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Classification of Squint
7/10/2013
1
Fakhruddin Aliasger
Squint
• Squint is a condition not disease in which two
visual axes are not directed towards the fixatory
object or fixati...
Heterophoria
• Heterophoria is a condition of latent squint in
which the deviation of the visual axes is present
on dissoc...
7/10/2013
4
Fakhruddin Aliasger
-
• Esophoria or latent convergent squint
• A tendency of one eye to turn in relative to other
• Exophoria or latent diver...
• Cyclophoria or latent torsional squint
• A tendency of one eye to wheel rotate relative to
other
• Incyclophoria
• When ...
Heterotropia
• Heterotropia is a condition of manifest squint,
which may not be present in all direction of gaze
in certai...
1. Classification according to direction
of the deviation
• Esotropia or manifest convergent
strabismus
• A turning in of ...
• Hypotropia or manifest deorsumvergent
strabismus
• A turning down of one eye relative to other eye
• Cyclotropia or mani...
• Excyclotropia
• When the 12’o clock meridian of the cornea leans
to the temporal side or lateral side
• It should be not...
Classification based on comitancy
• Comitant or Concomitant squint
• A comitant squint is one in which the eye moves
in co...
• Complete comitancy is rare
• It is common for the angle of a squint to vary
according to the direction of gaze, particul...
• If the alteration in the extent of the deviation is
large this may be described as the V –
phenomenon
7/10/2013Fakhruddi...
• If the convergent deviation found to increase on
looking up and decrease on looking down
• If the divergent deviation fo...
A - ESO A - EXO
7/10/2013
15
Fakhruddin Aliasger
Incomitant or Noncomitant squint
• A non comitant or incomitant squint is one in
which the eyes move in an in-coordinated
...
• Incomitant squint is due to presence of a paresis
(partial failure of action) or of a paralysis (total
failure of action...
Classification based on duration
• This classification is based on whether
heterotropia is constant or only occurs in cert...
• 2. Intermittent strabismus
• An intermittent strabismus is sometimes present
and sometimes absent in the same condition ...
Classification based on laterality
• Unilateral/ Uniocular
• A uniocular strabismus is one in which the
squinting eye is a...
Classification based on
Accommodation
• Accommodative Squint
• Deviation induced by influence of
accommodation. E.g. Accom...
Fleeting Squint
• This occurs in babies during the first few months
of life before the establishment of normal
binocular r...
Purposive Squint
• This is the term applied to a convergent squint
which may be produced voluntarily in persons
with norma...
Pseudo strabismus
• This the term applied to a false appearance of
squint in the absence of any deviation and it may
occur...
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Classification of squint

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Classification of squint

  1. 1. Classification of Squint 7/10/2013 1 Fakhruddin Aliasger
  2. 2. Squint • Squint is a condition not disease in which two visual axes are not directed towards the fixatory object or fixation target • Squint may be further divided into two categories • 1. Heterophoria • 2. Heterotropia 7/10/2013 2 Fakhruddin Aliasger
  3. 3. Heterophoria • Heterophoria is a condition of latent squint in which the deviation of the visual axes is present on dissociation of the two eye, but is absent on removal of dissociating factor • Heterophoria is classified according to the direction of deviation 7/10/2013 3 Fakhruddin Aliasger
  4. 4. 7/10/2013 4 Fakhruddin Aliasger
  5. 5. - • Esophoria or latent convergent squint • A tendency of one eye to turn in relative to other • Exophoria or latent divergent squint • A tendency of one eye to turn out relative to other • Hyperphoria or latent sursumvergent strabismus • A tendency for one eye to turn up relative to the other 7/10/2013 5 Fakhruddin Aliasger
  6. 6. • Cyclophoria or latent torsional squint • A tendency of one eye to wheel rotate relative to other • Incyclophoria • When the 12’o clock meridian of the cornea of the affected eye tends to lean toward the nasal side or medial side • Excyclophoria • When the 12’o clock meridian of the cornea of the affected eye tends to lean toward the temporal side or lateral side 7/10/2013 6 Fakhruddin Aliasger
  7. 7. Heterotropia • Heterotropia is a condition of manifest squint, which may not be present in all direction of gaze in certain cases • Heterotropia may be classified in several different ways 7/10/2013Fakhruddin Aliasger 7
  8. 8. 1. Classification according to direction of the deviation • Esotropia or manifest convergent strabismus • A turning in of one eye relative to the other eye • Exotropia or manifest divergent strabismus • A turning out of one eye relative to the other • Hypertropia or manifest sursumvergent strabismus • A turning up of one eye relative to other 7/10/2013Fakhruddin Aliasger 8
  9. 9. • Hypotropia or manifest deorsumvergent strabismus • A turning down of one eye relative to other eye • Cyclotropia or manifest torsional strabismus • A wheel rotation of one eye relative to other • Incyclotropia • When the 12’o clock meridian of the cornea of the affected eye leans to the nasal or medial side 7/10/2013Fakhruddin Aliasger 9
  10. 10. • Excyclotropia • When the 12’o clock meridian of the cornea leans to the temporal side or lateral side • It should be noted that vertical and torsional deviation rarely occur as isolated phenomena • A vertical deviation is usually associated with horizontal deviation • A torsional deviation is usually associated with vertical deviation 7/10/2013Fakhruddin Aliasger 10
  11. 11. Classification based on comitancy • Comitant or Concomitant squint • A comitant squint is one in which the eye moves in completely co-ordinated manner • Angle of deviation which is present in primary gaze is maintained to an equal extent in all direction of gaze • Angle of deviation is equal in all distances of fixation • Angle of deviation is equal on fixation with either eye 7/10/2013Fakhruddin Aliasger 11
  12. 12. • Complete comitancy is rare • It is common for the angle of a squint to vary according to the direction of gaze, particularly on vertical movements • A convergent deviation usually decrease on looking up and increases on looking down • A divergent deviation usually increases on looking up and decreases on looking down 7/10/2013Fakhruddin Aliasger 12
  13. 13. • If the alteration in the extent of the deviation is large this may be described as the V – phenomenon 7/10/2013Fakhruddin Aliasger 13
  14. 14. • If the convergent deviation found to increase on looking up and decrease on looking down • If the divergent deviation found to increase on looking down and increase on looking up then the alteration of deviation is termed as A - phenomenon 7/10/2013Fakhruddin Aliasger 14
  15. 15. A - ESO A - EXO 7/10/2013 15 Fakhruddin Aliasger
  16. 16. Incomitant or Noncomitant squint • A non comitant or incomitant squint is one in which the eyes move in an in-coordinated manner so that • 1. The angle of deviation varies in different direction of gaze • 2. Angle of deviation varies on changing fixation from one eye to another • 3. Angle of deviation varies in either eye 7/10/2013Fakhruddin Aliasger 16
  17. 17. • Incomitant squint is due to presence of a paresis (partial failure of action) or of a paralysis (total failure of action) of one or more extra ocular muscles 7/10/2013Fakhruddin Aliasger 17
  18. 18. Classification based on duration • This classification is based on whether heterotropia is constant or only occurs in certain circumstances or at certain times • 1. Constant strabismus • A constant strabismus is one in which there is a constant deviation of the visual axes in all directions of gaze in all distances of fixation and irrespective of which eye is used for fixation 7/10/2013Fakhruddin Aliasger 18
  19. 19. • 2. Intermittent strabismus • An intermittent strabismus is sometimes present and sometimes absent in the same condition of vision e.g. accommodative convergent squint • 3. Periodic strabismus • A periodic strabismus is one in which the deviation occurs only in certain circumstances or after regular interval 7/10/2013Fakhruddin Aliasger 19
  20. 20. Classification based on laterality • Unilateral/ Uniocular • A uniocular strabismus is one in which the squinting eye is always the same except under conditions of testing which force the squinting eye to take up fixation • Bilateral/ Alternating • An alternating strabismus is one in which the deviation may occur in either eye and in which there is no obvious preference for one eye to remain fixing eye 7/10/2013Fakhruddin Aliasger 20
  21. 21. Classification based on Accommodation • Accommodative Squint • Deviation induced by influence of accommodation. E.g. Accommodative convergent squint • Non – Accommodative Squint • Deviation present in the absence of accommodation effort • The deviation increases on the exercise of accommodation 7/10/2013Fakhruddin Aliasger 21
  22. 22. Fleeting Squint • This occurs in babies during the first few months of life before the establishment of normal binocular reflexes • Such a squint is usually momentary occurring usually when the baby is upset 7/10/2013Fakhruddin Aliasger 22
  23. 23. Purposive Squint • This is the term applied to a convergent squint which may be produced voluntarily in persons with normal binocular function 7/10/2013Fakhruddin Aliasger 23
  24. 24. Pseudo strabismus • This the term applied to a false appearance of squint in the absence of any deviation and it may occur under different condition • Visual axes are aligned toward fixation object • Any abnormality to lids, canthii or orbit may lead to pseudo strabismus 7/10/2013Fakhruddin Aliasger 24

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