Introduction 1 2 3 13 14 19 We therefore undertook a multicenter prospective controlled study of TA-assisted pars plana vitrectomy (PPV). Considering the enduring nature of the effect of PPV on ocular tissue, it is important to investigate the long-term results in order to evaluate TA-assisted PPV. Moreover, the crucial issue of the effects on patients’ vision must be explored before TA-assisted PPV can be recommended. The current report presents the 1-year results of the use of TA in PPV, and evaluates the procedure in light of the aforementioned issues. Methods Study design, randomization and sample size 13 13 13 13 Eligibility criteria and surgery Institutional review board (IRB)/ethics committee approval was obtained from all of the participating clinical establishments, such that all patients undergoing PPV at these hospitals were eligible to enroll in the study. Each patient was fully informed about the nature of the treatment, and provided written consent. The following groups were excluded: (1) patients with diagnoses that included macular holes; patients with uveitis, (2) patients with phakic lenses, (3) patients who were known to be steroid responders, to have glaucoma, or to have apparent infectious endophthalmitis, and (4) patients who were undergoing a second PPV. For ethical reasons, if at the time of surgery a surgeon felt that TA was necessary to achieve a successful PPV outcome, it was included in the procedure; for the purposes of the intent-to-treat analysis, these cases were included within the conventional PPV group. 2 13 13 During the follow-up period, additional surgeries were performed at each hospital as and when they were needed. For example, filtering surgeries were performed when the intra-ocular pressure (IOP) remained at an uncontrollably high level (25 mmHg or greater) even with full medication. Full medication included the use of all latanoprost, beta-blocker, and dorzolamide hydrochloride eyedrops and acetazolamide medicine. 13 Masking and outcome assessment The study records were collected by the principal investigator (TS) up until November 2006. After checking the records for harmful events, the data were sent to the controllers (YN) at Kyushu University. The remaining investigators were not permitted access to any information on the outcomes before completion of the analysis. Visual acuity was measured by ophthalmic technicians using the Snellen high-contrast acuity test. IOP was also measured by the ophthalmic technicians, and the findings were reviewed by the physicians. IOP was measured with pneumotonometer. The ophthalmic technicians were not informed of the purpose of the study or the assignment schedule. Anti-glaucoma eye drops and/or acetazolamide were used when an IOP of 22 mmHg or higher persisted for 3 days. Statistical analysis The visual acuity was converted to the logarithm of the minimum angle of resolution (LogMAR), and the baseline value was compared with those at 1 week, 1 month, 3 months, 6 months, and 1 year. The eyes were categorized into the following three groups: (1) the improved group, in which patients showed a 0.3 logMAR or greater improvement of visual acuity at the final examination compared with baseline, (2) the deteriorated group, in which patients showed a 0.3 logMAR or worse deterioration of visual acuity at the final examination compared with baseline, and (3) the unchanged group, in which patients did not meet the criteria of either the improved or the deteriorated group. A Kaplan-Meier survival analysis was used to estimate the probability of improved visual acuity with time after surgery. The improvement or deterioration was analyzed by the log rank test. The earliest time point after surgery at which the events in each category were reported was designated as the time point of each event. P Results Number of eyes 1 Fig. 1 TA PPV  Diagnoses 1 P P P P Table 1 Diseases of each group at baseline and 1 year after surgery   TA-assisted PPV Conventional PPV Baseline 1 year baseline 1 year N N N N AMD 7 (1.8%) 3 (1.0%) 3 (0.8%) 3 (1.0%) BRVO 50 (12.8%) 41 (13.4%) 37 (9.7%) 29 (9.8%) CRVO 11 (2.8%) 9 (3.0%) 7 (1.8%) 6 (2.0%) DME 67 (17.1%) 60 (19.7%) 42 (11.0%) 34 (11.5%) ERM 24 (6.1%) 19 (6.2%) 41 (10.7%) 37 (12.5%) Lens luxation 16 (4.1%) 11 (3.6%) 16 (4.2%) 12 (4.1%) Macroaneurysm 10 (2.6%) 8 (2.6%) 9 (2.3%) 4 (1.4%) PDR 113 (28.9%) 85 (27.9%) 131 (34.2%) 101 (34.2%) RRD 80 (20.5%) 59 (19.3%) 77 (20.1%) 54 (18.3%) VH 6 (1.5%) 6 (2.0%) 14 (3.7%) 11 (3.7%) Others 7 (1.8%) 4 (1.3%) 6 (1.6%) 4 (1.4%) total 383 (100%) 305 (100%) 391 (100%) 295 (100%) TA; triamcinolone acetonide: PPV; pars plana vitrectomy: AMD; age-related macular degeneration: BRVO;branch retinal vein occlusion: CRVO: central retinal vein occlusion: DME; diabetic macular edema: ERM; epiretinal membrane: PDR; proliferative diabetic retinopathy: RRD; rhegmatogenous retinal detachment: VH; vitreous hemorrhage. P P P P P P P P 13 Visual acuity P P P 2 P P P 2 Table 2 Factors affecting improvement of visual acuity Variable (no. of improved eyes/total eyes) Odds ratio (95%CI) P TA-assisted PPV (322/391) vs conventional PPV (312/383) 1.10 (0.860–1.183) 0.91 Age 1.00 (0.991–1.005) 0.54 Gender (male vs female) 0.92 (0.785–1.080) 0.31 Diseases RD vs PDR 1.04 (0.834–1.340) 0.71 DME vs PDR 0.63 (0.478–0.817) 0.0006* RVO vs PDR 1.21 (0.938–1.561) 0.14 ERM vs PDR 0.78 (0.568–1.061) 0.11 Others vs PDR 1.21 (0.924–1.579) 0.17 CI; confidence interval: TA; triamcinolone acetonide: PPV; pars plana vitrectomy: RVO; branch retinal vein occlusion + central retinal vein occlusion: DME; diabetic macular edema: ERM; epiretinal membrane: PDR; proliferative diabetic retinopathy: RRD; rhegmatogenous retinal detachment. * statistically significant Post-operative complications Subgroup analysis P P 3 Table 3 Post-operative complications in each group   n n P After cataract 18 (4.6%) 17 (4.4%) 0.91 Macular pucker 23 (5.9%) 22 (5.7%) 0.93 IOP increase 23 (5.9%) 13 (3.4%) 0.10 Retinal detachment 9 (2.3%) 9 (2.3%) 0.96 Vitreous hemorrhage 22 (5.6%) 29 (7.8%) 0.28 Fibrous membrane 1 (0.3%) 5 (1.4%) 0.10 Iris synechiae 6 (1.5%) 4 (1.0%) 0.55 Others 8 (2.0%) 12 (3.1%) 0.34 TA; triamcinolone acetonide: PPV; pars plana vitrectomy: PPL; pas plana lensectomy: IOP; intraocular pressure: * Chi-square test with the Yates’ correction. Additional surgery P 4 P Table 4 Causes of additional surgery after PPV   n n P Silicone removal 11 (2.8%) 7 (1.8%) 0.36 Retinal detachment 8 (2.0%) 9 (2.3%) 0.77 Vitreous hemorrhage 6 (1.5%) 12 (3.1%) 0.14 Filtering surgery 15 (3.8%) 7 (1.8%) 0.10 Others 7 (1.8%) 6 (1.6%) 0.81 Total ✝ ✝✝ 0.68 ✝ ✝✝ P P P P 5 6 Table 5 Factors affecting additional surgery Variable (no. of additional surgery/total) Odds ratio (95%CI) P TA-assisted PPV (37/391) vs conventional PPV (32/383) 1.23 (0.797–1.911) 0.35 Age 0.97 (0.950–0.984) 0.0001* Gender (male vs female) 1.15 (0.733–1.797) 0.55 Diseases RD vs PDR 0.60 (0.345–1.029) 0.06 DME vs PDR 0.29 (0.122–0.681) 0.005* RVO vs PDR 0.23 (0.084–0.657) 0.006* ERM vs PDR 0.087 (0.012–0.631) 0.02* Others vs PDR 0.64 (0.299–1.374) 0.25 CI; confidence interval: RVO; branch retinal vein occlusion + central retinal vein occlusion: DME; diabetic macular edema: ERM; epiretinal membrane: PDR; proliferative diabetic retinopathy: RRD; rhegmatogenous retinal detachment. * statistically significant Table 6 Factors affecting filtering surgery Variable (no. of filtering surgery/total) Odds ratio (95%CI) P TA-assisted PPV (12/391) vs conventional PPV (5/383) 1.74 (0.708–4.265) 0.23 Age 0.98 (0.941–1.018) 0.28 Gender (male vs female) 1.81 (0.696–4.728) 0.22 Diseases RRD vs PDR – 0.99 DME vs PDR – 0.99 RVO vs PDR – 0.99 ERM vs PDR – 0.99 Others vs PDR 0.83 (0.266–2.573) 0.74 CI; confidence interval: TA; triamcinlone acetonide: PPV; pars plana vitrectomy: RVO; branch retinal vein occlusion + central retinal vein occlusion: DME; diabetic macular edema: ERM; epiretinal membrane: PDR; proliferative diabetic retinopathy: RRD; rhegmatogenous retinal detachment Serious adverse events None of the serious adverse events related to surgery defined in this study (such as retinal degeneration, endophthalmitis, an unexplained decrease in visual acuity, or optic-disc atrophy) were observed in either group during the 1-year follow-up. Discussion 13 13 13 18 19 3 5 9 6 7 5 7 20 21 In summary, the intra-operative use of TA in PPV did not affect visual acuity over 1 year. As negative or adverse events were not observed in this case series, a more detailed study is warranted to establish the value of TA in PPV.