Question 7: Describe the patient’s OCT retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) analysis

Question 7: Describe the patient’s OCT retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) analysis

Answer

The OCT scans are of good quality and show ongoing asymmetry between the two eyes. The swelling in the affected right eye has improved with increased RNFL thickness seen inferiorly now. The left eye RNFL thickness is within normal limits.

The GCC scans in the right eye have worsened compared to the initial presentation. In the right eye the average GCL + IPL thickness is below the first percentile. The left eye remains unremarkable.

In NAION, the peripapillary RNFL may initially become thick while the disc is swollen. A retrospective observational case series of 14 eyes in 13 patients (Dotan et al 2013) reported RNFL thinning on average 6 months following the onset of NAION and no statistically significant difference at 13 months.

A prospective study of eyes with acute NAION showed that GCL thinning developed within 1 to 2 months of onset, which is prior to RNFL swelling resolution.(Kupersmith et al. 2016) Kupersmith et al reported that average GCC plus inner plexiform layer thinning below the fifth percentile of normal eyes occurred while the OCT still showed RNFL thickening.

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