1. Squint
Dr. ABDULRHMAN ALSAGAIHI
015

2. New words to Encounter Strabismus = heterotropias
Esotropia = turn inward
Exotropia= turn outward
Hypertropia= turn upward
Hypotropia = turn downward
Amblyopia = Lazy eye (vision deficiency in an eye when the brain turns off the visual processing of one eye.
Anisometropia= unequal refractive errors between the 2 eyes
Diplopia = Double vision
Monocular diplopia = diplopia persists when one eye is closed.
Binocular diplopia= diplopia seen only when both eyes are open

3. Binocular single vision
Binocular single vision: slightly dissimilar images from both retinas are fused centrally to be interpreted by the brain as a single image.

4. Ocular motility
CN III
CN IV
CN III
CN VI
CN III
CN III

5. Classification

6. PSEUDOSTRABISMUS
(Apparent) One of the most common reasons that an ophthalmologist is asked to evaluate an infant;
Pseudoesotropia- in prominent epicanthal folds, high myopia
Pseudoexotropia- in hypertelorism

7. Concomitant ( non-paralytic )
Manifest
Concomitant ( non-paralytic )
ETIOLOGY
High Refractive errors - High degree of uncorrected refractive error in children may cause deviation of the most affected eye.
Ocular conditions- causing visual axis obstruction eg. cataract, corneal opacities, retinoblastoma, ROP, macular disease etc.

8. Incomitant ( paralytic )
Manifest
Incomitant ( paralytic )
Characters:
Diplopia is maximal when attempting to look in the direction requiring the action of the weak muscle.
This type of strabismus may indicate either a nerve palsy or an extra-ocular muscle disease .

9. Incomitant ( paralytic )
Manifest
Incomitant ( paralytic )
Causes
Isolated nerve palsies
Trauma
Lesions affecting the EOM’s or CN’s especially no. III
Systemic dis- DM, stroke, botulism ,Thyroid dis

10. Causes of isolated nerve palsies
Vascular disease (DM, HTN, Aneurysm, CST)
Orbital disease
Trauma
Neoplasia
Raised intracranial pressure (3rd or 6th , False localizing)
Inflammation ( Sarcoidosis, Vasculitis, Infections, GBS) …
CST: Cavernous Sinus Thrombosis GBS: Guillain-Barre Syndrome

11. Extraocular muscles disease
Dysthyroid eye disease
Myasthenia gravis
Ocular myositis
Ocular myopathy
Browns Syndrome
Duane’s Syndrome …

12. Dysthyroid eye disease
Due to infiltration of the extraocular muscles with lymphocytes and the depositions of glycosaminoglycans.
Both Hyper and Hypo-Thyroidism.

13. Dysthyroid eye disease
The inferior rectus is the most commonly affected.
Mechanical limitation of the eye in up gaze.
Involvement of the medial rectuslimitation of abduction. (DDx6th nerve palsy)
Treatment:
Systemic steroids.
Radiotherapy.
Surgical orbital decompression.
Prisms.

14. Ocular myositis Inflammation of the extraocular muscles
Pain, diplopia and restriction of movement.
Systemic Disease, R/O thyroid disease.

15. ESOTROPIA

16. Definition Convergent misalignment of the visual axis Concomitant
Infantile esotropia
Accommodative esotropia
Incomitant
6th nerve palsy

17. Epidemiology Occurs in 2% of American children 1-3 years old;
No gender difference;
Most common strabismus of childhood (60%);
Amblyopia is commonly associated with esotropia.

18. Infantile (or congenital) esotropia
Equal sex distribution;
Present by 6 months of age;
Family history of strabismus is common;
Incidence is higher in patients with a history of prematurity, cerebral palsy, hydrocephalus, and other neurological disorders;
Maternal cigarette smoking and low birthrate have
also been linked to the development of esotropia1.

19. Infantile (or congenital) esotropia
Physical examination:
High incidence of amblyopia (40-72%);
Present by 6 months of age;
Large angle of esodeviation (usually ≥ 30 prism
diopters
Cycloplegic refractions similar to those of normal
children of the same age (low hyperopia).
Often cross-fixation (viewing targets in the right field of gaze with the left eye and vice versa) with equal visual acuity in each eye;
Apparent abduction deficit (pseudoparesis

20. Infantile (or congenital) esotropia
Treatment:
Nonsurgical:
Correct amblyopia before surgery (patching, atropine eye drops)
Cross-fixation suggests equal visual acuity of both eyes
Glasses (rarely necessary)
Surgical: mainly
Surgical alignment earlier than age 2 is associated with better sensory binocular fusion potential

21. Look at the corneal light reflex!

22. Accommodative esotropia
Convergent deviation of the eyes associated with activation of the
accommodation reflex;
Onset usually between ages 2 and 3
Often, positive family history;
May be intermittent at onset;
Associated with amblyopia (generally from anisometropia);
May be precipitated by trauma or illness;
High hyperopia (range to ; average: +4.00D).

23. Accommodative esotropia
May be partial or total
Treatment:
Full hyperopic correction
Treat amblyopia (patching, atropine eye drops)
If residual strabismus > 10 prism diopters: SURGERY

24. Look at the corneal light reflex!

25. 6th nerve palsy
Incomitant esotropia (esotropia varies in different fields of
gaze);
Congenital 6th nerve palsy is uncommon:
Usually resolves spontaneously within 6 weeks;
Thought to be caused by increased ICP associated with the birth process;
Trauma and neoplastic disorders are the most common cause;
Neurologic evaluation and CT or MRI recommended;
Surgery is indicated when spontaneous resolution does not take place after 6 months or more of follow-up and after exclusion of intracranial lesions.

27. EXOTROPIA

28. Definition Concomitant Incomitant
Divergent misalignment of the visual axis
Concomitant
Congenital exotropia
Intermittent exotropia
Sensory exotropia
Consecutive exotropia
Incomitant
3 rd nerve palsy

29. Epidemiology Less common than esotropia; Exact etiology unknown;
Most common form is intermittent exotropia.

30. Congenital exotropia Presents before age 6 months;
Large-angle constant exotropia (>35 prism diopters);
Often associated with neurologic impairment or craniofacial disorders;
Amblyopia uncommon
These children usually alternate fixation;
The refractive error is similar to that of the general population;
Treatment: Surgery early in life.

32. Intermittent exotropia
The most common divergent strabismus in childhood;
Onset usually before age 5;
Deviation becomes manifest during times of visual
inattention, fatigue, or stress;
Exposure to bright light often causes a reflex closure of one eye;
Amblyopia is uncommon.

33. Intermittent Exotropia

34. Straight eyes
Exotropic

35. Sensory exotropia
Due to vision loss or long-standing poor vision in one eye;
Children younger than 5 with unilateral vision loss may develop ET or XT; adults and older children usually develop XT;
Angle of deviation may be variable and usually increases with time.

36. Management of Strabismus
History:
3 most important questions:
Age of onset
Constant or intermittent
Unilateral or alternating 84

37. Management of Strabismus
Diagnosis
Management of Strabismus
1-Unilateral or alternating ? Cover test
Cover left eye and fix the right one 90

38. Management of Strabismus
Diagnosis
Management of Strabismus
1-Unilateral or alternating ?
Remove the cover
the right eye is rapidly squinting
unilateral 91

39. Management of Strabismus
Diagnosis
Management of Strabismus
1-Unilateral or alternating ?
Remove the cover
the right eye is maintain the fixation and left eye is squinting
Alternating 92

40. Management of Strabismus
Diagnosis
Management of Strabismus
2) Is convergent or divergent? By corneal reflection
Light image is temporally
Convergent
Light image is nasally
divergent 93

41. Management of Strabismus
Diagnosis
Management of Strabismus
Convergent (esotropia) Light image is temporally

42. Divergent (exotropia) Light image is nasally
Diagnosis
Management of Strabismus
Divergent (exotropia) Light image is nasally

43. Management of Strabismus
Diagnosis
Management of Strabismus
3) Squint angle ?
By Corneal reflection:
Center of pupil=0 degree (No squint 96

44. Management of Strabismus
Diagnosis
Management of Strabismus
3) Squint angle ?
By Corneal reflection:
( ) pupil edge and limbus=20-25 D 98

45. Management of Strabismus
Diagnosis
Management of Strabismus
3) Squint angle ?
By Corneal reflection:
At the limbus=40-45 D 99

46. Ocular mov.
6th nerve palsy

47. TREATMENT
Eye Patch
The stronger eye is patched to force the brain to interpret images from the strabismic eye.
if amblyopia is present.

48. TREATMENT
Prisms
The lenses provide comfort and can help prevent double vision from developing. k

49. TREATMENT Surgical Intervention:
1 )Recession: incision in the conjunctiva to expose the muscle, muscle is then disinserted on the globe.
2) Resection: cutting and shortening of the muscle and attaching it to its original position

50. Weakening (Recession)
Strengthening (Resection)

51. 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
Temporarily treatment of diplopia

52. mcqs Lazy eye is a-Esotropia b-Exotropia c-Amblyopia d-Anisometropia
6th nerve palsy lead to