Changes in circumpapillary retinal nerve fiber layer thickness after vitrectomy for rhegmatogenous retinal detachment.

The study aimed to evaluate the long-term changes in circumpapillary retinal nerve fiber layer (RNFL) thickness after vitrectomy for rhegmatogenous retinal detachment (RRD) repair. A total of 33 eyes of 33 patients were enrolled. By using optical coherence tomography, the circumpapillary RNFL thickness was measured before surgery and 1, 3, 6 months and 1, 2, 3 years after surgery and compared with the preoperative value. The effect of duration, location, and extent of RRD on RNFL thickness change was evaluated. There was a significant increase of circumpapillary RNFL thickness at the 1-month, 3-month [except in the nasal superior sector (P = 0.627)], and only in the nasal inferior sector at 6-month (P = 0.010) follow-up compared with the baseline value (all Ps < 0.05). No significant differences were observed 1, 2, and 3 years after the surgery (P > 0.05). The duration, location, and extent of detachment did not reveal significant correlations with RNFL parameters (P > 0.05). Circumpapillary RNFL thickness in eyes with RRD after vitrectomy demonstrated a transient increase during the early postoperative period. This increase was not associated with duration, location, and extent of RRD. At 3 years following surgery, no RNFL thinning or thickening was observed.

Management of Ocular Hypotony After Tube Surgery Using Bent Intraluminal Stents.

PURPOSE: We aimed to report a surgical technique for the management of ocular hypotony after tube surgery. METHODS: We occluded the tube with ab interno insertion of 2 bent 5-0 polypropylene threads into the tube lumen. Bent stents were used to prevent stent displacement. RESULTS: Our case series revealed that this procedure effectively resolved hypotony. Among the 3 cases, the stents were removed in 1 case and left in place in 2 cases. In all cases, the stent location remained stable without displacement. CONCLUSION: The insertion of bent intraluminal stents into the tube may be a useful method for the management of ocular hypotony after tube surgery.

Fluid Dynamics of Small Diameter Tubes Used in Membrane-tube Type Glaucoma Shunt Devices.

PURPOSE: To investigate the outflow characteristics of silicone tubes with intraluminal stents used in membrane-tube (MT) type glaucoma shunt devices. METHODS: The silicone tubes used in MicroMT (internal diameter of 100 µm with a 7-0 nylon intraluminal stent) and Finetube MT (internal diameter of 200 µm with a 5-0 nylon intraluminal stent) were connected to a syringe-pump that delivered a continuous flow of distilled water at flow rates of 2, 5, 10, and 25 µL/min. The pressures and resistances of tubes were measured at a steady flow rate with full-length, half-length, and absence of intraluminal stents. RESULTS: The mean outflow resistance of the two types of tubes ranged from 3.0 ± 1.9 to 3.8 ± 1.7 mmHg/µL/min with a full-length intraluminal stent, 1.8 ± 1.1 to 2.2 ± 1.1 mmHg/µL/min with a half-length intraluminal stent, and 0.1 ± 0.0 to 0.2 ± 0.0 mmHg/µL/min without an intraluminal stent. Theoretically, for a physiologic state with a flow rate of 2 µL/min and episcleral venous pressure of 6 mmHg, the mean pressures of tubes were expected to be 13.2 ± 3.0, 10.5 ± 2.4, and 6.4 ± 0.2 mmHg in MicroMT with full-length, half-length, and absence of intraluminal stents, respectively, and 12.5 ± 3.9, 9.6 ± 2.4, and 6.2 ± 0.2 mmHg in Finetube MT with full-length, half-length, and absence of intraluminal stents, respectively. The pressure variance also decreased with intraluminal stent retraction (p < 0.01). CONCLUSIONS: The small diameter tubes of 100 and 200 µm internal diameters, with 7-0 and 5-0 nylon intraluminal stents, respectively, used in the MT-type glaucoma shunt device showed safe and effective outflow characteristics.

Long-term comparison of postoperative refractive outcomes between phacotrabeculectomy and phacoemulsification.

PURPOSE: To compare long-term postoperative refractive outcomes between phacotrabeculectomy and phacoemulsification, both with posterior chamber intraocular lens implantation. SETTING: Department of Ophthalmology, Konyang University, Kim's Eye Hospital, Myung-Gok Eye Research Institute, Seoul, South Korea. DESIGN: Retrospective comparative study. METHODS: Postoperative refractive outcomes were compared between patients with cataract and coexisting primary or secondary open-angle glaucoma (OAG) who had phacotrabeculectomy (combined group) and patients with cataract with or without coexisting OAG who had phacoemulsification alone (phaco-only group). The refractive prediction error, mean absolute error, and median absolute error were compared between groups. Subgroup analysis based on preoperative axial length (AL) was performed (medium >22.0 to <24.5 mm; medium-long ≥24.5 to <26.0 mm; long ≥26.0 mm). RESULTS: The combined group comprised 51 eyes and the phaco-only group, 74 eyes. The mean interval between surgery and refraction measurement was 14.70 months ± 10.80 (SD) (median 13.0 months) and 4.81 ± 4.97 months (median 2.0 months), respectively. Postoperatively, there was no statistically significant between-group difference in the following mean values: refractive prediction error, -0.05 ± 0.64 versus -0.04 ± 0.52 (P = .905); mean absolute error, 0.46 ± 0.44 versus 0.38 ± 0.36 (P = .258); median absolute error, 0.32 (interquartile range [IQR], 0.17, 0.67) versus 0.28 (IQR, 0.13, 0.54) (P = .297). Subgroup analysis also did not show significant differences between the 2 groups (all P > .05). CONCLUSION: The long-term postoperative refractive outcomes of phacotrabeculectomy and phacoemulsification alone were not significantly different in eyes with OAG, regardless of preoperative AL.

Safety and Efficacy of a Membrane-Tube-Type Glaucoma Shunt Device: An Animal Trial.

PURPOSE: To evaluate the safety and efficacy of a membrane-tube-type glaucoma shunt device (MT-device), which was developed to control intraocular pressure (IOP) with a lower chance of complications than conventional glaucoma surgery, in a rabbit model. MATERIALS AND METHODS: The MT-device consists of an expanded polytetrafluoroethylene membrane (thickness 0.2 mm, area 2.5 × 2.5 mm2) and a tube (internal diameter 76 µm, external diameter 175.5 µm, length 7 mm) attached to the membrane. The device was implanted into the left eyes of nine New Zealand white rabbits. The tube was placed in the anterior chamber through paracentesis, and the membrane was fixated on the scleral surface; this induces aqueous drainage from the anterior chamber to the subconjunctival space. IOP, filtering bleb morphology, depth and inflammation of the anterior chamber, and possible complications were evaluated periodically for 8 weeks after surgery. Histological sections were analyzed at 2 and 8 weeks after the surgery. RESULTS: Mean IOP decreased from a preoperative value of 8.7 ± 1.2-4.7 ± 0.6 mmHg at postoperative 8 weeks (p < 0.05). The filtering bleb was maintained during the study period. There were no major postoperative complications. Histologic assessment revealed that 2 weeks after the surgery, fibrous encapsulation, inflammatory cells, and fibroblasts were observed around the MT-device; however, 8 weeks after the surgery, minimal inflammation was observed. CONCLUSIONS: The MT-device showed good biocompatibility and effective IOP reduction with a low risk of complications in a rabbit model.

Membrane-tube-type glaucoma shunt device for refractory glaucoma surgery.

PURPOSE: To evaluate the safety and efficacy of a novel membrane-tube (MT)-type glaucoma shunt device for refractory glaucoma surgery. The device consists of an expanded polytetrafluoroethylene membranous reservoir, as well as a silicone tube (300-µm external and 200-µm internal diameter) with an intraluminal stent. We named the device "Finetube MT". METHODS: The Finetube MT was implanted into 44 glaucomatous eyes that had insufficient intraocular pressure (IOP) control despite medical treatment or previous trabeculectomy. The membranous reservoir was placed underneath the Tenon's capsule, with each end located below the recti muscles; the tube was placed in the anterior chamber through a partial-thickness scleral track. We investigated the baseline and post-operative IOP values, the number of IOP-lowering medications used, and complications. RESULTS: The mean age of the subjects was 51.6 ± 17.2 years, and the mean follow-up duration was 22.5 ± 12.0 months. One year after the surgery, the mean IOP had decreased from 32.8 ± 12.2 mmHg to 16.9 ± 6.4 mmHg (48.5 % reduction; p < 0.01), and the mean number of IOP-lowering medications used had decreased from 2.5 ± 0.8 to 1.1 ± 0.9 (p < 0.01). We considered the surgery as a success when the IOP was between 6 and 21 mmHg, and had been reduced by ≥ 20 % from baseline; by this standard, the success rate was 92.4 % after 1 year, and 85.0 % after 3 years. Neither postoperative ocular hypotony-related complications nor tube exposure occurred in any case. CONCLUSIONS: The Finetube MT showed promising surgical outcomes as a treatment for refractory glaucoma, with minimal risk of postoperative ocular hypotony or tube-related complications.

Novel membrane-tube type glaucoma shunt device for glaucoma surgery.

BACKGROUND: The background of this study is to introduce the surgical technique and outcomes of a novel membrane-tube (MT) type glaucoma shunt device (MicroMT), which was developed to achieve safer and more predictable intraocular pressure (IOP) control compared with conventional trabeculectomy. DESIGN: This is a retrospective, non-comparative, interventional case series study. PARTICIPANTS: The MicroMT was implanted in 43 glaucomatous eyes with insufficient IOP control despite medical treatment. METHODS: The MicroMT consists of an expanded polytetrafluoroethylene membrane and a silicone tube with an intraluminal stent, which allows aqueous drainage from the anterior chamber to the lamellar scleral flap. The intraluminal stent prevents excessive aqueous drainage and allows additional IOP reduction through retraction or removal of the stent. MAIN OUTCOME MEASURES: The main outcome measures of this study are IOP changes and complications. RESULTS: The mean (SD) IOP decreased from a preoperative value of 22.5 (6.9) mmHg to 11.1 (3.6) mmHg 3 years after the operation (50.7% reduction from baseline; P < 0.01). Intraluminal stent removal 4 weeks after the operation induced an additional 40.2% IOP reduction (P < 0.01). When success was defined as an IOP between 6 and 21 mmHg, and an IOP reduction of ≥20% from baseline, the success rate was 89.5% at 3 years after the operation. No postoperative ocular hypotony (IOP <6 mmHg) or tube-related complications occurred. CONCLUSIONS: MicroMT implantation is a novel therapy that may reduce IOP safely and effectively, with no apparent risk of postoperative ocular hypotony. Glaucoma surgery using this device may be a good alternative to conventional glaucoma surgery.

Surgical Outcomes of Additional Ahmed Glaucoma Valve Implantation in Refractory Glaucoma.

PURPOSE: To evaluate the surgical outcomes of the implantation of an additional Ahmed glaucoma valve (AGV) into the eyes of patients with refractory glaucoma following previous AGV implantation. METHODS: This study is a retrospective review of the clinical histories of 23 patients who had undergone a second AGV implantation after a failed initial implantation. Age, sex, prior surgery, glaucoma type, number of medications, intraocular pressure (IOP), visual acuity, and surgical complications were analyzed. Surgical success was defined as IOP maintained below 21 mm Hg, with at least a 20% overall reduction in IOP, regardless of the use of IOP-lowering medications. RESULTS: Following the implantation of a second AGV, the mean IOP decreased from 39.3 to 18.5 mm Hg (52.9% reduction, P<0.001). The mean number of postoperative IOP-lowering medications administered decreased from 2.8 to 1.7 after the second AGV implantation (P<0.001). The cumulative probability of success for the procedure was 87% after 1 year and 52% after 3 years. Three patients (13.0%) experienced bullous keratopathy after the second AGV implantation. None of the patients showed any evidence of diplopia or ocular movement limitation as a result of the presence of 2 AGVs in the same eye. Prior trabeculectomy was found to be a significant risk factor for failure (P=0.027). CONCLUSIONS: A second AGV implantation can be a good choice of surgical treatment when the first AGV has failed to control IOP.

Comparison of the outcome of silicone Ahmed glaucoma valve implantation with a surface area between 96 and 184 mm² in adult eyes.

PURPOSE: To compare the success rates, complications, and visual outcomes between silicone Ahmed glaucoma valve (AGV) implantation with 96 mm(2) (FP8) or 184 mm(2) (FP7) surface areas. METHODS: This study is a retrospective review of the records from 132 adult patients (134 eyes) that underwent silicone AGV implant surgery. Among them, the outcomes of 24 eyes from 24 patients with refractory glaucoma who underwent FP8 AGV implantation were compared with 76 eyes from 76 patients who underwent FP7 AGV implantation. Preoperative and postoperative data, including intraocular pressure (IOP), visual acuity, number of medications, and complications were compared between the 2 groups. RESULTS: There were no significant differences in baseline characteristics between the 2 groups (p > 0.05). The postoperative visual acuity of the patients in the FP8 group was better than that of the patients in the FP7 group in some early postoperative periods (p < 0.05); however, after 10 postoperative months, visual acuity was not significantly different through the 3-year follow-up period (p > 0.05). Postoperative IOP was not significantly different between the 2 groups (p > 0.05) except for IOP on postoperative day 1 (11.42 mmHg for the FP7 group and 7.42 mmHg for the FP8 group; p = 0.031). There was no statistical difference in success rates, final IOP, number of medications, or complication rates between the 2 groups (p > 0.05). CONCLUSIONS: The FP7 and FP8 AGV implants showed no difference in terms of vision preservation, IOP reduction, and number of glaucoma medications required.

Capsule wrinkling during capsulorhexis in patients with primary angle-closure glaucoma and cataract.

PURPOSE: To evaluate the frequency of capsule wrinkling and associated factors during capsulorhexis in patients with primary angle-closure glaucoma (PACG) undergoing cataract surgery. METHODS: This prospective study enrolled 91 eyes of 91 patients (26 eyes with PACG, 65 control eyes) who underwent cataract surgery. Capsule wrinkling during capsulorhexis was determined intraoperatively. The PACG group was evaluated for factors associated with capsule wrinkling such as intraocular pressure (IOP) on presentation, history of acute attacks, previous laser or trabeculectomy surgery, iris atrophy, peripheral anterior synechiae, and posterior synechiae. RESULTS: The frequency of capsule wrinkling was higher in the PACG group (7/26, 26.9%) than in the control group (0/65, 0%) (P < 0.0001). Among the PACG patients, capsule wrinkling was associated with a higher IOP on presentation (54.71 ± 16.15 mmHg) than in patients without capsule wrinkling (32.95 ± 11.21 mmHg) (P = 0.001). Iris atrophy was significantly related to capsule wrinkling (P = 0.028), and the location of iris atrophy correlated with that of capsule wrinkling in 80% of cases (4/5). CONCLUSIONS: Capsule wrinkling during capsulorhexis was a significant finding in some patients with cataract and PACG, especially when the IOP on presentation was high and iris atrophy was present.