SQUINT/STRABISMUS/ CROSSED EYE

1. STRABISMUS

2. STRABISMUS
• occurs when both eyes do not look at the same
place at the same time; the eyes are unable to
align properly under normal conditions
• eye(s) may turn in, out, up, or down
• can be present in one or both eyes
• often referred to as: cross-eyed, crossed eyes,
cockeye, weak eye, wall-eyed, wandering eyes,
and/or eye turn
from: American Optometric Association

3. SQUINT
• It is a group of clinical conditions characterized
by misalignment of the visual axes of the two
eye.

4. CAUSES OF STRABISMUS
• result of the lack of coordination between the
muscles of the eye responsible for eye movement
• problems with the nerves that transmit information
to the eye muscles
• problems with the control center in the brain that
directs eye movement
• the lack of coordination prevents proper binocular
vision and keeps both eyes from gazing at the same
point
• in adults, can be caused by stroke, thyroid problems,
brain injury, or other trauma which disrupts the
ability of the eye muscles to work properly
from: The Cleveland Clinic

5. RISK FACTORS
• family history—if relatives have strabismus, a
person is more likely to develop it
• refractive errors—extreme farsightedness
(hyperopia) can develop strabismus due to the
amount of eye focusing necessary to keep vision
clear
• medical conditions—people with Down
syndrome or cerebral palsy and people who have
suffered a stroke or head injury are at higher risk
for developing strabismus
from: Strabismus.com

7. WHEN DOES IT OCCUR?
• congenital—developing during infancy; 50% of
children with strabismus are born with it
• acquired—developing in adulthood; can also
develop as a result of lack of treatment during
childhood
from: Strabismus.com

8. WHAT IT’S NOT
• Strabismus is NOT the same as Amblyopia!!
• Amblyopia is also called “lazy eye” and is a
condition where vision does not develop
normally during childhood
• Child may have one weak eye with poor vision
and one strong eye with normal vision
• Amblyopia DOES occur commonly with
Strabismus, but is a vision problem, where
strabismus is a muscle problem
from: Children’s Hospital Boston

9. DEVELOPMENT IN INFANTS
• a newborn’s eyes will typically move independently and
even drift outward
• it is not normal for an infant’s eyes to cross constantly
• by 3 to 4 months old, an infant should be able to focus on
objects and eyes should be straight, with no turning
• 30-50% of children with strabismus develop secondary
vision loss (amblyopia)
• the onset of strabismus is most common in children at 18
months to 6 years old
• if a parent notices their child’s eyes moving inward or
outward, the eyes seem to be crossed, or the child is not
focusing on objects, they should seek medical attention
from: Children’s Hospital Boston

10. DEVELOPMENT IN ADULTS
• most likely to develop as a result of injury or disease
• adult will most likely experience double vision, eye
fatigue, overlapped or blurred images, a pulling
sensation around the eyes, difficulty with reading,
and/or a loss of depth perception
• if loss of vision occurs, it is typically due to exotropia
(eye turns outward) rather than amblyopia because
vision is already developed in the adult brain and
the adult brain will not compensate for deviation the
way a child’s brain will
from: Eye Care America

11. DIAGNOSIS
• A comprehensive eye exam is necessary with focus on the
following:
• patient history—a comprehensive history is necessary
to assess symptoms, health problems, and medications
• visual acuity—measurements are taken to assess extent
to which vision is affected
• refraction—conducted to determine the lens power
necessary to compensate for any refractive error
• alignment and focusing—assessing how well your
eyes focus, move, and work together
• eye health exam—assessing the structures of the eye
(internal & external) to rule out possible disease
from: American Optometric Association

13. • APPARANT SQUINT
The presence of epicanthus and high errors of
refraction stimulate squint but in fact there is no
squint
• LATENT SQUINT
Is a clinical condition in which there is a
tendency of misalignment of the visual axes
which is corrected by the fusional capacity

14. Etiology
• Increased requirement for accommodation and
convergence results in esophoria
• Decreased requirement for accommodation and
convergence results in exophoria
• Occupations requiring too much close work
• General poor health, fatigue and advancing age

15. Symptoms
• Eye strain and head ache after prolonged work
• Blurring of prints and overlaping of words or
lines while reading
• Diplopia after close work for prolonged period
(intermittent squint ) or in the evening, on
reading or writing for an hour or two
• Crowding of words
• Symptoms of defective postural sensations
(difficulty to identify moving objects)

16. Diagnosis
• Patients case history regarding chief complaints,
onset and duration, previous treatment and
family history
• Visual acuity and monocular fixation pattern is
noted
• Cycloplegic refraction and fundus examination
• Ocular movements and head posture
• Measurement of convergence and
accommodation

17. • Assessment of binocular vision
• Cover- uncover test
• Maddox rod test
• Maddox wing test
• Prism vergence test

18. Treatment
• Optical correction of the underlying refractive
error
• Orthoptic exercises for improving convergence
insufficiency or divergence weakness
 Pencil exercise
 Exercise the weak muscles against prisms
• Surgical correction of the affected muscle
(resection or recession of the muscle)
• General improvement of health and nutrition
• Proper position , distance and illumination while
doing near work and suitable breaks in between

19. • MANIFEST SQUINT
• Dissociation of the eyes wherein the deviation
remains the same in all the directions of gaze
• Types
• Concomitant/ non paralytic squint
• Incomitant/ paralytic squint

20. Concomitant squint
• It is a type of squint characterized by normal
extraocular movements and constant degree of
squint in all the directions of gaze
• Types
• Esotropia (convergent squint)
• Exotropia (divergent squint)
• Hypertropia or hypotropia (Vertical squint)

21. Esotropia
• Convergent strabismus with eye deviated nasally
Types
• Accommodative esotropia- is due to the
increased convergence associated with
accommodation reflux
• Non accommodative esotropia- it includes
congenital or infantile esotropia and acquired
esotropia
• Secondary esotropia includes sensory
deprivation esotropia and consecutive or
surgical overcorrection related esotropia

22. ESOTROPIA
The left eye is turned
inward—note that the
light reflection in the
eyes is not symmetric
from: Minnesota Department of Health

23. Exotropia
• Divergent strabismus with eye deviated outward
temporally is called exotropia
• It can be infantile exotropia, primary exotropia,
and secondary exotropia

24. EXOTROPIA
The right eye is turned
outward—again, not
the light reflection in
the eyes is not
symmetrical
from: Minnesota Department of Health

25. Hypertropia
• It is characterized by vertical misalignment of
eyes with upward deviation of the squinting eye
The common causes are
• Trochlear nerve palsy
• Thyroid eye disease
• Brown’s syndrome

26. HYPERTROPIA
The right eye is turned
upward—light
reflection not
symmetrical
from: Minnesota Department of Health

27. • Hypotropia
• It is characterized by vertical misalignment of
the eyes with downward deviation of the
squinting eye

28. HYPOTROPIA
The right eye is turned
downward-light
reflection in eyes is
not symmetric
from: Pediatric Ophthalmic Consultants

30. Etiology
• Sensory problems- refractive error, cataract,
corneal opacity
• Motor problems- abnormalities of extra ocular
muscles, accommodation and convergence
• Central problems- defective fusion,
abnormalities in the cortical control of extra
ocular movements

31. • Incomitant squint
• It is characterized by limited or restricted
extraocular movements and varying degree of
squint in different directions of gaze
Types
• Paralytic and restrictive squint

32. Paralytic squint
• It is characterized by limited extraocular
movements in the direction of action of the
paralyzed muscle and varying degree of squint in
different directions of gaze

33. Etiology
• Is caused by paralysis or paresis of the extraocular
muscles due to
• Neurogenic causes- are congenital anomalies of the
nerves supplying the extraocular muscles,
inflammatory diseases affecting the nerves, brain
tumors, cerebrovascular accidents , thrombosis or
aneurysms
• Myogenic causes – congenital anomalies of the
extraocular muscles, traumatic causes
• Neuromauscular causes- diseases affecting the
neuromuscular junction (myasthenia gravis)

34. Clinical features
• Diplopia,
• vertigo,
• nausea, and vomiting
• False projection of the object
• Limitation of the ocular movements in the
direction of action of the paralyzes muscles
• Compensatory head posture to neutralize the
diplopia

35. Clinical types
• Oculomotor nerve plasy
• Trochlear nerve palsy
• Abducent nerve palsy
• Total opthalmoplegia
• Internal pthalmoplegia
• Internuclear opthalmoplegia

36. Diagnosis
• CT and MRI
• Diplopia charting
• Hess screen test
• Worth 4-dot test
• Forced duction test

37. Treatment
• Treating the underlying cause
• Treatment of diplopia by temporary occlusion of
the affected eye or the correction by opticals
• Surgical correction – recession and resection
muscle surgeries
• Injection of botulinum toxin to cause
chemodegeneration

38. Restrictive squint
• It is characterized by restriction of the extraocular
movements with small deviation in the primary position
of gaze
Etiology
• Usually caused by the fibrosis of the extraocular muscle
or by restriction of the movement of the extraocular
muscle
• The common clinical syndromes associated restrictive
squint includes,
• Brown’s syndrome
• Strabismus fixus
• Duane’s retraction syndrome

39. Diagnosis
• Assessment of visual acuity and refractive error
• Corneal reflux test
• Cover test
• Prism bar cover test
• Maddox rod test
• Maddox wing test
• Assessment of binocular vision

40. Treatment
• Optical correction of underlying refractive error
• Orthoptic exercises
• Occlusion therapy in case of amblyopia
• Surgical management
• Recession- done by making the muscle
slackening by shifting the insertion of the muscle
posteriorly towards its origin
• Resection- it is done by making the muscle taut
by shortening the muscle

41. Surgeries
The surgeries for the weakening of the muscle are,
• Recession
• Myotomy
• Tenotomy
Surgeries for strengthening the muscle are,
• Resection
• Tucking
• Transposition

42. For esotropia
• Recession of medial rectus and resection of
lateral rectus of the eye with squint
• Recession of medial rectus of both the eyes
For exotropia
• Recession of lateral rectus and resection of
medial rectus of the eye with squint
• recession of lateral rectus of both the eyes

43. TREATMENT
• there is no cure for strabismus
• with treatment, the effects of strabismus may be
corrected
• the goal of treatment is to help the patient
achieve as close to normal binocular vision as
possible in every direction of gaze and at all
distances
from: American Optometric Association

44. TREATMENT
Eye Patch
The stronger eye is patched to
force the brain to interpret
images from the strabismic
eye. Eye patches will not
change the angle of the
strabismus. Typically, eye
patching is used only if
amblyopia is present.
from: Strabismus.com and Pediatric Ophthalmic Consultants

45. TREATMENT
Eyeglass or
Contacts
Eyeglasses or Contacts are
used to improved the
positioning of the eye(s)
by modifying the patient’s
reaction to focus.
Eyeglasses and Contacts
can also redirect the line
of sight, which can help
straighten the eye.
from: Strabismus.com and Smith-Magenis Syndrome

46. TREATMENT
Prisms
Prisms are used to modify the way
light and images hit the eye. The
lenses provide comfort and can help
prevent double vision from
developing.
from: Strabismus.com and Optometrists Network

47. TREATMENT
Vision Therapy
A non-surgical method of therapy
that treats the eye and the brain. An
optometrist will oversee the therapy,
which is designed to strengthen or
develop visual skills. The
optometrist may also use eyeglasses,
prisms, eye patches and
computerized medical devices
during the therapy.
from: Strabismus.com and IU Optometry Clinics & Patient Care

48. TREATMENT
Eye Surgery
Surgery may be necessary in an
attempt to align the eyes by
modifying one or more muscles in
the eye. During surgery, the muscle
positions will be changed or the
length of the muscles will be
changed. Surgery may follow a
period of eye patching and then
eyeglasses may be used after surgery
to help treat strabismus.
from: Strabismus.com and Pediatric Ophthalmic Consultants
Surgery on medial rectus muscle of the left eye.

49. TREATMENT
The Bates Method
An alternative form of treatment that
uses natural remedies to correct vision
problems such as: relaxation, exercise,
games, and other activities. The Bates
Method claims to improve or restore
vision through the elimination of mental
strain. This is a very controversial
method in the medical field.
from: Strabismus.com and Seeing Without Glasses

50. TREATMENT
Botox Therapy
Used as an alternative to eye muscle
surgery. The idea is that the drug
will temporarily relax the eye
muscle, which will allow the
opposite eye to tighten and
straighten. The effects are short-
term—about 3 weeks. Eye muscle
exercises and eyeglasses may also be
used to help strengthen the eye.
from: Strabismus.com and IU Optometry Clinics & Patient Care