I N D U C E D P R I S M AT I C E F F E C T S D U E TO P O O R LY F I T T E D S P E C TA C L E Optom. ANJALI AHUJA¹, Optom. USMAN MEMON²

NAGAR SCHOOL OF OPTOMETRY¹²

0 1 I N T R O D U C T I O N

L o o k i n g a t t h e c u r r e n t s c e n a r i o o f m a r ke t t h e n o r m s

f o r m i n i m u m s t a n d a r d s f o r o p t i c a l d i s p e n s i n g p ra c -

t i c e a r e n o t b e i n g f o l l o w e d , t h e r e f o r e c u r r e n t s t u d y

w a s u n d e r t a ke n , t o u n d e r s t a n d t h e i m p o r t a n c e o f

f i t t i n g a s p e c t s o f s p e c t a c l e s w i t h r e s p e c t t o t h e i n -

t e r p u p i l l a r y d i s t a n c e , i n s p e c t a c l e w e a r e r s w i t h n o

c o m p l a i n t s .

0 2 A I M S A N D O B J E C T I V E S

To s t u d y t h e p r e v a l e n c e a n d u n d e r s t a n d t h e a s s o c i a t e d p r i s m a t i c e f f e c t s o f

p o o r l y f i t t e d s p e c t a c l e i n a s y m p t o m a t i c w e a r e r s .

To d e t e r m i n e t h e p e r c e n t a g e o f i n d u c e d h o r i z o n t a l a n d v e r t i c a l p r i s m a t i c e f f e c t s

a c c o r d i n g t o A N S I t o l e ra n c e Z 8 0 . 1 - 2 0 1 0 i n s i n g l e v i s i o n s p e c t a c l e w e a r e r s , w h o

w e r e u s i n g d e c e n t e r e d l e n s e s .

0 3 M E T H O D O LO G Y

Fo l l o w i n g s t e p w i s e p r o c e d u r e wa s f o l l o w e d f o r e a c h a n d e v e r y i n d i v i d ua l : - T h e I n t e r p u p i l l a r y d i s t a n c e w a s m e a s u r e d w i t h t h e h e l p o f P u p i l l o m e t e r

O p t i c a l c e n t e r s w e r e m a r k e d w i t h b l a c k m a r k e r a n d p o w e r w a s m e a s u r e d u s i n g L e n s o m e t e r

T h e c o - r e l a t i o n b e t w e e n f r a m e c e n t r a t i o n w i t h r e s p e c t t o P D w a s t a k e n i n t o c o n s i d e r a t i o n

T h e d i s t a n c e b e t w e e n f r a m e m a r k i n g s w e r e m e a s u r e d t o d e t e r m i n e t h e c e n t r a t i o n d i s t a n c e & w e r e

c o m p a r e d t o d i s t a n c e P D

O b l i q u e c y l i n d e r s w e r e r e s o l v e d i n t o h o r i z o n t a l a n d v e r t i c a l c o m p o n e n t s

A n y p r i s m a t i c e f f e c t p r e s e n t w e r e t h e r e a f t e r c a l c u l a t e d u s i n g P r e n t i c e ’ s r u l e & r e c o r d e d

1 . A t e x t b o o k o f O p t i c s S . C H A N D , N . S U B R A M A N Y A M B R I J L A L , M . N . A V A B H A N U L U . C h a p t e r 4 ( P a g e N o . 7 2 ) . w w w . p r e n t i c e i m a g e . c o m

2 . C l i n i c a l O p t i c s , S e c o n d E d i t i o n , T r o y E F e n n i n , O . D . T h e o d o r e G r o s v e n o r , O . D . C h a p t e r 4 ( P a g e N o . 8 5 , 8 6 , 9 5 , 9 6 , 9 7 , 9 8 ) .

3 . S y s t e m f o r O p h t h a l m i c d i s p e n s i n g , S e c o n d E d i t i o n , C l i f f o r d W . B r o o k , O . D . I r v i n M . B o r i s h , C h a p t e r 3 , 5 , 1 5 , 1 6 , 1 8 ( P a g e N o 2 6 , 2 7 , 4 2 5 , 4 2 7 , 4 3 4 ) .

4 . T e a c h e r s E y e C a r e . P r o p e r C a r e o f Y o u r S p e c t a c l e s .

5 . A v a i l a b l e f r o m : h t t p s : / / w w w . t e a c h e r s e y e c a r e . c o m . a u / n b s p n b s p p r o d u c t / P r o p e r C a r e o f y o u r s p e c t a c l e / t a b i d / 6 2 / D e f a u l t . a s p x ( A c c e s s e d o n t h e 0 2 / 0 9 / 2 0 1 0 ) .

6 . B r o o k s C W , B o r i s h I M . S y s t e m f o r O p h t h a l m i c d i s p e n s i n g . N e w Y o r k : P r o f e s s i o n a l P r e s s , 1 9 7 9 p p 2 7 - 6 5 .

7 . V R M o o d l e y , F K a d w a , B N x u m a l o , S P e n c e l i a h , B R a m k a l a m , A Z a m a . I n d u c e d p r i s m a t i c e f f e c t d u e t o p o o r l y f i t t i n g s p e c t a c l e f r a m e s .

8 . S A i r O p t o m 2 0 1 1 7 0 ( 4 ) 1 6 8 - 1 7 4 . I S S N 0 3 7 8 - 9 4 1 1 .

9 . F o w l e r C , L a t h a m P e t r e K . S p e c t a c l e l e n s e s : T h e o r y a n d p r a c t i c e . B u t t e r w o r t h - H e i n e m a n n O x f o r d 2 0 0 1 p p 3 7 - 5 1 .

1 0 . O s u o b e n i E P , A l - F a h d i M . D i f f e r e n c e s b e t w e e n a n a t o m i c a l a n d p h y s i o l o g i c a l i n t e r p u p i l l a r y d i s t a n c e . J A m O p t o m A s - s o c 1 9 9 4 6 5 2 6 5 - 7 1 .

1 1 . G r i f f i n J R , G r i s h a m J D , B i n o c u l a r a n o m a l i e s d i a g n o s i s a n d v i s i o n t h e r a p y , 4 t h e d . B u t t e r w o r t h H e i n e m a n n 2 0 0 2 ( P a g e n o 9 2 . ) .

1 2 . F e r n a n d e z - R u i z J . , D i a z R . P r i s m a d a p t a t i o n a n d a f t e r e f f e c t : s p e c i f y i n g t h e p r o p e r t i e s o f a p r o c e d u r a l m e m o r y s y s t e m . L e a r n M e m 1 9 9 9 6 ( 1 ) ( p g s . 4 7 - 5 3 ) .

1 3 . H e n s o n D B , N o r t h R . A d a p t a t i o n t o p r i s m i n d u c e d h e t e r o p h o r i a . A m J O p t o m P h y s i o l O p t 1 9 8 0 5 7 1 2 7 - 1 3 7 .

1 4 . D u T o i t R , R a m k e J , B r i a n G . T o l e r a n c e t o p r i s m i n d u c e d b y r e a d y m a d e s p e c t a c l e s : s e t t i n g a n d u s i n g s t a n d a r d . A m J O p t o m 2 0 0 7 8 4 ( 1 1 ) 1 0 5 3 - 9 .

1 5 . T o p l i s s W S . O p t i c a l d i s p e n s i n g a n d w o r k s h o p p r a c t i c e . B u t t e r w o r t h L o n d o n , 1 9 7 5 p p 4 2 - 5 9 . 1 6 . J a l i e M . T h e p r i n c i p l e s o f o p h t h a l m i c l e n s e s . 4 t h e d . T h e A s s o c i a t i o n o f B r i t i s h D i s p e n s i n g O p t i c i a n s L o n d o n 1 9 9 2 .

T h o u g h a l l t h e a s y m p t o m a t i c s u b j e c t s w e r e n o t l o o k i n g t h r o u g h t h e o p t i c a l c e n t e r o f t h e i r s p e c t a c l e s a r e

b e n e f i t t e d d u e t o p r o b a b l e p r i s m a d a p t a t i o n i n l o w e r p r e s c r i p t i o n s .

A s c u r r e n t s c e n a r i o d e m a n d s m o r e o f n e a r a n d i n t e r m e d i a t e w o r k p r o f i l e f o r l o n g e r d u ra t i o n , i t i s o f u t -

m o s t i m p o r t a n c e t h a t p u p i l l a r y d i s t a n c e s h o u l d c o i n c i d e w i t h o p t i c a l c e n t e r s o f t h e s p e c t a c l e i n c a s e o f

e v e r y i n d i v i d u a l s f o r z e r o o r l e a s t p r i s m a t i c e f f e c t . But if some prismatic effect still persist, it can be adapted.

INCLUSION CRITERIA

EXCLUSION CRITERIA

Asymptomatic single vision spectacle wearers

Bifocal wearers

Multifocal wearers

Strabismic Individuals

•As per ANSI tolerance, study subjects were divided in 2 groups :-

For power ≤ ±2.75D in

horizontal meridian

For power ≥ ±2.75 D In

horizontal meridian

Unwanted horizontal prism for both

eyes combined shall not be greater

than 0.67 ∆.

Horizontal difference from ordered

PD and Actual PD measured, dis-

tance between the PRP shall not be

greater than 2.5mm.

For power ≤±3.375D in

vertical meridian

For power ≥ ±3.375 D in

vertical meridian

Unwanted vertical imbalance shall not exceed 0.33 ∆.

Vertical difference between the PRP shall not be greater than 1mm.

S T U DY F I N D I N G S : -

Out of 100, there were 58 female subjects.

Horizontal Prismatic effect for lenses of power ≤ ±2.75D was effec-

tive in right eye of 47% subjects with effect of 1.31 ±0.91∆D left

eye of 43% subjects were with effect of 1.27 ±0.90∆D.

Horizontal Prismatic effect for lenses of power ≥ ±2.75D was effec-

tive in 17% with effect of 3.28 ±1.78∆D in right eye and 25% with

effect of 3.52 ±1.44∆D in left eye in the horizontal meridian .

Vertical Prismatic effect was effective in right eye of 30% subjects

with effect of 0.20 ±0.47∆D and in left eye of 34% subjects noticed

the prismatic effect of 0.24 ±0.51∆D for lenses of power ≤ ±3.375∆D.

And for lenses of power ≥ ±3.375∆D, in right eye 13% noticed

vertical differences between PRP was greater than 1 mm with

1.72 ±1.47∆D in vertical meridian and in left eye, 14% subjects

noticed vertical differences between PRP was greater than 1 mm

with 1.85 ±1.69∆D in vertical meridian.

0 6 R E F E R E N C E S

0 4 R E S U LT S

0 5 D I S C U S S I O N

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