The diagnostic accuracy and prognostic value of OCT for the evaluation of the visual function in children with a brain tumour: A systematic review.

PURPOSE: To systematically review the evidence on the diagnostic accuracy and prognostic value of retinal optical coherence tomography (OCT) to detect visual acuity (VA) or visual field (VF) loss in children with a brain tumour. METHODS: PubMed, Embase and Cochrane Library databases were searched from inception to February 2021. We included studies evaluating retinal OCT and standard visual function parameters (VA and or VF) in children with a brain tumour. Two authors independently extracted data from each included study. They also assessed the methodological quality of the studies using the QUADAS-2 or QUIPS tool. The diagnostic accuracy of OCT was evaluated with receiver operating characteristic analysis, sensitivity, specificity, positive predictive value and negative predictive value. The prognostic value of OCT was evaluated with predictive measures (odds ratio). RESULTS: We included five diagnostic studies, with a total of 186 patients, all diagnosed with optic pathway glioma. No prognostic studies were eligible for inclusion. Included studies evaluated either retinal nerve fiber layer (RNFL) thickness or ganglion cell layer-inner plexiform layer (GCL-IPL) thickness. There was considerable heterogeneity between OCT devices, OCT protocols, visual function parameters and threshold values. Sensitivity and specificity for RNFL thickness measurement ranged from 60.0% to 100.0% and 76.6% to 100%, respectively. For GCL-IPL thickness measurement, area under the curve ranged from 0.91 to 0.98 for different diameters. CONCLUSION: The literature regarding the diagnostic accuracy and prognostic value of OCT parameters in children with a brain tumour is scarce. Due to heterogeneity and a considerable risk of bias of included studies, we cannot draw solid conclusions regarding the accuracy of retinal OCT. Future research should investigate the potential of OCT as diagnostic and prognostic tool for the evaluation of the visual function and detection of visual impairment in children with any type of brain tumour.

Vision Outcomes for Pediatric Patients With Optic Pathway Gliomas Associated With Neurofibromatosis Type I: A Systematic Review of the Clinical Evidence.

Children with neurofibromatosis type I (NF1) have a higher predisposition for low-grade astrocytomas of the optic pathway, commonly referred to as optic pathway gliomas (OPGs). OPGs can result in visual deterioration. Treatment outcomes in OPG-NF1 management are often reported around tumor stabilization. We sought to compare vision outcomes associated with different OPG treatment strategies to inform about this important functional metric. A meta-analysis exploring the different modalities to treat children with OPG-NF1 was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using multiple databases. Of the 113 articles identified in the search, 23 full text articles, representing 564 patients, were included for review. These articles included retrospective, prospective, and randomized controlled studies on observation (n=9), chemotherapy (n=19), radiation therapy (n=6), and surgery (n=7). Of the patients undergoing observation, 87% (60/69) demonstrated stable acuity. In the chemotherapy studies, 27.3% (72/264) demonstrated improved acuity/visual field and/or visual-evoked potential amplitudes, 39.4% (104/264) stable acuity, and 33.3% (88/264) deterioration. Both the radiation and surgical treatments reported worsening acuity at 90.9% (10/11) and 73.3% (11/15), respectively. Causal associations are not known. Indications for and timing of treatment choice warrant larger scale study to provide further understanding.

Role of visual evoked potentials and optical coherence tomography in the screening for optic pathway gliomas in patients with neurofibromatosis type I.

PURPOSE: The purpose of the present study was to compare visual function assessment, visual evoked potential, and optical coherence tomography with measurement of retinal nerve fiber layer thickness for the diagnosis of optic pathway glioma in children with neurofibromatosis type 1. METHODS: This retrospective observational study included patients with neurofibromatosis type 1 who underwent brain magnetic resonance imaging scan, visual evoked potential study, and peripapillary retinal nerve fiber layer evaluation by optical coherence tomography. Patients were tested with pattern-reversal visual evoked potential and with flash visual evoked potential in case of poor cooperation. Optical coherence tomography was performed with HRA Spectralis (Heidelberg Engineering, Heidelberg, Germany). The area under the curve of receiver operating characteristic curves was used to evaluate the accuracy of each parameter for diagnosing optic pathway glioma. RESULTS: In all, 110 patients with neurofibromatosis type 1 were included in the study. Fifty of them had an optic pathway glioma diagnosed with magnetic resonance imaging, while 60 did not. Global retinal nerve fiber layer thickness demonstrated the highest diagnostic power for discriminating patients with and without optic pathway glioma (area under the curve = 0.758, sensitivity = 65.3%, specificity = 83.3%), followed visual acuity (area under the curve = 0.723, sensitivity = 51.1%, specificity = 91.7%) and P100 of visual evoked potential (area under the curve = 0.712, sensitivity = 69.6%, specificity = 63.8%). CONCLUSION: The results of the present study showed that the measurement of retinal nerve fiber layer thickness was the most efficient test for discriminating patients with and without optic pathway glioma. Brain magnetic resonance imaging remains the gold standard to confirm the diagnosis of optic pathway glioma. Longitudinal studies are required to define if the early detection of tumors with optical coherence tomography could prevent vision loss and morbidity.

Visual outcomes following everolimus targeted therapy for neurofibromatosis type 1-associated optic pathway gliomas in children.

Data for visual acuity (VA) after treatment of neurofibromatosis type 1-associated optic pathway gliomas (NF1-OPGs) are limited. We retrospectively collected VA, converted to logMAR, before and after targeted therapy with everolimus for NF1-OPG, and compared to radiologic outcomes (14/18 with NF1-OPG, 25 eyes [three without quantifiable vision]). Upon completion of treatment, VA was stable in 19 eyes, improved in four eyes, and worsened in two eyes; visual and radiologic outcomes were discordant. In summary, the majority of children with NF1-OPG exhibited stabilization of their VA after everolimus treatment. A larger, prospective study will help delineate visual outcomes after targeted therapy.

Visual field fluctuations correlating with the menstrual cycle in a patient with optic pathway glioma.

Optic pathway gliomas are commonly associated with vision loss in children. We describe an 18-year-old woman with neurofibromatosis, type 1 and an optic nerve glioma who showed reproducible visual field defects that worsened midmenstrual cycle and returned to baseline during menses. To our knowledge, this is the first reported case of visual field fluctuations in a patient with an optic nerve glioma that correlated with her menstrual cycle.

Neurofibromatosis tipos 1 y 2 / Neurofibromatosis type 1 and 2

La neurofibromatosis (NF) comprende un grupo de enfermedades genéticas de herencia autosómica dominante, que se clasifican de la siguiente manera: neurofibromatosis tipo 1 (NF1), neurofibromatosis tipo 2 (NF2) y schwannomatosis (también conocida como neurofibromatosis tipo 3). Esta última es una enfermedad muy infrecuente, con una prevalencia aproximada de 1/126 000 personas, por lo que solo profundizaremos las dos primeras. La NF1, también conocida como la enfermedad de Von Recklinghausen, es la más frecuente de las tres y afecta principalmente la piel y el sistema nervioso periférico. Se caracteriza por la presencia de máculas "café con leche", pecas axilares o inguinales, nódulos de Lisch (hamartomas en el iris) y neurofibromas (tumores de la vaina de nervios periféricos). Otras manifestaciones menos frecuentes, aunque de mayor gravedad, incluyen gliomas del nervio óptico, meningiomas, neurofibromas malignos, escoliosis y displasia de la tibia. Su diagnóstico se suele realizar al nacimiento o durante los primeros años de vida, y se estima que un 50% de quienes la padecen presenta dificultades cognitivas. No hay datos concluyentes sobre la mortalidad en los pacientes con NF1, aunque se sabe que la expectativa de vida es menor que en la población general. La NF2 tiene una prevalencia considerablemente menor que la NF1 y su inicio es más tardío, afectando principalmente a adultos jóvenes. La presentación clínica típica se caracteriza por acúfenos, hipoacusia y ataxia en contexto de la presencia de schwannomas vestibulares bilaterales. Otros hallazgos menos frecuentes incluyen schwannomas de nervios periféricos, meningiomas, ependimomas o astrocitomas. La esperanza de vida es de unos 36 años, con una supervivencia media desde el momento del diagnóstico de 15 años. (AU)

Neurofibromatosis (NF) includes a group of genetic diseases with an autosomal-dominant inheritance pattern, and they are classified as follows: Neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and Schwannomatosis (also known as neurofibromatosis type 3). This last one is a very rare disease, with an approximate prevalence of 1/126000, so we will only deepen in the first two. NF1, also known as von Recklinghausen disease, is the most frequent, and mainly affects the skin and peripheral nervous system. Its typical manifestations are the presence of café-au-lait macules, axillary or inguinal freckles, Lisch nodules (hamartomas in the iris) and neurofibromas (peripheral nerve sheath tumors). Less frequent manifestations, although more serious, include optic nerve gliomas, meningiomas, malignant neurofibromas, scoliosis and tibial dysplasia. The diagnosis is usually made at birth or during the first years of life, and approximately 50% of patients present cognitive difficulties. There is no conclusive data on mortality in patients with NF1, although it is known that life expectancy is lower than in general population. NF2 has a considerably lower prevalence than NF1, and its onset is later in life, mainly affecting young adults. Its typical clinical presentation is characterized by tinnitus, hearing loss and ataxia in the context in the presence of bilateral vestibular schwannomas. Less frequent findings include peripheral nerve schwannomas, meningiomas, ependymomas or astrocytomas. Life expectancy is about 36 years old, with a median survival from the moment of diagnosis of 15 years. (AU)

Assessment of the visual pathways in patients with neurofibromatosis-1 by 3S-space technique with 3-Tesla MRI

Background/aim/AIM: We aimed to evaluate the size/tortuosity of the optic nerve (ON) and the dilatation of the ON sheath (ONS) in neurofibromatosis type 1 (NF-1) patients with 3T-MRI, and to assess the usefulness of 3D-SPACE in imaging the optic pathway, ON, and ONS in NF-1 patients. Materials and methods: Twenty consecutive NF-1 patients without optic pathway glioma (OPG) (Group 1), 16 consecutive NF-1 patients with OPG (Group 2), and 19 controls were included in this study. The thickness and tortuosity of the ON and the diameter of the ONS were measured on STIR and 3D-SPACE images. Results: The thickness of the ON was similar in all groups on STIR images (P>0.05). The mean ONS diameter was higher in Group 2 with this sequence (P=0.009). Controls had significantly lower grades of ON tortuosity than Groups 1 and 2 (P=0.001), and Group 1 had significantly lower ON tortuosity compared to Group 2 (P=0.001). Severe tortuosity was only detected in Group 2. Conclusion: ON tortuosity and ONS diameter were increased in NF-1 patients in the presence of OPG. High-resolution cranium imaging with the 3D-SPACE technique using 3T-MRI seems to be helpful for detection of the optic pathway morphology and pathologies in NF-1 patients.

Central and peripheral steady-state visual evoked potentials in children with optic pathway gliomas.

PURPOSE: Treatment of optic pathway gliomas is prompted by neuroradiological evidence of tumor growth, usually associated with progressive visual loss. Despite therapy, approximately 40% will show visual deterioration. Treatment outcome is largely based on the preservation of vision. However, current visual function assessment is often unreliable in children with optic pathway gliomas who have limited collaboration. Thus, there is a need for new clinical tools to evaluate visual functions in these children. The aim of the study was to assess the value of steady-state visual evoked potentials as a tool to assess function in the central and peripheral visual fields of children with optic pathway gliomas. METHOD: Ten patients with optic pathway gliomas and 33 healthy controls (ages 3 to 18 years) were tested using steady-state visual evoked potentials. The dartboard stimulus consisted of one central circle alternating at 16 reversals/s and one peripheral hoop alternating at 14.4 reversals/s, separated by a hoop of gray space. It was presented monocularly at 30% and 96% contrasts. RESULTS: Results indicated that central signal-to-noise ratios were significantly lower in children with optic pathway gliomas compared to controls. However, no significant group difference was detected in the peripheral visual field. CONCLUSION: Steady-state visual evoked potentials could eventually be implemented in the clinical assessment and follow-up of central visual field deficits in uncooperative or nonverbal children but seem to have limited usefulness for evaluation of peripheral visual field deficits. Additional studies are needed to identify testing parameters for full visual field assessment.

Visual function assessed by visually evoked potentials in optic pathway low-grade gliomas with and without neurofibromatosis type 1.

PURPOSE: To investigate the contribution of full-field transient pattern-reversal visually evoked potentials (PRVEP) on cross-sectional evaluations of visual function in patients with and without neurofibromatosis type 1 (NF1) affected by optic pathway low-grade gliomas (OPLGG). METHODS: Participants were children and adolescents referred for visual function evaluation and receiving treatment for OPLGG, linked (NF1-OPLGG) or not to NF1 (Non-NF1-OPLGG). An age-adjusted control group was included for comparison. Monocular full-field PRVEPs were recorded from each eye in accordance with ISCEV standards. Parameters of peak-to-peak P100 amplitude (µV) and P100 peak time (ms) were measured. Cutoff normative values obtained from controls for 15' and 60' check sizes were ≥ 9.0 µV for N75-P100 amplitude and ≤ 103.0 ms for P100 peak time. The association of age, gender, tumor resection and NF1 with P100 amplitude reduction and P100 peak time delay was explored by Firth logistic regression modeling. RESULTS: Participants were 30 patients (15 males, 60% Non-NF1) with ages from 3.6 to 19.9 years (mean ± SD = 9.2 ± 3.8 years; median = 8.4 years) and 19 controls (12 males) with ages from 3.7 to 19.9 years (mean ± SD = 10.4 ± 4.9 years; median = 9.5 years). Overall, 68% of tested eyes presented reduced P100 amplitudes for both check sizes (46% in the NF-1 and 83% in the Non-NF1) and delayed P100 for both check sizes (38% in NF1 and 89% in Non-NF1). Absence of NF1 adjusted for age, gender and tumor resection was significantly associated with marginally reduced P100 amplitude for 15' checks [odds ratio (OR): 6.26; 95% confidence interval (CI) = 0.96-40.94; p = 0.055]. CONCLUSIONS: Full-field PRVEP on cross-sectional evaluations contributed to detect visual dysfunction in two-thirds of patients with OPLGG by highlighting subclinical evidence of visual loss. Abnormalities were more frequent and more severe in OPLGG not linked to NF1 than in NF1-OPLGG; however, there was a difference in surgical management between these groups. PRVEP parameters may provide reliable evidence of visual pathway involvement in OPLGG, helping to hasten treatment before optic atrophy is detected.

Optic Pathway Gliomas in Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1) is one of the most common brain tumor predisposition syndromes, in which affected children are prone to the development of low-grade gliomas. While NF1-associated gliomas can be found in several brain regions, the majority arise in the optic nerves, chiasm, tracts, and radiations (optic pathway gliomas; OPGs). Owing to their location, 35-50% of affected children present with reduced visual acuity. Unfortunately, despite tumor stabilization following chemotherapy, vision does not improve in most children. For this reasons, more effective therapies are being sought that reflect a deeper understanding of the NF1 gene and the use of authenticated Nf1 genetically-engineered mouse strains. The implementation of these models for drug discovery and validation has galvanized molecularly-targeted clinical trials in children with NF1-OPG. Future research focused on defining the cellular and molecular factors that underlie optic glioma development and progression also has the potential to provide personalized risk assessment strategies for this pediatric population.

Validation of an automated tractography method for the optic radiations as a biomarker of visual acuity in neurofibromatosis-associated optic pathway glioma.

INTRODUCTION: Fractional anisotropy (FA) of the optic radiations has been associated with vision deficit in multiple intrinsic brain pathologies including NF1 associated optic pathway glioma, but hand-drawn regions of interest used in previous tractography methods limit consistency of this potential biomarker. We created an automated method to identify white matter tracts in the optic radiations and compared this method to previously reported hand-drawn tractography. METHOD: Automated tractography of the optic radiation using probabilistic streamline fiber tracking between the lateral geniculate nucleus of the thalamus and the occipital cortex was compared to the hand-drawn method between regions of interest posterior to Meyer's loop and anterior to tract branching near the calcarine cortex. Reliability was assessed by two independent raters in a sample of 20 healthy child controls. Among 50 children with NF1-associated optic pathway glioma, the association of FA and visual acuity deficit was compared for both tractography methods. RESULTS: Hand-drawn tractography methods required 2.6±0.9min/participant; automated methods were performed in <1min of operator time for all participants. Cronbach's alpha was 0.83 between two independent raters for FA in hand-drawn tractography, but repeated automated tractography resulted in identical FA values (Cronbach's alpha=1). On univariate and multivariate analyses, FA was similarly associated with visual acuity loss using both methods. Receiver operator characteristic curves of both multivariate models demonstrated that both automated and hand-drawn tractography methods were equally able to distinguish normal from abnormal visual acuity. CONCLUSION: Automated tractography of the optic radiations offers a fast, reliable and consistent method of tract identification that is not reliant on operator time or expertise. This method of tract identification may be useful as DTI is developed as a potential biomarker for visual acuity.

Growth hormone excess in children with neurofibromatosis type-1 and optic glioma.

In children with neurofibromatosis type 1 (NF1) and optic pathways glioma (OPG), growth hormone (GH) excess has been rarely reported and mainly associated to central precocious puberty. The aim of our study is to evaluate the prevalence of GH excess, the association with central precocious puberty, the relation with tumor site and the evolution over time in a large cohort of children with NF1 and OPG. Sixty-four NF1 children with OPG were evaluated. Patients with stature and/or height velocity >2 SD for age were studied for GH secretion. Seven out of 64 children (10.9%) with NF1 and optic pathways glioma showed GH excess, isolated in 5 cases and associated to central precocious puberty in 2. All the children with GH excess had a tumor involving the chiasma. Children with GH excess underwent medical treatment with lanreotide and a minimum clinical/biochemical follow up of 2 years is reported. The present study demonstrates that GH excess should be considered as a relative frequent endocrine manifestation in NF1 patients, similarly to central precocious puberty. Therefore, these patients should undergo frequent accurate auxologic evaluations. On the other hand, an increase in height velocity in children with NF1, even despite normal ophthalmological exams, can suggest the presence of OPG and therefore represents an indication to perform brain MRI.

Natural history of optic pathway gliomas in a cohort of unselected patients affected by Neurofibromatosis 1.

Optic pathway glioma (OPG) represents the most common central nervous system tumor in children with Neurofibromatosis type-1 (NF1). Although overall survival is usually good, no clear prognostic factors have been identified so far. We assessed the natural history of OPG in a cohort of unselected patients affected by NF1. We retrospectively evaluated 414 consecutive patients affected by NF1 and referred to our NF1 clinic before age 6. Average follow-up was 11.9 years: 52 out of 414 patients had OPG with a total cumulative incidence of 15.4% at age 15 (Kaplan-Meier estimate) and a statistically significant difference according to sex. Brain and orbit MRI was performed in 44.7% of patients: 34.6% for screening purposes and 65.4% because of the presence of neurological, ocular or other symptoms. OPG was diagnosed in 12.5% of cases in the first group, whereas in 36.4% in the latter group (p = 0.001). Clinical management was conservative in most patients, while 8 of them underwent therapy mainly because of visual deterioration. OPG was diagnosed earlier in treated patients, but the difference was not statistically significant. Conversely, all patients who underwent screening MRI had normal visual outcome. In conclusion, OPG location does not correlate with need for treatment; female patients were more frequently affected by OPG but not more frequently treated. OPG diagnosis by screening MRI does not affect the natural history of the tumor.

Increased Tissue Stiffness in Tumors from Mice with Neurofibromatosis-1 Optic Glioma.

Children with neurofibromatosis type 1 (NF1) cancer predisposition syndrome are prone to the development of low-grade brain tumors (gliomas) within the optic pathway (optic gliomas). One of the key obstacles to developing successful therapeutic strategies for these tumors is the striking lack of information about the mechanical properties that characterize these tumors relative to non-neoplastic optic nerve tissue. To study the physical changes that may occur when an optic nerve glioma is present, we employed atomic force microscopy to measure the stiffness of healthy versus tumor-bearing optic nerve tissue. We found that the average elastic moduli of non-neoplastic and tumor-bearing optic nerves were ∼3 and ∼6 kPa, respectively. Based on previous studies implicating changes in extracellular matrix remodeling in other, related optic nerve pathological states, we found decreased expression of one major metalloproteinase protein (MMP-2) and unchanged expression of lysyl oxidase and a second metalloproteinase, MMP-9, in murine optic gliomas relative to normal non-neoplastic optic nerve. Collectively, these observations suggest a productive interplay between physical properties of mouse optic nerve gliomas and the extracellular matrix.

Optic pathway glioma in children: 10 years of experience in a single institution.

Optic pathway glioma (OPG) is a rare brain tumor that occurs more commonly during early childhood and is frequently associated with neurofibromatosis type 1 (NF1). In this study, our aim was to describe the characteristics, management, and outcome of patients with OPG. We retrospectively analyzed the clinical charts of all children diagnosed with OPG at our institution from 2003 to 2013. Twenty children (11 boys and 9 girls, median age: 5 and 3/12 years; NF1: 15/20) were diagnosed with OPG. The diagnosis was based on magnetic resonance imaging (MRI) findings. A biopsy was useful in 3 patients. The main reason for seeking medical advice was decreased vision (7/20 patients), whereas in 10/20 patients, the diagnosis was established during the routine follow-up for their NF1. Fifteen patients demonstrated MRI findings of optic nerve involvement and/or chiasmal tumor, whereas in 5 children, postchiasmal structures were also involved. Sixteen patients (16/20) received carboplatin-based regimens, whereas 4/20 patients were only under close observation. Six patients showed deterioration of visual acuity and/or imaging findings at the end of treatment and/or during their follow-up. Three of them (3/6) underwent tumor resection, whereas 1 (1/6) received radiation treatment. None of our patients had total blindness from both eyes. Half of our patients were diagnosed during follow-up for their NF1, the incidence of which was high in our group. Our data suggest that chemotherapy helps in the preservation of vision in the majority of children.

Treatment and Outcome in 65 Children with Optic Pathway Gliomas.

INTRODUCTION: Optic pathway gliomas (OPGs) are rare neoplasms in children with an unpredictable clinical course. There is significant controversy regarding the optimal management and outcome of these patients. METHODS: Charts of all patients with OPG diagnosed and treated at Children's Cancer Hospital Egypt between July 2007 and July 2014 were retrospectively reviewed. We evaluated the roles of surgical, ophthalmologic, endocrinologic, neurologic, and treatment aspects of care. RESULTS: Sixty-five patients were included in this study, with a mean age of 5.3 years. OPGs were chiasmatic (n = 25), optic nerve (n = 18), hypothalamic (n = 7), and chiasmatic/hypothalamic (n = 7). Extensive involvement of the optic pathway was seen in an additional 8 patients. Twenty cases had neurofibromatosis type 1. Four cases underwent surgical debulking, and 28 were biopsied (16 open, 11 stereotactic, and 1 endoscopic). Nine of the 18 optic nerve tumors were managed by total excision. Twenty-four patients did not undergo any surgical intervention. Forty-five patients received chemotherapy. Histopathology revealed pilocytic (n = 20), pilomyxoid (n = 15), fibrillary astrocytoma (n = 4), and grade I papillary-glioneuronal tumor (n = 1). Nonrepresentative sample (n = 1). The 4-year overall survival rate was 86.3% with mean follow-up period of 32.2 months. CONCLUSION: The initial role of surgery in newly developed OPG is biopsy for tissue diagnosis and relief of the hydrocephalus, if present, followed by chemotherapy. Chemotherapy decreases or stabilizes the tumor size in most cases, leading to preservation of both visual and endocrinal functions. The most significant prognostic factor confirmed in this study was the age of the patient.

Longitudinal Change of Circumpapillary Retinal Nerve Fiber Layer Thickness in Children With Optic Pathway Gliomas.

PURPOSE: To evaluate longitudinal changes in circumpapillary retinal nerve fiber layer (RNFL) thickness, as measured by spectral-domain optical coherence tomography (SD OCT), in children with optic pathway gliomas. DESIGN: Longitudinal cohort study. METHODS: Global and quadrant-specific circumpapillary RNFL thickness measures were acquired using either a hand-held SD OCT during sedation or a table-top SD OCT in children old enough to cooperate. Vision loss was defined as either a 0.2 logMAR decline in visual acuity or progression of visual field. Percent change in circumpapillary RNFL thickness in eyes experiencing vision loss was compared to eyes with stable vision. RESULTS: Fifty-five eyes completed 250 study visits. Ten eyes (18%) from 7 patients experienced a new episode of vision loss during the study and 45 eyes (82%) from 39 patients demonstrated stable vision across study visits. Percent decline of RNFL thickness between the baseline visit and first event of vision loss event was greatest in the superior (-14%) and inferior (-10%) quadrants as well as global average (-13%). Using a threshold of ≥10% decline in RNFL, the positive and negative predictive value for vision loss when 2 or more anatomic sectors were affected was 100% and 94%, respectively. CONCLUSIONS: Children experiencing vision loss from their optic pathway gliomas frequently demonstrate a ≥10% decline of RNFL thickness in 1 or more anatomic sectors. Global average and the inferior quadrant demonstrated the best positive and negative predictive values. Circumpapillary RNFL is a surrogate marker of vision and could be helpful in making treatment decisions for children with optic pathway gliomas.