Optical coherence tomography retinal nerve fiber layer analysis in eyes with long axial lengths

Figures & data

Table 1 Characteristics of the subjects

	Long AL group (N=18 eyes)			Normal AL group (N=152 eyes)
	Normal (N=11)	Glaucoma (N=7)	p-valuea	Normal (N=86)	Glaucoma (N=66)	p-valueb	p-valuec
Age (years)	58.64±5.39	68.00±5.66	<0.001	66.08±9.73	53.49±8.40	<0.001	<0.001
Females, no (%)	3 (27.27)	4 (57.14)	0.18	60 (65.93)	51 (77.27)	0.35	0.01
IOP (mmHg)	14.40±1.65	19.14±4.74	0.01	15.49±3.53	15.91±6.94	0.19	0.60
Refraction (diopters)	−5.29±3.67	−2.93±2.87	0.24	−0.48±2.36	−0.73±2.24	0.55	<0.001
AL (mm)	26.84±1.96	26.84±0.75	0.23	23.63±0.71	23.47±0.81	0.19	<0.001
Cup-to-disc ratio	0.63±0.17	0.79±0.21	0.09	0.55±0.15	0.70±0.19	<0.001	0.10
Mean deviation (db)	−11.06±9.90	−22.18±9.57	0.06	−6.75±6.93	−10.97±7.63	0.001	0.004
PSD (dB)	3.58±3.25	5.29±2.51	0.32	4.430±2.89	5.33±3.60	0.08	0.42

Notes: The data are given as the mean ± standard deviation.

a Value for comparing nonglaucoma and glaucoma in the long AL group.

b Value for comparing nonglaucoma and glaucoma in the normal AL group.

c Value for comparing myopia and nonmyopia. Statistically significant values are shown in bold.

Abbreviations: AL, axial length; IOP, intraocular pressure; PSD, pattern standard deviation.

Table 2 RNFL thickness in normal and glaucoma eyes in long AL and normal AL groups

	Long AL group (N=18)			Normal AL group (N=152)
RNFL thickness (μm)	Normal (N=11)	Glaucoma (N=7)	p-valuea	Normal (N=86)	Glaucoma (N=66)	p-valueb	p-valuec
Mean	74.82±12.77	50.29±15.64	<0.001	90.37±10.92	72.53±15.66	<0.001	<0.001
Superior	85.73±11.29	62.14±15.55	<0.001	111±18.93	88.50±23.49	<0.001	<0.001
Nasal	54.00±16.1	27.43±14.90	<0.001	69.73±11.89	57.44±16.82	<0.001	<0.001
Inferior	88.09±18.54	59.86±24.31	0.01	113.92±18.86	87.42±24.47	<0.001	<0.001
Temporal	71.18±30.09	51.14±17.84	0.13	67.21±14.86	58.73±16.76	<0.001	0.98
Superior/inferior	0.99±0.13	1.12±0.38	0.33	0.99±0.18	1.04±0.32	0.23	0.60
Nasal/temporal	0.82±0.31	0.60±0.46	0.23	1.09±0.30	1.03±0.40	0.30	<0.001d

Notes:

a Value for comparing normal and glaucoma in the long AL group.

b Value for comparing normal and glaucoma in the normal AL group.

c Value for comparing normal and long AL eyes without glaucoma.

d Ratio long AL: 0.73±0.37; N/T ratio normal AL: 1.06±0.34. Statistically significant values are shown in bold.

Abbreviations: AL, axial length; RNFL, retinal nerve fiber layer.

Table 3 Pearson correlation coefficients of the relationship between RNFL layer thickness and subject characteristics in nonglaucoma vs glaucoma eyes

	Mean RNFL (μm)
	Nonglaucoma group (n=97)	Glaucoma group (n=73)
Age (years)	0.255 (0.012)	−0.038 (0.75)
Sex	(0.340)	(0.091)
Refraction (diopters)	0.383 (<0.001)	0.122 (0.303)
Cup-to-disc ratio	−0.237 (0.019)	−0.380 (<0.001)
IOP (mmHg)	−0.038 (0.711)	0.101 (0.394)
Mean deviation (db)	0.23 (0.023)	0.570 (<0.001)
PSD (db)	0.007 (0.945)	−0.355 (0.003)

Notes: The data are given as the Pearson correlation coefficients with p-value in parenthesis. Significant values are bold, p-value <0.05.

Abbreviations: IOP, intraocular pressure; PSD, pattern standard deviation; RNFL, retinal nerve fiber layer.

Table 4 Pearson correlation coefficients of the relationship between axial length and RNFL thickness in nonglaucoma vs glaucoma eyes

Axial length (mm)
RNFL thickness (μm)	Nonglaucoma group (n=97)	Glaucoma group (n=73)
Mean	−0.408 (<0.001)	−0.245 (0.037)
Superior	−0.428 (<0.001)	−0.220 (0.061)
Nasal	−0.364 (0.001)	−0.350 (0.002)
Inferior	−0.449 (<0.001)	−0.180 (0.128)
Temporal	0.168 (0.099)	−0.016 (0.893)
ST	−0.299 (0.002)	−0.029 (0.808)
SN	−0.407 (<0.001)	−0.379 (<0.001)
IN	−0.505 (<0.001)	−0.256 (0.029)
IT	−0.241 (0.017)	−0.083 (0.485)

Notes: The data are given as the Pearson correlation coefficients with p-value in parenthesis. Significant values are bold, p-value <0.05.

Abbreviations: IN, inferonasal; IT, inferotemporal; RNFL, retinal nerve fiber layer; SN, superonasal; ST, superonasal.

Figure 1 Linear regression analysis of the relationship of mean RNFL thickness with AL.

Notes: Y axis represents AL in mm. X axis represents mean RNFL thickness in micrometers. R²=0.17, y =−3.6x +174.
Abbreviations: AL, axial length; RNFL, retinal nerve fiber layer.

Figure 2 Typical RNFL of nonglaucomatous long AL subject (AL =28 mm).

Note: Note the significant nasal thinning with normal temporal thickness.
Abbreviations: AL, axial length; RNFL, retinal nerve fiber layer; TMP, temporal; SUP, superior; NAS, nasal; INF, inferior.