Characterization of Peripheral Anterior Synechiae Formation After Microhook Ab-interno Trabeculotomy Using a 360-Degree Gonio-Camera

Figures & data

Figure 1 Representative gonioscope GS-1 images with PAS formation after µLOT in a 360-degree view of the angle, and the distribution of the average PAS formation rate in each angle position.

Notes: (A) The typical merged GS-1 image after µLOT displayed in a 360-degree view of the angle is shown on the right side, in which the ocular features are seen as in direct gonioscopy, with the extent of the incision indicated in red. Each PAS formation is indicated by a white arrow. The image shows the left eye of a patient with primary open-angle glaucoma, for whom five gonio-images show the extent of the PAS within the incision. In addition, a GS-1 image of the extent of the incision, in which PAS is present, is shown on the left. (B) The radar chart shows the distribution of the average PAS formation rates in each sector. PAS appears to form frequently in the incision.

Abbreviations: PAS, peripheral anterior synechia; µLOT, microhook ab interno trabeculotomy; S, superior; SST, superior-superior-temporal; ST, superior-temporal; STT, superior-temporal-temporal; T, temporal; ITT, inferior-temporal-temporal; IT, inferior-temporal; IIT, inferior-inferior-temporal; I, inferior; IIN, inferior-inferior-nasal; IN, inferior-nasal; INN, inferior-nasal-nasal; N, nasal; SNN, superior-nasal-nasal; SN, superior-nasal; SSN, superior-superior-nasal.

Table 1 Continuous Preoperative and Postoperative Variables

Variable	Preoperative Conditions (n=105)	Postoperative Conditions (n=105)	p*
Baseline characteristics
Age, years, mean ± SD (range)	64.1±15.6 (11–87)	NA
Mean Shaffer grade, mean ± SD (range)	3.5±0.72 (1–4)	NA
Axial length, mm, mean ± SD (range)	24.9±2.0 (21.2–30.7)	NA
Visual field mean deviation, dB, mean ± SD (range)	−12.6±8.4 (−29.71–1.16)	NA
Postoperative days, mean ± SD (range)	0	225±226 (14–1021)	<0.01
LogMAR best corrected visual acuity, mean ± SD (range)	0.19±0.43 (−0.08–2.30)	0.11±0.39 (−0.08–2.30)	<0.01
Intraocular pressure, mmHg, mean ± SD (range)	20.7±6.7 (12.0–51.0)	13.7±3.7 (6–21)	<0.01
Central anterior chamber depth, mm, mean ± SD (range)	3.28±0.42 (2.06–4.77)	3.69±0.67 (2.33–5.41)	<0.01
Aqueous flare, pc/ms, mean ± SD (range)	9.1±5.0 (2.6–27.9)	15.3±14.5 (2.3–121.3)	<0.01
Topical glaucoma medications, mean ± SD (range)	3.3±0.9 (1–5)	2.7±0.8 (0–4)	<0.01
Primary outcome variables
Peripheral anterior synechiae formation, number (%)	0	90 (86)	<0.01
Images of peripheral anterior synechiae formation in total, mean ± SD (range)	0	4.1±3.2 (0–14)	<0.01
Images of peripheral anterior synechiae formation in incision extent of µLOT, mean ± SD (range)	0	3.1±2.3 (0–8)	<0.01
Images of peripheral anterior synechiae formation in non–incision extent of µLOT, mean ± SD (range)	0	1.0±1.3 (0–7)	<0.01

Note: Statistical significance was analyzed by the paired t-test (*).

Abbreviations: SD, standard deviation; µLOT, microhook ab interno trabeculotomy; n, number of eyes; NA, not applicable; dB, decibels; logMAR, logarithm of the minimum angle of resolution; pc/ms, photon counts per millisecond.

Table 2 PAS Formation Frequencies and Rates After µlot Classified by Categorical Variables in Demographic Data

Variable	PAS Number (%)	Total PAS Rate, Mean ± SD	Rate Within µLOT Incision, Mean ± SD	Rate Outside of µLOT Incision, Mean ± SD	p^‡
All study subjects (n=105)	90 (86)	0.26±0.20	0.39±0.29	0.13±0.16	<0.0001
Sex
Male (n=60)	53 (88)	0.26±0.18	0.39±0.27	0.13±0.15	<0.0001
Female (n=45)	37 (82)	0.26±0.23	0.38±0.32	0.14±0.18	<0.0001
p*	0.38	0.96	0.81	0.74
Right or left eye
Right eye (n=53)	46 (87)	0.26±0.20	0.38±0.28	0.14±0.17	<0.0001
Left eye (n=52)	44 (85)	0.26±0.20	0.39±0.30	0.13±0.16	<0.0001
p*	0.75	0.96	0.84	0.76
µLOT combined with cataract surgery
Yes (n=79)	65 (82)	0.23±0.20	0.36±0.30	0.11±0.15	<0.0001
No (n=26)	25 (96)	0.33±0.19	0.48±0.24	0.19±0.19	<0.0001
p*	0.08	0.03	0.07	0.09
Glaucoma type
POAG (n=68)	62 (91)	0.25±0.17	0.39±0.27	0.11±0.12	<0.0001
PEG (n=27)	19 (70)	0.26±0.24	0.38±0.35	0.15±0.20	0.0005
JOAG (n=10)	9 (90)	0.29±0.25	0.38±0.28	0.20±0.26	0.02
p^†	0.03	0.86	0.96	0.23

Notes: Statistical significance was analyzed by the chi-square test for categorical data and the Student’s t-test for continuous data (*); by the chi-square test for categorical data and one-way analysis of variance for continuous data (^†); by the paired t-test (^‡).

Abbreviations: PAS, peripheral anterior synechiae; µLOT, microhook ab-interno trabeculotomy; n, number of eyes; POAG, primary open angle glaucoma; PEG, pseudoexfoliation glaucoma; JOAG, juvenile open angle glaucoma; SD, standard deviation.

Table 3 Possible Associations Among PAS Rates and Various Continuous Variables Analyzed by the Simple Linear Regression Model

Variable	Preoperative Conditions (n=105)						Postoperative Conditions (n=105)
	Total PAS Rate		PAS Rate Within µLOT Incision		PAS Rate outside of µLOT Incision		Total PAS rate		PAS Rate Within µLOT Incision		PAS Rate Outside of µLOT Incision
	r (95% CI)	p*	r (95% CI)	p*	r (95% CI)	p*	r (95% CI)	p*	r (95% CI)	p*	r (95% CI)	p*
Age (/year)	−0.0016	0.20	−0.0016	0.38	−0.0016	0.12	NA	NA	NA	NA	NA	NA
Mean Shaffer grade	−0.058	0.03	−0.070	0.08	−0.046	0.04	NA	NA	NA	NA	NA	NA
Axial length (/mm)	−0.023	0.02	−0.028	0.053	−0.019	0.02	NA	NA	NA	NA	NA	NA
Visual field mean deviation (/dB)	−0.0012	0.62	−0.0021	0.55	−0.00028	0.89	NA	NA	NA	NA	NA	NA
Postoperative days (/day)	NA	NA	NA	NA	NA	NA	0.00022	0.01	0.00034	<0.01	0.000096	0.18
LogMAR best-corrected visual acuity	0.060	0.18	0.12	0.07	0.00048	0.99	0.036	0.48	0.093	0.21	−0.020	0.63
Intraocular pressure (/mmHg)	0.00046	0.88	0.0050	0.25	−0.0040	0.10	−0.0055	0.23	−0.0052	0.43	−0.0056	0.13
Central anterior chamber depth (/mm)	−0.17	<0.01	−0.19	<0.01	−0.15	<0.01	−0.068	0.02	−0.096	0.03	−0.040	0.10
Aqueous flare (/pc/ms)	0.0012	0.77	0.00071	0.90	0.0016	0.63	−0.00050	0.71	−0.0018	0.38	0.00075	0.50
Topical glaucoma medications	0.062	<0.01	0.097	<0.01	0.027	0.12	0.024	0.32	0.056	0.11	−0.0066	0.74

Note: Possible association was analyzed by the simple linear regression model (*).

Abbreviations: PAS, peripheral anterior synechiae; n, number of eyes; µLOT, microhook ab-interno trabeculotomy; SD, standard deviation; r, regression coefficient; NA, not applicable; logMAR, logarithm of the minimum angle of resolution; dB, decibels; CI, confidence interval; pc/ms, photon counts per millisecond.

Table 4 Possible Associations Among PAS Rate and Various Variables Analyzed by the Mixed-Effect Model

Variable	Total PAS Rate (n=105)		PAS Rate Within µLOT Incision (n=105)		PAS Rate Outside of µLOT Incision (n=105)
	Estimate (95% CI)	p*	Estimate (95% CI)	p*	Estimate (95% CI)	p*
Postoperative days (/day)	0.00022	0.01	0.00037	0.004	0.000078	0.29
µLOT combined with cataract surgery (/yes)	0.062	0.06	0.064	0.17	0.054	0.048
Preoperative central anterior chamber depth (/mm)	−0.11	0.07	−0.12	0.19	−0.11	0.04
Preoperative topical glaucoma medications	0.031	0.19	0.060	0.08	0.0056	0.77
Axial length (/mm)	−0.013	0.28	−0.014	0.41	−0.0093	0.35
Mean Shaffer grade	−0.033	0.35	−0.054	0.29	−0.0079	0.79
Preoperative intraocular pressure (/mmHg)	0.0028	0.42	0.0092	0.07	−0.0035	0.23
Glaucoma type (JOAG/POAG)	0.016	0.78	0.012	0.89	0.022	0.65
Glaucoma type (PEG/POAG)	−0.0052	0.90	−0.024	0.70	0.0086	0.81

Notes: Possible association was analyzed by the mixed-effect model with crossed random effects to adjust for correlation between fellow eyes (*).

Abbreviations: PAS, peripheral anterior synechiae; µLOT, microhook ab-interno trabeculotomy; POAG, primary open angle glaucoma; JOAG, juvenile open angle glaucoma; PEG, pseudoexfoliation glaucoma; n, number of eyes; CI, confidence interval.