Structural Changes in the Optic Disc and Macula Detected by Swept-Source Optical Coherence Tomography After Surgical Intraocular Pressure Reduction in Patients with Open-Angle Glaucoma

Figures & data

Table 1 Baseline Characteristics

	Surgical Group (n= 29)	Control Group (n= 26)	P value
Gender (M/F)	11/18	6/19	0.27
Age	64.28± 11.55	67.08±8.50	0.32
Diagnosis (POAG/SOAG)	27/2	24/2
IOP at baseline (mmHg)	23.38 ± 5.78	15.4 ± 3.43	< 0.001
SAP MD (dB)	−11.21 ± 8.70	−6.44 ± 6.44	0.03
SAP PSD (dB)	7.10 ± 3.55	5.15 ± 4.06	0.07
OCT parameters at baseline
Optic disc area (mm^2)	2.05 ± 0.39	2.22 ± 0.47	0.157
Rim area (mm^2)	0.46 ± 0.43	0.53 ± 0.40	0.23
Linear cup-to-disc ratio	0.88 ± 0.11	0.87 ± 0.10	0.43
Vertical cup-to-disc ratio	0.89± 0.12	0.86 ± 0.07	0.06
Cup volume (mm^3)	0.51± 0.28	0.58 ± 0.38	0.68
Mean RNFL thickness (µm)	71.83 ± 19.64	78.16 ± 13.60	0.52
Superior RNFL thickness (µm)	91.31 ± 23.94	97.44 ± 20.46	0.42
Inferior RNFL thickness (µm)	82.69 ± 31.14	90.52 ± 24.12	0.29
Temporal RNFL thickness (µm)	52.27 ± 16.68	55.80 ± 15.22	0.42
Nasal RNFL thickness (µm)	61.41 ± 15.88	68.36 ± 13.87	95
Total macular thickness (µm)	242.72 ± 11.17	251.13 ± 16.74	0.03
Total mRNFL (µm)	24.24 ± 9.66	28.16 ± 7.69	0.109
Superior mRNFL (µm)	25.52 ± 9.33	28.80 ± 7.64	0.167
Inferior mRNFL (µm)	22.90 ± 11.19	27.60 ± 10.16	0.114
Total GCL+ (µm)	52.76 ± 5.62	55.44 ± 6.26	0.103
Superior GCL+ (µm)	52.69 ± 7.07	56.08 ± 6.28	0.07
Inferior GCL+ (µm)	52.59 ± 5.14	54.96 ± 6.69	0.147
Total GCL++ (µm)	77.03 ± 14.03	83.60 ± 12.18	0.07
Superior GCL++ (µm)	78.48 ± 14.80	84.84 ± 13.01	0.102
Inferior GCL++ (µm)	75.59 ± 14.59	82.40 ± 14.35	0.09

Notes: Values are shown in mean ± standard deviation. Values with statistical significance are in bold font.

Abbreviations: M/F, male/female; POAG, primary open-angle glaucoma; SOAG, secondary open-angle glaucoma; SAP, standard automated perimetry; IOP, intraocular pressure; MD, mean deviation; PSD, pattern standard deviation; RNFL, retinal nerve fiber layer; mRNFL, macular RNFL; GCL+, ganglion cell layer plus inner plexiform layer thickness; GCL++, average RNFL plus GCL+ thickness.

Table 2 SS-OCT Optic Disc, RNFL and Macular Parameters Measurements in the Control Group

	Baseline	1 Month After Surgery	2 Months After Surgery	P value
Optic disc parameters
Rim area (mm^2)	0.53 ± 0.40	0.54 ± 0.40	0.54 ± 0.39	0.99
Linear cup-to-disc ratio	0.87 ± 0.1	0.86 ± 0.1	0.87 ± 0.1	0.99
Vertical cup-to-disc ratio	0.86 ± 0.07	0.87 ± 0.08	0.87 ± 0.08	0.99
Cup volume (mm^3)	0.58 ± 0.38	0.59 ± 0.39	0.60 ± 0.37	0.75
RNFL parameters
Mean RNFL (µm)	78.16 ± 13.6	78.72 ± 13.8	78.12 ± 14.17	0.99
Superior RNFL (µm)	97.44 ± 20.46	99.16 ± 20.10	97.04 ± 20.05	0.99
Inferior RNFL (µm)	90.52 ± 24.12	89.8 ± 23.16	90 ± 24.02	0.99
Temporal RNFL (µm)	55.8 ± 15.22	56.6 ± 14.21	55.96 ± 15.2	0.99
Nasal RNFL (µm)	68.36 ± 13.87	67.96 ± 14.02	68.08 ± 14.9	0.99
Macular parameters
Average thickness (µm)	251.13 ± 16.74	251.23 ± 16.36	250.72 ± 16.85	0.64
mRNFL thickness (µm)	28.16 ± 7.68	28 ± 7.27	28.08 ± 7.76	0.69
Superior mRNFL (µm)	28.8 ± 7.64	28.2 ± 8.83	27.76 ± 8.69	0.21
Inferior mRNFL (µm)	27,6 ± 10.16	26,5 ± 10.65	27.6 ± 10	0.78
Total GCL+ (µm)	55.44 ± 6.26	55.28 ± 6.21	55 ± 6.64	0.39
Superior GCL+ (µm)	56.08 ± 6.28	55.84 ± 6.46	55.76 ± 6.92	0.99
Inferior GCL+ (µm)	54.96 ± 6.69	54.6 ± 6.37	54.32 ± 6.64	0.13
Total GCL++ (µm)	83.6 ± 12.18	83.32 ± 11.7	83.2 ± 12.14	0.44
Superior GCL++ (µm)	84.84 ± 13.01	84.36 ± 12.98	84.44 ± 13.29	0.61
Inferior GCL++ (µm)	82.4 ± 14.35	82.24 ± 13.28	81.92 ± 14.23	0.36

Note: All data are shown in mean ± standard deviation.

Abbreviations: RNFL, retinal nerve fiber layer; mRNFL, macular RNFL; GCL+, ganglion cell layer plus inner plexiform layer thickness; GCL++, average RNFL plus GCL+ thickness.

Table 3 SS-OCT Optic Disc, RNFL and Macular Parameters Measurements in the Surgical Group

	Baseline	1 Month After Surgery	P value	2 Months After Surgery	P value
Optic disc parameters
Rim area (mm^2)	0.46 ± 0.43	0.54 ± 0.44	<0.001	0.55 ± 0.49	0.02
Linear cup-to-disc ratio	0.88 ± 0.11	0.86 ± 0.11	<0.001	0.86 ± 0.12	0.004
Vertical cup-to-disc ratio	0.89 ± 0.12	0.87± 0.11	0.002	0.86 ± 0.12	0.01
Cup volume (mm^3)	0.51± 0.28	0.44 ± 0.23	0.16	0.46 ± 0.26	0.04
Macular parameters
Average thickness (µm)	242.72 ± 11.17	246.53 ± 11.05	<0.001	246.18 ± 12.01	0.004
Total mRNFL thickness (µm)	24.24 ± 9.66	24.69 ± 10.05	0.57	23.79 ± 9.40	0.99
Superior mRNFL (µm)	25.52 ± 9.33	26.03 ± 8.88	0.99	25.03 ± 9.14	0.99
Inferior mRNFL (µm)	22.86 ± 11.23	23.10 ± 12.78	0.99	22.55 ± 11.17	0.99
Total GCL+ (µm)	52.90 ± 5.56	53.59 ± 4.97	0.003	53.76 ± 5.07	0.02
Superior GCL+ (µm)	52.76 ± 7.04	53.55± 6.71	0.99	53.83 ± 6.88	0.02
Inferior GCL+ (µm)	52.79 ± 5.05	53.62 ± 4.62	0.84	53.83 ± 4.77	0.01
Total GCL++ (µm)	77.13 ± 13.98	78.10 ± 14.13	0.006	77.86 ± 13.75	0.99
Superior GCL++ (µm)	78.59 ± 14.76	79.35 ± 14.28	0.009	78.59 ± 14.40	0.99
Inferior GCL++ (µm)	75.69 ± 14.56	76.66 ± 15.68	0.14	76.31 ± 14.21	0.99
	Baseline	1 Month After Surgery	2 Months After Surgery		P value
RNFL parameters
Mean RNFL (µm)	71.82 ± 19.64	73.48 ± 19.11	72.59 ± 18.60		0.22
Superior RNFL (µm)	91.31 ± 23.94	93.51± 24.32	92.21 ± 25.31		0.49
Inferior RNFL (µm)	82.69 ± 31.13	83.83 ± 30.23	83.41 ± 29.86		0.62
Temporal RNFL (µm)	52.28 ± 16.68	53.62 ± 17.61	53.41 ± 16.66		0.19
Nasal RNFL (µm)	61.41 ± 15.88	62.86 ± 15.25	61.55 ± 15.36		0.45

Notes: All data are shown in mean ± standard deviation. Values with statistical significance are in bold font.

Abbreviations: RNFL, retinal nerve fiber layer; mRNFL, macular RNFL; GCL+, ganglion cell layer plus inner plexiform layer thickness; GCL++, average RNFL plus GCL+ thickness.

Table 4 Correlation Between SS-OCT Parameters Change and IOP Change in the Surgical Group

	IOP Change 1 Month After Surgery (mmHg)		IOP Change 2 Months After Surgery (mmHg)
	r	P value	r	P value
Rim area (mm^2)	−0.78	<0.001	−0.23	0.23
Linear cup disc ratio	0.55	0.002	0.25	0.2
Vertical cup disc ratio	0.63	<0.001	0.25	0.19
Cup volume (mm^3)	0.38	0.04	0.14	0.47
Macular average thickness (µm)	−0.63	<0.001	−0.69	<0.001
Total GCL+ (µm)	−0.52	0.004	−0.70	<0.001
Superior GCL+ (µm)	−0.55	0.002	−0.66	<0.001
Inferior GCL+ (µm)	−0.33	0.08	−0.51	0.004
Total GCL++ (µm)	−0.57	0.001	−0.37	0.04
Superior GCL++ (µm)	−0.42	0.02	−0.27	0.15
Inferior GCL++ (µm)	−0.43	0.02	−0.51	0.004

Note: Values with statistical significance are in bold font.

Abbreviations: RNFL, retinal nerve fiber layer; mRNFL, macular RNFL; GCL+, ganglion cell layer plus inner plexiform layer thickness; GCL++, average RNFL plus GCL+ thickness.

Figure 1 Scatter plots showing the relationship between topographic parameters improvement and macular parameters change. Rim area change demonstrated significant relationship with total macular thickness change (A) and superior GCL+ change (B). Linear cup-to-disc change demonstrated significant relationship with superior GCL+ change (C).