ABSTRACTCongenital cranial dysinnervation disorders (CCDD) is a new term describing a collection of non-progressive neurogenic syndromes. Initially referred to as congenital fibrosis syndrome, it was thought that the primary problem was extraocular muscular maldevelopment. Recent advancements in genetics and neuro-radiology have now determined the initial observation of fibrotic muscles is secondary to a primary lack of innervation from deficient, absent, or misguided cranial nerves. This presentation provides an overview of the known genes and phenotypes currently recognized within the CCDD domain. It will also highlight areas of current research being done in the area of cranial nerve development. Increased knowledge and awareness of these disorders has resulted in more research being conducted. These studies have provided a more complete understanding of efferent motor system development and are leading to improved treatment strategies for patients.

Background and Purpose: Nystagmus is a commonly encountered clinical finding both in children and adults. Despite its complexities, a fundamental understanding of the basic etiology and underlying pathophysiology of nystagmus is critical to manage these patients appropriately.Patients and Method: The subset of ocular motility disorders that constitutes true nystagmus is identified and delineated from saccadic intrusions. Once defined, we explore the causes of commonly encountered forms of nystagmus and their clinical features.Results: Three separate mechanisms work to integrate sensory input and calibrate ocular movements: the afferent visual pathway, the neural integrator, and the vestibular system. Specific neuroanatomical pathways and corresponding pathologic changes are reviewed.Conclusion: A basic understanding of the underlying pathophysiology of nystagmus is essential to clinical practice. Three main mechanisms utilize multifactorial sensory input to produce a normally functioning ocular mo...

ABSTRACTExamining a child with nystagmus can be intimidating even for an experienced clinician. The purpose of this paper is to provide examination pearls for the clinical assessment of the pediatric patient with nystagmus. By employing these techniques, the clinician should be able to document the necessary information for determining the underlying cause of the nystagmus and to direct the patient's plan of care.

Nystagmoid eye movements are involuntary eye movements that are not pure forms of nystagmus. Nystagmus, by definition, is involuntary eye movements off of fixation that are initiated by a slow phas...

ABSTRACTStrabismus is often found in patients with nystagmus. It is valuable to understand this association to counsel patients. Strabismus can be difficult to quantify with alternate cover testing when there is a large amplitude nystagmus. Hirschberg or Krimsky measurements can be misleading.

Examining a child with nystagmus can be intimidating even for an experienced clinician. The purpose of this paper is to provide examination pearls for the clinical assessment of the pediatric patient with nystagmus. By employing these techniques, the clinician should be able to document the necessary information for determining the underlying cause of the nystagmus and to direct the patient's plan of care.

ABSTRACTBackground: “Dragged-fovea diplopia syndrome” is a type of central binocular diplopia that is secondary to a foveal displacement, caused by epiretinal membranes (ERMs) or other macular diseases. Its management is difficult, because prisms are not effective.Case Reports: Two cases of dragged-fovea diplopia syndrome were presented. Both patients were affected with a unilateral epiretinal membrane. Therefore, the pathophysiology underlying their diplopia was the conflict between central and peripheral fusion mechanisms.Conclusions: Diplopia caused by ERM “shift” deserves a complex management. We suggest to be careful about subjective symptoms and to optimize the residual visual function to customize the orthoptic management. A strict cooperation between ophthalmologists and orthoptists could lead to a successful outcome.

ABSTRACTBackground and Purpose: Early onset exodeviations in systemically and ocularly healthy young children, diagnosed at less than 1 year of age, may be of the constant, “infantile XT” type, or early X(T) type. The onset of common childhood X(T) is not clearly known. The purpose of this lecture is to discuss theories and characteristics of early onset exodeviations, and report on our observations of infantile XT and early X(T) at Children's Eye Care in Michigan.Patients and Methods: A retrospective review of 470 cases of childhood exodeviations (ages 6 months to 15 years) were reviewed and met inclusion criteria of no prior surgical treatment, no ocular, CNS or craniofacial disease, and no significant prematurity. Thirty-nine cases were diagnosed at less than 1 year of age: thirty-five patients with early X(T) and four patients with infantile XT, based upon a motility evaluation at 6 m and 1/3 m fixation using dissociative methods. The clinical characteristics and outcomes of these two groups were described and compared.Results: Comparing infantile XT and early X(T) groups, reported onset by caregivers was significantly younger in the infantile XT group (3 months vs. 6 months), and size of the deviation at both distance and near fixation ranges was significantly larger in the infantile XT group (XT-43/XT′-48Δ vs. X(T)-25/X(T)′-23Δ). Three of 4 infantile XT patients received surgery, one spontaneously resolved, and all resulted in small, residual XT, and DVD without measurable stereoacuity. Many patients with early X(T) demonstrated good/excellent control at near range and fair/poor control at distance range. Four early X(T) patients who did not receive surgical correction either resolved, remained the same, or decompensated. Surgical correction for X(T) resulted in a 50% success rate for one procedure with a minimum of 2 years postoperative follow-up. Stereoacuity outcomes did not appear to correlate with quality of control. Conclusions: Most healthy children with X(T) are diagnosed by age 5 years, although many have a reported onset by caregivers of less than 1 year of age. Good control of X(T) at near range may preclude early examinations. Motility evaluation by dissociative methods at near and far-range fixation may facilitate early diagnosis. Infantile XT is less common than early X(T), by a ratio of 1:10. Characteristics of infantile XT and early X(T) have significant differences in report onset, deviation size, and outcomes with and without surgical intervention. Patients with either infantile XT or early X(T) may spontaneously resolve over time.