Strabismus is defined as a misalignment of the eyes.
Strabismus also called as squint.
Orthophoria – Implies as perfect ocular alignment
without efforts.
Strabismus consists of two subgroups. 1.Hetrotropia – this is a manifest squint.
Esotropia – deviation of eye towards inside.
Exotropia -- deviation of eye towards towards
outside.
Hypertropia-- deviation of eye towards
upside. 2.Hetrophoria—this is a latent ocular
deviation. Eye alignment is maintained with fusional
effort.
Esophoria – inward deviation of eye when fusion is
disrupted.
Exophoria-- outward deviation of eye when fusion is
disrupted.
Hyperphoria-- upward deviation of eye when fusion is
disrupted.
Incyclophoria-- Intortional movement of eye when
fusion is disrupted.
Excyclophoria-- Extortional movement of eye when
fusion is disrupted.
Exotrpoia With
V Patterns
If exotropia is atleast 15 prism
diopter more in up gaze (
25 degree up) than the down gaze
(35 degree) then it called as V
pattern exotropia.(Fig1,2,3)
Causes of V-pattern strabismus
Inferior oblique muscle
overaction
Relative underaction of the
superior oblique muscles
Hypoplasia of the
malar bones
Anti-Mongoloid lid slants
S-shaped contours of the
lower lid
Fig 1.Very
large exotropia
in up gaze ( Pic. Curtsey Dr Sudhir Singh)
Fig 2.Less
exotropia
in primary gaze ( Pic. Curtsey Dr Sudhir Singh)
Fig 3 Exotropia
in down gaze ( Pic. Curtsey Dr Sudhir Singh)
Management
Of V-Pattern strabismusSurgical treatment of
Exotropia with V-pattern
strabismus with oblique muscle
overaction
Lateral rectus muscle
recessions with inferior
oblique muscle weakening
Lateral rectus muscle
recession with Medial rectus
resection with inferior
oblique muscle weakening
Surgical treatment of
Exotropia with V-pattern
strabismus without oblique
muscle overaction
Exotropia with V-pattern -
Bilateral lateral rectus
muscle recessions with
upshift
Or
Exotropia with V-pattern -
lateral rectus muscle
recessions with upshift +
medial rectus muscle
resections with downshift
Or
Exotropia with V-pattern -
Bilateral medial rectus
muscle resections with
downshift
Surgical
treatment of Esotropia with
V-pattern strabismus with oblique
muscle overaction
Medial rectus muscle
recessions with inferior oblique
muscle weakening
Medial rectus muscle
recession with lateral rectus
resection with inferior oblique
muscle weakening
Surgical
treatment of Esotropia with
V-pattern strabismus without oblique
muscle overaction
Bilateral medial
rectus muscle recessions with
downshift
Or
Bilateral lateral
rectus muscle resections with
upshift
Or
Medial rectus
muscle recessions with down
shift + lateral rectus muscle
resections with upshift
