William F. Hoyt and the Neuro-Ophthalmology of Superior Oblique Myokymia and Ocular Neuromyotonia.

The contributions of William F. Hoyt, MD, to the field of neuro-ophthalmology are immense. His precision in history-taking and examination skills provided the foundation to fully understand a clinical disorder-determining its underlying pathophysiology, prognosis, and management. We describe two unusual eye movement disorders, superior oblique myokymia and ocular neuromyotonia, and how Dr. Hoyt's contributions shaped our understanding of these clinical entities.

Recurrent Superior Oblique Myokymia Treated by Distal Tendon Extirpation.

BACKGROUND: We describe successful surgical treatment of superior oblique myokymia, which had recurred after superior oblique tenectomy. METHODS: Single case report. RESULTS: The distal stump of the superior oblique tendon was extirpated by stripping it from the globe. The ipsilateral superior rectus muscle also was recessed, to correct a hypertropia that had resulted from the original superior oblique tenectomy. CONCLUSIONS: Complete removal of the distal superior oblique muscle tendon provided definitive relief of superior oblique myokymia. Superior rectus muscle recession, combined with previous inferior oblique myectomy, compensated effectively for loss of superior oblique function.

Inner retinal dystrophy in a patient with biallelic sequence variants in BRAT1.

BACKGROUND: Mutations in the BRCA1-associated protein required for the ataxia telangiectasia mutated (ATM) activation-1 (BRAT1) gene cause lethal neonatal rigidity and multifocal seizure syndrome characterized by rigidity and intractable seizures and a milder phenotype with intellectual disability, seizures, nonprogressive cerebellar ataxia or dyspraxia, and cerebellar atrophy. To date, nystagmus, cortical visual impairment, impairment of central vision, optic nerve hypoplasia, and optic atrophy have been described in this condition. This article describes the retinal findings in a patient with biallelic deleterious sequence variants in BRAT1. MATERIALS AND METHODS: Case report of a child with biallelic sequence variants in the BRAT1 gene. RESULTS: This patient had developmental delay, microcephaly, nystagmus, and esotropia, and full-field electroretinography (ERG) revealed an inner retinal dystrophy. She was found on exome sequencing to have compound heterozygous sequence variants in the BRAT1 gene: one maternally inherited frameshift variant (c.294dupA, predicting p.Leu99Thrfs*92), which has previously been reported, and one paternally inherited novel missense variant (c.803G>A, p.Arg268His), which is likely to affect protein function. CONCLUSIONS: Biallelic sequence variants in BRAT1 have been reported to cause a variety of ocular and systemic manifestations, but to our knowledge, this is the first report of inner retinal dysfunction manifest as selective loss of full-field ERG scotopic and photopic b-wave amplitudes.

Laterality of brain and ocular lesions in Aicardi syndrome.

This study reports a large case series of children with Aicardi syndrome. A new severity scoring system is established to assess sidedness of ocular and brain lesions. Thirty-five children were recruited from Aicardi syndrome family conferences. All children received dilated ophthalmologic examinations, and brain magnetic resonance images (MRIs) were reviewed. Ocular and brain MRI Aicardi lesion severity scores were devised. A linear mixed model was used to compare each side for the ocular and brain MRI severity scores of Aicardi-associated disease. Twenty-six children met the inclusion criteria for the study. All subjects were female, ages 3 months to 19 years. Rates per child of optic nerve coloboma, severe lacunae, and microphthalmos in one or both eyes (among those with complete fundus examinations available) were 10/24 (42%), 8/22 (36%), and 7/26 (27%), respectively. Ocular and brain MRI asymmetry was found in 18% (4/22) and 58% (15/26) of subjects, respectively, with more right-sided brain lesions than left-sided ones (V = 52, P = 0.028). A significant correlation between sidedness of brain disease and microphthalmos was noted (T = 2.54, P = 0.02). This study substantiates the range and severity of Aicardi syndrome-associated ophthalmologic and brain MRI lesions from prior smaller case series.

Amblyopia: a neuro-ophthalmic view.

Amblyopia designates monocular or binocular visual loss associated with form deprivation caused by obstruction or deformation of a light stimulus, strabismus, or uncorrected refractive error. Elegant neuroscientific studies have identified a critical period early in life in which the visual system is vulnerable to amblyopia and the site of pathology as the primary visual cortex. However, recent observations have challenged these concepts. A broader understanding of the pathophysiology of amblyopia will be critical to refining therapy for this condition.

Completion rate of continuous curvilinear capsulorhexis in pediatric cataract surgery using different viscoelastic materials.

PURPOSE: To determine whether viscoelastic materials with a higher viscosity allow better control of the lens capsule, reducing the rate of incomplete continuous curvilinear capsulorhexis (CCC) during pediatric cataract surgery. SETTING: Department of Ophthalmology, University of California, San Francisco Medical Center, San Francisco, California, USA. METHODS: This retrospective study comprised 25 eyes of 18 children who had cataract surgery by 1 surgeon. The type of viscoelastic agent used for the CCC portion of the surgery was obtained from surgical dictations and nursing charts and information on complications during the CCC, from surgical dictations. The patient's age, type of cataract, and intraocular lens placement were also obtained. RESULTS: A CCC was successfully performed in 7 of 15 eyes (46.7%, mean age 7.6 years) using cohesive Healon (sodium hyaluronate 1%) or dispersive Viscoat (sodium hyaluronate 3%-chondroitin sulfate 4%) viscoelastic material and in 9 of 10 eyes (90%, mean age 6.4 years) using the high-viscosity viscoadaptive agent Healon 5 (sodium hyaluronate 2.3%) (chi square = 4.8900; P<.05). The unsuccessful CCCs in the Healon/Viscoat group were in 2 eyes with mature cataract, 1 eye with posterior polar cataract, 1 eye with posterior subcapsular cataract, and 4 eyes with lamellar cataract. The unsuccessful CCC in the Healon5 group was in 1 eye with mature cataract. CONCLUSION: The superviscous properties of Healon5 under low turbulence conditions appear to lead to a higher CCC completion rate in children.