Thin minimal rim width at Bruch’s membrane opening is associated with glaucomatous paracentral visual field loss

Figures & data

Figure 1 Examples of patterns of VF loss on HVFs (Swedish Interactive Threshold Algorithm 24-2) as defined in this study.

Notes: Pattern deviation plots from left eyes are shown. Numeric values are in the top row and probability plots are in the bottom row. Examples of early paracentral loss with superior paracentral region outlined in black (left) and isolated peripheral loss with superior nasal step zone outlined in black (right) are included.
Abbreviations: VF, visual field; HVF, Humphrey visual field.

Figure 2 Quantitative assessment of the ONH with SS-OCT in an eye with early paracentral loss and in an eye with isolated peripheral loss.

Notes: Top row shows an eye with early paracentral loss: disc photograph (left), minimal BMO-MRW =34.8 μm (center left), LCDH =449.1 μm (center), LCDV =478.4 μm (center right), and peripapillary RNFL thickness profile (right). The corresponding HVF is shown in Figure 1 (left). Bottom row shows an eye with isolated peripheral loss: disc photograph (left), minimal BMO-MRW =139.5 μm (center left), LCDH =397.6 μm (center), LCDV =454.9 μm (center right), and peripapillary RNFL thickness profile (right). The corresponding HVF is shown in Figure 1 (right). Arrows in different colors and patterns indicate location and orientation of scans. Minimal BMO-MRW indicated by red circle and red line (center left), LCDH and LCDV as averages of blue lines (center and center right) were measured on images taken with SS-OCT. The red line delineates the anterior lamina cribrosa surface and the green line connects termination points of Bruch’s membrane (center and center right). RNFL thickness was measured with SD-OCT as shown in the RNFL sector maps (right). The average RNFL is the value in the center (G, global). The minimal RNFL was the lowest value in the sectors (NS, superonasal; TS, superotemporal; T, temporal; N, nasal; NI, inferonasal and TI, inferotemporal).
Abbreviations: BMO-MRW, minimum rim width at Bruch’s membrane opening; LCDH, horizontal lamina cribrosa depth; LCDV, vertical lamina cribrosa depth; ONH, optic nerve head; RNFL, retinal nerve fiber layer; HVF, Humphrey visual field; SS-OCT, swept-source optical coherence tomography; SD-OCT, spectral-domain optical coherence tomography.

Table 1 Clinical characteristics among the studied groups

Clinical characteristics	Control eyes (N=20)	Early paracentral loss eyes (N=I5)	Isolated peripheral loss eyes (N=I4)	p-value Control vs early paracentral loss	p-value Control vs isolated peripheral loss	p-value Early paracentral vs isolated peripheral loss
Age (years)	66.6±7.1	61.9±6.3	69.8±9.9	0.26	0.71	0.03*
Gender, female (%)	60.0%	80.0%	64.3%	0.28	>0.99	0.43
Ethnicity, Caucasian (%)	95.0%	93.3%	92.9%	>0.99	>0.99	>0.99
lOP (mmHg)	14.4±2.2	14.0±2.5	13.6±3.0	>0.99	>0.99	>0.99
Maximum lOP (mmHg)a	15.4±1.8	20.3±3.2	19.2±3.6	<0.001*	0.002*	0.84
VF MD (dB)	N/A	−5.3±2.7	−3.7±3.0	N/A	N/A	0.15
VF PSD (dB)	N/A	5.8±3.3	3.3±1.7	N/A	N/A	0.02*

Notes: Values are expressed as mean ± standard deviation unless otherwise specified.

* Statistically significant difference, p<0.05.

a Known untreated maximum IOP was available for all control eyes and 28 of 29 glaucoma eyes.

Abbreviations: IOP, intraocular pressure; VF MD, visual field mean deviation; VF PSD, visual field pattern standard deviation; N/A, not available.

Table 2 Quantitative parameters among the studied group

ONH parameters (μm)	Control eyes (N=20)	Early paracentral loss eyes (N=15)	Isolated peripheral loss eyes (N=14)	p-value Control vs early paracentral loss	p-value Control vs isolated peripheral loss	p-value Paracentral vs isolated peripheral loss
SS-OCT global BMO-MRW	322.7±62.2	187.6±43.4	200.6±36.3	<0.001*	<0.001*	>0.99
SS-OCT scaled global BMO-MRW	308.3±70.8	187.3±40.2	207.9±60.6	<0.001*	<0.001*	>0.99
SS-OCT minimal BMO-MRW	200.1±40.8	69.0±33.6	107.7±40.2	<0.001*	<0.001*	0.03*
SS-OCT scaled minimal BMO-MRW	191.4±45.0	69.5±35.6	114.0±55.53	<0.001*	<0.001*	0.04*
SS-OCT minimal sector BMO-MRW	229.1±44.1	109.3±38.2	139.2±39.5	<0.001*	<0.001*	0.17
SS-OCT scaled minimal sector BMO-MRW	219.5±51.6	110.3±41.4	145.7±57.9	<0.001*	<0.001*	0.20
SS-OCT LCDH	433.5±94.6	465.4±104.5	414.5±113.2	>0.99	>0.99	0.57
SS-OCT LCDV	448.8±105.2	487.9±94.6	418.4±82.3	0.72	>0.99	0.19
SD-OCT average RNFLT	96.6±10.4	70.4±9.7	75.9±14.3	<0.001*	<0.001*	0.61
SD-OCT thinnest RNFLT	66.7±8.0	47.1±8.9	53.6±10.7	<0.001*	0.001*	0.19

Notes: Values are expressed as mean ± standard deviation.

* Statistically significant difference, p<0.05.

Abbreviations: SS-OCT, swept source optical coherence tomography; BMO-MRW, minimum rim width at Bruch’s membrane opening; LCDH, horizontal lamina cribrosa depth; LCDV, vertical lamina cribrosa depth; ONH, optic nerve head; SD-OCT, spectral domain optical coherence tomography; RNFLT, retina nerve fiber layer thickness.

Table 3 Multivariate linear regression for the measurement of minimal BMO-MRW

	Variable	β	95% CI		p-value
			Lower bound	Upper bound
Covariates	Age	−0.1	−1.8	1.5	0.86
	Gender (reference: male)	−28.2	−59.7	−3.2	0.08
	Visual field MD	−3.2	−8.2	1.9	0.21
	BMO circumference	0.03	0.005	0.05	0.02*
	Early paracentral VF loss (reference: isolated peripheral VF loss)	−38.3	−69.8	−6.8	0.02*

Note:

* Statistically significant association, p<0.05.

Abbreviations: MD, mean deviation; BMO, Bruch’s membrane opening; BMO-MRW, minimum rim width at Bruch’s membrane opening; VF, visual field; CI, confidence interval.

Figure S1 Diagram showing scans included in each sector for calculating sector BMO-MRW in a right eye.

Notes: N: 10, 11, 12, 1, 2, 3, 4; SN: 5, 6, 7; ST: 8, 9, 10; T: 11, 12, 1, 2, 3; IT: 4, 5, 6; IN: 7, 8, 9. Similarly, the corresponding scans were used for calculating sector BMO-MRW in left eyes.

Abbreviations: BMO-MRW, minimum rim width at Bruch’s membrane opening; N, nasal; SN, superonasal; ST, superotemporal; T, temporal; IT, inferotemporal; IN, inferonasal.

Figure S2 Example of a left eye with early paracentral loss.

Notes: The corresponding visual field test is shown in Figure 1 left side. The minimal BMO-MRW is 34.8 μm and the minimal sector BMO-MRW, as an average over three adjacent scans, is thicker at 92.4 μm. (A) Minimal BMO-MRW (34.8 μm) is in the inferotemporal sector (red arrow) on scan 6. (B) BMO-MRW in the inferotemporal sector (red arrowheads) is 109.3 μm on scan 5. (C) BMO-MRW in the inferotemporal sector (red arrowheads) is 133.0 μm on scan 4.

Abbreviation: BMO-MRW, minimum rim width at Bruch’s membrane opening.