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

Optic 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).

A 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.

60 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).

We found that both RNFL thickness on OCT and VEP were useful in predicting future visual acuity and vision and potentially in planning treatment. We had a high prevalence of homonymous hemianopia.