Excessive scleral shrinkage, rather than choroidal thickening, is a major contributor to the development of hypotony maculopathy after trabeculectomy

Usefulness of Eye Deformation in the Corvis ST Measurement to Predict Postoperative Hypotony Complications in Glaucoma

PURPOSE

This study aimed to investigate the usefulness of measuring biomechanical parameters using the Corvis ST to predict the occurrence of hypotony maculopathy and choroidal detachment (CD) following trabeculectomy or bleb needling revision with mitomycin C.

DESIGN

Clinical cohort study.

METHODS

This study included 100 eyes of 100 patients who underwent trabeculectomy (88 eyes of 88 patients) or bleb needling (12 eyes of 12 patients) with mitomycin C. A significant predictor of hypotony complications was identified from (1) operation (trabeculectomy or bleb needling), (2) age, (3) sex, (4) disease type (primary open-angle glaucoma, exfoliation glaucoma or other), (5) lens status (phakia or pseudophakia), (6) preoperative Goldmann applanation tonometry (GAT) intraocular pressure (IOP), (7) preoperative central corneal thickness (CCT), (8) preoperative axial length (AL), (9) preoperative anterior chamber depth, (10) "Min IOP" (IOP value when hypotony complications occurred, otherwise the minimum IOP during 3 months from trabeculectomy or bleb needling), (11) preoperative corneal curvature, and (12-24) 12 Corvis ST parameters using multivariate logistic regression.

RESULTS

There were 13 and 21 eyes developed hypotony maculopathy and CD, respectively. Male gender, greater preoperative GAT IOP, and greater highest concavity deflection Amplitude were significant predictors of the occurrence of hypotony maculopathy (P < .05). On the other hand, shorter AL, thinner CCT, greater preoperative GAT IOP and pseudophakia were significant predictors of the occurrence of CD (P < .05).

CONCLUSIONS

A careful attention should be paid to the occurrence of hypotony maculopathy with male gender and greater highest concavity deflection Amplitude despite higher preoperative GAT IOP. Different risk factors were identified; shorter AL, thinner CCT, greater preoperative GAT IOP, and pseudophakia.

Navigating hypotony challenges with XEN gel implantation

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.

Ex-PRESS Implantation versus Trabeculectomy for Long-Term Maintenance in Patients with Open-Angle Glaucoma

Purpose

To compare the efficacy of Ex-PRESS implantation (EXP) with that of trabeculectomy (TLE) with mitomycin C for maintaining low target intraocular pressure (IOP) in patients with open-angle glaucoma.

Patients and Methods

Patients were randomly assigned to receive EXP or TLE. Surgical success was defined according to three target mean IOP ranges (5 mmHg ≤ IOP ≤ 18 mmHg [criterion A], 5 mmHg ≤ IOP ≤ 15 mmHg [criterion B], and 5 mmHg ≤ IOP ≤ 12 mmHg [criterion C]) representing reductions of at least 20% below the baseline on two consecutive follow-up visits 3 months post-surgery, with or without antiglaucoma medication and without further glaucoma surgery. Participants were divided into three subgroups based on baseline mean deviation (MD) values: early (MD ≥ -6 dB), moderate (-6 dB > MD ≥ -12 dB), and advanced (-12 dB > MD). Survival rates were calculated by subgroup.

Results

A total of 73 patients, including 30 in the EXP group and 43 in the TLE group, were included in the study. No significant differences in baseline ocular or demographic characteristics were found between the two groups. No significant difference in IOP was noted every 6 months. After the 3-year follow-up, success rates were A) 60.0% and 60.2%, B) 45.7% and 58.1%, and C) 31.5% and 40.5% for the EXP and TLE groups, respectively. Moreover, there was no difference in success rate based on glaucoma level. Many glaucoma medications administered before surgery were associated with a higher failure rate in the TLE group but not in the EXP group.

Conclusion

Both procedures resulted in similar IOP reductions and success rates for a low target IOP. The number of preoperative glaucoma medications was a risk factor for TLE failure.

Gel Stent Versus Trabeculectomy: The Randomized, Multicenter, Gold-Standard Pathway Study (GPS) of Effectiveness and Safety at 12 Months

PURPOSE

To compare effectiveness and safety of the gel stent to trabeculectomy in open-angle glaucoma (OAG).

DESIGN

Prospective, randomized, multicenter, noninferiority study.

METHODS

Patients with OAG and intraocular pressure (IOP) 15 to 44 mm Hg on topical IOP-lowering medication were randomized 2:1 to gel stent implantation or trabeculectomy. Primary end point (surgical success): percentage of patients at month 12 achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or secondary surgical intervention (SSI) in a noninferiority test with 24% margins. Secondary end points (month 12) included mean IOP and medication count, postoperative intervention rate, visual recovery, and patient-reported outcomes (PROs). Safety end points included adverse events (AEs).

RESULTS

At month 12, the gel stent was statistically noninferior to trabeculectomy (between-treatment difference [Δ], -6.1%; 95% CI, -22.9%, 10.8%); 62.1% and 68.2% achieved the primary end point, respectively (P=.487); mean IOP and medication count reductions from baseline were significant (P<.001); and the IOP change-related Δ (2.8 mm Hg) favored trabeculectomy (P=.024). The gel stent resulted in fewer eyes requiring in-office postoperative interventions (P=.024 after excluding laser suture lysis), faster visual recovery (P≤.048), and greater 6-month improvements in visual function problems (ie, PROs; P≤.022). The most common AEs were reduced visual acuity at any time (gel stent, 38.9%; trabeculectomy, 54.5%) and hypotony (IOP <6 mm Hg at any time) (gel stent, 23.2%; trabeculectomy, 50.0%).

CONCLUSIONS

At month 12, the gel stent was statistically noninferior to trabeculectomy, per the percentage of patients achieving ≥20% IOP reduction from baseline without medication increase, clinical hypotony, vision loss to counting fingers, or SSI. Trabeculectomy achieved a statistically lower mean IOP, numerically lower failure rate, and numerically lower need for supplemental medications. The gel stent resulted in fewer postoperative interventions, better visual recovery, and fewer AEs.

The Japan Glaucoma Society guidelines for glaucoma 5th edition

We are pleased to bring you the 5th edition of the Glaucoma Clinical Practice Guidelines. Clinical practice guidelines are based on evidence (scientific grounds). It is a document that presents the treatment that is the most appropriate for the patient. "Glaucoma Clinical Guidelines" was first published in 2003. This was the first guideline for glaucoma treatment in Japan. The principle of glaucoma treatment is to lower intraocular pressure. Means for lowering intraocular pressure includes drugs, lasers, and surgery; Glaucoma is a disease that should be considered as a complex syndrome rather than a single condition. Therefore, the actual medical treatment is not as simple as one word. This time we set the Clinical Questionnaire with a focus on glaucoma treatment. We hope that you will take advantage of the 5th edition.

Maculopathies in Glaucoma

In the presence of glaucoma, various changes in the macula can occur during the course of the disease itself or its treatment. Maculopathies that can be observed in glaucoma include cystoid macular edema, hypotony maculopathy, and microcystic macular edema. The following article discusses the pathophysiology, causes, course, clinical presentation, and treatment of these maculopathies.

Risk Factors for Corneal Striae in Eyes After Glaucoma Surgery

PRCIS

Eyes with corneal striae had steeper cornea, induced astigmatism, and higher corneal hysteresis (CH), which implies a relationship between striae, corneal shape, and the cornea's resistance to deformation at low intraocular pressures (IOPs).

BACKGROUND

Anterior corneal striae (ACS) are associated with low IOP. However, the clinical significance of ACS is unclear. Here, we aim to evaluate differences in eyes with striae compared with eyes without striae.

METHODS

Adults with ACS (cases) and without ACS (controls) ≥8 weeks after glaucoma surgery with an IOP ≤10 mm Hg were enrolled. Optical coherence tomography and optical biometry were performed. CH, defined as the difference in pressure between corneal indentation and reformation in response to an air jet, was obtained by the ocular response analyzer. Hypotony maculopathy (HM) was defined as optic disc swelling, vascular tortuosity attributed to hypotony, or clinical presence of chorioretinal folds confirmed on OCT.

RESULTS

One hundred sixteen eyes (76 cases, 40 controls) were included. Cases had a lower IOP compared with controls (6.5±2.3 vs. 8.5±1, P<0.0001). A 1 mm Hg increase in CH increased ACS odds [odds ratio (OR)=1.51, P=0.01]. A 1 D increase in the flattest presurgical and postsurgical corneal power increased ACS odds by 1.83 (P=0.01) and 1.41 (P=0.02), respectively. Astigmatism increased in eyes with ACS by 1.11 D (P<0.001). ACS odds were increased with every 1 minute increase in mitomycin-C duration (OR=1.58, P=0.047) and decreased with the use of topical glaucoma medication (OR=0.62, P=0.03). Visual acuity decreased from logarithm of the minimal angle of resolution 0.22 (20/33 Snellen) presurgery to 0.28 (20/38) postsurgery (P=0.008), independent of ACS. HM occurred in 19% of cases (P=0.05). A higher postsurgical CH increased HM odds (OR=1.8, P=0.003). HM predicted a 0.41 mm decrease in axial length (P<0.0001), independent of IOP.

CONCLUSION

ACS were associated with a steeper cornea, induced astigmatism, and higher CH, suggesting a relationship between striae, corneal shape, and the cornea's ability to resist deformations at lower IOP. CH, HM, and axial length shortening were associated independently of IOP.

[On refraction shift after trabeculectomy]

PURPOSE

To determine the factors affecting the shift of refraction after trabeculectomy.

MATERIAL AND METHODS

The study included 42 patients who were examined prior to trabeculectomy and at the following timepoints: 1 week, 1 month and 3 months after surgery. Examination included tonometry with assessment of corneal biomechanical properties, keratorefractometry with vector analysis, and biometry. The obtained data was processed for regression analysis and to find the possible correlations.

RESULTS

All significant correlations between the measured parameters only occur on week 1. Postoperative spherical component of refraction (sphere) correlates negatively both with preoperative axial length (AL) and anterior chamber depth (ACD) (r=-0.699 and r=-0.458, p<0.05) and postoperative AL and ACD (r= -0.767 and r= -0.415, p<0.011). Dependence of sphere on AL is also expressed as a regression model. The magnitude of AL change depends on the magnitude of intraocular pressure (IOP) change (r=0.729, p<0.0001) and correlates negatively with postoperative IOP (r=-0.454, p=0.009) and baseline corneal hysteresis (CH; r= -0.482, p=0.009). Dependence of AL on IOP is also expressed as a regression model. The magnitudes of sphere and cylinder shifts correlate negatively with each other (r=-0.416, p=0.038). Keratometry reveals that the overall cylinder value correlates with the corneal cylinder, and so do the magnitudes of their shifts (r=0.589 and r=0.574, p<0.0001). Dependence of corneal hysteresis on IOP is expressed as a regression model; however, neither tonometric nor biomechanical corneal properties correlate with refraction.

CONCLUSIONS

Sphere correlates negatively with AL and ACD. In turn, AL is related to the reduction in IOP. This dependence is likely the most important one for the refraction shift after trabeculectomy. No correlations were found for the change of astigmatism.

Non-inferiority of Microhook to Trabectome: Trabectome vs. ab interno Microhook Trabeculotomy Comparative Study (TramTrac Study)

PURPOSE

To elucidate the non-inferiority of ab interno microhook trabeculotomy (μTLO) using a recently developed reusable stainless spatula-type microhook device to incise the trabecular meshwork to trabectome (TOM) in terms of the 1-year postoperative outcomes of Japanese patients with glaucoma by means of propensity score analyses.

DESIGN

A multicenter retrospective cohort study.

PARTICIPANTS

We enrolled 553 and 392 patients who underwent TOM and μTLO, respectively, between January 2014 and March 2020 at 10 facilities.

METHODS

Logistic regression analysis was conducted to calculate the propensity score, which indicates the likelihood of treatment assignment (TOM or μTLO). We set the following factors as outcome-related covariates: age, sex, facility, glaucoma disease types, preoperative intraocular pressure (IOP), glaucoma drug score, mean deviation of the Humphrey visual field test and antithrombotic drug use, the presence or absence of combined cataract surgery, and incision range of trabecular meshwork (one or two quadrants). We analyzed four different methods (matching, inverse probability of treatment weighting (IPTW), stratification, and regression adjustment) using the propensity score. We set 15% as the non-inferiority margin based on previous trabectome meta-analysis results.

MAIN OUTCOME MEASURES

The primary outcome was surgical success at 1 year postoperatively. We defined surgical success as satisfying all three criteria: (1) IOP within 5-21 mmHg; (2) IOP reduction of ≥20% from preoperative IOP; and (3) no additional glaucoma surgery.

RESULTS

The 95% confidence interval of risk difference of surgical failure in μTLO in reference to TOM was -12.1 to +9.5% in matching, -12.7 to +11.1% in IPTW, -12.2 to +7.0 in stratification, and -9.7 to +8.1% in regression adjustment, all of which fell within the predetermined non-inferiority margin of 15%.

CONCLUSIONS

Surgical success of μTLO at 1-year postoperatively was not inferior to that of TOM.

Hypotony-associated Complications After Deep Sclerectomy: Incidence, Risk Factors, and Long-term Outcomes

PRECIS

Chronic hypotony is not uncommon following deep sclerectomy (DS), but only a minor proportion of patients develop hypotony-associated complications. Numerical hypotony does not affect the visual outcomes. This study identifies factors associated with hypotony.

PURPOSE

To investigate the incidence and risk factors of hypotony and hypotony-associated complications after DS.

METHODS

Retrospective cohort study of 1765 eyes (1385 patients) undergoing DS with or without cataract extraction between 2001 and 2020 in 2 UK centers. Chronic hypotony was defined as intraocular pressure (IOP) ≤5 mm Hg in ≥2 consecutive visits lasting >90 days or as any IOP ≤5 mm Hg associated with hypotony-related complications or requiring surgical intervention. Clinical hypotony was defined as the presence of: serous or hemorrhagic choroidal detachment, hypotony maculopathy, flat anterior chamber requiring reformation, decompression retinopathy. The incidence of hypotony was calculated with Kaplan-Meier statistics, and Cox regression was used to identify risk factors.

RESULTS

The median (interquartile range) age and follow-up were 76 (67 to 82) years and 45.4 (20.9 to 79.8) months, respectively. The incidence (95% confidence interval) of chronic and clinical hypotony at 5 years was 13.4% (11.5%-15.3%) and 5.6% (4.3%-6.9%), respectively. Sixteen eyes (15.7%) with hypotony-associated complications had IOP >5 mm Hg. Male sex (hazard ratio [HR]: 1.89, P=0.018), non-Caucasian ethnicity (HR: 2.49, P=0.046), intraoperative bevacizumab (HR: 3.96, P=0.01), pigmentary glaucoma (HR: 3.59, P=0.048), previous vitreoretinal surgery (HR: 5.70, P=0.009), intraoperative microperforation (HR: 4.17, P<0.001) and macroperforation (HR: 20.76, P<0.001), and avascular bleb (HR: 1.80, P=0.036) were associated with clinical hypotony.

DISCUSSION

Chronic hypotony is not uncommon following DS, but clinical hypotony is infrequent. Hypotony associated-complications can occur in eyes without statistical hypotony.

[Refractive shift after glaucoma surgery]

Filtering glaucoma surgery can affect certain biometric features of the eye: it can change the axial length and anterior chamber depth, while redistribution of mechanical tensions in the fibrous tunic can alter the shape of the cornea. Among these changes that affect refraction, reshaping of corneal curvature is the principle one. Contrary to the expectations, and in contrast to changes associated with cataract surgery, glaucoma surgery led to decrease in vertical corneal radius (steepening) and development of the with-the-rule astigmatism. A number of studies helped reveal the features of corneal astigmatism that appears after glaucoma surgery: its power, duration, possibility of horizontal meridian flattening, influence of topical cytostatic drugs and drainage devices, etc. Potential reasons of astigmatism development were suggested: conjunctival incisions and sutures in the limbal area, quantity and strength of flap sutures, intraocular pressure level, shift of fistula edges, tissue contraction after cauterization, etc. The key role in pathogenesis of the refractive shift due to change of corneal curvature may belong to particularities of wound healing in the cornea and sclera: healing in sclera is similar to one of connective tissue - its ultrastructure undergoes aging process followed by change of rigidity. At the same time, the main reason for the development of corneal astigmatism after glaucoma surgery remains unclear.

Discordance of Disc-Fovea Raphe Angles Determined by Optical Coherence Tomography and MP-3 Microperimetry in Eyes With a Glaucomatous Hemifield Defect

Purpose

The purpose of this study was to evaluate the concordance of a temporal raphe architecture estimated using optical coherence tomography (OCT) and MP-3 microperimetry.

Methods

We enrolled 25 eyes with either an upper or lower glaucomatous hemifield defect, as detected on the Humphrey visual field 30-2 test. A structural temporal raphe was extrapolated from visible end points of retinal nerve fiber bundles present in a perimetrically normal hemiretina on an en face Spectralis OCT image. A functional temporal raphe was drawn as a line from the fovea to the border of at least a 10-dB difference in sensitivity, at vertically adjacent test points, with at least three consecutive pairs among 25 test points placed at 8° to 18° from the fovea (2° intervals) on the MP-3. An angle determined by the optic disc center, the fovea, and the temporal raphe line (the DFR angle) was calculated. Correlations and agreement of the OCT- and MP-3-derived DFR angles and factors affecting discordance of the two estimates were evaluated.

Results

Despite no significant demographic differences, the functional DFR angle (mean ± SD, 171.8° ± 3.5°) was significantly larger than that of the structural DFR angle (166.5° ± 3.2°) in 14 eyes with upper hemifield defects and vice versa in 11 eyes with lower hemifield defects (163.4° ± 3.0° vs. 170.5° ± 3.2°). The mean deviation was significantly associated with the functional and structural DFR angle difference in eyes with only upper hemifield defects.

Conclusions

The structural temporal raphe was more deviated to the perimetrically normal hemiretina side than to the functional temporal raphe, thereby suggesting that a structural change may precede a functional loss.