Juvenile ocular myasthenia gravis: a report of two cases.

We report 2 cases of pediatric ocular myasthenia gravis. The first case was a 7-year-old girl who presented with bilateral ophthalmoplegia and ptosis that correlated with the onset of upper respiratory symptoms. Neuroimaging and acetylcholine receptor antibody testing were unremarkable. The ice pack test was positive. Symptoms greatly improved with pyridostigmine, with full resolution of ophthalmoplegia achieved by 8-month follow-up. The second case was a 4-year-old girl who presented emergently with ptosis and bilateral ophthalmoplegia. Acetylcholine receptor antibodies testing was positive. The patient was started on pyridostigmine and intravenous immunoglobulin and is scheduled to follow-up with pediatric ophthalmology in the outpatient setting.

Using the RETeval Device in Healthy Children to Establish Normative Electroretinogram Values.

PURPOSE: To provide normative data of full-field electro-retinogram (ERG) responses in the pediatric population using the RETeval ERG device (LKC Technologies, Inc) in healthy children without evidence of retinal disease. METHODS: This was a single-site cross-sectional study of healthy pediatric patients with normal dilated fundus examinations and no known retinal diseases. Participants were recruited to undergo dilated full-field ERG using the handheld RETeval device. The International Society for Clinical Electrophysiology of Vision 5-step protocol was used. Photopic and dark-adapted scotopic responses were recorded using skin electrodes. RESULTS: Main outcome measures were normative RETeval ERG values and correlation of age with measured ERG parameters. Thirty-eight eyes of 20 healthy patients (aged 4 to 17 years) were included in the study. Of the 20 normal patients, 9 were male and 11 were female. Normative mean, median, and range values were recorded for the measured full-field ERG parameters. Pearson correlation was moderately positive between age and oscillatory potential and scotopic dim flash amplitude (r = 0.59, P = .006 for both). A positive correlation was also found between age and cone a-wave implicit time (r = 0.67, P = .001). CONCLUSIONS: The handheld RETeval system is a useful tool for obtaining full-field ERGs in children without anesthesia. Moderate positive correlations were observed between age and oscillatory potential and scotopic dim flash amplitude. A strong correlation was found between age and cone a-wave implicit time. The current study provides a baseline of normative full-field ERG values in children. [J Pediatr Ophthalmol Strabismus. 2021;58(1):17-22.].

Malignant melanoma presenting as amelanotic caruncular lesion in a child.

Conjunctival melanoma is a rare malignant neoplasm that can present in childhood in any part of the conjunctiva. The infrequency with which conjunctival melanoma is encountered in childhood caruncular lesions makes it a formidable but important aspect of the differential diagnosis. We report the case of a 10-year-old boy who presented with a left caruncular lesion. On histopathologic analysis, the lesion was determined to be BRAF-negative invasive melanoma arising in association with melanocytic nevus. The melanoma was excised using no-touch technique and double freeze thaw cryotherapy. A full systemic work-up revealed no metastasis or abnormality.

Insights into uveitis in association with spondyloarthritis from a large patient survey.

BACKGROUND: Uveitis is reported to be the most common extra-articular feature in spondyloarthritis (SpA). OBJECTIVE: The objective of this study was to investigate the relationship between uveitis and SpA in a cohort identified from a survey. METHODS: Eight hundred sixty-three respondents completed a survey conducted by the Spondylitis Association of America. Data on baseline demographics, quality of life, medication use, and joint involvement were compared in SpA patients with and without uveitis. Logistic regression analysis was used to identify characteristics associated with the presence of uveitis. RESULTS: Of the 863 respondents, 168 (19.5%) reported a diagnosis of uveitis. Baseline demographics including sex, age, and ethnicity were similar between the uveitis and no-uveitis groups. The presence of uveitis had a significant positive association with the use of the biologic drug infliximab (adjusted odds ratio [ORadj] = 1.66, P = 0.044), "lower jaw" involvement (ORadj = 1.60, P = 0.015), heel involvement (ORadj = 1.51, P = 0.023), and a diagnosis of arthritis associated with inflammatory bowel disease (ORadj = 1.92, P = 0.005). It had a significant negative association with the use of the biologic drug etanercept (ORadj = 0.49, P = 0.011) or a coexisting diagnosis of diabetes (ORadj = 0.02, P = 0.020). CONCLUSIONS: The relationship of uveitis to medication presumably reflects the choice of a specific tumor necrosis factor inhibitor in the setting of a history of uveitis. One prior study has also correlated heel pain and uveitis, thus supporting the validity of the association and suggesting potentially a common pathogenesis. Because diabetes has been proposed as a risk factor for uveitis, the negative association is surprising and may distinguish the pathogenesis of uveitis in association with SpA from other forms of uveitis.

Water-use efficiency and relative growth rate mediate competitive interactions in Sonoran Desert winter annual plants.

PREMISE OF THE STUDY: A functional approach to investigating competitive interactions can provide a mechanistic understanding of processes driving population dynamics, community assembly, and the maintenance of biodiversity. In Sonoran Desert annual plants, a trade-off between relative growth rate (RGR) and water-use efficiency (WUE) contributes to species differences in population dynamics that promote long-term coexistence. Traits underlying this trade-off explain variation in demographic responses to precipitation as well as life history and phenological patterns. Here, we ask how these traits mediate competitive interactions. • METHODS: We conducted competition trials for three species occupying different positions along the RGR-WUE trade-off axis and compared the effects of competition at high and low soil moisture. We compared competitive effect (ability to suppress neighbors) and competitive response (ability to withstand competition from neighbors) among species. • KEY RESULTS: The RGR-WUE trade-off predicted shifts in competitive responses at different soil moistures. The high-RGR species was more resistant to competition in high water conditions, while the opposite was true for the high-WUE species. The intermediate RGR species tended to have the strongest impact on all neighbors, so competitive effects did not scale directly with differences in RGR and WUE among competitors. • CONCLUSIONS: Our results reveal mechanisms underlying long-term variation in fitness: high-RGR species perform better in years with large, frequent rain events and can better withstand competition under wetter conditions. The opposite is true for high-WUE species. Such resource-dependent responses strongly influence community dynamics and can promote coexistence in variable environments.

Plus disease diagnosis in retinopathy of prematurity: vascular tortuosity as a function of distance from optic disk.

PURPOSE: To examine vascular tortuosity as a function of distance from the optic disk in infants with retinopathy of prematurity. METHODS: Thirty-four wide-angle retinal images from infants with retinopathy of prematurity were reviewed by 22 experts. A reference standard for each image was defined as the diagnosis (plus vs. not plus) given by the majority of experts. Tortuosity, defined as vessel length divided by straight line distance between vessel end points, was calculated as a function of distance from the disk margin for arteries and veins using computer-based methods developed by the authors. RESULTS: Mean cumulative tortuosity increased with distance from the disk margin, both in 13 images with plus disease (P = 0.007 for arterial tortuosity [n = 62 arteries], P < 0.001 for venous tortuosity [n = 58 veins] based on slope of best fit line by regression), and in 21 images without plus disease (P < 0.001 for arterial tortuosity [n = 94 arteries], P <0 .001 for venous tortuosity [n = 85 veins]). Images with plus disease had significantly higher vascular tortuosity than images without plus disease (P < 0.05), up to 7.0 disk diameters from the optic disk margin. CONCLUSION: Vascular tortuosity was higher peripherally than centrally, both in images with and without plus disease, suggesting that peripheral retinal features may be relevant for retinopathy of prematurity diagnosis.

Level Sets for Retinal Vasculature Segmentation Using Seeds from Ridges and Edges from Phase Maps.

In this paper, we present a novel modification to level set based automatic retinal vasculature segmentation approaches. The method introduces ridge sample extraction for sampling the vasculature centerline and phase map based edge detection for accurate region boundary detection. Segmenting the vasculature in fundus images has been generally challenging for level set methods employing classical edge-detection methodologies. Furthermore, initialization with seed points determined by sampling vessel centerlines using ridge identification makes the method completely automated. The resulting algorithm is able to segment vasculature in fundus imagery accurately and automatically. Quantitative results supplemented with visual ones support this observation. The methodology could be applied to the broader class of vessel segmentation problems encountered in medical image analytics.