Table 2.

Effects of clinical factors on OCT measurement variability - Full model (Multivariable analysis)

Variable	β Coefficient	SE	P-value
(Intercept)	−0.041	1.602	0.980
Age, per 1 year older	−0.003	0.003	0.349
Gender: Female (vs. male)	−0.044	0.062	0.475
Race: African American (vs. others)	0.180	0.068	0.009
Diabetes (yes/no)	0.066	0.088	0.451
Hypertension (yes/no)	−0.030	0.066	0.646
Laterality: Right eye	0.033	0.046	0.479
CCT, per 1 μm thicker	0.001	0.001	0.486
AL, per 1 mm longer	0.034	0.032	0.289
Spherical equivalent, per 1 D higher	0.038	0.019	0.042
Baseline VF MD, per 1 dB higher	−0.017	0.007	0.019
Baseline IOP, per 1 mmHg higher	−0.022	0.007	0.002
IOP fluctuation, per 1 mmHg higher	0.133	0.024	< 0.001
Baseline medication use (yes/no)	−0.024	0.081	0.773
History of CE at baseline (yes/no)	0.110	0.094	0.240
CE during follow-up (yes/no)	0.511	0.077	< 0.001
History of glaucoma surgery at baseline (yes/no)	0.119	0.081	0.144
Glaucoma surgery during follow-up (yes/no)	0.127	0.077	0.101
Baseline RNFLT, per 1 μm thicker	0.008	0.002	0.001
RNFL thinning rate, per 1 μm/year more positive	0.058	0.023	0.012
Scan quality, per 1 unit higher	0.001	0.001	0.681
Mean ART, per 1 unit higher	0.001	0.001	0.987
Follow-up duration, per 1 year longer	−0.001	0.012	0.913
Visit/testing frequency, per 1 time/year higher	−0.115	0.057	0.047
	Total R2: 0.76

^*A positive co-efficient indicates increased RNFLT variability, while a negative co-efficient indicates decreased RNFLT variability.

Abbreviation: AL = axial length, ART = automated real time value, CCT = central corneal thickness, CE = cataract extraction, IOP = intraocular pressure, OCT = optical coherence tomography, RNFL = retinal nerve fiber layer, RNFLT= RNFL thickness, SE = standard error, VF MD = visual field mean deviation