PO CKET O p h t h a l m ic Dic tion a ry INCLUDING Pronun ciation , Derivation an d De fin itio n O F THE W O RDS USED IN O ptometry a n d O phthalmology T ogeth er wi th a comp l ete d escrip h h a v h eo tion of t e lig t w e t ry , n a t m f h E f un ct on s . A o y o t e ye, i bl ood a n d n erve s up p l y of th e d if f er n a r s e n os co e G h e t p t , R ti p , p th l mos o e r a a s e a n d h ow a c p , T i l C h em u s T ra n s os i s . e t o u e t . R l , p n or a n d o h e n ses . t io , T i c t r l e a r s t on s S ta te b o d q ue i . B I h D LEW S O . AMES . y J J , p Profes s or of O p t ometry in th e North e rn Illi n ois Col h h a o h ca o of t mo o a n d tol C . lege O p l l gy 0 gy , i g FI FTH EDITIO N Revi s e d a n d Enl arge d Ill us tra ted C t 1 08 1 10 1 1 1 1 6 LEW S opyri gh , 9 , 9 , 9 3 , 9 , J. I . I To the P ro fe s s io n i This e ditio n ha s be e n c o m p il e d w ith a g re a t de a o f ca re Re a lizin a t e l . g th p rfe c tio n in its full s e n s e ha s n e v e r be e n a tta in e d b m o ta a y r l m n , the a u th o r in v ite s the u n bia s e d a n d c o n s c ie n tio u s c ritic is m o f th e re a de rs a n d us e rs o f this Dic tion a ry a n d he re by e a rn e s tly s o lic its the s a m e t o th e e n d tha t th e fu ture e ditio n s ma y p ro fit by the h o n e s t c o n vic tio n s o f s tu dio u o c uli ts h i s s , p y s c ia n s a n d O t t p o m e tris s . I c a n n o t c o n c lude w ith o u t e x p re s s in g m y de e p s e n s e o f o bliga tio n t o th e p ro fe s s io n fo r th e ir kin d n w o e t s re c e p tio o f this rk . F e lin g he re p o n s ibility d o s e h tte t o te h o the rs in c u rre by th w o a m p t a c , I h a v e s p a re d n o a m o u n t o f lab o r o r c o s t t o re n de r i v o l m e e a r r tic a a n s e fu th s u c l , p a c l d u l . e e tfu V ry re s p c lly , ‘ THE AUTHO R . P R E F A C E \ . l T O T H E F I F T H E D ITIO N H E very favorable reception accorded the fourth edition of this work has encoura ged the author to still further revise it , incorporating in its pages a considerable number of new d efin i tions , as well as giving an accurate and complete derivation of all the technical terms used in of O ptical nomenclature , making the book the highest value to the practitioner and student al ike . In presen ting this fifth edition of the L ewi s D ictionary and E ncyclopedia , I wish to express my appreciation for the invaluable assistance extended by Mc F A I H M M J B . TR . D . C , S ‘ P ro f e s s o r of t h e P rin cip l es o f O p h th a lm o l o g y a n d O to o g v. LB A H M M F T R I D . GE O . WI UR C C , . , P ro f e s s o r o f C l in ic a l a n d D id a c tic O p h th a lm ol o g y a n d o o O t l g y . M Y E M . H E N R S . T U C K R , A . , . D ‘ P ro f e s s o r o f A n a tom y a n d P h y s iol o g y o f t h e E y e u nr ra in B . E E . B R DG M . G TR O W I , . D , ro o D io ri P f es s r of p t c s . J . J . L . Abbreviation s an d O p tical Sign s Accommodation . Age . Ametropia . Anisometropia . Astigmatism . Asth Asthenopia . Axi s . Co. or ( minus ) Concave . Centigrade . Centimeter . Cx . or ( plus ) Convex . Cyl Cylinder . D ioptry . U . Cc D ouble concave . U . Cx D ouble convex . U T . D istance test . H r E m . o E mmetropia . D {. g . F or example . H . or H y H ypermetropia . In Inches . L L . E L . or eft eye. M M M . or y yopia . M illimeter . N asal . Nv Naked vision . D D t R 0 . ( O culus ex er ) ight eye . L S . 0 . S . ( O culus inister ) eft eye . n ti O . U . ( O cul i U a ) Both eyes . P . or P b P resbyopia . P . Cc P eriscopic concave . P . Cx P eriscopic convex . i n — n Abbreviation s an d O ptical S g s Co . - Inter P upillary di stance . P l P lano . P p . p . ( unctum mum P rox i ) Near point . P p . r . ( unctum R m tum F r e o ) a point . P rism . R R E R . or . ight eye . R eading test . P rescription . S trabismus . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 S pherical . Temporal . Type . V ision . Visual acuteness . Working point . P lus convex . M inus concave . Combined with . Degree . P D rism ioptry . E qual to . t 2 0 . Infini y , ft or farther . ' L 1 2 th ine , part of inch . P lus or ( and ) minus . Centrad . M ultiplied by ; times . D ivided by . Is ( or are ) greater than . [S (or are ) less than . Lewis O phthalmic Diction ary Gr . A. ( alpha , privative ) A prefix conveying a f . negative m eaning ; a s w ithout , away , not , rom ’ x - - - A ba i a l ( a b aks e a l ) . Not situated in the line of the axis . e P E r ‘ A bb , rof . ns t . A German professor and in ven tor of an apparatus for measuring the ih f 4 - d ices of re raction . 1 8 5 1 905 . ' b n a - - L A du ce s ( b du senz ) . ( . ab . from d ucere to draw . ) The external rectus muscle , whose e action it is to rotate the eye outward . It aris s by two heads , one from the lower margin of the sphenoidal fi ssure ; the other from the outer ' margin of the optic foramen . Its tendon is ih s rt d e e into the sclera 8 m m . from the outer margin of th ecornea . Under normal condition s these muscles should overcome about 8 degrees \ , of prism a s e in . It i s controlled hy the sixth , b pair of cranial nerves ( abducens ) . ’ - - n A bdu c ent ( a b du sent ) . Ad Cti g ; drawing from the center . = d cere t . A bdu ct ( ab away , u o lead ) To draw away from the m edian line . ’ - - A bd uct ion ( a h duc shun ) . The act of turning the eye outward from its position of rest . F or test ing the power of the abductors or external rec ti t muscles , use the strongest prism , base in , wi h which th e eyes can overcome diplopia , looking 2 . 0 f eet away , and deduct any imbalance 8 L E W ’ IS P O C KE T ’ - -t b d c t or ah or .