Evaluation of Retinal Nerve Fiber Layer and Ganglion Cell Layer Thickness in Alzheimer’s Disease Using Optical Coherence Tomography

Figures & data

Table 1 Demographic and Clinical Characteristics

Baseline Characteristics	AD (N=29)	Controls (N=29)	P-value
Eyes studied, n	54	57
Age, years (mean ± SD)	75.61 ± 6.24	75.80 ± 6.32	0.089
Female sex, n (%)	20 (68.97)	20 (68.97)	1.000
Education			1.000
Elementary level, n (%)	9 (31.03)	9 (31.03)
Short secondary level, n (%)	3 (10.34)	3 (10.34)
Higher level, n (%)	17 (58.62)	17 (58.62)
BCVA, log MAR (median, IQR)	0.28 (0.1, 0.4)	0.17 (0.0, 0.3)	0.008
IOP, mmHg (mean ± SD)	12.02 ± 2.51	11.84 ± 3.06	0.844
MoCA, score (mean ± SD)	14.52 ± 6.21	26.62 ± 1.18	<0.001
Hypertension, n (%)	18 (62.07)	18 (62.07)	1.000
Diabetes, n (%)	6 (20.69)	8 (27.59)	0.754
Dyslipidemia, n (%)	17 (58.62)	20 (68.97)	0.607
Duration of cognitive symptoms, years (median, IQR)	4.21 (2, 6)

Notes: Bold values indicate statistically significant at P-value < 0.05.

Abbreviations: AD, Alzheimer’s disease; n, number; SD, standard deviation; BCVA, best-corrected visual acuity; log MAR, logarithm of the minimum angle of resolution; IOP, intraocular pressure; MoCA, Montreal Cognitive Assessment; IQR, interquartile range.

Figure 1 Line chart showing a comparison of RNFL thickness based on each quadrant between the two groups.

Table 2 Comparison of Optical Coherence Tomography (OCT) Parameters Between Alzheimer’s Disease (AD) Patients and Healthy Controls

OCT Parameters	AD (54 Eyes)		Controls (57 Eyes)		Adjusted P-value
	Mean	SD	Mean	SD
RNFL (µm)
Mean thickness	85.24	8.73	90.68	10.57	0.014
Superior	101.06	16.37	109.74	18.41	0.033
Temporal	64.39	9.671	68.74	12.17	0.075
Inferior	109.41	16.64	114.75	18.68	0.117
Nasal	66.00	8.57	69.60	7.65	0.063
GCL-IPL (µm)
Mean thickness	68.81	15.52	76.42	11.69	0.014
Superotemporal	67.85	17.96	74.98	15.08	0.067
Inferotemporal	70.07	14.69	76.11	11.15	0.024
Inferior	67.49	16.24	74.23	11.51	0.018
Inferonasal	67.06	16.68	76.25	11.98	0.004
Superonasal	70.65	16.53	79.09	15.67	0.014
Superior	69.69	18.35	79.02	16.52	0.009

Notes: Bold values indicate statistically significant at adjusted P-value < 0.05.

Abbreviations: SD, standard deviation; RNFL, retinal nerve fiber layer; GCL-IPL, ganglion cell layer and inner plexiform layer.

Figure 2 Scatterplot of the association between age and RNFL thickness in the full set of participants.

Figure 3 Scatterplot of the association between age and GCL-IPL thickness in the full set of participants.