Strabismus

Strabismus

DR. USAMA JIHAD ABDUL QADER
*Squint
*Crossed Eyes

Definition:

*Misalignment of the eyes.
- heterophoria.
- heterotropia.
- eso/exo deviation.
- hypo/hyper deviation.
- monocular/ alternate.

BINOCULAR SINGLE VISION:

- Corresponding retinal elements.
- Horopter.
- Panums fusional area.
*Adaptation to strabismus:
- sensory.
- motor.


Points that will be discussed in the lecture
Anatomy
Why we treat
Examination
ET
XT
Syndromes

Anatomy Of The EOM’s in details with their actions

Six Extra ocular muscles surround each eye:
Medial Rectus

Lateral Rectus

Superior Rectus
Inferior Rectus
Superior Oblique
Inferior Oblique
The two Obliques are Abductors
The two Recti are Adductors
The two Superiors are Intorters
The two Inferiors are Extorters

Origin

A common tendinous ring (annulus of Zinn)


Insertion

Blood supply

Each muscle is supplied by two Anterior Ciliary
Arteries except the Lateral Rectus which is only
supplied by one.

Nerve supply

Third: MR, IR, SR, IO
Fourth: Superior Oblique
Sixth: Lateral Rectus
Why We Treat
1- Restore Stereopsis
2- Prevent Amblyopia
3- Prevent Confusion and Diplopia
4- Appearance
1- Restore Stereopsis
Three dimensional vision.
2- Amblyopia
Amblyopia is the unilateral or bilateral decrease of Vision caused by form vision deprivation and/or abnormal binocular interaction for which there is no obvious cause found by physical examination of the eye.
3- Confusion and Diplopia
DEFINITIONS
1. Visual axis is a line that passes through the point of fixation and the fovea. The normal visual axes intersect at the point of fixation.
2. Strabismus is a malalignment of the visual axes which, initially, results in confusion and diplopia.
3. Confusion is the simultaneous appreciation of two superimposed but dissimilar images caused by stimulation of corresponding points (usually foveae) by images of different objects.
4. Diplopia is the simultaneous appreciation of two images of one object. Jt results from a failure to maintain binocular vision.

4- Appearance

Anatomy
Why we treat
Examination- ophthalmoscope
Esotropia
Exotropia
Syndromes

Cover – Uncover test

Orthophoria, normal
No complaints, asymptomatic

Cover – Uncover test

Esophoria, abnormal, common
Only seen when eye is covered
Often asymptomatic, no complaints
Note OS does not move.

Alternate Cover test

Exotropia, intermittent
May be visible with or without alternate cover
May have intermittent diplopia, especially when tired or sick


Mom sees misalignment every now and then.

Alternate Cover test

Exotropia, Constant
May be visible with or without alternate cover
May or may not have constant diplopia


Alternate Cover test with PrismExotropia, ConstantUse prism to quantitate the deviation.Change prism power until movement is neutralized. Use this number to plan surgeryHow much to operate…
20

Esotropia

Inward deviation of the eyes

Classification of Esotropia:
Comitant or incomitant.
Accommodative or non-accommodative
ACCOMMODATIVE ESOTROPIA
1. Refractive
. fully accommodative
. partially accommodative
2. Non-refractive
. with convergence excess
. with accommodation weakness


NON-ACCOMMODATIVE ESOTROPIA
. Infantile
. microtropia
. basic
. convergence excess
. convergence spasm
. divergence insufficiency
. divergence paralysis
. sensory
. consecutive
. acute-onset
. cyclic

Refractive Accommodative Esotropia

AC/A ratio, is a physiological response to excessive hypermetropia and is beyond the patient's fusional divergence amplitude.
The deviation presents at about the age of 2.5 years, with a range of 6 months to 7 years. The two types are:
1. Fully accommodative, which is completely eliminated by correction of the hypermetropic refractive error
2. Partially accommodative, which is only partially eliminated by correction of hypermetropia
MANAGEMENT
1.Refraction is performed and any significant error corrected.
2. Bifocals may be prescribed if there is accommodative esotropia for near.

3. Surgery should be considered if spectacles do not fully correct the deviation .

4.treat amblyopia.
5.Use miotic agents.

Infantile Esotropia

Infantile (Congenital) Esotropia

CLINICAL FEATURES

Infantile Esotropia is defined as Esotropia
developing within the first 6 months of birth in an
otherwise normal infant.

Infantile Esotropia

1. Signs
(a) The angle is usually fairly large (>30) and stable.
(b) Fixation in most infants is alternating in the primary position and cross fixating in side gaze, so that the child uses the right eye in left gaze and the left eye in right gaze.
This pattern of crossed fixation will give the false impression of abduction deficit with a bilateral sixth nerve palsy. However, abduction can usually be demonstrated by either using the doll's head manoeuvre or rotating the child.
(c) Nystagmus.
(d) The refractive error is usually normal for the age of the child (about +1.50 D).
(e) Inferior oblique .
(f) Poor potential for BSV.
2. Differential diagnosis
(a) Congenital sixth nerve palsy.
(b) Sensory Esotropia due to organic eye disease.
(c) Nystagmus blockage syndrome .
(d) Duane syndrome .
(e) Mobius syndrome.
(f) Strabismus fixus


MANAGEMENT
Initial management. Ideally, the eyes should be aligned at the very latest by the age of 2 years. This usually means performing the initial surgery before the age of 12 months, but only after amblyopia has been corrected.

Exotropia

Classification

1. Constant
. Congenital
. Sensory
. Consecutive
2. Intermittent
. divergence excess (worse for distance)
. convergence weakness (worse for near)
. basic exotropia (same for distance and near)
CONGENITAL EXOTROPIA
1. Presentation is at birth, in contrast to infantile esotropia.
2. Signs
(a) Normal refraction.
(b) Large and constant angle.
3. Treatment is mainly surgical.
OTHER TYPES
1. Sensory Exotropia, which is the result of disruption of binocular reflexes by acquired lesions, such as cataract or other opacities of the media.
2. Consecutve exotropia: which most frequently follows previous correction or overcorrection of an esodeviation


Intermittent Exotropia
Presentation is most frequent at around 2 years.
The Exotropia may be precipitated by bright light
(resulting in reflex closure of the affected eye),
day-dreaming, fatigue, ill health or visual
distraction. Occasionally, the deviation remains
constant and very rarely it may decrease.

MANAGEMENT

1. Spectacle correction in myopic patients may, in some cases, control the deviation.
2. Orthoptic treatment consisting of occlusion therapy.
3. Surgery is necessary in most patients by about the age of 5 years.

Syndromes

Duane Syndrome
Brown Syndrome
Duane Syndrome
The hallmark of Duane syndrome is retraction of the globe on attempted adduction caused by co-contraction of the medial and lateral recti.

Strabismus

*Refer to an Ophthalmologist.
*Talk to the parents.
*AMBLYOPIA
*Normal Visual function (Streopsis)

Treatment:

Should be started as early as possible
Glasses
Surgery