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CLASSIFICATION OF SQUINT

CLASSIFICATION OF SQUINT 

SQUINT- DEFINITION

•        Squint or strabismus can be defined as the condition in which the visual axis of the two eyes are not both directed towards the fixation point.

•       “strabismus” is word derived from the Greek word ‘STRABOS’ meaning ‘CROOKED’

 

CLASSIFICATION OF SQUINT BASED ON…

  •  FUSIONAL STATUS
  •  COMITANCY
  •  FREQUENCY
  •  FIXATION
  •  LATERALITY
  •  AGE OF ONSET
  •  ESOTROPIA

 

ACCORDING TO FUSIONAL STATUS
  

  A.HETEROPHORIA.

 B.HETEROTROPIA.

 

A.HETEROPHORIA

   It is the condition of latent squint in which the deviation of visual axis is present on dissociation of the eyes.

 ACCORDING TO THE DIRETION OF DEVIATION…

    a) ESOPHORIA

    b) EXOPHORIA

    c) HYPERPHORIA

    d) HYPOPHORIA

    e) CYCLOPHORIA

                  i) INCYCLOPHORIA

                  ii) EXCYCLOPHORIA

    

      f) ANISOPHORIA

a) ESOPHORIA (latent convergent squint)

   It is the tendency of one eye to turn in relative to the other eye.

b) EXOPHORIA (latent divergent squint)

   It is the tendency of one eye to turn out relative to the other eye.

c) HYPERPHORIA (latent sursumvergent squint)

    It is the tendency for one eye to turn up relative to the other

d) HYPOPHORIA (latent deorsumvergent squint)

    It is the tendency for one eye to turn down relative to the other eye.

e) CYCLOPHORIA (Latent torsional squint)

   It is the tendency for one eye to wheel rotate relative to the other eye.

i) INCYCLOPHORIA (Conclination squint)

   when the 12 o’ clock meridian of the cornea of the affected eye tends to lean to the nasal or medial side.

ii) EXCYCLOPHORIA (Declination squint)

   When the 12 o’ clock meridian of the cornea of the affected eye tends to lean to the temporal or lateral side.

    f) ANISOPHORIA

   It is a significant difference in the angle of deviation when fixation is changed from one eye to the other eye.

•       B.HETEROTROPIA

   Heterotropia is a condition of manifest squint, although this may not be present in all direction of gaze in certain cases.

 

•       According to the direction of deviation:

    a) ESOTROPIA

    b) EXOTROPIA

    b) HYPERTROPIA

    c) HYPOTROPIA

    d) CYCLOTROPIA

                  i) INCYCLOTROPIA

                  ii) EXCYCLOTROPIA

•       According to the direction of deviation:

e) CYCLOTROPIA (Manifest torsional strabismus)

    It is the wheel rotation of one eye relative to the other eye.

i) INCYCLOTROPIA (Intorsional strabismus)

    When the 12 o’ clock meridian of the cornea of the affected eye leans to the nasal or medial side.

ii) EXCYCLOTROPIA (Extorsional strabismus)

    When the 12 o’ clock meridian of the cornea leans to       the temporal or lateral side.

   

ACCORDING TO COMITANCY

·         Comitant or Concomitant squint/Non paralytic squint

·         Incomitant or Non Comitant/Paralytic Squint

 

ACCORDING TO FREQUENCY

A) Constant Squint

   

B) Periodic Strabismus

C) Intermittent Strabismus

  

ACCORDING TO FIXTATION

A) Uniocular Strabismus

B) Alternating Strabismus

 

ACCORDING TO LATERALITY

A) Unilateral Squint

B) Bilateral Squint

        

ACCORDING TO AGE OF ONSET

     A) Congenital

     B) Acquired

 

ACCORDING TO ESOTROPIA

ACCOMMODATIVE ESOTROPIA

·         It is also called an accommodative convergent squint.

·         The convergent deviation is present only during the exercise of accommodation.

NON-ACCOMMODATIVE ESOTROPIA:

Here the convergent squint is manifest even in the absence of any accommodative efforts. In most of the convergent squint, the deviation increases on the exercise of accommodation.

 

PSEUDO STRABISMUS OR APPARENT SQUINT

  This is the term applied to a false appearance of squint in the absence of any deviation & it may occur under different.

PSEUDO CONVERGENT SQUINT

     e.g.  Small IPD, Facial asymmetry, Enopthalmos

     

 PSEUDO DIVERGENT SQUINT 

        e.g. Patient with wide IPD, Exophthalmos, Narrowing of the lateral canthus

 PSEUDO VERTICAL SQUINT

       e.g. patient with Facial asymmetry, ptosis, Lid retraction

 

FLEETING SQUINT

•       This is the type of squint that may occur in babies during the first few months of life before the establishment of normal binocular reflexes.

 

PURPOSIVE SQUINT

•       This is the term applied to convergent squint which may be produced voluntarily in a person with normal binocular function.

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