Visual outcomes and predictors in optic pathway glioma: a single centre study

Abstract

Background/AimsOptic pathway gliomas (OPGs) may cause progressive visual loss despite chemotherapy. Newer, less toxic treatments might be given earlier, depending on visual prognosis. We aimed to investigate the prognostic value of visual evoked potentials (VEP) and optical coherence tomography (OCT). MethodsA retrospective study of OPG patients (treated 2003-2017) was conducted. Primary outcome was PEDIG category visual acuity in better and worse eyes (good <= 0.2, moderate 0.3-0.6 and poor >=0.7 logMAR). Binary logistic regression analysis was used to identify predictors of these outcomes. Results60 patients (32 Neurofibromatosis type 1 [NF1] and 28 sporadic) had median presentation age 49 months (range 17-183) (NF1) and 27 months (range 4-92) (sporadic). Median follow up was 82 months (range 12-189 months). At follow up 24/32 (75%) of NF1 children and 14/28 (50%) of sporadic children had good better eye visual acuity and 11/32 (34%) of NF1 children and 15/28 (54%) of sporadics had poor worse eye acuity. Mean peripapillary retinal nerve fibre layer (RNFL) thickness predicted good better eye final acuity (OR 0.799, 95%CI 0.646-0.987, p=0.038). Presenting with visual symptoms (OR 0.22 95% CI 0.001-0.508, p=0.017) and poorer VEP scores (OR 2.35 95% CI 1.1-5.03, p=0.027) predicted poor worse eye final acuity. 16 children had homonymous hemianopias at follow up, predicted by poor presenting binocular VEP score (OR 1.449 95%CI 1.052-1.995, p=0.02). ConclusionsWe found that both RNFL thickness on OCT and VEP were useful in predicting future visual acuity and visual field and potentially in planning treatment. We had a high prevalence of homonymous hemianopia.

Visual Deficits and Diagnostic and Therapeutic Strategies for Neurofibromatosis Type 1: Bridging Science and Patient-Centered Care

“…In response to visual stimulation, VEPs record the generation of electrical impulses from the visual cortex in the brain through electrodes placed in the scalp [ 31 , 113 ]. Reduced amplitudes or delayed responses indicate the magnitude of visual deficits; however, they cannot reveal the nature of the vision loss, and some reports question the correlation between VEP evaluations and vision loss [ 114 , 115 , 116 ].…”

The Present and Future of Optic Pathway Glioma Therapy

“…Visual decline serves as a prominent criterion for determining the optimal timing of treatment initiation in OPGs. However, it is critical to be able to identify the predictive factors of visual decline in order to anticipate the clinical evolution and intervene therapeutically before there is a significant visual impairment [108]. Several studies have endeavored to establish a therapeutic window that exploits the lag between the onset of RGC loss and the initial manifestation of declining visual acuity, typically occurring after a 50% reduction in RGC count [109].…”

“…Several studies have endeavored to establish a therapeutic window that exploits the lag between the onset of RGC loss and the initial manifestation of declining visual acuity, typically occurring after a 50% reduction in RGC count [109]. Diagnostic modalities employed in this context include optical coherence tomography (OCT) for measuring the retinal nerve fiber layer (RNFL) and visual evoked potentials (VEPs) [108]. Neuro-ophthalmological manifestations depend upon tumor localization, such as vision loss due to monocular or bilateral optic neuropathy when the optic nerves are involved, bitemporal hemianopsia in cases involving the optic chiasm, or homonymous hemianopsia in retrochiasmatic location [110].…”

Neurofibromatosis Type 1-Associated Optic Pathway Gliomas: Current Challenges and Future Prospects

“…67 While VEP has nearly 90% sensitivity at detecting the presence of an OPG, the specificity is much lower, and reports conflict on whether it correlates with vision loss. [78][79][80] In addition, VEP requires patient cooperation for reliable results, which can be difficult in children with NF1 due to their young age and cognitive comorbidities.…”