Portable OCT retinal evaluation of children undergoing vigabatrin treatment

Abstract

Purpose : The antiepileptic drug for infantile spasms, vigabatrin (VGB), is sometimes associated with visual toxicity in young children. Retinal nerve fiber layer (RNFL) thickness attenuation with VGB use has been shown in older children. In this prospective, cross-sectional study, our purpose was to evaluate RNFL thickness using handheld optical coherence tomography (HH-OCT). Specifically, we evaluated the intra-visit reliability and clinical utility of noninvasive HH-OCT to monitor for VGB-related retinal changes in children ≤ 3 years of age.

Methods : After consent, 20 patients (9.5±6.1 months) taking VGB were recruited. Eight children from this group completed a 4-month follow-up assessment. Following a clinical sedated ERG, we performed HH-OCT in sedated children lying supine using a flexible handheld OCT (Envisu™, Bioptigen, NC, USA). The RNFL thickness was evaluated with a segmentation software; and intra-visit reliability of the RNFL thickness was calculated using intraclass correlation coefficient (ICC) statistics. The first-visit results were used as controls for comparisons within the follow-up group to detect changes in RNFL thickness. Decline in RNFL thickness >10% was considered abnormal.

Results : The HH-OCT was successfully recorded in all 20 children during the initial visit, and in all 8 children who had follow-up testing. The average circumpapillary RNFL thickness (µm) in the superior, inferior, nasal, and temporal quadrants were 112.0±22.6, 105.8±23.7, 73.4±18.4, and 67.6±20.0, respectively. These results are within published normal limits for children aged 0.79-13 years. High intra-visit reliability was shown with an average ICC of 0.79 (range 0.55-0.88) across 4 retinal divisions. During the second visit, the average overall RNFL thickness reduced from 86.2µm to 79.0µm, with comparative sparing of temporal quadrant which showed a decline of only 2%. Half of the patients at follow-up demonstrated a decline >10%. Specifically, one child showed reductions within all 4 quadrants, and 3 children had changes in 2 quadrants not including the temporal quadrant.

Conclusions : In this cohort, HH-OCT was a well-tolerated monitoring technique in children, and RNFL assessment using HH-OCT showed intra-visit reliability. The relative sparing of temporal quadrant RNFL thickness agree with previous studies. These results support the notion that the HH-OCT may be a useful structural biomarker for young children taking VGB.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.