RT Book, Section
A1 Motley, W. Walker
A2 Riordan-Eva, Paul
A2 Augsburger, James J.
SR Print(0)
ID 1144468906
T1 Strabismus
T2 Vaughan & Asbury's General Ophthalmology, 19e
YR 2017
FD 2017
PB McGraw-Hill Education
PP New York, NY
SN 9780071843539
LK accessmedicine.mhmedical.com/content.aspx?aid=1144468906
RD 2020/03/31
AB Under  normal  binocular  viewing  conditions,  the  image  of  the  object  of  regard  falls  simultaneously  on  the  fovea  of  each  eye  (bifoveal  fixation),  and  the  vertical  retinal  meridians  are  both  upright.  Strabismus  is  any  ocular  misalignment  in  which  only  one  eye  fixates  with  the  fovea  on  the  object  of  regard.  (In  everyday  language,  squint  means  partial  closure  of  the  eye  to  see  more  clearly,  but  sometimes  it  is  used  to  mean  strabismus.)  Misalignment  of  the  eyes  may  be  in  any  direction—inward  (eso-),  outward  (exo-),  up  (hyper-),  down  (hypo-),  or  torsional.  The  amount  of  deviation  is  the  angle  by  which  the  deviating  eye  is  misaligned.  Tropia  (manifest  strabismus,  heterotropia;  Box  12–1)  is  strabismus  present  under  binocular  viewing  conditions.  Phoria  (latent  strabismus,  heterophoria)  is  a  deviation  present  only  after  binocular  vision  has  been  interrupted  by  occlusion  of  one  eye.