Table 3.

Comparison between ETDRS groups assembled by severity level

Metric	Acq. protocol	Area	Healthy	Healthy vs ETDRS10-35	ETDRS10-35	ETDRS10-35 vs ETDRS43-53	ETDRS43-53
Vessel density SCP, mm-1	PlexElite 3 mm × 3 mm	Inner ring (5, 10)°	14.7±1.3	0.000	12.6±1.9	0.017	11.9±1.5
	PlexElite 15 mm × 9 mm	Extended 1 (21, 31)°	28.2±3.1	0.018	26.4±4.3	0.304	24.9±5.5
		Extended 2 (31, 42)°	23.2±2.4	0.047	21.5±4.2	0.137	20.2±4.3
		Extended 3 (42, 52)°	16.7±3.7	0.976	16.5±5.2	0.059	14.3±5.1
Vessel density DCP, mm-1	PlexElite 3 mm × 3 mm	Inner ring (5, 10)°	14.5±1.5	0.000	12.7±2.2	0.003	11.6±1.6
	PlexElite 15 mm × 9 mm	Extended 1 (21, 31)°	22.4±6.7	0.023	18.4±7.9	0.046	15.1±7.4
		Extended 2 (31, 42)°	20.6±6.0	0.071	17.2±7.6	0.032	13.6±6.8
		Extended 3 (42, 52)°	17.3±7.0	0.288	15.1±7.9	0.015	10.9±6.2
Vessel density FR, mm-1	PlexElite 3 mm × 3 mm	Inner ring(5, 10)°	17.9±1.1	0.000	16.1±2.0	0.002	15.2±1.4
	PlexElite 15 mm × 9 mm	Extended 1 (21, 31)°	31.0±3.5	0.009	28.8±5.0	0.062	26.5±6.6
		Extended 2 (31, 42)°	27.2±3.3	0.042	24.8±5.3	0.030	22.7±5.4
		Extended 3 (42, 52)°	20.9±4.8	0.861	20.1±6.6	0.016	17.0±6.1
Thickness GCL+IPL, µm	PlexElite 3 mm × 3 mm	Inner ring (5, 10)°	93.7±8.2	0.324	88.2±11.6	0.747	84.0±21.4
	PlexElite 15 mm × 9 mm	Extended 1 (21, 31)°	43.7±3.8	0.184	44.8±3.6	0.897	45.3±5.9
		Extended 2 (31, 42)°	41.0±4.1	0.007	43.7±4.6	0.188	43.1±7.1
		Extended 3 (42, 52)°	35.3±3.1	0.167	36.8±4.5	0.787	37.0±5.9

Data are presented as mean±SD.

Vessel density and GCL+IPL thickness values were calculated using Zeiss PlexElite MultiLayer segmentation algorithm. Comparisons between individuals with diabetes and healthy controls were performed using Mann-Whitney U-test. Bonferroni correction was applied to vessel density comparisons setting the statistical significance to p<0.0167, otherwise p<0.05. Statistical significance highlighted in bold and in grey cells.

DCP, deep capillary plexus; FR, full retina; GCL+IPL, ganglion cell layer and inner plexiform layer; SCP, superficial capillary plexus.