Baseline characteristics
Table 1 shows the baseline characteristics. A total of 48 eyes underwent trabeculectomy followed by phacoemulsification, whereas 93 eyes underwent trabeculectomy combined with phacoemulsification. Significant differences were observed in the number of secondary glaucoma due to uveitis (p = 0.02), preoperative logMAR visual acuity (p < 0.01), and the base of conjunctival flap (p = 0.03) between the two groups. Preoperative IOP (mean ± SD) was not significantly different between the trabeculectomy followed by phacoemulsification group (24.0 ± 10.1 mmHg) and trabeculectomy combined with phacoemulsification group (24.4 ± 8.0 mmHg; p = 0.35).
Table 1. Baseline characteristics
|
TLE followed by Phaco
|
TLE combined with Phaco
|
p value
|
N
|
48
|
93
|
|
Age (years)
|
64.5 ± 12.0
|
67.7 ± 9.95
|
0.197
|
Sex, male (%)
|
56.2
|
53.8
|
0.86
|
Sub-types of OAG
|
|
|
|
POAG, n (%)
|
31 (65)
|
50 (54)
|
0.29
|
EXG, n (%)
|
8 (17)
|
7(8)
|
0.17
|
SG, n (%)
|
9 (19)
|
36 (39)
|
0.02†
|
LogMAR VA
|
0.14 ± 0.28
|
0.48 ± 0.50
|
< 0.01*
|
Base, fornix (%)
|
34.7
|
54.8
|
0.03†
|
IOP (mmHg)
|
24.0 ± 10.1
|
24.4 ± 8.0
|
0.35
|
Glaucoma medication (n)
|
2.3 ± 1.1
|
2.7 ± 1.0
|
0.14
|
VF (MD)
|
−18.1 ± 7.31
|
−15.6 ± 11.1
|
0.40
|
TLE = trabeculectomy, Phaco = phacoemulsification, POAG = primary open-angle glaucoma, EXG = exfoliation glaucoma, SG = secondary glaucoma, Posner = Posner-Schlossman syndrome, LogMAR = logarithm of minimum angle of resolution, VA = visual acuity, IOP = intra ocular pressure, VF = visual field, MD = mean deviation
†Chi-square test * Wilcoxon non-parametrical test
Primary outcome
Results of the Kaplan–Meier survival curve analysis between the trabeculectomy followed by phacoemulsification group and the trabeculectomy combined with phacoemulsification group for criteria A, B, and C are shown in Figure 1. No significant differences were observed between the trabeculectomy followed by phacoemulsification group and the trabeculectomy combined with phacoemulsification group in any criteria.
Secondary outcomes
Figure 2 shows that the trabeculectomy combined with phacoemulsification group had significantly lower cumulative probabilities of success for criteria A, B, and C (p = 0.02, p < 0.01, and p < 0.01, respectively) than the trabeculectomy followed by phacoemulsification group when data on phacoemulsification during the 5-year follow-up were censored. For criterion A, the cumulative probabilities of success of trabeculectomy followed by phacoemulsification and trabeculectomy combined with phacoemulsification at 5 years were 66.7% and 43.0% (p = 0.02), respectively. For criterion B, the cumulative probabilities of success of trabeculectomy followed by phacoemulsification and trabeculectomy combined with phacoemulsification at 5 years were 64.6% and 37.6% (p < 0.01), respectively. For criterion C, the cumulative probabilities of success of trabeculectomy followed by phacoemulsification and trabeculectomy combined with phacoemulsification at 5 years were 54.2% and 22.6% (p < 0.01), respectively.
Risk factors for surgical failure
Results of the Cox proportional hazards model are listed in Table 2, when data on phacoemulsification during the 5-year follow-up were censored. Trabeculectomy combined with phacoemulsification was consistently associated with poorer surgical outcomes for criteria A (p = 0.01), B (p = 0.01), and C (p < 0.01). Preoperative lower IOP was associated with poorer surgical outcomes for criteria A (p < 0.01) and B (p = 0.04). Younger age was associated with poorer surgical outcomes for criteria A (p = 0.02) and B (p = 0.04).
Table 2. Hazard ratio analyzed using the multivariate cox proportional hazards regression models
Factor
|
Criteria
|
A
|
B
|
C
|
HR (95% Cl)
|
p value
|
HR (95% Cl)
|
p value
|
HR (95% Cl)
|
p value
|
Age (years)
|
0.97 (0.95–0.99)
|
0.02*
|
0.98 (0.95–0.99)
|
0.04*
|
0.98 (0.96–1.00)
|
0.07
|
Sex F / M
|
1,24 (0.75–2.07)
|
0.41
|
1.01 (0.62–1.64)
|
0.96
|
0.98 (0.64–1.50)
|
0.93
|
Preoperative IOP per mmHg
|
0.94 (0.91–0.98)
|
< 0.01*
|
0.96 (0.93–0.99)
|
0.04*
|
1.00 (0.96–1.03)
|
0.71
|
Conjunctival incision (Fornix-based/limbus-based)
|
0.93 (0.55–1.55)
|
0.77
|
0.96 (0.58–1.58)
|
0.86
|
1.06 (0.69–1.64)
|
0.80
|
Subtypes of OAG
|
|
|
|
|
|
|
EXG / POAG
|
0.58 (0.26–1.29)
|
0.18
|
0.67 (0.31–1.47)
|
0.65
|
1.07 (0.50–2.31)
|
0.86
|
SG / POAG
|
0.71 (0.28–1.77)
|
0.46
|
0.79 (0.32 −1.95)
|
0.61
|
0.99 (0.42–2.32)
|
0.98
|
TLE combined with phaco
|
2.31 (1.22–4.38)
|
0.01*
|
2.26 (1.22–4.18)
|
0.01*
|
2.23 (1.30–3.82)
|
< 0.01*
|
The number of glaucoma medication
|
1.04 (0.80–1.35)
|
0.77
|
1.06 (0.82–1.35)
|
0.68
|
1.12 (0.90–1.40)
|
0.31
|
HR = hazard ratio, F = female, M = male, IOP = intraocular pressure, OAG = open-angle glaucoma, POAG = primary, OAG = open-angle glaucoma, EXG = exfoliation glaucoma, SG = secondary glaucoma due to uveitis, Posner = Posner-Schlossman syndrome, TLE = trabeculectomy, Phaco = phacoemulsification
*Log-rank test
Δ Visual acuity change
The 5-year Δ visual acuity changes of trabeculectomy followed by phacoemulsification and trabeculectomy combined with phacoemulsification are shown in Figure 3. The Δ visual acuity in the trabeculectomy followed by phacoemulsification group and trabeculectomy combined with phacoemulsification group were 0.13 ± 0.25 and −0.16 ± 0.47 at 6 months (p < 0.01), 0.20 ± 0.46 and −0.15 ± 0.53 at 12 months (p < 0.01), 0.06 ± 0.29 and −0.03 ± 0.60 at 36 months (p = 0.12), and 0.11 ± 0.41 and 0.07 ± 0.76 at 60 months (p = 0.40), respectively.