In vivo assessment of changes in corneal hysteresis and lamina cribrosa position during acute intraocular pressure elevation in eyes with markedly asymmetrical glaucoma

Figures & data

Figure 1 Application of the ophthalmodynamometer on the infratemporal eyelid during an SD-OCT examination.

Abbreviation: SD-OCT, spectral-domain optimal coherence tomography.

Figure 2 Vertical distances from the line connecting the Bruch’s membrane ends to the anterior surface of the lamina cribrosa and the prelaminar tissue at baseline (A and C) and during IOP elevation (B and D) in an eye with mild glaucoma.

Abbreviation: IOP, intraocular pressure.

Figure 3 Vertical distances from the line connecting the Bruch’s membrane ends to the anterior surface of the lamina cribrosa and the prelaminar tissue at baseline (A and C) and during IOP elevation (B and D) in an eye with severe glaucoma.

Abbreviation: IOP, intraocular pressure.

Figure 4 Vertical distances from the line connecting the Bruch’s membrane ends to the anterior surface of the lamina cribrosa and the prelaminar tissue at baseline (A and C) and during IOP elevation (B and D) in a control eye.

Abbreviation: IOP, intraocular pressure.

Table 1 Demographic data of the participants to the study

	MG–SG patients	Controls	p-valuea
Age, years	59.5±4.6 (53 to 67)	58.8±6.4 (50 to 73)	0.298
Gender, M:F	10:2	10:2	–
Ethnicity	100% caucasian	100% caucasian	–

Note:

a Mann–Whitney U-test.

Abbreviations: F, female; M, male; MG, mild glaucoma; SG, severe glaucoma.

Table 2 Values at baseline and comparison among groups

	MG patients	SG patients	Controls	p-valuea (MG–SG)	p-valueb (MG–controls)	p-valueb (SG–controls)
VF MD, dB	−4.21±1.51 (−2.32 to −5.96)	−16.56±5.76 (−12.13 to −21.67)	−1.60±0.65 (−0.68 to −1.98)	0.024	0.006	0.002
VF PSD, dB	3.54±0.87 (2.52 to 5.11)	10.95±3.51 (6.62 to 15.31)	1.35±0.24 (1.12 to 1.64)	0.019	0.002	0.001
CCT, µm	517.4±10.16 (510.1 to 539.7)	514.9±12.6 (496.8 to 540.2)	517.8±11.41 (500.6 to 540.9)	0.695	0.910	0.492
b-IOP, mmHg	15.4±5.4 (8.3 to 20.8)	16.6±5.4 (9.8 to 20.7)	13.7±2.5 (11.4 to 18.6)	0.425	0.425	0.250
b-CH, mmHg	8.62±2.16 (7.2 to 10.4)	9.30±3.66 (7.1 to 11.6)	10.96±1.79 (9.7 to 12.2)	0.970	0.095	0.596
b-CRF, mmHg	8.61±2.3 (7.1 to 10.1)	9.02±1.48 (8.1 to 10.0)	10.64±1.28 (9.2 to 10.1)	0.769	0.039	0.034

Notes:

a Wilcoxon signed-rank test;

b Mann–Whitney U-test.

Abbreviations: b-CH, baseline corneal hysteresis; b-CRF, baseline corneal resistance factor; b-IOP, baseline intraocular pressure; CCT, central corneal thickness; MD, mean deviation; MG, mild glaucoma; PSD, pattern standard deviation; SG, severe glaucoma; VF, visual field.

Table 3 Baseline IOP with GAT, Tonopen, and ORA

	GAT IOP, mmHg	Tonopen IOP (b-IOP), mmHg	ORA IOPcc, mmHg	p-valuea
MG patients	15.4±3.9 (12 to 19)	15.4±5.4 (8.3 to 20.8)	16.8±4.9 (10 to 23)	0.293
SG patients	16.5±4.8 (10 to 19)	16.6±5.4 (9.8 to 20.7)	18.2±5.2 (14 to 23)	0.187
Controls	13.3±2.5 (11 to 18)	13.7±2.5 (11.4 to 18.6)	14.7±2.9 (10 to 19)	0.293

Note:

a Friedman test.

Abbreviations: b-IOP, baseline intraocular pressure; GAT, Goldmann applanation tonometer; MG, mild glaucoma; ORA, ocular response analyzer; SG, severe glaucoma.

Table 4 IOP during ophthalmodynamometer application and forces applied

	MG patients	SG patients	Controls	p-valuea (MG–SG)	p-valueb (MG–controls)	p-valueb (SG–controls)
i-IOP (OCT), mmHg	28.3±5.7 (22.2 to 35.1)	29.2±5.4 (21.8 to 32.4)	27.4±5.2 (19.7 to 33.1)	0.402	0.387	0.429
i-OCT (ORA), mmHg	27.9±6.5 (19.8 to 38.1)	28.7±6.4 (18.9 to 32.0)	25.3±6.7 (17.9 to 31.3)	0.337	0.214	0.465
Ophthalmodyn (OCT), Pa	31.6±2.4 (29 to 36)	31.2±1.7 (29 to 34)	30.7±1.1 (28 to 33)	0.311	0.472	0.396
Ophthalmodyn (ORA), Pa	30.3±1.5 (27 to 32)	30.6±1.5 (28 to 34)	30.8±1.0 (29 to 32)	0.347	0.294	0.286

Notes:

a Wilcoxon signed-rank test;

b Mann–Whitney U-test.

Abbreviations: IOP, intraocular pressure; i-IOP (OCT), IOP on ophthalmodynamometer application during OCT scan; i-IOP (ORA), IOP on ophthalmodynamometer application during ORA measurement; MG, mild glaucoma; ORA, ocular response analyser; OCT, optimal coherence tomography; Ophthalmodyn (OCT), force applied during OCT scan; Ophthalmodyn (ORA), force applied during ORA measurement; SG, severe glaucoma.

Table 5 Values during IOP elevation and comparison among groups

	MG patients	SG patients	Controls	p-valuea (MG–SG)	p-valueb (MG–controls)	p-valueb (SG–controls)
i-CH, mmHg	7.23±2.29 (5.8 to 8.7)	6.92±3.04 (5.1 to 8.9)	10.59±1.78 (9.3 to 11.8)	0.519	0.011	0.003
i-CRF, mmHg	12.38±3.65 (10.1 to 14.7)	15.2±2.06 (13.7 to 16.7)	11.27±1.46 (10.2 to 12.3)	0.027	0.922	0.019
LD, µm	29.08±19.28 (16.8 to 41.3)	−6.58±26.09 (−23.2 to 26.1)	30.3±10.9 (22.5 to 38.1)	<0.001	0.833	0.001
PTD, µm	22.33±33.14 (1.3 to 43.4)	13.08±17.06 (2.2 to 23.9)	36.0±17.9 (23.2 to 48.8)	0.518	0.131	0.001

Notes:

a Wilcoxon signed-rank test;

b Mann–Whitney U-test.

Abbreviations: i-CH, induced corneal hysteresis; i-CRF, induced corneal resistance factor; i-IOP, induced intraocular pressure; LD, laminar displacement; MG, mild glaucoma; PTD, prelaminar tissue displacement; SG, severe glaucoma.

Table 6 Intragroup comparison between values at baseline and during IOP increase

	MG			SG			Controls
	Baseline	IOP increase	p-valuea	Baseline	IOP increase	p-valuea	Baseline	IOP increase	p-valuea
CH, mmHg	8.62±2.16 (7.2 to 10.4)	7.23±2.30 (5.8 to 8.7)	0.176	9.30±3.65 (7.1 to 11.6)	6.92±3.04 (5.1 to 8.9)	0.012	10.95±1.79 (9.7 to 12.2)	10.59±1.78 (9.3 to 11.8)	0.921
CRF, mmHg	8.61±2.30 (7.1 to 10.1)	12.38±3.64 (10.1 to 14.7)	0.002	9.02±1.48 (8.1 to 10.0)	15.20±2.06 (13.7 to 16.7)	0.002	10.64±1.28 (9.2 to 10.1)	11.27±1.46 (10.2 to 12.3)	0.275

Note:

a Wilcoxon signed-rank test.

Abbreviations: CH, corneal hysteresis; CRF, corneal resistance factor; IOP, intraocular pressure; MG, mild glaucoma; SG, severe glaucoma.

Figure 5 Scatterplot illustrating the inverse correlation by Spearman’s test between CRF and LD in eyes with severe glaucoma.

Abbreviations: CRF, corneal resistance factor; LD, laminar displacement.