. 2020 Dec 22;3(12):e2030824. doi: 10.1001/jamanetworkopen.2020.30824

Table 2. Visual Structure and Function Slope Measures in TBI and Control Subjects: Analysis of Variance and Mixed-Effects Model Results.

Variable	Slope, mean (SE)		F	P value	Cohen d	Mixed-effects model
Variable	TBI	Controls	F	P value	Cohen d	Difference in slope, β^a^,^b	P value
OCT retinal nerve fiber thickness, μm/y (n = 63 TBI; n = 61 controls)
Averaged eyes	−1.47 (0.24)	−0.31 (0.32)	8.42	.004^c	0.52	−1.80	.001^c
OD	−1.55 (0.27)	−0.01 (0.36)	11.77	<.001^c	0.62	−1.50	.001^c
OS	−1.16 (0.33)	−0.29 (0.52)	2.01	.16	0.26	−0.81	.02^c
OCT ganglion cell layer complex, μm/y (n = 63 TBI; n = 66 controls)
Averaged eyes	−0.17 (0.07)	−0.02 (0.09)	2.00	.16	0.25	0.08	.51
OD	−0.20 (0.08)	−0.11 (0.10)	0.46	.49	0.12	−0.08	.58
OS	−0.19 (0.06)	0.01 (0.10)	2.76	.10	0.29	−0.19	.16
Visual acuity in change, No. of letters correct per y (n = 60 TBI; n = 62 controls)^a
Averaged eyes	−0.71 (0.41)	0.36 (0.45)	3.08	.08	0.32	Not analyzed
OD	−0.98 (0.50)	−0.10 (0.60)	1.25	.27	0.20	−1.50	.26
OS	−0.42 (0.48)	0.80 (0.53)	2.93	.09	0.31	−1.16	.05
Visual field mean deviation, dB/y (n = 60 TBI; n = 64 controls)
Averaged eyes	−0.09 (0.14)	0.46 (0.23)	4.08	.046^c	0.36	Not analyzed
OD	−0.004 (0.18)	0.26 (0.26)	0.71	.40	0.15	−0.19	.46
OS	−0.14 (0.14)	0.66 (0.23)	8.43	.004^c	0.52	−0.52	.03^c
Visual field pattern standard deviation, dB/y (n = 60 TBI; n = 64 controls)
Averaged eyes	0.09 (0.06)	−0.10 (0.07)	4.78	.03^c	0.39	Not analyzed
OD	0.06 (0.07)	−0.14 (0.08)	3.23	.07	0.32	0.12	.15
OS	0.11 (0.07)	−0.07 (0.07)	3.33	.07	0.33	0.11	.11
Contrast sensitivity (2 units/y = 0.3 log unit change) (n = 63 TBI; n = 62 controls)^d
1.5 cpd
Averaged eyes	−1.91 (0.99)	0.20 (0.91)	2.48	.12	0.28	Not analyzed
OD	−2.04 (1.03)	2.01 (1.03)	7.73	.006^c	0.50	−3.14	.008^c
OS	−1.48 (1.22)	−2.39 (1.37)	0.25	.62	0.09	0.56	.70
3 cpd
Averaged eyes	0.44 (1.22)	0.31 (1.77)	0.003	.95	0.01	Not analyzed
OD	1.61 (1.75)	1.69 (1.82)	0.001	.97	0.01	−1.55	.42
OS	−0.51 (1.26)	−0.81 (2.54)	0.01	.92	0.02	−0.53	.78
6 cpd
Averaged eyes	−0.73 (1.82)	2.15 (2.06)	1.11	.29	0.19	Not analyzed
OD	−1.08 (2.17)	2.74 (2.55)	1.31	.25	0.20	−3.86	.13
OS	0.23 (2.20)	1.73 (2.40)	0.21	.65	0.08	−2.19	.37
12 cpd
Averaged eyes	−1.51 (0.93)	1.49 (0.84)	5.70	.02^c	0.43	Not analyzed
OD	−1.51 (1.10)	1.33 (1.04)	3.50	.06	0.33	−1.15	.39
OS	−1.55 (1.01)	1.78 (1.06)	5.15	.02^c	0.41	−1.26	.30
18 cpd
Averaged eyes	−0.30 (0.52)	0.41 (0.44)	1.08	.30	0.19	Not analyzed
OD	−0.62 (0.81)	0.23 (0.54)	0.76	.39	0.16	0.008	.99
OS	0.02 (0.56)	0.37 (0.54)	0.21	.65	0.08	0.23	.69

Abbreviations: cpd, cycles per degree; OCT, optical coherence tomography; OD, oculus dexter (right eye); OS, oculus sinister (left eye); TBI, traumatic brain injury.

^{^a}

Visual acuity is measured in number of letters correct; a change in 5 letters = 0.1 logMAR acuity and 1 line of letters on an EDTRS chart. For example, a slope of 1 letter lost per year means that in 5 years, it would be expected that 1 line of letters would be lost (eg, 20/25 worsening to 20/30 visual acuity).

^{^b}

The test of β = 0 assesses whether the mean slopes are the same in the mixed-effects model. Change is defined as the difference from control. If change is negative, TBI slope is less than control slope.

^{^c}

Denotes statistical significance.

^{^d}

For each spatial frequency, 9 sine-wave gratings in 0.15 log contrast sensitivity decrements were presented (eg, a negative slope of 2/y would mean that there was a loss of 0.3 log contrast sensitivity).