Characteristics and Treatment Outcomes of Hypotony Maculopathy Postglaucoma Filtering Surgery: An Optical Coherence Tomography-Based Study.

PRCIS: Bleb revision procedures for hypotony maculopathy (HM) following glaucoma filtering surgery show promising outcomes, including notable improvements in visual acuity and IOP. PURPOSE: This study assesses morphologic characteristics using SD-OCT in patients with HM following glaucoma filtering surgery and evaluates the results of its treatment. MATERIALS AND METHODS: A retrospective analysis of all HM patients between January 2019 and March 2023. Inclusion criteria consisted of both preoperative and postrevision SD-OCT images of the macula and the presence of HM as observed on OCT images preoperatively. HM was graded according to its appearance in OCT both prerevision and postrevision surgery. Changes in visual acuity and IOP were assessed. RESULTS: A total of 45 eyes of 45 patients were included. In all, 21 eyes had HM limited to retinal pigment epithelium (RPE), 18 eyes had involvement of RPE and photoreceptor layers, and 6 eyes had additional intraretinal or subretinal edema. After revision surgery with IOP elevation, 64% of eyes had complete HM regression with no HM signs in OCT imaging. Overall, 80% of patients achieved at least 1 grade improvement in HM. Preoperative visual acuity increased from 0.7±0.4 (logMAR) to 0.4±0.4 at 2 weeks postoperatively, over the course of an increase of IOP from 3.5±1.8 to 17.1±10.6 mm Hg at day 1. Eyes with complete HM regression had higher IOP at day 1 compared with those without improvement ( P =0.04). The median time between HM onset and revision was 10.0 days for those with complete regression and 27 days for those without improvement ( P =0.04). CONCLUSIONS: Bleb revision procedures for HM following glaucoma filtering surgery show promising outcomes, including notable improvements in visual acuity and IOP. The timing of revision surgery appears to influence the outcome. In our study, earlier intervention was associated with better results. Even delayed surgeries can lead to an improvement, although complete morphologic restoration may not be achieved in advanced grades of HM.

Intraluminal Suture Placement for Management of Hypotony After Glaucoma Drainage Device Surgery.

PRCIS: Intraluminal 3-0 Supramid stent placement can be an effective long-term solution for hypotony after glaucoma drainage device surgery. This procedure may obviate the need for conjunctival dissection. In some cases, additional procedures are required. PURPOSE: To describe the utility of implantation of a multifilament polyamide suture (Supramid) in the tube lumen to reverse hypotony after glaucoma drainage device (GDD) surgery. PATIENTS: Patients who underwent tube revision with intraluminal placement of a 3-0 Supramid stent, with or without external ligature, to manage hypotony following GDD surgery between January 2010 and October 2020. METHODS: Resolution of hypotony was defined as IOP >5 mm Hg and the absence of hypotony-related structural abnormalities. Overall success was the absence of failure criteria (IOP ≤5 mm Hg, >21 mm Hg, or <20% reduction below baseline IOP after 3 months for 2 consecutive study visits; additional glaucoma surgery; or loss of light perception), with or without adjunctive ocular hypotensive therapy. RESULTS: Nine eyes of 9 patients underwent placement of a 3-0 Supramid stent with a resolution of hypotony in all eyes with a mean follow-up duration of 33.3 ±24.0 months. Overall success was achieved in 7 of 9 eyes. Four eyes required intervention after stent placement: 1 eye required selective laser trabeculoplasty followed by replacement of the original stent with a shorter 3-0 Supramid suture and external ligature; 1 eye underwent revision for tube exposure; and 2 eyes underwent laser suture lysis to release an external suture ligature. CONCLUSIONS: In cases of hypotony after GDD, particularly when it is desirable to reduce the extent of additional conjunctival dissection, intraluminal placement of a 3-0 Supramid stent via an intracameral approach can be an effective long-term solution. Postoperative adjustments were required in many cases.

Ab Interno Ahmed Glaucoma Valve Plugs In An Eye With Persistent Hypotony.

PURPOSE: This case report aims to describe a new method for increasing intraocular pressure (IOP) in patients with acute hypotony resulting from uveitis flare-ups and preexisting glaucoma drainage devices. The temporary glaucoma tube plug method described is effective and safe. METHODS: This case report presents a 47-year-old female patient with a history of chronic panuveitis and secondary glaucoma, who had 2 previously implanted Ahmed glaucoma valves. The patient developed panuveitis flare-up and persistent hypotony. A novel method of ab interno plugging of the glaucoma tubes using 2-0 prolene suture plugs was performed. Following treatment, the IOP increased successfully and remained within the normal range. CONCLUSION: The temporary ab interno glaucoma tube plug method effectively increased IOP in a patient with 2 preimplanted Ahmed glaucoma valves with persistent low IOP due to uveitis.

Hypotony Failure Criteria in Glaucoma Surgical Studies and Their Influence on Surgery Success.

PURPOSE: Review hypotony failure criteria used in glaucoma surgical outcome studies and evaluate their impact on success rates. DESIGN: Systematic literature review and application of hypotony failure criteria to 2 retrospective cohorts. PARTICIPANTS: A total of 934 eyes and 1765 eyes undergoing trabeculectomy and deep sclerectomy (DS) with a median follow-up of 41.4 and 45.4 months, respectively. METHODS: Literature-based hypotony failure criteria were applied to patient cohorts. Intraocular pressure (IOP)-related success was defined as follows: (A) IOP ≤ 21 mmHg with ≥ 20% IOP reduction; (B) IOP ≤ 18 mmHg with ≥ 20% reduction; (C) IOP ≤ 15 mmHg with ≥ 25% reduction; and (D) IOP ≤ 12 mmHg with ≥ 30% reduction. Failure was defined as IOP exceeding these criteria in 2 consecutive visits > 3 months after surgery, loss of light perception, additional IOP-lowering surgery, or hypotony. Cox regression estimated failure risk for different hypotony criteria, using no hypotony as a reference. Analyses were conducted for each criterion and hypotony type (i.e., numerical [IOP threshold], clinical [clinical manifestations], and mixed [combination of numerical or clinical criteria]). MAIN OUTCOME MEASURES: Hazard ratio (HR) for failure risk. RESULTS: Of 2503 studies found, 278 were eligible, with 99 studies (35.6%) lacking hypotony failure criteria. Numerical hypotony was predominant (157 studies [56.5%]). Few studies used clinical hypotony (3 isolated [1.1%]; 19 combined with low IOP [6.8%]). Forty-nine different criteria were found, with IOP < 6 mmHg, IOP < 6 mmHg on ≥ 2 consecutive visits after 3 months, and IOP < 5 mmHg being the most common (41 [14.7%], 38 [13.7%], and 13 [4.7%] studies, respectively). In both cohorts, numerical hypotony posed the highest risk of failure (HR, 1.51-1.21 for criteria A to D; P < 0.001), followed by mixed hypotony (HR, 1.41-1.20 for criteria A to D; P < 0.001), and clinical hypotony (HR, 1.12-1.04; P < 0.001). Failure risk varied greatly with various hypotony definitions, with the HR ranging from 1.02 to 10.79 for trabeculectomy and 1.00 to 8.36 for DS. CONCLUSIONS: Hypotony failure criteria are highly heterogenous in the glaucoma literature, with few studies focusing on clinical manifestations. Numerical hypotony yields higher failure rates than clinical hypotony and can underestimate glaucoma surgery success rates. Standardizing failure criteria with an emphasis on clinically relevant hypotony manifestations is needed. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Morphologic Changes in the Lamina Cribrosa Upon Intraocular Pressure Lowering in Patients With Normal Tension Glaucoma.

Purpose: The purpose of this study was to investigate whether the lamina cribrosa (LC) curve changes in response to intraocular pressure (IOP) reduction following administration of topical ocular hypotensive eye drops in eyes with normal tension glaucoma (NTG). Methods: Ninety-three eyes of 93 patients with treatment naïve NTG at initial examination and with ≥20% reduction from baseline IOP following administration of topical ocular hypotensive eye drops were included. Serial horizontal B-scan images of the optic nerve head (ONH) were obtained from each eye using enhanced depth imaging spectral domain optical coherence tomography (OCT) before and 1 year after IOP-lowering treatment. The LC curvature in each eye was assessed by measuring the LC curvature index (LCCI) in horizontal OCT B-scan images obtained at three (superior, central, and inferior) locations spaced equidistantly across the vertical optic disc diameter before and after IOP-lowering treatment. We evaluated the OCT detectible change in the LC curvature based on the interval change of LCCI to exceed the intersession standard deviation of 1.96 times and factors associated with the magnitude of the LCCI change in the eyes showing significant LC change. Results: IOP decreased from 15.7 ± 2.5 mm Hg at baseline to 11.2 ± 1.7 mm Hg after topical glaucoma medication. Among the 93 subjects, 62 (66.7%) eyes showed the significant reduction of the LCCI (interssetional change over 1.5) after the treatment; greater interssessional change of the LCCI after IOP reduction was associated with younger age (P = 0.020) and larger baseline LCCI (P < 0.001). Conclusions: The OCT detectible changes in LC curvature occurred in response to a modest decrease in the IOP in the naïve NTG eyes. The therapeutic benefit of these changes need to be assessed in longitudinal studies.

Analytical model for managing hypotony after implantation surgery of a glaucoma drainage device.

The main aim of glaucoma treatment is to reduce the intraocular pressure (IOP). One of the most common surgical treatments of glaucoma is the implantation of a glaucoma drainage device to drain the aqueous humor from the anterior chamber to a filtration bleb, where the aqueous humor is absorbed. In some cases, the excess of drainage causes ocular hypotony, which constitutes a sight-threatening complication. To prevent hypotony after this intervention, surgeons frequently introduce a suture into the device tube, which increases the hydraulic resistance of the tube and, therefore, the IOP. This study aims to provide an analytical model to correct hypotony following implantation surgery of a glaucoma drainage device, which may help glaucoma surgeons decide on hypotony treatment. The results indicate that the IOP after implanting a cylindrical tube around 300 µm in diameter is essentially the same as that built up in the filtering bleb and can hardly be controlled by introducing a straight suture unless the suture diameter is slightly lower than that of the tube. On the contrary, when the tube diameter is smaller than, for example, 100 µm, significant reductions of the IOP can be obtained by introducing a thin suture into the tube.

Hypotony Without Globe Rupture During Orbital Fracture Repair.

A 29-year-old male presented to the emergency department with an orbital fracture. He denied ocular symptoms and CT showed bilateral fracture of nasal bones, left medial orbital wall, and left orbital floor, with herniation of orbital fat and minimal retrobulbar hematoma. Pre-operative ophthalmic exam was unremarkable. Intra-operatively, intraocular pressure of the left eye was 5 mm Hg, a significant change from 17 mm Hg preoperatively. Globe exploration revealed no injury. Post-operatively, IOP normalized. With these findings it was felt that ocular manipulation related to the orbital fracture repair placed significant and intermittent pressure on the globe, thereby lowering IOP. Laryngoscope, 131:2238-2240, 2021.

Optic Disc Edema and Posterior Globe Flattening Secondary to Ocular Hypotony: Case Report and Discussion Regarding Pathophysiology and Clinical Findings.

ABSTRACT: We describe a case of a young female patient presenting with ocular hypotension (4 mm Hg) secondary to cyclodialysis, and optic disc edema (ODE) after a blunt trauma in the right eye (right eye). MRI showed posterior globe flattening of the right eye, drawing our attention to the pathophysiology behind these findings. The combination of ODE and posterior globe flattening, as observed in the present case of ocular hypotony, is known from other conditions such as intracranial hypertension and space-flight neuro-ocular syndrome, pointing to a common pathophysiological mechanism, possibly resulting from axoplasmic stasis at the level of the lamina cribrosa due to a high translaminar pressure difference.

Micropulse transscleral cyclophotocoagulation using a standard protocol in patients with refractory glaucoma naive of cyclodestruction.

PURPOSE: To assess the efficacy and safety of a standardized micropulse transscleral diode laser cyclophotocoagulation procedure in refractory glaucoma. METHODS: Retrospective, interventional study in a series of 37 consecutive patients with refractory glaucoma, cyclodestructive procedure-naive, who underwent micropulse transscleral diode laser cyclophotocoagulation from December 2016 to October 2017. A successful laser treatment was defined as (1) intraocular pressure between 6 and 18 mm Hg; (2) 20% of baseline intraocular pressure reduction; (3) no additional glaucoma medications; (4) no decrease in vision due to complications or change in intraocular pressure; and (5) no need for additional glaucoma surgery except micropulse transscleral diode laser cyclophotocoagulation retreatment. RESULTS: Mean age was 60.2 years. Mean follow-up was 9.7 ± 3.9 months. The mean preoperative intraocular pressure (28.7 mm Hg) significantly decreased to 21.0 mm Hg at 1 month, 18.5 mm Hg at 3 months, 18.4 mm Hg at 6 months, and 18.5 mm Hg at 12 months (p < 0.01 at all time points). The mean number of preoperative glaucoma medications (4.7) decreased to 4.0 at 1 month (p = 0.14), 4.5 at 3 months (p < 0.05), 3.9 at 6 months (p < 0.05), and 3.6 at 12 months (p < 0.05). At 1 year, the success rate was 35% with a mean intraocular pressure lowering of 36%. One patient had hypotony and a loss of best-corrected visual acuity. Mild transient postoperative inflammation was observed in 8% of the cases. CONCLUSION: Using a standardized procedure, micropulse transscleral diode laser cyclophotocoagulation allows a mild intraocular pressure decrease with a low rate of complications and thus achieves a relatively good profit risk benefit, mostly for moderately hypertensive refractory glaucoma.

Loss of Pressure Control Resulting from Tube Bending during Glaucoma Drainage Tube Perforations.

PURPOSE: Tube perforations are a common method of achieving early intraocular pressure control with ligated glaucoma drainage devices (GDDs). Our purpose was to investigate how bending GDD tubes affects the performance of needle perforations. DESIGN: Experimental report. PARTICIPANTS: Twenty silicone GDD tubes attached to 27 G Rycroft cannulae tied with 7-0 Vicryl 10 mm from the cannulae tips. METHODS: Silicone GDD tubing was fitted over a 27 G Rycroft cannula and tied with a 7-0 suture 10 mm from the cannula tip. The tube was perforated 4 mm from the cannula tip with a 25 G needle (tube was kept straight). The tube was secured in a 50-mm water bath. Aqueous food dye was infused through the cannula from an adjustable height. The tube was observed under magnification while the height of the fluid column was adjusted to establish the pressure gradient at which the tube leaked dye (opening pressure) and ceased to leak (closing pressure), while the tube was held straight and bent 90 degrees. Measurements were repeated after a second perforation and a third perforation. Ten tubes were tested this way with 3 sequential slits. The entire experiment was repeated with another 10 tubes, but this time the tube was allowed to bend within the 3.5-mm open prongs of a needle holder during needle perforation. MAIN OUTCOME MEASURES: Opening and closing pressures. RESULTS: For each tube, the opening and closing pressures were similar and highly reproducible, but there was wide variation between tubes. In the tubes kept straight when perforated, the opening/closing pressure ranged from 5 to 25 cmH2O. The opening and closing pressures of slits made in the bent tube were significantly lower, frequently leaking at <1 cmH2O. Bending the tube after perforation could close a slit and prevent leakage at high perfusion pressure. The second and third successive perforations caused lower opening and closing pressures. CONCLUSIONS: Tube perforations behave like pressure-sensitive valves, opening whenever intraluminal pressure increases above a specific value. However, we found a large variation in the performance of fenestrations made with a 25-G hypodermic needle. Allowing the GDD tube to bend during needle perforation increases the risk of very low opening and closing pressures.

Association Between Structure-function Characteristics and Visual Field Outcomes in Glaucoma Subjects With Intraocular Pressure Reduction After Trabeculectomy.

PRECIS: Improvements in post-trabeculectomy visual field (VF) outcomes were found to be significantly associated with preoperative nerve fiber layer thickness parameters extracted from the sectorized structure-function relationship, baseline VF, and severity of glaucoma. OBJECTIVE: To determine whether the preoperative structure-function relationship helps to predict visual outcomes at 1-year post-trabeculectomy. PATIENTS AND METHODS: In total, 91 eyes from 87 participants who successfully underwent trabeculectomy were included in our study. All eyes received optical coherence tomography imaging and VF assessment using 30-2 standard automated perimetry preoperatively at baseline and postoperatively 1 year after trabeculectomy. The linear mixed-model analysis was used to assess the association of structure and function at baseline, and multivariate analysis to investigate factors associated with postoperative VF outcomes. RESULTS: Results from multivariate and univariate analysis for VF 1 year after trabeculectomy showed that a positive preoperative retinal nerve fiber layer thickness deviation from the structure-function model was found to be significantly associated with improved postoperative VF outcomes [ß=0.06 dB/µm; 95% confidence interval (CI), 0.03-0.09]. Other significant factors included baseline VF MD (ß=-0.18; 95% CI, -0.23 to -0.13) and the presence of severe glaucoma (ß=-1.69; 95% CI, -2.80 to -0.57). Intraocular pressure was positively associated with improved VF outcomes only in univariate analysis (ß=0.06; 95% CI, 0.01-0.11). CONCLUSIONS AND RELEVANCE: Characteristics derived from the baseline structure-function relationship were found to be strongly associated with postoperative VF outcomes. These findings suggest that the structure-function relationship could potentially have a role in predicting VF progression after trabeculectomy.

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.

Intraocular Pressure Reduction After Real-world Cataract Surgery.

PRéCIS:: A large cohort undergoing cataract extraction was retrospectively analyzed to ascertain the degree of real-world intraocular pressure (IOP) reduction in normal eyes and those with glaucoma, and a predictive formula was developed. PURPOSE: The purpose of this study was to define the real-world degree of IOP reduction after cataract extraction to guide its role as an isolated intervention for glaucoma. MATERIALS AND METHODS: A retrospective analysis was carried out of clinical data collected in 8 clinical sites in the United Kingdom from an electronic medical record system between January 2006 and May 2015. A total of 20,508 eyes without known pathology and 2251 eyes from patients with glaucoma undergoing phacoemulsification and intraocular lens insertion were included. Eyes with intraoperative complications, undergoing additional procedures, axial lengths outside 22 to 26.5 mm, preoperative IOP under 6 mm Hg or over 30 mm Hg, and copathology, except for amblyopia or glaucoma, were excluded. The main outcome measure was the change in preoperative IOP compared with the next recorded visit for up to 12 weeks. RESULTS: In eyes without pathology, the mean reduction in IOP was 1.40 mm Hg (±3.74) compared with 1.03 (±5.02), P-value <0.001, in eyes with a diagnosis of glaucoma. A multiple linear regression model identified preoperative IOP, a glaucoma diagnosis, preoperative corrected visual acuity, age, and axial length as determinants of IOP reduction. The model was validated against an independent cohort. CONCLUSIONS: We quantify mean IOP reduction achieved in a real-world setting from cataract surgery alone. In glaucomatous eyes where angle closure is not differentiated, phacoemulsification alone yields only a modest reduction of IOP.

Intraocular Pressure After Cataract Surgery Combined With Ab Interno Trabeculectomy Versus Trabecular Micro-bypass Stent: An Intrasubject Same-surgeon Comparison.

PRECIS: Combining Trabectome or iStent with phacoemulsification equally reduces intraocular pressure (IOP) and IOP-lowering medication burden during a 24-month follow-up, with a possible advantage to the Trabectome in the early postoperative period. PURPOSE: Intrasubject same-surgeon comparison between phacoemulsification combined with Trabectome (Phaco/Trabectome) versus one first-generation iStent (Phaco/iStent). SETTINGS: Private glaucoma and cataract practice. DESIGN: This is a retrospective interventional case series. METHODS: Data collected at 3 to 4 and 20 to 24 hours and up to 30 months following Phaco/Trabectome in 1 eye and Phaco/iStent in the contralateral eye in patients with bilateral visually-significant cataract and open-angle glaucoma. Evaluations included IOP, intraocular pressure-lowering medications (IOPmeds), visual acuity, and complications. RESULTS: Forty-five patients (90 eyes) were identified (age 76.5, 57 to 95 y). At 3 to 4 hours, IOP was above baseline in 12 and 13 eyes following Phaco/Trabectome and Phaco/iStent, respectively, but the degree of IOP elevation was smaller (P=0.048) following Phaco/Trabectome: 4.3 mm Hg, 2.0 to 6.6 mm Hg (95% confidence interval) versus Phaco/iStent: 8.7 mm Hg, 3.8 to 13.6 mm Hg. At 20 to 24 hours, compared with baseline, IOP was significantly lower after Phaco/Trabectome (P=0.004) but not after Phaco/iStent (P=0.14) although the rate of hyphema was higher following Phaco/Trabectome (12/45 vs. 2/45 eyes, P=0.007). IOP reduction from baseline at 3 to 4 hours was significantly larger (P=0.020) in the 21 eyes with hyphema: -3.9, -6.4 to -1.4 versus the 69 eyes without hyphema: -0.3, -2.0 to +1.4. At 1, 6, 12, and 24 months, IOP and number of IOPmeds were similar and significantly lower compared with baseline following either procedure. No complications were encountered in either group. CONCLUSIONS: Combined phacoemulsification with either Trabectome or first-generation iStent similarly lowers IOP and IOPmeds burden at 1, 6, 12, and 24 months following surgery. The Trabectome may have an advantage in lowering IOP faster and lessening the degree of IOP elevations in the early postoperative period.

Rate of hypotony and intraocular pressure fluctuation immediately after intravitreal dexamethasone implantation in vitrectomized eyes.

PURPOSE: To observe the rate of hypotony and intraocular pressure (IOP) fluctuations immediately following intravitreal dexamethasone implantation in vitrectomized eyes. METHODS: The study included previously vitrectomized eyes scheduled to receive intravitreal dexamethasone implants. IOP measurements were performed at minute 1, minute 10, hour 1, hour 2, hour 3 and day 1. The primary outcome measure of the study was the rate of hypotony at the various time points, while the secondary outcome measure was the IOP profile over time. RESULTS: A total of 26 eyes were enrolled in the study. Immediately following the injection, 11 (42.3%) of the eyes exhibited an IOP<6mm Hg. Hypotony was observed in one eye (3.8%) at hour 3 and day 1. After the immediate IOP reduction, IOP recovered rapidly and showed a peak at hour 1, with 5 eyes (19.2%) exhibiting IOP levels ≥25mmHg and 1 eye (3.8%) ≥30mm Hg. Aside from the eye with persistent hypotony resulting in a choroidal effusion, no other complication was observed. CONCLUSIONS: Injection of dexamethasone implants in vitrectomized eyes resulted in immediate IOP reduction. Hypotony showed a short, self-limited course in the majority of eyes. In the presence of additional risk factors for wound incompetency, regular follow-up in the early post-injection period appears to be needed.

MP3 Plus: A Modified Micropulse Transscleral Cyclophototherapy Technique for the Treatment of Refractory Glaucoma.

PRéCIS:: In advanced refractory glaucoma which has failed prior MP3 laser, MP3 Plus is effective in reducing intraocular pressure (IOP) without significant complications. It is also useful as a temporizing procedure before incisional surgery. PURPOSE: To evaluate the efficacy and safety of MP3 Plus, a novel technique using modified micropulse transscleral cyclophototherapy (MPTCP) in eyes with refractory glaucoma or failed MPTCP treatment. METHODS: This is a retrospective interventional case series. In total, 32 consecutive eyes from 29 patients with uncontrolled IOPs who had previous MPTCP or refractory glaucoma underwent MP3 Plus, a modified MPTCP where additional discrete pulses are applied. The main outcome measurement was IOP at 1, 3, 6, and 12 months postprocedure, with success defined as a 20% reduction in baseline IOP, an IOP of 25 mmHg or less, and no need for further reoperation. We collected and analyzed visual acuity, number of glaucoma medications, and complications. RESULTS: The patients had an average of 1.4±0.9 glaucoma procedures before treatment, where 87.5% underwent one or more previous MPTCP with suboptimal response. Of the eyes presenting for follow-up, 51.6% (n=31), 37.0% (n=27), 35.7% (n=28), and 25.9% (n=27) achieved the primary outcome at 1, 3, 6, and 12 months, respectively. Baseline IOP was 33.7±11.6 mmHg (n=32 eyes) and posttreatment IOP at 1, 3, 6, and 12 months were 21.0±9.0 mmHg (n=31; P<0.0001), 26.2±10.8 mmHg (n=25; P<0.0001), 23.2±9.4 mmHg (n=20; P<0.05), and 24.6±9.8 mmHg (n=16; P<0.001), respectively. There was a reduction in glaucoma medications from 3.4±0.8 preoperatively to 2.8±1.2 (n=16; P<0.05) at 12 months. There were no cases of prolonged inflammation or hypotony. CONCLUSIONS: MP3 Plus is effective and safe in lowering IOP in eyes with refractory glaucoma after previous failed MPTCP.

Development of a rabbit model of persistent hypotony without ciliary body injury.

In order to study the pathophysiological alterations of the ciliary body (CB) during persistent hypotony, it is necessary to develop an animal model without CB injury. In this study, we successfully established a modified model of persistent hypotony without CB injury in New Zealand rabbits. A 23-gauge pars plana vitrectomy (PPV) was performed and a trocar-formed fistula was allowed to remain in situ, to produce a continuous outflow of intraocular fluid. Both eyes underwent PPV with normal intraocular pressure (IOP); eyes with no surgical intervention were used as controls. The IOP was monitored and used to evaluate the reliability of the model. Secondary changes of hypotony were evaluated by slit-lamp biomicroscopy and B scans while morphological changes of the CB were observed by haematoxylin and eosin staining. The mean IOP in the hypotony groups were consistently lower than 6 mmHg. Furthermore, there were no significant differences in IOP between the PPV control group and normal eyes. Collectively, our data indicate that this model successfully simulates the secondary changes of hypotony, including a reduction in corneal size, corneal oedema, anterior chamber inflammation, morphological alterations of the CB, cataract, retinal detachment, and choroidal detachment. The morphological structure of the CB tissue changed dramatically after persistent hypotony, indicating that normal IOP may be required in order to maintain normal function in the CB. This model of persistent hypotony potentially represents a valuable tool for future studies aiming to investigate the pathophysiological mechanisms underlying CB dysfunction and other secondary changes that occur during hypotony.