Balance in the Strabismic Patient Undergoing Strabismus Surgery

Assessment of Balance in the Strabismic Patient Undergoing Strabismus Surgery

Strabismus is a clinical condition characterized by the failure of the visual axes of the two eyes to align on the stared object. There are many possible causes of strabismus, but it can be divided into two main groups: concomitant strabismus, which is characterized by an almost equal angle of deviation in all positions of gaze, and incomitant or paralytic strabismus, which is characterized by a deficit of ocular motility in one or more directions of gaze. Depending on the age of onset, congenital strabismus and acquired strabismus are distinguished. Concomitant strabismus and incomitant strabismus can occur in both plastic age and adults. They are accompanied by diplopia or confusion if they arise in adulthood; there is no diplopia if they arise in plastic age due to cortical compensation mechanisms such as suppression or abnormal retinal matching. Causes of incomitant strabismus in adults can be: decompensation of a preexisting heterophoria; acute incomitant strabismus; injury to fusional centers. Paralytic incomitant strabismus is characterized by a reduction in the force developed by one or more muscles of an eye. Among incomitant strabismus, restrictive strabismus represent clinical pictures of very different etiology united by a single distinguishing feature: the existence of a mechanical obstacle to the free movement of the bulb in the orbit that prevents or reduces the excursion of the eye in one or more directions of gaze.

In about 4% of the young population, the sensory and/or motor pathways are not adequately developed, resulting in misalignment of the visual axes and strabismus. Eye surgery for strabismus is one of the most widely used treatment methods.

Only a few studies in the literature have analyzed changes in postural control after strabismus surgery and on a limited number of patients.

A French study evaluated the effect of surgery on postural control in children with strabismus, concluding that eye surgery affects the somatosensory properties of extraocular muscles, leading to improved postural control and that binocular visual perception could affect the whole body.

Patients belonging to the UOC Ophthalmology, the UOS Diagnosis and Treatment of Ocular Motility Disorders and the Pediatric Ophthalmology Outpatient Clinic, Fondazione Policlinico Universitario A. Gemelli IRCCS in Rome who meet the inclusion criteria will be recruited. Patients will be divided into two groups according to the nature of strabismus (congenital or acquired). All patients, regardless of the nature of strabismus, will undergo a complete ophthalmologic and orthoptic examination and balance examination before strabismus surgery (baseline, T0), at 30 days after surgery (T1), at 90 days after surgery (T2), and at 180 days after surgery (T3).

All patients will undergo clinical evaluation and assessment of balance and fall risk at all assessment timepoints

Inclusion Criteria:

• Age between 16 and 65 years;
• Presence of congenital strabismus or acquired strabismus in the care of the Ophthalmology OU, the Diagnosis and Treatment of Ocular Motility Disorders OU, and the Pediatric Ophthalmology Outpatient Clinic
• Ability to maintain balance safely for at least 180 seconds;
• In case of adult patient, Ability to understand and sign informed consent
• In case of minor patient, Ability to understand and sign the assent for participation in the study and consent from the parent

Exclusion Criteria:

• Presence of diplopia associated with nystagmus;
• Presence of psychomotor and cognitive delay, as assessed by the Mini Mental State Examination (adjusted score < 24);
• Noncooperation of the patient;
• Inability to provide informed consent, in the case of adult patients.
• Inability to provide consent in case of minor patients, or consent from parents.