Effect of peripapillary retinoschisis on retinal nerve fibre layer thickness measurement in glaucomatous eyes

Background/aims To investigate the effect of peripapillary retinoschisis on the peripapillary retinal nerve fibre layer (RNFL) thickness measurement by using optical coherence tomography (OCT) in glaucomatous eyes. Methods We included 19 glaucomatous eyes of 19 subjects with peripapillary retinoschisis defined as the splitting of the peripapillary RNFL with schisis cavities (retinoschisis group) and 38 age-matched, refractive error-matched and visual field mean deviation-matched glaucomatous eyes from 38 subjects without peripapillary retinoschisis (control group) that had undergone RNFL thickness measurements by using OCT. RNFL thickness was compared between the two groups. For the retinoschisis group, the RNFL thicknesses prior to peripapillary retinoschisis formation, at the time of peripapillary retinoschisis, and after peripapillary retinoschisis resolution were compared. Results The average RNFL was greater in the eyes in the retinoschisis group (median, 81.6 mm) than in those in the control group (median, 69.7 mm, p=0.009). In the retinoschisis group, the average RNFL thickness at the time of peripapillary retinoschisis was greater than that prior to peripapillary retinoschisis formation (p=0.013) or after peripapillary retinoschisis resolution (p=0.001). The RNFL thickness was not different prior to peripapillary retinoschisis formation and after peripapillary retinoschisis resolution (p>0.05). Conclusions Transient increase in RNFL thickness as determined by OCT was observed in glaucomatous eyes with peripapillary retinoschisis. Caution is warranted when interpreting the RNFL thickness measurement in eyes with peripapillary retinoschisis.