Segmentation error in spectral domain optical coherence tomography measures of the retinal nerve fibre layer thickness in idiopathic intracranial hypertension

Table 1 Qualitative assessment of the distribution of RNFL thickness segmentation error comparing the IIH and control cohorts using median values and ranges

Location	Overall IIH % error (n = 46)	Mild IIH % error (n = 23)	Moderate-severe IIH % error (n = 23)	Control % error (n = 14)	p overall	p moderate-severe
Using ImageJ
Total area of RNFL	5 (0–58)	2 (0–16)	10 (0–58)	1 (0–6)	0.009^a	<0.001^a
Using spectalis automated software
Average
Overall	4 (0–58)	2 (0–16)	10 (0–58)	2 (0–6)	0.031^a	0.002^a
Superior	8 (0–375)	6 (0–115)	11 (0–375)	3 (0–10)	0.007^a	0.001^a
Nasal	2 (0–81)	2 (0–30)	1 (0–81)	1 (0–14)	NS	NS
Inferior	4 (0–79)	3 (0–12)	6 (0–79)	2 (0–11)	0.031^a	0.008^a
Maximum
Highest Single Point	5 (0–62)	5 (0–43)	7 (0–62)	4 (0–14)	NS	NS
Superior	7 (0–60)	5 (0–42)	12 (0–60)	3 (0–26)	0.044^a	0.017^a
Nasal	6 (0–70)	5 (0–51)	8 (0–70)	7 (0–133)	NS	NS
Inferior	5 (0–96)	3 (0–114)	7 (0–96)	3 (0–17)	NS	0.049^a
Temporal	3 (0–43)	3 (0–21)	3 (0–43)	1 (0–28)	NS	NS

NB values are compared with the control group. There were no significant differences in mild disc swelling for any of the above parameters. NS not significant; ^aindicates statistical significance

ISSN: 1471-2415