Evaluation of the learning curve of laser peripheral iridectomy: the 20th case reaches the turning point.

AIM: To explore the learning curve for ophthalmologists at the start of laser peripheral iridectomy (LPI) training. METHODS: The learning curve of 4 doctor groups without previous LPI experience was studied. Three main parameters of LPI were reviewed: total energy, argon energy and neodymium-doped yttrium aluminum garnet (Nd:YAG) energy. Procedures were evaluated in cohorts of 20 cases to identify the turning points of the three variables. RESULTS: There was no significant difference in terms of age or eye among the 4 doctor groups. There were stable trends on the learning curve for the Doctor A and C groups regarding total energy and argon energy. In addition, the turning points on the learning curve were determined after the 20th procedure for the Doctor B and D groups regarding total energy and argon energy. Moreover, the Nd:YAG energy was relatively stable since the first procedure. CONCLUSION: It requires approximately 20 procedures for a beginner to reach a turning point on the learning curve regarding LPI. It can serve as a point of reference or guideline for training beginners to perform LPI.

Ex-PRESS implantation versus trabeculectomy in Chinese patients with POAG: fellow eye pilot study.

AIM: To compare the outcomes of Ex-PRESS implantation in one eye versus trabeculectomy with mitomycin C in the fellow eye in Chinese patients with primary open-angle glaucoma (POAG). METHODS: This was a prospective, non-randomized comparative study. Forty-eight eyes of 24 patients with bilateral POAG necessitating surgery were included and underwent Ex-PRESS implantation under the scleral flap in one eye and trabeculectomy in the other eye according to patients' choice. Primary outcome measures included mean intraocular pressure (IOP) and success rate. Secondary outcome measures were aqueous flare, postoperative medication use, visual acuity, and incidence of complications. RESULTS: All 24 patients finished a 1-year follow-up. Both groups maintained significant reductions in IOP after surgery throughout the follow-up period. At any point in time, the IOP of the two groups did not differ significantly. The Kaplan-Meier survival curve analysis showed no significant differences in success between the two groups (P=0.289). The mean number of anti-glaucoma medicines and visual acuity in both groups were not significantly different. Eyes with Ex-PRESS implantation had lower aqueous flare values on days 1 and 3 (both P<0.05). Instances of early postoperative hypotony and choroidal effusion were significantly fewer in frequency after Ex-PRESS implantation under the scleral flap compared with those after trabeculectomy (P<0.001). CONCLUSION: Ex-PRESS is comparable to trabeculectomy in terms of IOP, success rate, number of glaucoma medications used, and visual acuity. However, Ex-PRESS resulted in fewer cases of inflammation and a lower rate of complications.

Short-term effect of intravitreal ranibizumab on intraocular concentrations of vascular endothelial growth factor-A and pigment epithelium-derived factor in neovascular glaucoma.

BACKGROUND: This study aims to evaluate concentrations of pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF)-A in aqueous of patients with neovascular glaucoma prior to, and shortly after, an intravitreal ranibizumab injection. DESIGN: Interventional comparative study. PARTICIPANTS: The study included patients undergoing an intravitreal ranibizumab injection about one week before anti-glaucomatous surgery (study group) or who underwent routine cataract surgery (control group). METHODS: Aqueous and blood samples were collected at the occasions of intravitreal injections, anti-glaucomatous surgery or cataract surgery. They were analysed by enzyme-linked immunosorbent assay. MAIN OUTCOME MEASURES: Concentrations of PEDF and VEGF-A in aqueous. RESULTS: At baseline, concentrations VEGF-A (3698 ± 2105 pg/mL vs. 233 ± 98 pg/mL) and PEDF (18.9 ± 11.9 ug/mL vs. 2.2 ± 0.6 ug/mL) were higher (P < 0.001) in the study group (n = 20 patients) than control group (n = 20 patients). The VEGF-A/PEDF concentration ratio was higher in the study group (396 ± 554 vs. 110 ± 49; P = 0.02). One week after the ranibizumab injection, iris neovascularization had completely regressed in 17 (85%) eyes, and VEGF-A concentration decreased significantly (P < 0.001) to 184 ± 130 pg/mL. The PEDF concentration remained unchanged (19 ± 12 ug/mL). The VEGF-A/PEDF concentration ratio decreased to 13.2 ± 13.6. Plasma concentrations of VEGF-A and PEDF did not differ significantly between both groups (P = 0.65 and P = 0.15, respectively) nor were they significantly correlated with the aqueous concentrations (all P > 0.15). CONCLUSIONS: Aqueous concentrations of VEGF-A and PEDF were significantly elevated in eyes with neovascular glaucoma. Within one week after intravitreal injection of ranibizumab, VEGF-A concentration decreased to subnormal levels, while the PEDF concentration remained unchanged and the VEGF-A/PEDF ratio decreased.

[The blood-aqueous barrier changes after laser peripheral iridotomy or surgery peripheral iridectomy].

OBJECTIVE: To investigate the ocular blood-aqueous barrier (BAB) alteration after laser peripheral iridotomy (LPI) or surgery peripheral iridectomy (SPI) in patients with primary chronic angle-closure glaucoma (PCACG). METHODS: This was a clinical randomized controlled trial. Sixty eyes of 60 subjects with early stage of PCACG were randomly received either LPI or SPI and followed up postoperatively at day 3, week 1, 2, 3, and 4. Aqueous flare in anterior chamber was measured by FC-2000 flare-cell photometry, intraocular pressure (IOP) measured by tonometer, central corneal endothelium cell counted by endothelioscopy, peripheral anterior synechiae (PAS) detected by gonioscopy. Data were analyzed by using two-way ANOVA for repeated measures, independent samples t-test, paired t-test, nonparametric test, and Spearman rank correlation test. RESULTS: On follow-ups of pre-operative and post-operative 3 days, 1 week (w), 2w, 3w and 4w respectively, the mean aqueous flare values for LPI group were (5.47 ± 1.09), (11.96 ± 3.07), (8.08 ± 2.18), (5.68 ± 0.83), (5.80 ± 1.00), (5.69 ± 1.12) PC/ms, and for SPI group were (5.43 ± 1.13), (8.44 ± 3.22), (6.42 ± 1.77), (5.35 ± 0.71), (5.53 ± 1.26), (5.45 ± 1.23) PC/ms. During post-operative 1w the flare values in both LPI and SPI groups were significantly higher than that on pre-operation (t = -12.753, -8.101, P < 0.05; t = -5.971, -3.870;P < 0.05) and LPI group had a significantly higher mean flare value than SPI group (t = 4.329, 3.231;P < 0.05). The IOP spike in LPI group was significantly (χ(2) = 5.079, 4.022, P < 0.05) higher than that in SPI group at week 1 of post-operation. Increased IOP was positively correlated with BAB damage (r = 0.899, 0.833; P < 0.05). The numbers of medications required to maintain IOP ≤ 21 mm Hg (1 mm Hg = 0.133 kPa) at week 4 of post-operation in LPI was significantly (Z = -1.984, P < 0.05) more than that in SPI group. There were no significant differences in central corneal endothelium cell count at week 1 (t = -0.696, 0.008) and in extension of PAS at week 4 (Z = -1.270, -1.490) of post-operation when compared to pre-operation (P > 0.05). No obvious complications occurred in both groups. CONCLUSIONS: Our results demonstrated that IOP spike in both of LPI and SPI is due, at least in part, to BAB damage, which appears to be more severe in LPI group and can recover within two weeks. PAS progression and central corneal endothelium cell loss are not aggravated in 1 month after operation.