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PURPOSE: To compare surgical results between ab-externo microshunt surgery and trabeculectomy, focusing on postoperative corneal astigmatism. STUDY DESIGN: Retrospective study. METHODS: Subjects were patients with glaucoma who underwent either standalone ab-externo microshunt surgery or trabeculectomy. Data on ophthalmic examinations obtained preoperatively and 1, 3, and 5 months postoperatively were analyzed. To assess corneal astigmatism, two separate data sets measured by anterior segment optical coherence tomography and autorefractometer were evaluated. Multivariate linear mixed model analyses were conducted to identify factors associated with the astigmatism changes. RESULTS: Sixty eyes were examined: 13 eyes underwent microshunt surgery, and 47 eyes underwent trabeculectomy. The total corneal astigmatism measurements by anterior segment optical coherence tomography (AS-OCT) were: - 1.15 ± 0.85 D and - 1.17 ± 0.81 D for the microshunt and trabeculectomy groups, respectively, preoperatively. At five months postoperatively they were - 0.92 ± 0.47 D and - 1.61 ± 0.83 D, respectively (P = 0.807 for the microshunt group and P = 0.005 for the trabeculectomy group: Wilcoxon signed-rank test). AS-OCT also indicated similar results for posterior corneal astigmatism. Autorefractometry also found the total corneal astigmatism was significantly changed only in the trabeculectomy group. The linear mixed model analysis revealed that trabeculectomy (P = 0.001), older age (P = 0.004), and longer postoperative period (P = 0.015) were correlated with greater astigmatism changes. The intraocular pressures significantly decreased following both surgical treatments. CONCLUSIONS: Standalone ab-externo microshunt surgery has less effect on corneal astigmatism during a 5 month period than trabeculectomy. Both surgical procedures significantly reduced intraocular pressure.

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To evaluate the effectiveness of the PRESERFLO MicroShunt (PFM) in reducing intraocular pressure (IOP) ex vivo in porcine eyes using an infusion pump system and to simulate various IOP conditions, In this study, porcine eyes received increasing flows between 2 and 20 µL/min. IOP measurements were taken under conditions with and without the PFM [PFM (+) and PFM (-), respectively]. In the PFM (-) group, IOP increased from 7.4 mmHg to 46.3 mmHg as the flow rate increased from 2 µL/min to 20 µL/min. The rate of IOP reduction (%ΔIOP) rose with increasing flow rates, although the absolute IOP values achieved with the PFM insertion also increased. The correlation between IOPs in the PFM (-) conditions and the %ΔIOP was modeled as %ΔIOP = 22.4 Ln [PFM(-) IOP] - 41.7. According to this equation, IOP reduction by PFM insertion is 0% at IOPs of 6.4 mmHg or lower. IOP reductions of 10%, 20%, 30%, and 40% were observed when the pre-insertion IOPs were 10.1, 15.7, 24.6, and 38.4 mmHg, respectively. Achievable post-insertion IOP levels of ≤21 mmHg, ≤18 mmHg, ≤15 mmHg, and ≤12 mmHg corresponded to the initial IOPs of 33 mmHg, 26 mmHg, 20 mmHg, and 14.8 mmHg, respectively. In conclusion, the PFM effectively reduced IOP within a specific range of IOP values in an ex vivo experimental system. In clinical situations, the PFM is unlikely to be effective at low IOP levels. At higher levels, the PFM reduces IOP, but it may be insufficient to achieve the target IOP.

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PURPOSE: Postoperative hypotony following PRESERFLO MicroShunt (PMS) implantation is a frequent cause of complications such as choroidal detachment and hypotony maculopathy. This study aims at evaluating the impact of intraluminal stenting of the PMS during the early postoperative period. METHODS: We retrospectively analyzed the data of 97 patients who underwent PMS implantation with intraoperative placement of a Nylon 10-0 suture as intraluminal stent (PStent) and compared the outcomes to those of an existing database of the traditional MicroShunt implantation technique (PTrad, n = 120). The primary outcome measure was the intraocular pressure (IOP) at one week postoperatively. As a secondary outcome measure, adverse hypotony, defined as an IOP ≤ 5 mmHg with significant choroidal effusion and/or anterior chamber shallowing or the presence of macular folds was also assessed. Additionally, the time to stent removal and the IOP one week after stent removal were reported. RESULTS: Preoperative median IOP was 25.0 (20.5-30.3) mmHg in PStent and 25.0 (19.3-32.0) mmHg in PTrad (p = 0.62). One week after surgery, the median IOP dropped to 10.0 (8.0-13.0) mmHg in PStent and 7.0 (5.0-9.0) in PTrad (p < 0.01). At one month, the IOP was 12.0 (10.0-14.0) mmHg in PStent and 10.0 (8.0-11.0) mmHg in PTrad (p < 0.01). After 3 months, both groups showed similar median IOP levels of 11.0 (8.0-13.5) mmHg and 10.0 (9.75-13.0) mmHg in PStent and PTrad, respectively (p = 0.66). The presence of adverse hypotony was significantly lower in PStent compared to PTrad (6.2% vs 15.8%, p < 0.05). In PStent the stent was removed after 30.0 (21.0-42.5) days. One week after stent removal the mean IOP drop was 6.1 ± 0.5 mmHg (p < 0.01). CONCLUSION: In the early follow-up period, intraluminal stenting of the PMS appears to be safe and effective in controlling the IOP while reducing early postoperative hypotony. Surgical success is not compromised by stent placement. Based on our data, it is recommended to remove the suture two to six weeks after surgery for most patients with uncomplicated postoperative clinical findings.

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This study aimed to present an effective and minimally invasive method for treating prolonged hypotony after PreserFlo MicroShunt (PMS) implantation, which can cause serious complications. A 79-year-old man with primary open-angle glaucoma of the right eye underwent ab interno intraluminal stent insertion for prolonged hypotony after PMS implantation. After making two corneal incisions at the 5 and 8 o'clock positions in the right eye, a viscoelastic material was injected into the anterior chamber. A 10-0 nylon suture was inserted into the anterior chamber through a corneal incision in the 5 o'clock position. Next, the 10-0 nylon suture was grasped and inserted into the PMS lumen as a stent with forceps, following which it was cut approximately 1 mm from the tip of the PMS using micro-iris scissors. Finally, the viscoelastic material in the anterior chamber was washed with a balanced salt solution, and self-closure of the two corneal incisions was confirmed. After ab interno intraluminal stent insertion, hypotony improved and stabilized at approximately 10 mmHg. The shallow anterior chamber, choroidal detachment, and hypotonic maculopathy improved rapidly. This novel technique demonstrated effectiveness and minimal invasiveness in treating prolonged hypotony after PMS implantation.

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INTRODUCTION: Preserflo MicroShunt is a novel microinvasive bleb forming device for the treatment of primary open-angle glaucoma. The intermediate- and long-term success and the impact of this procedure on corneal endothelial cell density remain to be investigated. METHODS: In this prospective observational study, 62 eyes of 55 glaucoma patients (mean age ± SD: 67.0 ± 15.0 years) receiving a Preserflo MicroShunt were included. Corneal endothelial cell density, intraocular pressure and best corrected visual acuity were assessed preoperatively and at 3, 6, 9, 12, 18 and 24 months postoperatively. Success rates, bleb revision rates and complications were analysed. Complete success was defined as an intraocular pressure reduction of ≥ 20% and achieving a target pressure of ≤ 18, ≤ 15 or ≤ 12 mmHg without antiglaucoma medication. Qualified success indicated that the criteria were reached with or without medication. RESULTS: Corneal endothelial cells showed no significant decline over 24 months (p > 0.05). Intraocular pressure showed a substantial reduction postoperatively (p < 0.001), decreasing from 29.6 ± 8,3 mmHg to 13.0 ± 4.3 mmHg after 24 months (p < 0.001). Complete and qualified success with a target pressure ≤ 15 mmHg was achieved in 52.9% and 54.6% of cases after 24 months, respectively. Best corrected visual acuity did not change after 24 months. CONCLUSION: Preserflo MicroShunt had no negative side effects on corneal endothelial cells and showed favourable success rates after 2 years in patients with open-angle glaucoma.

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Background: The purpose of this study was to evaluate the effectiveness and safety of the PreserFlo™ microshunt (PMS) using a 25-Gauge vs. 27-Gauge needle tract. Methods: This is a prospective postoperative examination of 60 glaucoma eyes that received a PMS. The main outcome measures were intraocular pressure (IOP), glaucoma drug score (GDS), Kaplan-Meier success rates, complications, and secondary intervention rates. Two subgroups were formed for data comparison: 27-Gauge (27G), and 25-Gauge (25G). Success was defined as IOP < 18 mmHg together with ≥20% IOP reduction with medication allowed (qualified success = QS18) or not (full success = FS18). Results: IOP and GDS were reduced from baseline to the 1-year study visit as follows: All eyes from 23.4 ± 8.6 mmHg (3.1 ± 0.9) to 15.1 ± 5.9 mmHg (0.8 ± 1.1); 25G from 24.2 ± 7.3 mmHg (3.0 ± 0.8) to 12.7 ± 2.7 mmHg (0.5 ± 0.8); and 27G from 23.1 ± 9.2 mmHg (3.1 ± 1.0) to 16.2 ± 6.7 mmHg (0.9 ± 1.2). IOP at one year was lower in the 25G group compared to the 27G group (p = 0.035). Bleb needling was required in eight (13.3%) eyes and open bleb revisions in three (5.0%). Transient hypotony occurred in 21% and choroidal effusion in 8% of all eyes. Choroidal effusions were more frequent in the 25G group (21%) compared to the 27G group (2%, p = 0.031). One-year success rates were significantly higher in the 25G group compared to the 27G group for both QS18 (25G: 67.9% vs. 27G: 35.7%, p = 0.002) and FS18 (25G: 63.6% vs. 27G: 29.2%, p = 0.007). Conclusions: The PreserFlo microshunt is an effective and safe glaucoma surgery with a low rate of bleb revisions or needlings. We show that the 25G needle tract might be more efficient for IOP control at the cost of increased IOP-related complications compared to 27G.

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INTRODUCTION: The PRESERFLO™ MicroShunt (PMS) has been proven to significantly lower intraocular pressure (IOP) in patients with glaucoma and has been available for use since 2019. With increasing published evidence and growing experience of glaucoma surgeons, the aim of this modified Delphi panel was to build on the findings of a previous Delphi panel conducted in 2021 and provide further guidance on the role of the PMS to treat patients with glaucoma in Europe. METHODS: Thirteen European glaucoma surgeons experienced in the PMS procedure participated in a 3-round modified Delphi panel. A targeted literature review and expert steering committee guided Round 1 questionnaire development. Consensus was pre-defined at a threshold of ≥ 70% of panellists selecting 'strongly agree'/'agree' or 'strongly disagree'/'disagree' for 6-point Likert scale questions or ≥ 70% selecting the same option for multiple or single-choice questions. Questions not reaching consensus were restated/revised for the next round, following guidance from free-text responses/scoping questions. RESULTS: In total, 28% (n = 9/32), 52% (n = 16/31) and 91% (n = 10/11) of statements reached consensus in Rounds 1, 2 and 3, respectively. There was agreement that the PMS may be used in patients with pigmentary, post-trauma or post-vitrectomy glaucoma and for patients with uveitic glaucoma without active inflammation. The PMS may be more suitable for patients with contact lenses than other subconjunctival filtering surgeries, without eliminating bleb-associated risks. Consensus was reached that combining PMS implantation and phacoemulsification may be as safe as standalone PMS surgery, but further efficacy data are required. Following a late rise in IOP ≥ 4 months post-surgery, topical aqueous suppressant drops or bleb revision may be suitable management options. CONCLUSIONS: This Delphi panel builds on the considerations explored in the 2021 Delphi panel and provides further detailed guidance for glaucoma surgeons on the use of the PMS, reflecting the availability of novel evidence and surgical experience. Videos are available for this article.

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PURPOSE: The success of XEN Gel Stent (XEN) and Preserflo MicroShunt (Preserflo) implantation depends mainly on the development of bleb fibrosis. This study aimed to describe the histological findings of bleb fibrosis after XEN and Preserflo surgery. METHODS: This retrospective study included patients with different types of glaucoma who underwent revision surgery after XEN or Preserflo implantation. The available clinical information and histological samples of removed fibrotic tissue were analyzed. RESULTS: Thirty-six patients were included. Revision surgery was performed at a median of 195 (range = 31-1264) days after primary surgery. The mean intraocular pressure changed from 29.1 (± 10.3) mmHg at baseline to 18.3 (± 8.7) mmHg (- 37%; p < 0.0001) and 16.2 (± 4.2) mmHg (- 45%; p < 0.0001) after 6 and 12 months, respectively. Histological analysis revealed an increase in activated fibroblasts and macrophages in all specimens and a parallel orientation of fibroblasts in a minor part of the probe in 60% of the specimens. No pronounced inflammatory reaction in the form of lymphocytic or granulocytic infiltration was observed. The comparison of specimens from uveitic glaucoma and primary open-angle glaucoma patients revealed no significant differences. CONCLUSIONS: The histological analysis of fibrotic blebs from the XEN and Preserflo implants did not show any pronounced immune or foreign-body reaction and revealed a similar histological pattern of failed blebs after trabeculectomy.

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Implantes de Drenaje de Glaucoma , Presión Intraocular , Stents , Humanos , Estudios Retrospectivos , Masculino , Femenino , Anciano , Persona de Mediana Edad , Implantes de Drenaje de Glaucoma/efectos adversos , Stents/efectos adversos , Presión Intraocular/fisiología , Reoperación , Glaucoma/cirugía , Glaucoma/diagnóstico , Glaucoma/fisiopatología , Fibrosis , Anciano de 80 o más Años , Conjuntiva/patología , Conjuntiva/cirugía , Adulto , Estudios de Seguimiento , Complicaciones Posoperatorias/diagnóstico , Cirugía Filtrante/efectos adversos , Cirugía Filtrante/métodos , Diseño de Prótesis , Vesícula/diagnóstico , Vesícula/cirugía , Vesícula/etiología

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Background This study aimed to evaluate postoperative changes in ocular biometry following initial PreserFlo MicroShunt implantation and trabeculectomy. Methodology This prospective, observational study analyzed 27 cases of PreserFlo MicroShunt implantation and 29 cases of trabeculectomy performed by a single surgeon. Visual acuity, intraocular pressure, corneal curvature, central corneal thickness, anterior chamber depth, and axial length were assessed at baseline and postoperatively at one day, one week, two weeks, one month, two months, three months, and six months. Patients requiring additional surgery and those with missing data were excluded. Consecutive data were compared with the baseline values using multiple comparisons. Results In both groups, intraocular pressure was significantly decreased from baseline at all postoperative time points (all p < 0.01). Visual acuity decreased in both groups at one day and one week postoperatively. Corneal curvature remained unchanged in both groups throughout the six-month follow-up. Central corneal thickness increased at one day and one week postoperatively in the PreserFlo group, but not in the trabeculectomy group. Anterior chamber depth exhibited a significant decrease at one week postoperatively in both groups. Axial length significantly decreased postoperatively until three months in the PreserFlo group and at all postoperative time points in the trabeculectomy group. Conclusions Ocular biometry following PreserFlo and trabeculectomy had a similar tendency postoperatively.

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INTRODUCTION: The XEN Gel, a hydrophilic tube meticulously crafted to adhere to the principles of the Hagen - Poiseuille law, is designed to facilitate efficient aqueous shunting without inducing hypotony. Implantable ab interno or ab externo, with or without conjunctival opening, the device shows no significant outcome differences. Despite numerical hypotony signaling failure, patients may fare well below 6 mmHg. AREAS COVERED: This review provides insights into device variability, challenges related to hypotony, associated risk factors, and hypotony management. EXPERT OPINION: The progressive evolution of the XEN Gel constitutes a significant advancement in the field of glaucoma management. Comparative studies investigating diverse implantation methodologies, particularly the ab interno and closed conjunctival approaches, highlight the device versatility in addressing individual patient needs. Exploring hypotony from both statistical and clinical perspectives challenges the traditional view of intraocular pressure as a straightforward success or failure indicator. The incidence of hypotony-related issues varies between device models, emphasizes the need for an individualized approach during device selection. Overall, understanding the dynamics of hypotony is crucial for optimizing the outcomes of XEN Gel implantation.

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PURPOSE: Bleb failure is a common complication after glaucoma filtration surgery. Different bleb classification schemes incorporating filtration bleb vascularization have been proposed, but the reported correlation with intraocular pressure (IOP) has been variable, possibly because of subjective vascularization grading. The purpose of the present study was to evaluate bleb vascularization after Preserflo Microshunt (PM) implantation using anterior segment OCT-angiography (AS-OCTA) as a biomarker for bleb failure. METHODS: Twenty-three eyes of twenty-three patients underwent PM implantation. Up to 12 months after surgery PM scleral passage-centred AS-OCTA measurements (PLEX Elite 9000) for bleb-vessel density (BVD) determination were performed and IOP as well as necessity for surgical revisions (needling and open revision) were documented. After multi-step image analysis (region of interest definition, artefact removal, binarization, BVD calculation), the predictive value of early postoperative BVD for surgical revisions was assessed using logistic regression modelling. RESULTS: Baseline IOP (23.57 ± 7.75 mmHg) decreased significantly to 8.30 ± 2.12, 9.17 ± 2.33 and 11.70 ± 4.40 mmHg after 1, 2 and 4 week(s), and 13.48 ± 5.83, 11.87 ± 4.49, 12.30 ± 6.65, 11.87 ± 3.11 and 13.05 ± 4.12 mmHg after 2, 3, 6, 9 and 12 month(s), respectively (p < 0.001). Nine patients (39%) needed surgical revisions after a median time of 2 months. Bleb vessel densities at 2 and 4 weeks were significantly associated with future surgical revisions upon logistic regression analysis (2 W/4 W likelihood-ratio test p-value: 0.0244/0.0098; 2 W/4 W area under the receiver operating characteristics curve: 0.796/0.909). CONCLUSION: Filtration bleb vessel density can be determined using AS-OCTA in the early postoperative period and is predictive for bleb failure after PM implantation.

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Presión Intraocular , Reoperación , Tomografía de Coherencia Óptica , Humanos , Femenino , Masculino , Presión Intraocular/fisiología , Anciano , Tomografía de Coherencia Óptica/métodos , Persona de Mediana Edad , Angiografía con Fluoresceína/métodos , Estudios de Seguimiento , Glaucoma/cirugía , Glaucoma/fisiopatología , Glaucoma/diagnóstico , Implantes de Drenaje de Glaucoma/efectos adversos , Cirugía Filtrante/métodos , Estudios Prospectivos , Fondo de Ojo , Conjuntiva/irrigación sanguínea , Conjuntiva/cirugía , Densidad Microvascular

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To carry out the preclinical and histological evaluation of a novel nanotechnology-based microshunt for drainage glaucoma surgery. Twelve New Zealand White rabbits were implanted with a novel microshunt and followed up for 6 weeks. The new material composite consists of the silicone polydimethylsiloxane (PDMS) and tetrapodal Zinc Oxide (ZnO-T) nano-/microparticles. The microshunts were inserted ab externo to connect the subconjunctival space with the anterior chamber. Animals were euthanized after 2 and 6 weeks for histological evaluation. Ocular health and implant position were assessed at postoperative days 1, 3, 7 and twice a week thereafter by slit lamp biomicroscopy. Intraocular pressure (IOP) was measured using rebound tonometry. A good tolerability was observed in both short- and medium-term follow-up. Intraocular pressure was reduced following surgery but increased to preoperative levels after 2 weeks. No clinical or histological signs of inflammatory or toxic reactions were seen; the fibrotic encapsulation was barely noticeable after two weeks and very mild after six weeks. The new material composite PDMS/ZnO-T is well tolerated and the associated foreign body fibrotic reaction quite mild. The new microshunt reduces the IOP for 2 weeks. Further research will elucidate a tube-like shape to improve and prolong outflow performance and longer follow-up to exclude medium-term adverse effects.

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Implantes de Drenaje de Glaucoma , Glaucoma , Óxido de Zinc , Animales , Conejos , Implantes de Drenaje de Glaucoma/efectos adversos , Glaucoma/cirugía , Glaucoma/etiología , Presión Intraocular , Tonometría Ocular , Cámara Anterior/cirugía , Nanotecnología

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Purpose: We describe a rare case of tube obstruction caused by intraocular lens (IOL) capture following a PreserFlo MicroShunt (PMS) surgery and its subsequent management. Observations: Tube obstruction was noted following PMS implantation at 8 days postoperatively. The intraocular pressure (IOP) increased to 42 mmHg because of tube occlusion that was caused by iris and IOL capture at the tip of the tube. The occlusion was released surgically to free the lumen, and the IOP rapidly decreased to 14 mmHg. Conclusions and importance: IOP elevation due to tube obstruction caused by iris and IOL capture after PMS surgery was resolved by surgical intervention without tube reinsertion. Extra care is required regarding the IOL position in relation to the PMS tube when hypotony occurs in the early postoperative period.

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BACKGROUND: This study aimed to evaluate the impact of PreserFlo Microshunt on the ocular surface, focusing on both objective and subjective parameters. METHODS: Prospective-observational study on 48 eyes undergoing PreserFlo Microshunt implantation, standalone or combined with phacoemulsification. At baseline, 1-month, 6-months and 12-months post-operative follow-ups, we performed Ocular Surface Disease Index (OSDI) questionnaire, Schirmer's test (ST), Tear-film break-up time (TBUT), fluoresceine staining (FS), tear osmolarity and minimum corneal epithelial thickness (Epi-ThkMIN. ) measurements. RESULTS: OSDI score improved from 37.43 ± 17.49 at baseline, to 24.13 ± 12.55 at 1-month (p = 0.003) and to 12.89 ± 8.54 and 13.09 ± 10.22 at 6-months and 12-months (p < 0.0001). TBUT and ST, in a similar way, non-significantly increased at 1-month, but then improved at 6-months and 12-months (p < 0.05 for both). Tear osmolarity significantly decreased from 308.2 ± 7.3 mOsm/L at baseline, to 303.3 ± 8.2 mOsm/L, 295.6.2 ± 7.0 mOsm/L and 297.6 ± 6.8 mOsm/L at 1-month, 6-months and 12-months (p < 0.05 for all). Epi-ThkMIN was stable when comparing baseline (44.9 ± 5.7 µm) and 1-month (p = 0.28), and successively increased in 6-months (47.8 ± 5.5 µm, p = 0.02) and 12-months (48.0 ± 3.6 µm, p = 0.01). In subgroup analysis, OSDI score and tear osmolarity were significantly higher at 1-month in combined group compared to standalone group (p = 0.03 and p = 0.02, respectively), but reaching comparable values in successive follow-ups. Further, Oxford scale grades for FS were significantly improved when comparing baseline-6-months and baseline-12-months. CONCLUSION: PreserFlo implantation improved ocular surface subjective symptoms, increased TBUT and ST, and reduced FS, highlighting the potential benefits of this surgical intervention. Moreover, we reported significant improvements of tear osmolarity and corneal epithelium.

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Síndromes de Ojo Seco , Humanos , Síndromes de Ojo Seco/diagnóstico , Síndromes de Ojo Seco/cirugía , Estudios Prospectivos , Calidad de Vida , Lágrimas , Fluoresceína , Concentración Osmolar

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PURPOSE: A comparison of the safety and efficacy of the MicroShunt versus trabeculectomy in the early postoperative period, with a particular focus on hypotony. METHODS: In this registry study, we evaluated 200 eyes of 200 glaucoma patients who underwent filtration surgery at Oslo University Hospital between 2017 and 2021. Of these patients, 100 had a Preserflo MicroShunt (Santen) implantation and 100 had a trabeculectomy procedure. The patients were examined per standard hospital protocol after filtration surgery. Data were extracted from the 4- and 8-week visits. We defined hypotony as intraocular pressure (IOP) < 6 mmHg. RESULTS: The mean preoperative IOP was 20.6 ± 7.1 mmHg in the MicroShunt group and 21.6 ± 7.1 mmHg in the trabeculectomy group, and the patients used a mean of 3.0 ± 0.9 and 3.1 ± 0.9 glaucoma medications, respectively. After 8 weeks, IOP was reduced to 10.4 ± 5.4 mmHg and 11.3 ± 4.6 mmHg, respectively (p = 0.23). During the early postoperative period, hypotony was registered in 63% of the MicroShunt patients and in 21% of the patients in the trabeculectomy group (p < 0.001); and 11% and 1%, respectively, of the patients developed choroidal detachments (p < 0.003). One patient in the MicroShunt group required reoperation due to hypotony. CONCLUSIONS: In this registry study, we found that the Preserflo MicroShunt and trabeculectomy had equally satisfactory IOP-lowering effects during the early postoperative period. In this same period, a high number of patients in the MicroShunt group developed hypotony.

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Glaucoma , Trabeculectomía , Humanos , Trabeculectomía/métodos , Glaucoma/cirugía , Presión Intraocular , Ojo , Periodo Posoperatorio , Estudios Retrospectivos , Resultado del Tratamiento

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Purpose: To describe a clinical case of lumen obstruction a few days after implantation of the PreserFlo® Microshunt which has been resolved by anterior vitrectomy. Observation: A 76-year-old patient with advanced and progressing primary open-angle glaucoma (POAG) presented ten days after PreserFlo® Microshunt implantation in his left eye with an intraocular pressure (IOP) of 24 mmHg because of vitreous obstruction. Anterior vitrectomy with 25 Gauge vitrector was performed to remove the vitreous using a bimanual technique with two corneal accesses. The surgery was successful in lowering uncontrolled IOP without device repositioning. A free lumen and a IOP in the low range of tens was observed during follow-up. Conclusions and importance: PreserFlo ® MicroShunt obstruction by vitreous in pseudophakic patient is a possible complication. Anterior vitrectomy without the need of tube repositioning was successful in lowering uncontrolled IOP.

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This study aims to investigate the pressure characteristics of the PRESERFLO MicroShunt, a microinvasive glaucoma device, using an in vitro setup. Additionally, the study explores the impact of the scleral tissue surrounding the device on its pressure and lumen area. Ten PRESERFLO MicroShunts were subjected to an in vitro experimental setup. A constant flow of physiological saline was maintained at 2 µL/min using an infusion syringe pump. The PRESERFLO was connected to a pressure transducer via a 23 G needle. Pressure characteristics were measured under three different conditions: without sclera [sclera (-)], passing through sclera at a 90° angle (sclera 90°), and passing through sclera at a 30° angle (sclera 30°). The lumen area of the device was measured using microscopic observation. We observed peak and trough pressures in this experimental setting; the peak pressure (6.76 mmHg) was significantly higher than the trough pressure of 4.74 mmHg (p = 0.0020) in the sclera (-) condition. Compared to sclera (-), the peak pressures were significantly higher in the sclera 90° (7.81 mmHg, p = 0.0020) and the sclera 30° (7.96 mmHg, p = 0.0039) conditions. Additionally, compared to sclera (-), the trough pressure was significantly higher in the sclera 90° (6.25 mmHg, p = 0.0039) and the sclera 30° (5.76 mmHg, p = 0.037) conditions. The lumen area was significantly smaller in the sclera 90° condition (3515 µm2) than the sclera (-) condition (3927 µm2, p = 0.0078). The study found that when the distal end of PRESERFLO MicroShunt was free and in air, it exhibited both peak and trough pressures. The presence of scleral tissue surrounding the PRESERFLO MicroShunt affects its lumen area and pressure characteristics. Understanding these effects can provide valuable insights into the device's performance.

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INTRODUCTION: The aim of this study was to describe and evaluate double PreserFlo MicroShunt implantation as a modified micro-invasive glaucoma surgery technique and to retrospectively compare the outcomes in a cohort of glaucoma patients with single or double implantation. MATERIALS AND METHODS: A retrospective data analysis of 57 glaucoma patients who consecutively underwent PreserFlo implantation was performed. Medical records were examined for patients' demographics, glaucoma type, intraocular pressure (IOP), medication, complications, and re-interventions. Two groups with single (n = 29) or double (n = 28) implantation were formed, and the outcomes were compared. In cases of two-stage double implantation (n = 17), the courses of the initial and the second implantations were compared. RESULTS: Mean preoperative IOP was significantly higher in the double compared to the single implantation group (29.4 ± 10.0 mm Hg; 21.7 ± 8.2 mm Hg; p = 0.003). Postoperatively, IOP was significantly lower in the double implantation group at various time-points (day 1, week 1, months 3 and 6; all p < 0.021). In the subgroup with two-stage procedures, mean preoperative IOP was 24.5 ± 8.5 mm Hg and 29.8 ± 10.1 mm Hg, respectively (p = 0.128). While immediately postoperatively, mean IOP lowering was clinically significant and similar following both procedures, the longer sustainable effect was observed after the second procedure (month 12: 25.5 ± 7.5 mm Hg; 12.4 ± 4.8 mm Hg; p = 0.001). No serious complications were observed. DISCUSSION/CONCLUSION: Double PreserFlo implantation appears safe and efficient for lowering IOP in glaucoma patients. Our preliminary findings suggest that double is superior to single implantation in terms of IOP lowering and the need for additional topical medication. Patients with insufficient IOP lowering following single implantation may benefit from a second implantation. Further research is warranted to evaluate double implantation as a first-line, one-stage procedure.

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Implantes de Drenaje de Glaucoma , Glaucoma de Ángulo Abierto , Glaucoma , Humanos , Estudios Retrospectivos , Glaucoma de Ángulo Abierto/cirugía , Glaucoma/cirugía , Presión Intraocular , Tonometría Ocular , Resultado del Tratamiento

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Trabeculectomy has traditionally been upheld as the gold standard in glaucoma surgery, but recent advancements, including the PRESERFLO® MicroShunt, have introduced less invasive techniques to mitigate complications and reduce intraocular pressure (IOP). The examination of bleb morphology post-filtering surgery is critical for modulating wound healing and ensuring long-term success. While previous evaluations of PRESERFLO-generated blebs have relied on data from trabeculectomy blebs, the differing surgical techniques used in PRESERFLO and trabeculectomy surgeries suggest potential variations in bleb morphologies. This study conducted a comparative analysis of blebs resulting from PRESERFLO and trabeculectomy procedures. Retrospective descriptive assessments using the Jenaer Bleb Grading System were performed, along with quantitative evaluation using eight-dimensional parameters utilizing anterior segment OCT. We included 93 eyes (57 following PRESERFLO, 36 following trabeculectomy). In the descriptive assessment, PRESERFLO-generated blebs exhibited fewer conjunctival cysts (3.5% vs. 22.2%, p = 0.007) and cavernous changes (10.5% vs. 30.5%, p = 0.021) compared to trabeculectomy. Quantitatively, overall bleb dimensions were comparable (maximal bleb height, width, and length, p > 0.05 for all). However, PRESERFLO blebs displayed a shallower (0.52 ± 0.24 vs. 0.67 ± 0.3 mm, p = 0.017) yet longer (4.12 ± 1.54 vs. 3.23 ± 1.64 mm, p = 0.024) episcleral lake. A thicker bleb wall (1.52 ± 0.46 vs. 1.10 ± 0.37 mm, p < 0.001) along with more posteriorly positioned blebs (distance to limbus = 6.16 ± 1.36 vs. 4.87 ± 1.34 mm, p < 0.001) were observed following PRESERFLO. This study illuminates the nuanced morphological differences between PRESERFLO and trabeculectomy blebs. Understanding these distinctions is vital, empowering clinicians to make informed postoperative decisions and avoid misinterpretation of bleb morphology.

RESUMEN

We report a case of PreserFlo MicroShunt (PFM) dislocation following a postsurgical needling procedure. A 58-year-old woman underwent PFM implantation for exfoliation glaucoma in her left eye (OS). There were no intraoperative complications. Preoperatively, her best-corrected visual acuity (BCVA) was 0.6, and her intraocular pressure (IOP) was 25 mmHg with three antiglaucoma medications in the OS. On postoperative day 21, the IOP was 21 mmHg OS, and the filtration bleb had shrunk. A needling procedure was performed using a sharp 26-gauge needle to lower the IOP. On postoperative day 29, the BCVA was 0.02, and the IOP was 60 mmHg OS. Gonioscopy revealed no device tip in the anterior chamber, and peripheral anterior synechia was observed at the site of PFM insertion. Anterior segment optical coherence tomography showed a dislocated device in the subconjunctival space. On postoperative day 35, the dislocated PFM was removed, and a new device was inserted. Following the reoperation, no further complications were observed, and bleb formation was obtained. In conclusion, like other glaucoma filtering surgeries, PFM may require postsurgical needling procedures. Needling procedures may cause PFM dislocation and IOP rise, resulting in the requirement for further IOP-reducing procedures.