Strabismus surgery

Learning objectives

Strabismus surgery is surgery of the extraocular muscles (tightening, lengthening, transposing, or shortening the eye muscles) to correct strabismus, the misalignment of the eyes
It is the most common ophthalmic surgery in pediatric patients
Strabismus occurs in 3-5% of children worldwide
Strabismus results from an imbalance in extraocular muscle function → two different images (one from each eye) are transmitted to the brain, resulting in loss of visual depth → in children, the brain may suppress the image from the weaker eye, impairing visual development and leading to amblyopia (decreased vision in a normal healthy eye; lazy eye)
The prognosis is good if the correction is performed as early as possible (before the child reaches the age of 8 years)

Strabismus may involve one or both eyes
The affected eye can deviate outward (exotropia), inward (esotropia), upward (hypertropia), or downward (hypotropia)
The deviation may be intermittent or constant, large magnitude (large angle) or small magnitude (small angle)
Diplopia (double vision)
Loss of stereopsis
Headache
Inability to read comfortably
Fatigue when reading
Amblyopia (loss of visual acuity)
Psychosocial issues (interferes with normal eye contact with others)

Infantile strabismus needs early surgery (6-12 months) for the best visual outcome
Rare association with primary muscle diseases and malignant hyperthermia
Associated syndromes: Apert syndrome, Cri du chat syndrome, Crouzon syndrome, Down syndrome, Goldenhar syndrome, Marfan syndrome, Moebius syndrome, Stickler syndrome, Turner syndrome

Airway not accessible because of the microscope’s position
Avoid suxamethonium
Can trigger malignant hyperthermia in susceptible patients
Can cause tonic contracture of extraocular muscles, interferes with forced duction test
Oculocardiac reflex
Topical adrenaline is often used to reduce bleeding and may be absorbed systemically, watch dose in small children
High incidence of postoperative nausea and vomiting (PONV)