Optic nerve involvement in CACNA1F-related disease: observations from a multicentric case series.

BACKGROUND: Congenital Stationary Night Blindness (CSNB) constitutes a group of non-progressive retinal disorders characterized by disturbances in scotopic vision and/or by a delay in adaptation to darkness, as well as by low visual acuity, myopia, nystagmus, and strabismus. Color vision and fundus appearance tend to be normal. To date, several CACNA1F gene variants have been linked to a CSNB phenotype but only few reports have focused on the optic nerve in this disease. MATERIALS AND METHODS: Twelve patients underwent standard ophthalmological and genetic evaluation including spectral domain optical coherence tomography (SD-OCT), full-field electroretinography (ffERG), kinetic perimetry, fundus photography, magnetic resonance imaging (MRI), and next-generation sequencing (NGS). Bilateral thinning of the peripapillary nerve fiber layer (pRNFL) and the ganglion cell complex (GCC) supported involvement of the optic nerves. MRI, when available, was assessed for gross intracranial optic pathway abnormalities. RESULTS: All patients were shown to carry pathogenic variants in the CACNA1F gene, and all showed signs of optic nerve involvement. All patients showed a certain degree of myopic refractive error. Low average pRNFL thickness was evident in all patients. In three of them, pRNFL thickness was evaluated longitudinally and was proven to be stable over time. MRI imaging was unremarkable in all cases. CONCLUSION: Our data support the hypothesis that CACNA1F could be related to early-onset or congenital optic nerve involvement without any signs of a progressive optic neuropathy. Even though additional data from larger cohorts and longer follow-up periods are needed to further support and confirm our findings, there is a clear significance to our findings in the preparation for future CACNA1F gene therapy trials.

Optical Coherence Tomography Significance in Managing Early Onset of Optic Pathway Gliomas in Children Younger than 5 Years of Age-A Retrospective Study.

We aimed to investigate the significance of optical coherence tomography (SD-OCT) in managing pediatric optic pathway gliomas (OPGs) in children younger than 5 years of age. A retrospective monocentric study was conducted. SD-OCT scans were obtained using the handheld iVue system to assess peripapillary retinal nerve fibre layer (pRNFL) thickness at three time points: baseline (OCT1), end of treatment (OCT2), and at last follow-up (OCT3). We compared the median value of pRNFL (and interquartile range-IQR) at different follow-up times and in different sub-groups (stable disease-SD, partial response-PR, and progression disease-PD). Thirteen children younger than 5 years of age were included. The Median follow-up time was 3.9 years (IQR 1.2). Six patients showed a pRNFL change of more than 10% during follow-up. Seven patients showed PD during follow-up. Median pRNFL at baseline was 81.5 µm (IQR 31.5); median pRNFL at the end of treatment was 73 µm (IQR 33); median pRNFL at last follow-up was 72 µm (IQR 38.5). The mean pRNFL at baseline was significantly lower than the mean normative values. Only subjects with PD showed pRNFL change close to statistical significance. This study confirms the role of SD-OCT in managing OPGs for therapeutic decisions and strategy planning of visual rehabilitation.

Binocular Rivalry Measured 2 Hours After Occlusion Therapy Predicts the Recovery Rate of the Amblyopic Eye in Anisometropic Children.

PURPOSE: Recent studies on adults have shown that short-term monocular deprivation boosts the deprived eye signal in binocular rivalry, reflecting homeostatic plasticity. Here we investigate whether homeostatic plasticity is present also during occlusion therapy for moderate amblyopia. METHODS: Binocular rivalry and visual acuity (using Snellen charts for children) were measured in 10 children (mean age 6.2 ± 1 years) with moderate anisometropic amblyopia before the beginning of treatment and at four intervals during occlusion therapy (2 hours, 1, 2, and 5 months). Visual stimuli were orthogonal gratings presented dichoptically through ferromagnetic goggles and children reported verbally visual rivalrous perception. Bangerter filters were applied on the spectacle lens over the best eye for occlusion therapy. RESULTS: Two hours of occlusion therapy increased the nonamblyopic eye predominance over the amblyopic eye compared with pretreatment measurements, consistent with the results in adults. The boost of the nonamblyopic eye was still present after 1 month of treatment, steadily decreasing afterward to reach pretreatment levels after 2 months of continuous occlusion. Across subjects, the increase in nonamblyopic eye predominance observed after 2 hours of occlusion correlated (rho = -0.65, P = 0.04) with the visual acuity improvement of the amblyopic eye measured after 2 months of treatment. CONCLUSIONS: Homeostatic plasticity operates during occlusion therapy for moderate amblyopia and the increase in nonamblyopic eye dominance observed at the beginning of treatment correlates with the amblyopic eye recovery rate. These results suggest that binocular rivalry might be used to monitor visual cortical plasticity during occlusion therapy, although further investigations on larger clinical populations are needed to validate the predictive power of the technique.

Factors influencing severity of and recovery from anisometropic amblyopia.

PURPOSE: To evaluate the correlation between the degree of anisometropia with depth of amblyopia and presence of stereopsis. METHODS: A retrospective chart review of 119 patients treated during 1995-2004 was carried out. All patients had undergone a full ophthalmological examination. Inclusion criteria were: anisometropia >1 diopter (spherical and/or cylindrical), age at first examination between 2 and 8 years, no previous optical correction, absence of ocular and neurological disorders, absence of ocular motility disorders, and minimum follow-up of 2 years (mean 7.9 +/- 4.3). Optical correction was prescribed at first visit and, at a second visit, the need for patching or penalization was evaluated. RESULTS: The results show a correlation between the degree of anisometropia and visual acuity at first visit (p < 0.001). There were, however, several subjects with good levels of visual acuity despite considerable anisometropia, and also subjects where mild or moderate anisometropia was sufficient to induce a severe amblyopia. Compared to other types of anisometropia, anisomyopic patients appeared to have a higher degree of binocular vision recovery when corrected optically. First evaluation with the presence of good stereoacuity seems to be a prognostic indicator for amblyopic recovery. CONCLUSIONS: This study demonstrates the difficulty of developing a guideline for screening and treatment of anisometropia. Even though there seems to be a correlation between type and degree of anisometropia in a majority of patients, there is also a significant number of cases that do not follow this pattern. Another important observation is the presence of binocular vision at the first evaluation as a good prognostic indicator for visual recovery with optical correction alone, even without penalization therapy.