Table 2.

Comparison of measurements between instruments with the same platform.

	Lateral width			CFT			1 mm right PFT			1 mm left PFT
	Mean (SD) μm	COV	ANOVA $p$ value	Mean (SD) μm	COV	ANOVA $p$ value	Mean (SD) μm	COV	ANOVA $p$ value	Mean (SD) μm	COV	ANOVA $p$ value
Zeiss Cirrus™
Instrument 1	5171 (15)	0.286	0.034	187 (3)	1.559	$<0.001$	307 (4)	1.163	$<0.001$	316 (3)	1.120	0.037
Instrument 2	5180 (14)	0.269		196 (3)	1.640		315 (4)	1.174		314 (3)	1.059
All instruments	5176 (14)			191 (3)			311 (4)			315 (3)
Difference, %	0.16			5.24			2.25			0.63
Heidelberg Spectralis™
Instrument 1	5273 (65)	1.223	0.002	184 (3)	1.332	$<0.001$	312 (3)	0.920	0.004	308 (2)	0.775	$<0.001$
Instrument 2	5290 (69)	1.309		188 (3)	1.513		315 (3)	0.904		312 (3)	0.991
All instruments	5282 (67)			186 (3)			314 (3)			310 (3)
Difference, %	0.32			2.12			0.88			1.08
Bioptigen Envisu™
Instrument 1	5215 (12)	0.236	0.002	180 (2)	0.857	$<0.001$	302 (2)	0.755	$<0.001$	300 (3)	0.983	$<0.001$
Instrument 2	5230 (15)	0.282		183 (3)	1.536		311 (3)	0.836		305 (3)	0.493
All instruments	5222 (14)			181 (2)			306 (3)			303 (2)
Difference, %	0.27			1.79			2.12			1.65
Bioptigen SDOIS
Instrument 1	5209 (26)	0.489	0.042	162 (2)	1.210	0.029	269 (3)	1.013	0.016	268 (3)	1.198	0.029
Instrument 2	5205 (29)	0.559		163 (2)	1.648		267 (3)	1.219		273 (3)	1.220
All instruments	5207 (27)			162 (2)			268 (3)			270 (3)
Difference, %	0.08			0.64			0.65			2.05

Note: CFT, central foveal thickness; PFT, parafoveal thickness; SD, standard deviation; COV, coefficient of variance; ANOVA, analysis of variance.