Strabismus Nursing Care Planning and Management

Strabismus is misalignment of the eyes, "crossed eyes" or "squint." The stakes in a child are not cosmetic: untreated misalignment drives amblyopia and loss of binocular vision, so the nursing work centers on protecting vision, supporting patch and occlusion therapy, keeping the child safe with impaired sight, and teaching families to stay with a treatment that runs for years.

What is Strabismus?

Strabismus is inward deviation of the eyes noted before age 6 months. It is associated with maldevelopment of stereopsis, motion processing, and eye movements: the eyes are not aligned and point in different directions. The exact cause is still unknown and no single effective treatment strategy has been settled.

Pathophysiology

The exact cause remains unknown. Worth held that esotropia is an inborn, irreversible defect of fusion, a primary dysfunction in the normal development of binocular sensitivity. Chavasse countered that the neural components for normal binocular vision are present at birth in strabismic individuals, but fusion is eventually impeded by abnormalities of optical input (such as monocular cataracts) or muscular output (such as cranial nerve palsies). Authors have implicated nearly everything from the extraocular muscles to the visual cortex, and the condition remains incompletely understood.

Statistics and Incidences

Strabismus is one of the most prevalent ocular problems in children, affecting 5 in every 100 US citizens, about 12 million people in a population of 245 million. A population-based study from 1965 to 1994 reported a birth prevalence of 25 per 10,000, or 1 in 403 live births. To test whether esotropia is present at birth or develops later, Nixon et al observed 1,219 alert infants in a normal newborn nursery and found only 40 babies (3.2%) had esotropia (intermittent esotropia in 17 patients, 14 patients varying between esotropia and exotropia, and 9 patients with variable esotropia). Greenberg et al reported an annual age- and gender-adjusted childhood strabismus incidence of 111 per 100,000 patients younger than 19 years. By definition, strabismus is seen in infants before age 6 months.

Causes

The exact cause has not been distinctly identified. Tychsen and Lisberger reported in 1986 that the strabismic patient with the most severe pursuit/motion processing asymmetry had two siblings with strabismus. Nonsyndromic strabismus has a suggested relationship to susceptibility loci on regions 3p26.3-26.2 and 6q24.2-25.1 and may share alleles underlying Duane retraction syndrome.

Clinical Manifestations

Per Tychsen, strabismus presents with a constellation of ocular motor signs. Esotropia is in-turning of one or both eyes, intermittent or constant, with near fixation, distance fixation, or both. In pursuit asymmetry, horizontal smooth pursuit for targets moving temporal to nasal develops before pursuit in the nasal to temporal direction; this developmental lag in nasally directed pursuit is seen only under monocular conditions with one eye covered. Latent fixation nystagmus is a horizontal binocular oscillation evoked by unequal visual input to the two eyes and develops primarily with congenital esotropia. Amblyopia is relatively common; per Weakley et al it should be suspected strongly in esotropia with asymmetric inferior oblique activity, specifically in the eye with more inferior oblique overaction.

Assessment and Diagnostic Findings

Perform the alternate prism cover test to measure the angle of strabismus accurately; it gauges the full magnitude of any combined esotropia and esophoria.

Medical Management

Smaller angles of deviation may be addressed with prism lenses, with or without occlusion therapy, depending on whether amblyopia is present. A common cycloplegic combination is 2.5% phenylephrine and 1% cyclopentolate; occlude one eye at a time during retinoscopy so the examiner stays aligned with the visual axis. Corrective lenses are generally prescribed for hyperopia greater than +2.50 diopter (D) and/or anisometropia exceeding 1.50 D; any cylinder greater than or equal to +0.50 D warrants spectacles, and myopia above -4.00 D warrants corrective lenses. The rule of thumb for occlusion therapy is 1 to 2 weeks of high-percentage occlusion (for example, 90% of waking hours) of the non-amblyopic eye per year of life, especially with a strong fixation preference for one eye; reexamine the infant after a few weeks to check response and to confirm that occlusion-induced amblyopia has not developed in the occluded dominant eye. Botulinum toxin (BOTOX) injection into the medial rectus has been explored as an alternative to surgery, with contrasting results across studies.

Pharmacologic Management

Few medications are used. Combination antibiotic-steroid ointments are prescribed for the first postoperative week to control inflammation and prevent infection, particularly in the conjunctiva. Botulinum toxin type A (BOTOX) is the neurotoxin most commonly used; it inhibits transmission of nerve impulses in neuromuscular tissue and serves as an alternative to initial or repeat surgical ocular alignment.

Nursing Management

Nursing Assessment

Risk factors associated with strabismus include prematurity, family or secondary ocular history, perinatal or gestational complications, systemic disorders, supplemental oxygen as a neonate, systemic medications, and male sex. On exam, strabismus may present with amblyopia, impaired binocularity, central scotomas, and incomitance.

Nursing Diagnoses

Based on assessment data, the major nursing diagnoses are:

• Risk for injury related to impaired sensory function.
• Disturbed sensory perception related to structural damage.
• Knowledge deficit related to impaired vision.
• Social isolation related to limited ability to participate in diversional and social activities secondary to impaired vision.

Nursing Care Planning and Goals

The major goals are that the patient remains free from injury, has restored, functioning sensory perception, that patient and family understand the condition, the treatment, and any surgery, and that the patient can interact socially with others.

Nursing Interventions

Prevent injury: orient the patient thoroughly to the surroundings, keep the call light within reach and teach how to use it, respond to it immediately, place an injury-prone patient near the nurses' station, and teach safe ambulation at home including handrails in the bathroom; for visual impairment, teach the patient or caregiver to mark key spots with bright colors such as yellow or red (stair edges, stove controls, light switches). Patch therapy covers the stronger eye to force the weaker eye to work harder; vision therapy uses supervised in-office exercises to change how the eyes process visual information and is not about strengthening eye muscles. Reinforce caregiver knowledge: note existing misconceptions, acknowledge cultural differences at the outset, consider the patient's and caregiver's learning style, include them in building the teaching plan and setting objectives, and give clear, thorough explanations and demonstrations.

Evaluation

Goals are met when the patient is free from injury, has restored, functioning sensory perception, when patient and family understand the condition, the treatment, and surgery, and when the patient can interact socially with others.

Documentation Guidelines

Document baseline and subsequent assessment findings including signs and symptoms, cultural or religious restrictions and personal preferences, the plan of care and persons involved, the teaching plan, the client's responses to teaching and interventions, attainment or progress toward outcomes, and long-term needs and who is responsible for actions to be taken.