n a l E y e I n s t i t u t e t a n d t h e N a t i o n a l H e a r t a n d L u n g I n s t i t u t e * ,T h e N a t i o n a l I n s t i t u t e s o f H e a l t h , B e t h e s d a , M a r y l a n d 2 0 0 I 4 , U . S . A .

T h i s s t u d y o f a h o r i z o n t a l c u p / d i s c r a t i o (CDR-H)among a s a m p l e o f n o r m a l s u b j e c t s c a l l s a t t e n t i o n t os e v e r a l l i k e l y sources o f a c q u i r e d e n l a r g e m e n ta n d m o u l d i n g o f t h e p h y s i o l o g i c a l c up i n normo-t e n s i v e eyes. Some o f t h e f i n d i n g s ar e new, b u t t h ec h i e f purpose o f t h i s r e p o r t i s t o e m p h a s i z e t h el i k e l i h o o d t h a t t h e p h y s i o l o g i c a l cup o f t h e " n o r m a l "eye i s not a s t a t i c s t r u c t u r e a n d t h a t g r e a t e r u n d e r -s t a n d i n g o f a c q u i r e d c h a n g e s i n t h i s l e a s t s t u d i e da f f i l i a t e o f t h e g l a u c o m a t r i a d i s n e e d e d .MethodsC l i n i c a l measurements o f a CDR-H were o b t a i n e d asp a r t o f a b a s e - l i n e e x a m i n a t i o n o f i 6 o t w i n s u b j e c t s wh op a r t i c i p a t e d i n a s t u d y on t h e o c u l a r h y p e r t e n s i v e res-ponse t o t o p i c a l d e x a m e t h a s o n e , d e s c r i b e d p r e v i o u s l y( S c h w a r t z , R e u l i n g , F e i n l e i b , G a r r i s o n , and C o l l i e , 1972;I 9 7 3 a , b ) . M e t h o d s o f i d e n t i f y i n g t h e t w i n s , s e l e c t i n g t h es a m p l e , a n d p e r f o r m i n g t o n o m e t r i c measurements h a v eb e e n d e s c r i b e d i n e a r l i e r r e p o r t s .I n t h i s s t u d y , C D R - H was t a k e n as t h e r a t i o o f t h ew i d e s t h o r i z o n t a l d i a m e t e r o f t he o p t i c cup t o t h e w i d e s th o r i z o n t a l d i a m e t e r o f t h e o p t i c d i s c , e s t i m a t e d t o t h en e a r e s t t e n t h . T h i s d e s i g n a t i o n was a d a p t e d f r o m t h a td e s c r i b e d b y S n y d a c k e r ( i 9 6 4 ) a n d m o d i f i e d b y A r m a l y( 1 9 6 7 ) . The d e m a r c a t i o n f r o m p a p i l l a r y s u r f a c e t o o p t i cA d d r e s s f o r r e p r i n t s : J . T h e o d o r e S c h w a r t z , M . D . , S e c t i o n onO p h t h a l m i c F i e l d and Development R e s e a r c h , Of f i ce o f B i o m e t r yand E p i d e m i o l o g y , N a t i o n a l Eye I n s t i t u t e , The N a t i o n a l I n s t i t u t e so f H e a l t h , B e t h e s d a , M a r y l a n d 2 0 0 1 4 , U . S . A .

cup was d i s t i n g u i s h e d as t h e l o c a t i o n o f t h a t i m a g i n a r ycontour l i n e w h i c h b e s t r e p r e s e n t e d t h e f i r s t d i s c e r n i b l ec h a n g e i n s u r f a c e c u r v a t u r e as t h e s u r f a c e o f t h e o p t i cnerve h e a d c o u r s e d p o s t e r i o r l y a t t h e r i m o f t h e cup. T herange i n s h a p e s o f p h y s i o l o g i c a l cups o b s e r v e d i n t h i ss t u d y s a m i p l e f o r m e d s e v e r a l groups, t wo o f w h i c h m e r i ts p e c i a l m e n t i o n .( i ) I f a d e f i n i t e c e n t r a l d e p r e s s i o n was p r e s e n t , b u tc u r v a t u r e o f t h e t e m p o r a l s u r f a c e o f t h e nerve h e a di n c r e a s e d g r a d u a l l y f r o m t h e o p t i c r i m t o t h e f l o o r o ft h e d e p r e s s i o n w i t h o u t an i d e n t i f i a b l e d e m a r c a t i o nw i t h i n t h e b r o a d , g e n t l y s l o p i n g curve, t h e n t h e o p t i cr i m was t a k e n as t h e t e m p o r a l m a r g i n .( 2 ) F o r e c c e n t r i c or i r r e g u l a r cups, t h e w i d e s t h o r i z o n t a lcup and d i s c d i a m e t e r s were u s e d w h e t h e r t h e y b o t ho c c u r r e d a l o n g t h e same s t r a i g h t l i n e or n o t .To measure CDR-H, p u p i l s were d i l a t e d u s i n g t h r e ei n s t i l l a t i o n s o f I per c e n t . M y d r i a c y l ( A l c o n L a b o r a t o r i e s )a t 5 - m i n . i n t e r v a l s . A l l measurements were made c l i n i c a l l yb y one e x a m i n e r ( F H R ) , a n d were b a s e d on a s t e r e o -s c o p i c v i e w o f t h e o p t i c nerve h e a d u s i n g t h e A l l e n -T h o r p e c o n t a c t l e n s w i t h t h e H a a g - S t r e i t b i o m i c r o s c o p e .

R e f r a c t i o n s d e s c r i b e d i n t h i s r e p o r t were o b t a i n e d b yo r d i n a r y c l i n i c a l p r o c e d u r e s w i t h o u t t h e u se o f a s t a n d -a r d i z e d p r o t o c o l . A l l b u t 23 o f t h e i 6 o r e f r a c t i o n s wereo b t a i n e d u n d e r c y c l o p l e g i a . A l l e x c e p t i o n s were e i t h e rm y o p i c or o f a g e > 4 5 years.ResultsThe age, sex, a n d race o f t h e s a m p l e ar e g i v e n i nT a b l e I. The f r e q u e n c y d i s t r i b u t i o n o f C D R - H f o r

T a b l e I S t u d y s a m p l e o f 8 o t w i n p a i r s c h a r a c t e r i z e d b y a g e , s e x , a n d r a c eS e x T o t a l p a i r sA g e( y r s ) M a l e F e m a l e N o . P e r c e n t .

1 5 - 2 4 2 6 ( 2 ) 2 7 ( 3 ) 5 3 6 6 . 2 52 5 - 3 4 2 ( I ) 5 ( I ) 7 8 . 7 53 5 - 4 4 4 3 ( I ) 7 8 . 7 545+ 3 I 0 ( I ) 1 3 I 6 - 2 5Mean 2 5 - 6 3 5 4 5 8 o ( 9 ) 1 0 0 - 0 0 ( I I - 2 5 )

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A c q u i r e d c u p p i n g o f o p t i c n e r v e h e a d 217

a l l 32 0 n o r m a l eyes i n c l u d e d i n t h i s i n v e s t i g a t i o ni s s h o w n i n F i g . i. The e x t e n t t o w h i c h t h e d i s t r i b u -t i o n o f C D R - H c o n f o r m s t o a n o r m a l or G a u s s i a nc o n f i g u r a t i o n can b e a s s e s s e d f r o m F i g . 2 , w h e r e t h esame d a t a are r e p l o t t e d as a p e r c e n t a g e c u m u l a t i v ef r e q u e n c y d i s t r i b u t i o n on a p r o b a b i l i t y o r d i n a t e s c a l e .By t h i s m e t h o d , a G a u s s i a n c o n f i g u r a t i o n w i l l appearas a s t r a i g h t l i n e . The d a t a d o n o t d e v i a t e m a t e r i a l l yf r o m a G a u s s i a n d i s t r i b u t i o n .

D i f f e r e n c e s i n CDR-H, as o b s e r v e d b e t w e e n t h er i g h t a n d l e f t eyes o f t h e s e s u b j e c t s , are s u m m a r i z e di n T a b l e I I .A s s h o w n i n T a b l e I I I , t h e average C D R - H wasvery s i m i l a r when c o m p a r e d b y l a t e r a l i t y , sex, a n drace. H o w e v e r , r e l a t i v e l y f e w n o n - w h i t e s u b j e c t swere s t u d i e d .The a s s o c i a t i o n b e t w e e n C D R - H a n d age, i n t r a -o c u l a r pressure ( I O P ) , a n d r e f r a c t i v e error wass t u d i e d b y r e g r e s s i o n a n a l y s i s . R e s u l t s are s u m m a r i z e di n T a b l e I V . S i n c e i n t h e p r e s e n t s t u d y t h e s u b j e c t s

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T a b l e I I D i s t r i b u t i o n o f p a i r e d d i f f e r e n c e s b e t w e e nh o r i z o n t a l c u p l d i s c r a t i o o f r i g h t e y e a n d l e f t e y e f o r i 6 os u b j e c t sC D R - H ( R i g h t ) P e r c e n t a g em i n u s N o . o f o fC D R - H ( L e f t ) s u b j e c t s t o t a l-0-2 7 4- 4-O-I I 8 I 1 I - 3

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I8.0 0 1 0 - 2 03 0 4 0 - 5 Ob 07 0 - 8H o r i z o n t a l c u p / d i s c r a t i oFIG. I P e r c e n t a g e f r e q u e n c y d i s t r i b u t i o n o f h o r i z o n t a l c u p / d i s c r a t i o f o r 320 e y e sFIG. 2 D a t a f r o m F i g . I s h o w n as p e r c e n t a g e c u m u l a t i v e f r e q u e n c y d i s t r i b u t i o n u s i n g a p r o b a b i l i t y o r d i n a t e s c a l e .I n t h i s c u m u l a t i v e d i s t r i b u t i o n , a b s c i s s a v a l u e s are p l o t t e d a t t h e e n d o f c o r r e s p o n d i n g i n t e r v a l s on t h e o r i g i n a l h i s t o g r a m ,i . e . a t v a l u e s m i d - w a y b e t w e e n s u c c e s s i v e b a r s o f F i g . IT a b l e I I I M e a n s a n d s t a n d a r d d e v i a t i o n s o f h o r i z o n t a l c u p / d i s c r a t i o b y l a t e r a l i t y , r a c e a n d s e x

C D R - HV a r i a b l e N o . o f o b s e r v a t i o n s Mean v a l u e S t a n d a r d d e v i a t i o n * * *L a t e r a l i t y * R i g h t 8 0 0 - 4 0 0 1 3 3L e f t 8 0 O 0 3 9 0 - 1 3 7R a c e * * W h i t e 7 1 o 0 3 9 0 - 1 2 7N o n - w h i t e 9 0 o 3 8 I 7 8S e x * * M a l e 3 5 0 o 4 0 0 1 4 6F e m a l e 4 5 O - 3 9 0 - I 2 3

* A v e r a g e f o r b o t h r i g h t o r b o t h l e f t e y e s o f t h e p a i r* * A v e r a g e o f f o u r e y e s f o r t h e p a i r* * * S t a n d a r d d e v i a t i o n s a r e b a s e d o n mean v a l u e o f C D R - H f o r t w o o r f o u r e y e s ( a s i n d i c a t e d ) a n d a r e t h e r e f o r e s m a l l e rt h a n e x p e c t e d f o r t h e s a m e number o f s i m p l e i n d e p e n d e n t m e a s u r e m e n t s .



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T a b l e IV S t a t i s t i c a l s u m m a r y o f t e s t s o n h o r i z o n t a l c u p l d i s c r a t i o ( C D R - H ) , a g e , i n t r a o c u l a r p r e s s u r e ( I O P ) , a n d s p h e r i ce q u i v a l e n t r e f r a c t i o n ( R E F ) a m o n g 8 o p a i r s o f t w i n sR e g r e s s i o n c o e f f i c i e n tC o r r e l a t i o nV a r i a b l e c o e f f i c i e n t V a l u e t P

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-_00 - bO 4 - 0 0 - 2 - 0 0 000R e f r a c t i v e e r r o r ( d i o p t r e s )FIG. 5 H o r i z o n t a l c u p / d i s c r a t i o v . r e f r a c t i v e e r r o r f o r e i g h t y t w i n p a i r s . A v e r a g e v a l u e s f o r t h e p a i r a r e b a s e d o n i n d i -v i d u a l a v e r a g e s o f s p h e r i c e q u i v a l e n t f o r r i g h t a n d l e f t e y e sFIG. 6 F r e q u e n c y d i s t r i b u t i o n o f r e f r a c t i v e e r r o r among i 6 o t w i n s u b j e c t s . E a c h s u b j e c t r e p r e s e n t e d b y a v e r a g e s p h e r i ce q u i v a l e n t f o r b o t h e y e s

D i s c u s s i o nT h r e e f i n d i n g s i n t h i s s t u d y are o f c l i n i c a l i n t e r e s tw i t h r e s p e c t t o a c q u i r e d c u p p i n g i n n o r m o t e n s i v eeyes:( i ) The s i g n i f i c a n t a s s o c i a t i o n b e t w e e n CDR-Ha n d ag e when t h e e f f e c t o f pressure i s p a r t i a l l e d - o u t ;( 2 ) The s i g n i f i c a n t a s s o c i a t i o n b e t w e e n CDR-Ha n d pressure when t h e e f f e c t i v e o f ag e i s p a r t i a l l e d -o u t ;

( 3 ) The a b s e n c e o f a s i g n i f i c a n t a s s o c i a t i o nb e t w e e n C D R - H a n d s m a l l t o m i d - r a n g e v a l u e s o fa m e t r o p i a .

A g e v . c u p s i z eThe r e l a t i v e s i z e o f t h e p h y s i o l o g i c a l cup i n com-p a r i s o n t o t h e o p t i c nerve was f i r s t e x p r e s s e d as ar a t i o b y P i c k a r d ( I 9 2 1 ) , w h o s e o r i g i n a l r e p o r ts t a n d s as an e a r l y e x a m p l e o f c a r e f u l c l i n i c a l a n ds t u d y d e s i g n m e t h o d s . U s i n g an e s t i m a t e o f c u p / d i s cr a t i o b a s e d on r e l a t i v e areas ( C D R - A ) , P i c k a r dr e p o r t e d t h a t t h e p h y s i o l o g i c a l cup i n n o r m a l s u b -j e c t s e n l a r g e d w i t h age. H i s a c t i v e i n t e r e s t i n t h i sq u e s t i o n p e r s i s t e d f o r many years ( P i c k a r d , 1923,I 9 3 1 , 1 9 3 5 ) , as d i d h i s b e l i e f i n a s i g n i f i c a n t agee f f e c t . H i s f i n a l r e p o r t ( P i c k a r d , I 9 4 8 ) i n c l u d e dd a t a on a c o h o r t o f 2 3 4 eyes f o l l o w e d p r o s p e c t i v e l yf o r 15 years a n d a l s o an e s t i m a t e o f t h e average r a t eo f i n c r e a s e i n C D R - A w i t h age.L a t e r i n v e s t i g a t o r s r e p o r t e d mixed f i n d i n g s w i t hr e s p e c t t o an age e f f e c t . U s i n g d i f f e r e n t m e t h o d s o fe s t i m a t i n g cup s i z e , C o l e n b r a n d e r ( I 9 6 0 ) , Ford andS a r w a r ( I 9 6 3 ) , a n d B . S c h w a r t z , R e i n s t e i n , andL i e b e r m a n ( 1 9 7 3 ) o b s e r v e d a s i g n i f i c a n t i n c r e a s e i ncup s i z e w i t h age, w h e r e a s S n y d a c k e r ( I 9 6 4 ) ,H o l l o w s a n d M c G u i n n e s s ( I 9 6 7 ) , and Armaly

( I 9 6 7 ) d i d n o t . A r m a l y and S a y e g h ( I 9 6 9 ) s u b -s e q u e n t l y n o t e d l a r g e r h o r i z o n t a l c u p / d i s c r a t i o samong o l d e r s u b j e c t s , b u t c o n c l u d e d t h a t t h e f i n d i n gr e f l e c t e d a h i g h e r i n t r a o c u l a r pressure i n t h e o l d e rage group. I t i s p o p u l a r l y t a u g h t ( K o l k e r andH e t h e r i n g t o n , I 9 7 0 ) a t t h e p r e s e n t t i m e t h a t , con-t r a r y t o e a r l i e r r e p o r t s i n t h e l i t e r a t u r e , c u p p i n gd o e s n o t i n c r e a s e w i t h a g e . T he f i n d i n g o f a s i g n i -f i c a n t a s s o c i a t i o n b e t w e e n CDR-H and age whenc o n s i d e r e d a p a r t f r o m an e f f e c t o f i n t r a o c u l a r p r e s -sure h a s not b e e n r e p o r t e d i n t h e p a s t .T a b l e IV s h o w s t ha t t h e s i m p l e r e g r e s s i o n c o e f f i -c i e n t o f C D R - H on age i s 0 o 0 0 3 5 CDR-H pe r y earf o r t h i s p a r t i c u l a r s a m p l e o f s u b j e c t s , w h e r e a st h e p a r t i a l r e g r e s s i o n c o e f f i c i e n t i s o - o o 2 6 . I t i sn o t e w o r t h y t h a t P i c k a r d ( 1 9 4 8 ) o r i g i n a l l y r e p o r t e dan i n c r e a s e o f C D R - A f o r h i s s a m p l e i n t h e amount o f0 o 3 5 p e r c e n t a g e CDR-A u n i t s ( p r e s s u r e e f f e c t notp a r t i a l l e d ) . I n o r d e r t o compare our d a t a w i t ht h o s e o f P i c k a r d , we c o n v e r t e d our f u l l s e t o f CDR-Hmeasurements t o v a l u e s o f p e r c e n t a g e C D R - Au n i t s ( a s s u m i n g a c i r c u l a r d i s c and c u p ) , and t h ef i n d i n g s o f b o t h s t u d i e s were c o m p a r a b l e . A n n u a li n c r e a s e i n p e r c e n t a g e area r a t i o , as e s t i m a t e d f r o mour d a t a , became 0 o 2 7 per c e n t . as c o m p a r e d w i t hP i c k a r d ' s o b s e r v e d 0-35 per c e n t .The p a r t i a l r e g r e s s i o n c o e f f i c i e n t s f o r ag e a n d IOPi n t h e m u l t i p l e r e g r e s s i o n e q u a t i o n p r o v i d e a quan-t i t a t i v e e s t i m a t e o f t h e average e f f e c t o f e a c h o f t h e s ev a r i a b l e s a p a r t f r o m t h e o t h e r . T h u s , p a r t i a l re-g r e s s i o n c o e f f i c i e n t s r e p r e s e n t r e l a t i v e l y " p u r e "e f f e c t s . I n an a p p l i e d p e r s p e c t i v e , a d i f f e r e n c e i nage b e t w e e n 15 a n d 6 o years, as o b s e r v e d i n t h i ss a m p l e , w o u l d b e e q u i v a l e n t t o average d i f f e r e n c e si n CDR-H o f o - i 6 a n d O - I 2 , b a s e d on t h e s i m p l eand p a r t i a l r e g r e s s i o n c o e f f i c i e n t s r e s p e c t i v e l y .( S u c h p r o s p e c t i v e c o n s i d e r a t i o n o f " c r o s s - s e c t i o n a l "

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d a t a assumes t h a t t h e n a t u r a l h i s t o r y o f t h e p h e n -omenon i s s t a b l e i n t h e p o p u l a t i o n a n d i s i n d e p e n d e n to f t h e year o f b i r t h . )C o e f f i c i e n t s o f t h e r e g r e s s i o n e q u a t i o n s r e f l e c t anaverage a s s o c i a t i o n b e t w e e n CDR-H a n d age f o rt h e s a m p l e . The c l i n i c i a n , h o w e v e r , i s n o t c o n c e r n e dw i t h s t a t i s t i c a l averages when h e a t t e m p t s t o d i a g n o s eh i s p a t i e n t s . He n e e d s t o know s o m e t h i n g a b o u tt h e h i g h e r ranges o f ag e e f f e c t as n o r m a l l y e x p e c t e damong i n d i v i d u a l s u b j e c t s . S e v e r a l a d d i t i o n a l con-s i d e r a t i o n s are i n v o l v e d . " A v e r a g e " e f f e c t s w o u l d ,o f course, m i s - s t a t e b y v a r y i n g amounts t h e a s s o c i a -t i o n b e t w e e n age a n d c up s i z e f o r many i n d i v i d u a l sc o m p r i s i n g a g i v e n s a m p l e . S e c o n d l y , t h e averagee f f e c t s o b s e r v e d i n T a b l e IV p e r t a i n t o t h i s p a r t i c u l a rs a m p l e . O t h e r s a m p l e s m i g h t show h i g h e r or l o w e raverage c h a n g e i n CDR-H w i t h age. T h i r d l y , a l -t h o u g h C D R - H i s r e g a r d e d as i n c r e a s i n g l i n e a r l yw i t h ag e i n t h e r e g r e s s i o n e q u a t i o n s , t h e p r e s e n td a t a cannot b e r e g a r d e d as s u f f i c i e n t t o e s t a b l i s hl i n e a r i t y over t h e range o f ages s t u d i e d , nor d o t h e yp r o v i d e i n f o r m a t i o n r e g a r d i n g i n d i v i d u a l s u n d e r I 5or over 6 i years o f age. A c c o r d i n g l y , t h e p o s s i b i l i t y o fc o n t r a s t i n g age e f f e c t s f o r p o r t i o n s o f t h e c o m p l e t eag e spectrum cannot b e r u l e d o u t b y t h e s e d a t a .From t h e s e s t a t i s t i c a l p e r s p e c t i v e s , i t i s r e a s o n a b l e t oa n t i c i p a t e t h a t some n o r m a l i n d i v i d u a l s are l i k e l yt o e x h i b i t an i n c r e a s e i n C D R - H w i t h ag e w h i c hw o u l d b e m a t e r i a l l y g r e a t e r t h a n e x p r e s s e d b y t h eaverage c i t e d i n T a b l e I V . I t m i g h t a l s o b e e x p e c t e d ,s i m p l y on t h e b a s i s o f b i o l o g i c a l v a r i a t i o n , t h a t t h eo p t i c nerve h e a d s o f d i f f e r e n t i n d i v i d u a l s w o u l d b es u b j e c t t o v a r y i n g d e g r e e s o f s t r e s s a n d v a r y i n gd e g r e e s o f r e s i s t a n c e t o t i s s u e l o s s i n a s s o c i a t i o n w i t ha g e i n g , w h a t e v e r t h e u n d e r l y i n g p a t h o p h y s i o l o g i c a lm e c h a n i s m . A h i g h l y r e l e v a n t s t a t i s t i c a l o b s e r v a t i o nwas a g a i n c o n t r i b u t e d b y P i c k a r d ( I 9 4 8 ) , whop u b l i s h e d a d e s c r i p t i o n o f n i n e t y p e s o f i n c r e a s e i nC D R - A w h i c h h e o b s e r v e d among i n d i v i d u a l s d u r i n gt h e i r 15-year f o l l o w - u p . P i c k a r d d i d no t e s t a b l i s ht h a t h i s n i n e e x a m p l e cases c o m p r i s e d a r e p r e s e n t a t i v es a m p l e o f a l l 2 34 eyes s t u d i e d , b u t f o u r o f h i s n i n ee x a m p l e s s h o w e d r a t e s o f i n c r e a s e i n C D R - H( c o n v e r t e d f r o m C D R - A ) o f as much as o-o2 t o0 - 0 5 per year. T h i s i s e q u i v a l e n t t o a c h a n g e i nC D R - H f o r some " n o r m a l " i n d i v i d u a l s i n t h eamount o f t wo f u l l t e n t h u n i t s over a p e r i o d as s h o r tas 4 years. T h u s , on t h e b a s i s o f a v a i l a b l e i n f o r m a -t i o n as w e l l as on t h e o r e t i c a l g r o u n d s , i t appearst h a t a p o s s i b l e " n o r m a l " e n l a r g e m e n t o f t h e p h y s i o -l o g i c a l cup w i t h a d v a n c i n g years s h o u l d b e g i v e nc o n s i d e r a t i o n when t h e c l i n i c i a n uses c h a n g e i n cups i z e as an e l e m e n t i n h i s d i a g n o s i s o f g l a u c o m a .I n t r a o c u l a r p r e s s u r e v. c u p s i z eFew i n v e s t i g a t o r s h a v e e x a m i n e d t h e r e l a t i o n s h i pb e t w e e n cup s i z e a n d i n t r a o c u l a r pressure among

h e a l t h y " n o r m o t e n s i v e " e y e s . I n t h e i r s t u d y a tR h o n d d a F a c h , H o l l o w s a n d Graham ( I 9 6 6 a , b )o b s e r v e d t h a t t h e o p t i c c u p s i n s u b j e c t s w i t h o c u l a rh y p e r t e n s i o n w i t h o u t f i e l d l o s s w e r e n o t d i s t i n g u i s h -a b l e f r o m t h o s e o f n o r m o t e n s i v e i n d i v i d u a l s . I n af u r t h e r a n a l y s i s o f t h e s p e c i f i c r e l a t i o n s h i p b e t w e e nc u p s i z e a n d p r e v a i l i n g o c u l a r t e n s i o n amongn o r m o t e n s i v e s u b j e c t s , H o l l o w s a n d M c G u i n n e s s( I 9 6 7 ) o b s e r v e d n o s i g n i f i c a n t a s s o c i a t i o n . I n al a t e r s t u d y among n o r m o t e n s i v e s u b j e c t s , A r m a l ya n d S a y e g h ( I 9 6 9 ) r e p o r t e d a n i n c r e a s e i n h o r i z o n t a lc u p / d i s c r a t i o w i t h h i g h e r l e v e l s o f a p p l a n a t i o np r e s s u r e w h i c h w a s s i g n i f i c a n t when t e s t e d b y n o n -p a r a m e t r i c m e t h o d s . T h e y r e p o r t e d n o a g e e f f e c t .The f i n d i n g among n o r m a l s u b j e c t s o f a s i g n i f i c a n ta s s o c i a t i o n b e t w e e n C D R - H a n d i n t r a o c u l a r p r e s s u r ew i t h a g e e f f e c t p a r t i a l l e d - o u t , a n d a q u a n t i t a t i v ee s t i m a t e o f t h e p r e s s u r e e f f e c t h a v e n o t b e e n r e p o r t e di n t h e p a s t .The r e g r e s s i o n e q u a t i o n s i n T a b l e IV p e r t a i n i n gt o p r e s s u r e c a n b e i n t e r p r e t e d i n s i m i l a r f a s h i o n t ot h o s e f o r a g e . The s i m p l e r e g r e s s i o n c o e f f i c i e n t o fC D R - H o n p r e s s u r e i s o o i 8 , w h e r e a s t h e p a r t i a lr e g r e s s i o n c o e f f i c i e n t f o r p r e s s u r e w i t h a g e p a r t i a l l e d -o u t i s o o 1 3 . A g e n e r a l " f e e l " f o r t h e r e l a t i v e" p o t e n c y " o f t h e v a r i a b l e s a g e a n d p r e s s u r e c a n b eo b t a i n e d u s i n g t h e i n f o r m a t i o n i n T a b l e I V . Fromt h e r e g r e s s i o n o f IOP o n a g e , i t c a n b e e s t i m a t e dt h a t a v e r a g e p r e s s u r e l e v e l s c o r r e s p o n d i n g t o t h ea g e r a n g e I 5 t o 6 o y e a r s f o r t h i s s a m p l e w o u l d b ea p p r o x i m a t e l y I 3 * ' t o i 6 - o mm. H g . The s l o p e o f t h ep a r t i a l r e g r e s s i o n o f C D R - H o n I O P , s u g g e s t s t h a tt h i s d i f f e r e n c e i n p r e s s u r e i s e q u i v a l e n t t o a n a v e r a g ed i f f e r e n c e i n C D R - H o f a p p r o x i m a t e l y o 0 o 4 . Thea v e r a g e d i f f e r e n c e i n C D R - H a s s o c i a t e d w i t h t h ep a r t i a l l e d a g e e f f e c t a c r o s s t h i s s a m e t i m e b a s e w a sp r e v i o u s l y e s t i m a t e d a t o I 2 . T h i s c o m p a r i s o n f u r t h e rs u p p o r t s t h e c o n c e p t o f a r e l a t i v e l y i m p o r t a n t a g ee f f e c t among n o r m a l e y e s .E a r l i e r c o m m e n t s w i t h r e s p e c t t o a g e e f f e c t a l s oa p p l y t o t h e v a r i a b l e p r e s s u r e . Some n o r m a l i n d i -v i d u a l s w o u l d b e e x p e c t e d t o b e m o r e s u s c e p t i b l et o c h a n g e t h a n t h e a v e r a g e . T h e s e o b s e r v a t i o n s l e n ds u p p o r t t o t h e n e e d f o r a c l i n i c a l a w a r e n e s s o f p o t e n -t i a l c h a n g e i n c o n t o u r o f t h e " n o r m a l " p h y s i o l o g i c a lc u p a n d f o r a b e t t e r u n d e r s t a n d i n g o f s u c h c h a n g e .R e f r a c t i v e e r r o r v . c u p s i z eI t i s o f i n t e r e s t t h a t c o m m u n i t y - b a s e d s t u d i e s a n ds t u d i e s among r a n d o m l y s e l e c t e d o p h t h a l m i c p a t i e n t sw i t h o u t o c u l a r d i s e a s e h a v e c o m m o n l y f a i l e d t od e m o n s t r a t e a s t r o n g a s s o c i a t i o n b e t w e e n r e f r a c t i v es t a t u s a n d h o r i z o n t a l c u p d i a m e t e r . T h i s i s t r u e o fs t u d i e s b y H o l l o w s a n d M c G u i n n e s s ( I 9 6 7 ) a n d b yS n y d a c k e r ( I 9 6 4 ) a s w e l l a s o u r o w n . I n t h e i r s e r i e so f r o u t i n e e x a m i n e e s w i t h o u t p a t h o l o g i c a l d i s c s ,F o r d a n d S a r w a r ( I 9 6 3 ) c l a s s i f i e d p h y s i o l o g i c a l



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A c q u i r e d c u p p i n g o f o p t i c n e r v e h e a d 2 2 I

c u p s a s a b s e n t o r s m a l l more c o m m o n l y i n h y p e r o p i ce y e s a n d a s l a r g e more c o m m o n l y i n m y o p i a w i t ha s t i g m a t i s m . A f u l l q u a n t i t a t i v e d e s c r i p t i o n o f t h i sd i f f e r e n c e was n o t g i v e n , h o w e v e r , a n d t h e s e i n v e s t i -g a t o r s d i d n o t i n c lu d e r e f r a c t i v e e r r o r i n t h e i r c o n -t l u d i n g d e s c r i p t i o n o f v a r i a b l e s a s s o c i a t e d w i t h c u ps i z e . T o m l i n s o n a n d P h i l l i p s ( I 9 6 9 ) , i n a c a r e f u lc o m p a r i s o n o f c u p m o r p h o l o g y w i t h a x i a l l e n g t h a n dr e f r a c t i v e e r r o r among a s a m p l e o f s t u d e n t s , f o u n d an e g a t i v e a s s o c i a t i o n b e t w e e n a r e a CDR a n d r e -f r a c t i v e e r r o r w h i c h w a s s i g n i f i c a n t a t t h e P


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2 2 2 B r i t i s h J o u r n a l o f O p h t h a l m o l o g y

i t w a s n o t p r e v i o u s l y o b s e r v e d t h a t " n o r m a l " c u p p i n g o c c u r r i n g i n a s s o c i a t i o n w i t h a g e , p r e s s u r e ,c u p p i n g o c c u r s w i t h a g e a p a r t f r o m t h e e f f e c t o f o r h i g h m y o p i a , a l o n e o r i n c o m b i n a t i o n , m e r i t sp r e s s u r e . T h e a v e r a g e e f f e c t o f a g e o n c u p / d i s c c o n s i d e r a t i o n i n t h e c l i n i c a l e v a l u a t i o n o f g l a u c o m ar a t i o , a m o u n t i n g t o a n i n c r e a s e o f o - o o 2 6 p e r y e a r s u s p e c t s a n d s e r v e s t o r e - e m p h a s i z e t h e i m p o r t a n c e o ff o r t h i s s a m p l e , i s s m a l l . B u t , a l l o w i n g f o r i n d i v i d u a l a n a d e q u a t e c e n t r a l v i s u a l f i e l d e x a m i n a t i o n i n t h ev a r i a t i o n , s o m e p e r s o n s c o u l d s h o w a r e c o g n i z a b l e d i a g n o s i s o f g l a u c o m a . S t u d i e s a r e n e e d e d o n t h ea c q u i r e d i n c r e a s e i n c u p / d i s c r a t i o w i t h a g e , e v e n i n d i f f e r e n t i a t i o n b e t w e e n " n o r m a l " a n d " m o r b i d "t h e a b s e n c e o f g l a u c o m a . T h e p o s s i b i l i t y o f " n o r m a l " m o u l d i n g o f t h e o p t i c n e r v e h e a d .R e f e r e n c e sA R M A L Y , M . F . ( I 9 6 7 ) A r c h . O p h t h a l . ( C h i c a g o ) , 7 8 , 3 5a n d s A Y E G H , R . E . ( I 9 6 9 ) I b i d . , 8 2 , 1 9 1C H A N D L E R , P . A . , a n d G R A N T , W . M . ( I 9 6 5 ) " L e c t u r e s o n G l a u c o m a " . L e a a n d F e b i g e r , P h i l a d e l p h i aC O L E N B R A N D E R , M . c . ( i g 6 0 ) O p h t h a l m o l o g i c a ( B a s e l ) , 1 3 9 , 4 9 IF O R D , M . , a n d S A R W A R , M . ( I 9 6 3 ) B r i t . J . O p h t h a l . , 4 7 , 5 0H O G A N , M . j . , a n d Z I M M E R M A N , L . E . ( i 9 6 2 ) " O p h t h a l m i c P a t h o l o g y . An A t l a s a n d T e x t b o o k " , 2 n d e d .S a u n d e r s , P h i l a d e l p h i aH O L L O W S , F . C . , a n d G R A H A M , P . A . ( I 9 6 6 a ) B r i t . J . O p h t h a l . , 5 0 , 5 7 0a n d ( I 9 6 6 b ) " G l a u c o m a " , e d . L . B . H u n t . L i v i n g s t o n e , E d i n b u r g h- a n d M C G U I N N E S S , R . ( I 9 6 7 ) T r a n s . o p h t h a l . S o c . A u s t . , I 9 6 6 , 2 5 , 3 8K O L K E R , A . E . , a n d H E T H E R 1 N G T O N , J . ( r e v i s e r s ) ( 1 9 7 0 ) " B e c k e r a n d S h a f f e r ' s D i a g n o s i s a n d T h e r a p y o ft h e G l a u c o m a s " , 3 r d e d . M o s b y , S t . L o u i sL E V E N E , R . Z . ( I 9 7 i ) A r c h . O p h t h a l . ( C h i c a g o ) , 8 5 , 2 2 7P I C K A R D , R . ( I 9 2 I ) P r o c . r o y . S o c . M e d . , 1 4 ( S e c t . O p h t h a l . ) , 3 I( 1 9 2 3 ) B r i t . J . O p h t h a l . , 7 , 8 I( I 9 3 I ) I b i d . , 1 5 , 3 2 3- - ( I 9 3 5 ) T r a n s . o p h t h a l . S o c . U . K . , 5 5 , 5 9 9-9 4 8 ) B r i t . J . O p h t h a l . , 3 2 , 3 5 5S C H W A R T Z , B . , R E I N S T E I N , N . M . , a n d L I E B E R M A N , D . M . ( 1 9 7 3 ) A r c h . O p h t h a l . ( C h i c a g o ) , 8 9 , 2 7 8S C H W A R T Z , J . T . " T h e i n f l u e n c e o f m e t h o d o l o g i c d i f f e r e n c e s o n m e a s u r e m e n t s o f c u p / d i s c r a t i o . Ane p i d e m i o l o g i c a s s e s s m e n t " . ( S u b m i t t e d f o r p u b l i c a t i o n ), R E U L I N G , F . H . , FEINLEIB, M . , GARRIS ON, R . j . , a n d COLLIE, D. J . ( 1 9 7 2 ) J . m e d . G e n e t . , 9 , 1 3 7--, - - , - , a n d - ( I 9 7 3 a ) A m e r . J . O p h t h a l . , 7 6 , I 2 6a n d ( I 9 7 3 b ) A r c h . O p h t h a l . ( C h i c a g o ) , g o , 2 8 IS N Y D A C K E R , D . ( I 9 6 4 ) A m e r . j . O p h t h a l . , 5 8 , 9 5 8T O M L I N S O N , A . , a n d P H I L L I P S , C . I . ( I 9 6 9 ) B r i t . J . O p h t h a l . , 5 3 , 7 6 5



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doi: 10.1136/bjo.59.4.2161975 59: 216-222Br J Ophthalmol

J. T. Schwartz, F. H. Reuling and R. J. Garrisonnerve head in normotensive eyes.Acquired cupping of the optic

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