Predicting Glaucoma Surgical Outcomes Using Neural Networks and Machine Learning on Electronic Health Records

Purpose

To develop machine learning (ML) and deep learning (DL) models to predict glaucoma surgical outcomes, including postoperative intraocular pressure, use of ocular antihypertensive medications, and need for repeat surgery.

Methods

We identified glaucoma surgeries performed at Stanford from 2013-2024, with two or more postoperative visits with intraocular pressure (IOP) measurement. Patient features were identified from the electronic health record (EHR), including demographics, prior diagnosis and procedure codes, medications and eye exam findings. Classical ML and DL models were developed to predict which glaucoma surgeries would result in surgical failure, defined as (1) IOP not reduced by more than 20% of preoperative baseline on two consecutive postoperative visits, (2) increased classes of glaucoma medications, and (3) need for additional glaucoma surgery or revision of original surgery.

Results

A total of 2398 glaucoma surgeries of 1571 patients were included, of which 1677 surgeries met failure criteria. Random forest performed best for prediction of overall surgical failure, with accuracy of 75.5% and area under the receiver operator curve (AUROC) of 76.7%, similar to the deep learning model (accuracy 75.5%, AUROC 76.6%). Across all models, prediction performance was better for IOP outcomes (AUROC 86%) than need for an additional surgery (AUROC 76%) or need for additional glaucoma medication (AUC 70%).

Conclusions

ML and DL algorithms can predict glaucoma surgery outcomes using structured data inputs from EHRs.

Translational Relevance

Models that predict outcomes of glaucoma surgery may one day provide the basis for clinical decision support tools supporting surgeons in personalizing glaucoma treatment plans.

Calcification of a Hydrophilic Acrylic Intraocular Lens after Glaucoma Surgery

A Japanese woman in her 70s was referred to our hospital for the evaluation and treatment of high intraocular pressure (IOP) in her right eye. She had undergone bilateral cataract surgeries and the insertion of hydrophilic acrylic intraocular lenses (IOLs). We performed trabeculotomy and trabeculectomy to lower her right IOP; thereafter, a circular opacity was observed on the right eye's IOL surface. We removed the right IOL because that eye's vision had decreased due to IOL opacification. The analysis of the removed IOL revealed that the main opacity component was calcium phosphate. This is the first post-glaucoma-surgery IOL calcification case report.

VEGF-C and 5-Fluorouracil Improve Bleb Survival in a Rabbit Glaucoma Surgery Trabeculectomy Model

Purpose

To evaluate VEGF-C-induced lymphoproliferation in conjunction with 5-fluorouracil (5-FU) antimetabolite treatment in a rabbit glaucoma filtration surgery (GFS) model.

Methods

Thirty-two rabbits underwent GFS and were assigned to four groups (n = 8 each) defined by subconjunctival drug treatment: (a) VEGF-C combined with 5-FU, (b) 5-FU, (c) VEGF-C, (d) and control. Bleb survival, bleb measurements, and IOP were evaluated over 30 days. At the end, histology and anterior segment OCT were performed on some eyes. mRNA was isolated from the remaining eyes for RT-PCR evaluation of vessel-specific markers (lymphatics, podoplanin and LYVE-1; and blood vessels, CD31).

Results

Qualitatively and quantitatively, VEGF-C combined with 5-FU resulted in blebs which were posteriorly longer and wider than the other conditions: vs. 5-FU (P = 0.043 for longer, P = 0.046 for wider), vs. VEGF-C (P < 0.001, P < 0.001) and vs. control (P < 0.001, P < 0.001). After 30 days, the VEGF-C combined with 5-FU condition resulted in longer bleb survival compared with 5-FU (P = 0.025), VEGF-C (P < 0.001), and control (P < 0.001). Only the VEGF-C combined with 5-FU condition showed a negative correlation between IOP and time that was statistically significant (r = -0.533; P = 0.034). Anterior segment OCT and histology demonstrated larger blebs for the VEGF-C combined with 5-FU condition. Only conditions including VEGF-C led to increased expression of lymphatic markers (LYVE-1, P < 0.001-0.008 and podoplanin, P = 0.002-0.011). Expression of CD31 was not different between the groups (P = 0.978).

Conclusions

Adding VEGF-C lymphoproliferation to standard antimetabolite treatment improved rabbit GFS success and may suggest a future strategy to improve human GFSs.

Wound Modulations in Glaucoma Surgery: A Systematic Review

Excessive fibrosis and resultant poor control of intraocular pressure (IOP) reduce the efficacy of glaucoma surgeries. Historically, corticosteroids and anti-fibrotic agents, such as mitomycin C (MMC) and 5-fluorouracil (5-FU), have been used to mitigate post-surgical fibrosis, but these have unpredictable outcomes. Therefore, there is a need to develop novel treatments which provide increased effectiveness and specificity. This review aims to provide insight into the pathophysiology behind wound healing in glaucoma surgery, as well as the current and promising future wound healing agents that are less toxic and may provide better IOP control.

No Changes in Keratometry Readings and Anterior Chamber Depth after XEN Gel Implantation in Patients with Glaucoma

Background: This study aimed to compare keratometry and anterior chamber depth (ACD) changes after XEN implantation in primary open-angle glaucoma (POAG) cases over a 3-month follow-up period. Methods: Twenty patients with POAG who underwent XEN63 implantation, either standalone or combined with cataract surgery, were included. Preoperative data, including best-corrected visual acuity (BCVA), refraction, gonioscopy, ophthalmoscopy, intraocular pressure (IOP) evaluation, and axial length, were collected. Corneal topography and ACD measurements were assessed preoperatively and at postoperative days 1, 7, 15, 30, 60, and 90. Each patient's eye that underwent XEN surgery was included in the study group, with the fellow eye serving as a control. Results: In the study group, there was a significant decrease in IOP after XEN stent implantation at all investigated time intervals (p < 0.05). However, changes in mean ACD did not show statistically significant differences at any follow-up examination in both the study and control groups. Additionally, keratometry readings revealed no significant changes in total astigmatism or steep keratometry values in either group. Conclusions: XEN implantation in POAG cases resulted in a significant decrease in IOP over the 3-month follow-up period. However, there were no significant changes observed in mean ACD or keratometry readings, indicating stability in these parameters post-XEN implantation. These findings suggest that XEN implantation may be an effective option for IOP reduction without affecting corneal curvature or ACD in POAG patients.

Comparison of GATT versus micropulse transscleral diode laser cyclophotocoagulation combined with GATT in patients with advanced glaucoma

PURPOSE

To compare the efficacy of gonioscopy-assisted transluminal trabeculotomy (GATT) versus micropulse transscleral diode laser cyclophotocoagulation(MP-TDLC) combined with GATT in the treatment of advanced glaucoma.

METHODS

This retrospective comparative study study included 82 patients (82 eyes) with a diagnosis of advanced glaucoma: 36 patients underwent GATT, and 46 underwent GATT + MP-TDLC. Intraocular pressure (IOP) changes in patients who underwent GATT and GATT MP-TDLC were analyzed retrospectively at regular intervals during the 6-month follow-up period.

RESULTS

For the 82 patients included in this study, the mean ± SD IOPs before the procedures were 27.2 ± 8.5 mmHg in the GATT group and 26.6 ± 6.9 mmHg in the GATT + MP-TDLC group (p = 0.866), and the numbers of glaucoma medications used were 3.41 ± 0.5 in the GATT group and 3.36 ± 0.4 in the GATT + MP-TDLC group (p = 0.605). The mean IOP after GATT was 13.6 ± 3.9 mmHg at day 1, 13.9 ± 3.7 mmHg at week 1, 14.6 ± 4.0 mmHg at month 1, 15.3 ± 4.3 mmHg at month 3, and 14.7 ± 3.3 mmHg at month 6. In the GATT + MP-TDLC group, the postoperative day 1, week 1, month 1, month 3, and month 6 IOP values were 12.4 ± 2.5, 11.8 ± 1.8, 12.1 ± 2.0, 11.8 ± 1.09, and 11.8 ± 1.5 mmHg, respectively.

CONCLUSION

GATT was found to be effective in the treatment of patients with advanced glaucoma, and results closer to the targeted low teens IOP values were obtained with GATT + MP-TDLC.

Visual Field Outcomes in the Primary Tube Versus Trabeculectomy Study

PURPOSE

To describe visual field outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study.

DESIGN

Cohort analysis of a prospective multicenter randomized clinical trial.

SUBJECTS

A total of 155 eyes from 155 subjects randomly assigned to treatment with tube shunt surgery (n=84) or trabeculectomy with mitomycin C (n=71).

METHODS

The PTVT Study was a multicenter randomized clinical trial comparing the safety and efficacy of trabeculectomy and tube shunt surgery in eyes without prior intraocular surgery. Subjects underwent standard automated perimetry (SAP) at baseline and annually for five years. SAP tests were deemed reliable if the false positive rate was ≤15%. Tests were excluded if visual acuity was ≤20/400 or loss of ≥2 Snellen lines from baseline were attributed to a non-glaucomatous etiology. Linear mixed-effects models were used to compare rates of change in SAP mean deviation (MD) between the two treatment groups. Intraocular pressure (IOP) control was assessed by percentage of visits with IOP <18 mmHg and mean IOP.

OUTCOME MEASURES

Rate of change in SAP MD during follow-up.

RESULTS

A total of 730 SAP tests were evaluated, with an average of 4.7 tests per eye. The average SAP MD at baseline was -12.8±8.3 dB in the tube group and -12.0±8.4 dB in the trabeculectomy group (p=0.57). The mean rate of change in SAP MD was -0.32±0.39 dB/year in the trabeculectomy group and -0.47±0.43 dB/year in the tube group (p=0.23). Eyes with mean IOP 14-17.5 mmHg had significantly faster rates of SAP MD loss compared to eyes with mean IOP <14 mmHg (-0.59±0.13 vs. -0.27±0.08 dB/year, p=0.012) and eyes with only 50-75% of visits with IOP <18 mmHg had faster rates than those with 100% of visits with IOP <18 mmHg (-0.90±0.16 vs. -0.29±0.08 dB/year, p<0.001). Multivariable analysis identified older age and worse IOP control as risk factors for faster progression in both treatment groups.

CONCLUSIONS

No statistically significant difference in mean rates of visual field change was observed between trabeculectomy and tube shunt surgery in the PTVT Study. Worse IOP control was significantly associated with faster rates of SAP MD loss during follow-up. Older patients were also at risk for faster progression.

PRESERFLO™ Microshunt: 1-Year Results of a 25-Gauge vs. 27-Gauge Needle Tract

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.

Uveitic Flare-Ups After Gonioscopy-Assisted Transluminal Trabeculotomy (GATT) in Patients with Uveitic Glaucoma

PURPOSE

To assess the risk of gonioscopy-assisted transluminal trabeculotomy (GATT) inducing an uveitic flare-up in patients with uveitic glaucoma (UG).

METHODS

This retrospective study included consecutive UG patients who underwent GATT at a single medical center between June 2020 and September 2022. The main outcome measure was the occurrence of a surgery-related uveitic complication defined as either an uveitic flare-up defined by the Standardization of Uveitis Nomenclature (SUN) criteria, or the appearance of cystoid macular edema (CME) from 2 weeks to 3 months after surgery.

RESULTS

A total of 25 eyes of 22 patients were included in the study. Age ranged from 10-78 and 64% were women. The most common uveitic etiologies were juvenile idiopathic arthritis (JIA, 24%) and herpetic infection (24%). A total of 48%of the patients were on systemic immunosuppressants prior and unrelated to surgery. Eight eyes (32%) had severe glaucomatous damage prior to surgery, and 20% of the patients had undergone previous glaucoma surgery. Two cases (8%) demonstrated uveitic flare-up in the early postoperative period: a case of mild anterior chamber reaction and a case of CME with persistent edema prior to surgery. Average intraocular pressure (IOP) was reduced from 26.7 mm Hg on four medications to 12.2 on 1.1 after 1 year. One patient required reoperation for IOP control.

CONCLUSIONS

With careful pre and postoperative care, GATT seems to be a low-risk procedure for uveitic flare-ups in patients with UG.

Preserflo TM MicroShunt implantation combined with Ologen TM in primary and secondary glaucoma patients in a clinical setting

PURPOSE

This study aims to assess the effectiveness and safety of combining the Preserflo™ MicroShunt implant (MicroShunt) with a simultaneous Ologen™ implant in patients with glaucoma.

METHODS

We conducted a retrospective study on consecutive patients with medically uncontrolled glaucoma who underwent MicroShunt + Ologen implantation as a standalone procedure or in combination with phacoemulsification (combined procedure). Success was defined as achieving an intraocular pressure (IOP) of 6-15 mmHg at 18 months post surgery, with a preoperative IOP reduction of at least 20%, and without (complete success) or with (qualified success) the need for antiglaucoma medications. The primary endpoint was the success rate.

RESULTS

Forty-eight eyes from 47 patients were included, with 28 eyes (58.3%) undergoing the standalone procedure and 20 eyes (41.7%) undergoing the combined procedure. Overall, there was a significant reduction in preoperative IOP from 19.7 ± 5.8 mmHg to 11.4 ± 2.6 mmHg at 18 months ( P < 0.0001). In the standalone procedure group, preoperative IOP decreased from 21.5 ± 5.2 mmHg to 11.7 ± 2.5 mmHg ( P < 0.0001), and in the combined procedure group, preoperative IOP decreased from 17.1 ± 5.8 mmHg to 10.9 ± 2.7 mmHg ( P = 0.0002), with no significant difference between the two groups regarding final IOP. The mean number of antiglaucoma medications significantly decreased from 3.2 ± 1.1 to 0.3 ± 0.7 in the overall study population ( P < 0.0001). At 18 months, 40 eyes (83.3%) were classified as successful. Regarding safety, out of the total number of eyes, two (4.2%) experienced choroidal detachment without visual impairment, two (4.2%) had transient hyphema, one (2.1%) showed reactivation of a corneal herpetic ulcer, one (2.1%) had diplopia, and one (2.1%) exhibited a shallow anterior chamber during the first week.

CONCLUSION

The combination of Ologen™ and Preserflo™ MicroShunt, either alone or in conjunction with phacoemulsification, demonstrated a favorable profile in terms of IOP reduction and safety.

Quantification of Postoperative Inflammation in Laser and Surgical Procedures for Glaucoma with Laser Flare Photometry: A Review of the Literature

PURPOSE

To review the application of laser flare photometry (LFP) in the objective quantification of aqueous flare (anterior chamber inflammation) post laser and surgical procedures for glaucoma.

METHODS

A search was undertaken using the following: PubMed (all years), the Web of Science (all years), Ovid MEDLINE (R) (1980 to 30 March 2023), Ovid MEDLINE (R) Daily Update 30 March 2023, MEDLINE and MEDLINE non-indexed items, Embase (1980-2021, week 52), Ovid MEDLINE (R) and Epub Ahead of Print, in-Process & Other Non-Indexed Citations and Daily (1980 to 30 March 2023), CENTRAL (including Cochrane Eyes and Vision Trials Register), metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (www.who.int/ictrp/search/en). Search terms included "aqueous flare," "anterior chamber inflammation," "tyndallometry," "laser flare photometry" combined with "laser," "iridotomy," "trabeculoplasty," "cataract surgery," "phacoemulsification," "glaucoma surgery," "minimally invasive glaucoma surgery," "trabeculectomy," "aqueous shunt," "glaucoma drainage" and "cyclophotocoagulation."

RESULTS

The majority of studies utilizing laser flare photometry in grading flare have been post laser trabeculoplasty. The degree of flare produced varies according to the type of glaucoma laser or surgery performed, with filtration procedures and glaucoma drainage devices having marked and prolonged detectable levels. Aqueous flare in cyclodestructive procedures positively correlated with intraocular pressure (IOP) reduction.

CONCLUSION

In comparison to clinician grading, laser flare photometry provides a more objective measure of post-surgical inflammation in eyes that have undergone laser and surgery for glaucoma. Further research is warranted into how this instrument can be utilized to identify eyes at high risk of failure and other adverse outcomes after glaucoma surgery.

Proactive Decision Support for Glaucoma Treatment: Predicting Surgical Interventions with Clinically Available Data

A longitudinal ophthalmic dataset was used to investigate multi-modal machine learning (ML) models incorporating patient demographics and history, clinical measurements, optical coherence tomography (OCT), and visual field (VF) testing in predicting glaucoma surgical interventions. The cohort included 369 patients who underwent glaucoma surgery and 592 patients who did not undergo surgery. The data types used for prediction included patient demographics, history of systemic conditions, medication history, ophthalmic measurements, 24-2 VF results, and thickness measurements from OCT imaging. The ML models were trained to predict surgical interventions and evaluated on independent data collected at a separate study site. The models were evaluated based on their ability to predict surgeries at varying lengths of time prior to surgical intervention. The highest performing predictions achieved an AUC of 0.93, 0.92, and 0.93 in predicting surgical intervention at 1 year, 2 years, and 3 years, respectively. The models were also able to achieve high sensitivity (0.89, 0.77, 0.86 at 1, 2, and 3 years, respectively) and specificity (0.85, 0.90, and 0.91 at 1, 2, and 3 years, respectively) at an 0.80 level of precision. The multi-modal models trained on a combination of data types predicted surgical interventions with high accuracy up to three years prior to surgery and could provide an important tool to predict the need for glaucoma intervention.

Functional and Morphological Outcomes after Trabeculectomy and Deep Sclerectomy-Results from a Monocentric Registry Study

The aim of this study was to compare the effectiveness of trabeculectomy (TE) and deep sclerectomy (DS) in lowering intraocular pressure (IOP) and thereby preserving visual field and peripapillary retinal nerve fiber layer (RNFL) tissue in primary open-angle glaucoma (POAG) cases. IOP, number of IOP-lowering medications, visual acuity, mean defect of standard automated perimetry, and mean peripapillary RNFL thickness were retrospectively collected and followed up for 3 years after surgery. TE was performed in 104 eyes and DS in 183 eyes. Age, gender, laterality, IOP, number of medications, visual acuity, perimetry mean defect, and peripapillary RNFL thickness were equally distributed at baseline. Mean IOP decreased from 23.8 ± 1.4 mmHg and 23.1 ± 0.4 mmHg to 13.4 ± 0.6 mmHg (p < 0.001) and 15.4 ± 0.7 mmHg (p = 0.001) in the TE and DS groups, respectively. Mean defect remained stable (TE: -11.5 ± 0.9 dB to -12.0 ± 1.1 (p = 0.090); DS: -10.5 ± 0.9 dB to -11.0 ± 1.0 dB (p = 0.302)), while mean peripapillary RNFL thickness showed further deterioration during follow-up (TE group: 64.4 ± 2.1 μm to 59.7 ± 3.5 μm (p < 0.001); DS group: 64.9 ± 1.9 μm to 58.4 ± 2.1 μm (p < 0.001)). Both TE and DS were comparably effective concerning postoperative reduction in IOP and medication. However, glaucoma disease further progressed during follow-up.

Comparative Analysis of Surgical Durations and Fees Across Eight Types of Glaucoma Surgery Performed by a Single Surgeon

The duration of several types of glaucoma surgery and reimbursement amounts per minute of surgery remain unknown. This study compared the surgical duration of glaucoma procedures (ab interno trabeculotomy, PreserFlo, ab externo trabeculotomy, bleb revision, EXPRESS, trabeculectomy, Ahmed, and the Baerveldt implant) and their reimbursement amounts in Japan. We retrospectively analyzed 30 consecutive surgeries of each type of glaucoma surgery. The reimbursement amount per surgical hour was calculated by subtracting the implant cost from the total medical fees. Amounts were converted to dollars based on an exchange rate of 1 USD = 133 JPY. The average surgical time was as follows: ab interno trabeculotomy, 7.8 ± 2.1; PreserFlo, 13.5 ± 4.0; ab externo trabeculotomy, 15.2 ± 4.1; bleb revision, 15.6 ± 2.3; EXPRESS, 16.9 ± 2.7; trabeculectomy, 18.5 ± 3.1; Ahmed, 35.8 ± 8.2; and Baerveldt, 39.2 ± 6.2. The reimbursement amounts after implant deduction were as follows: ab interno trabeculotomy, $1,089; PreserFlo, $1,538; ab externo trabeculotomy, $1,430; bleb revision, $259; EXPRESS, $1,600; trabeculectomy, $1,774; Ahmed, $1,600; and Baerveldt, $1,765. Reimbursement amounts per minute varied, with the highest and lowest for ab interno trabeculotomy and bleb revision at $140 per minute and $17 per minute, respectively. Reimbursement amounts per minute of surgery for eight types of glaucoma surgery vary by up to eightfold.

The Evolution and Current Landscape of Minimally Invasive Glaucoma Surgeries: A Review

This review examines the evolution, current status, and future potential of minimally invasive glaucoma surgeries (MIGS), a significant advancement in the treatment of glaucoma, a leading cause of irreversible blindness. MIGS offer a less invasive alternative to traditional glaucoma surgeries, primarily aimed at reducing intraocular pressure, minimizing tissue trauma, and providing a safer profile. With the emergence of devices such as the Trabectome, iStent, and others, MIGS have expanded the surgical toolkit, allowing personalized, patient-centered care. Despite their advantages, MIGS face challenges such as efficacy in severe cases, long-term data, and accessibility. Ongoing research and technological innovations continue to refine their capabilities and applications, promising to further transform glaucoma management and patient outcomes. This paper provides an in-depth analysis of MIGS, reflecting on their impact and contemplating future directions in this dynamically evolving field.

Efficacy and safety of deep sclerectomy with uveoscleral implant plus collagen matrix implant overcoming the superficial scleral flap in glaucoma surgery

AIM

To assess the efficacy and safety of non-penetrating deep sclerectomy (NPDS) with uveoscleral implant plus subconjunctival and intrascleral collagen matrix overcoming the superficial scleral flap lips (modified deep sclerectomy technique, DS) and minimal use of mitomycin C in glaucoma surgery.

METHODS

A retrospective review of 47 consecutive glaucoma patients who underwent NPDS with DS between January 2017 and May 2018. Best-corrected visual acuity, intraocular pressure (IOP), post-operative need for glaucoma medications, visual field mean deviation (MD), re-interventions, needling revisions and laser goniopuncture were noted. Absolute success was defined as IOP≤18 mm Hg without topical medication. Relative success was defined as the same criteria but with the addition of any antihypertensive medication. IOP over 18 mm Hg on two consecutive follow-up visits was considered as a failure.

RESULTS

Fifty-two eyes of 47 patients were evaluated. Mean preoperative IOP was 25.37±6.47 mm Hg, and decreased to 15.04±4.73 at 12mo and 12.21±4.1 at 24mo (all P<0.0001). Requirement for topical medications dropped from a mean of 3.06±0.25 per patient to 0.51±0.99 and 1.11±1.23 respectively after 12 and 24mo (all P<0.0001). No medications were required in 45.5% of patients after 24mo. Relative and absolute success rate at 24mo were 85.5%±5% and 48.5%±7.4%, respectively.

CONCLUSION

DS is a safe and effective non-penetrating glaucoma surgery variation. It aims to retain the patency of all pathways created for aqueous humor drainage: the intrascleral bleb, the supraciliary space and the open communication between intrascleral and subconjunctival compartments.

Bleb morphology of glaucoma drainage devices on magnetic resonance imaging

PURPOSE

To evaluate bleb morphology features of different glaucoma drainage devices (GDD) using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Prospective cohort study of GDD and bleb morphology in consecutive glaucoma patients implanted with Ahmed Glaucoma Valve (AGV), Paul Glaucoma Implant (PGI), Baerveldt Glaucoma Implant (BGI) and Ahmed ClearPath (ACP) devices. Thirty-six eyes from 30 consecutive patients underwent standardized GDD implantation followed by MRI at least 1 month after surgery. Main outcomes included bleb volume and endplate position relative to the optic nerve. Secondary outcomes included intraocular pressure (IOP), medication and surgical complications during a 12-month follow-up.

RESULTS

Seven eyes were implanted with the AGV (19%), 5 with BGI (14%), 16 with PGI (44%) and 8 with ACP (22%). MRI scans were obtained 85 ± 66 days after surgery. Mean total bleb volume was 563 ± 390 mm3 . This bleb volume was inversely correlated with early post-operative IOP (day 7; rs  = -0.3326, p = 0.0475) but positively correlated with IOP at 12 months (rs  = 0.3592, p = 0.0341). No significant difference in total bleb volume was found between GDD types (p = 0.1223). A double-layered bleb was observed in 34 eyes (94%). The inferior bleb volume was significantly larger in PGI devices versus other GDD types (380 ± 205 vs. 193 ± 161 mm3 ; p = 0.0043). Distance from the endplate to the optic nerve was 9.5 ± 4.0 mm, similar across GDDs (p = 0.2519).

CONCLUSIONS

Double-layered blebs are a common finding with GDDs. Bleb volume showed different correlations with IOP at distinct timepoints and the PGI device formed larger blebs. A standardized GDD implantation technique ensures a safe distance from the GDD endplate to the optic nerve.

Eyewatch adjustable drainage device in vitrectomized eyes with refractory glaucoma

BACKGROUND

To describe the efficacy and safety of the adjustable system eyeWatch in vitrectomized glacomatous eyes.

METHODS

Prospective, non-comparative, small case series of 2 patients who underwent glaucoma drainage device implant with the eyeWatch system. Intraocular pressure, number of medications and early and late complications were evaluated.

RESULTS

None of the operated eyes developed early or late complications. After 1 week post operatively, the IOP raised at 28 mmHg in the first eye and 25 mmHg in the second one. The eyeWatch Pen was used to open and set the device into position 3 (that means implant half opened) After waiting for 30 min, IOP was 15 mmHg and 11 mmHg, respectively. Thirty days after surgery we set the EyeWatch into position 0 (that means implant full opened) even though the IOP was under control. A new IOP measurement was done and we registered that IOP was 14 mmHg and 10 mmHg respectively, and it remained stable after six months of follow up.

CONCLUSION

In conclusion, in our case series the use of eyeWatch adjustable system allows a safe and gradual regulation of the flow during post-operative management also in vitrectomized eyes. Considering the percentage of hypotony related complications in vitrectomized eyes this system is an effective and safe technique to handle glaucoma in post vitreoretinal surgery eyes.

Swept-Source Anterior Segment Optical Coherence Tomography Imaging and Quantification of Bleb Parameters in Glaucoma Filtration Surgery

This paper describes a technique for using swept-source anterior segment optical coherence tomography (AS-OCT) to visualize internal bleb microstructure and objectively quantify dimensions of the scleral flap and trabeculo-Descemet window (TDW) in non-penetrating glaucoma filtration surgery (GFS). This was a cross-sectional study of 107 filtering blebs of 67 patients who had undergone deep sclerectomy surgery at least 12 months prior. The mean post-operative follow-up duration was 6.5 years +/- 4.1 [standard deviation (SD)]. The maximal bleb height was significantly greater in the complete success (CS) blebs compared to the qualified success (QS) and failed (F) blebs (1.48 vs. 1.17 vs. 1.10 mm in CS vs. QS vs. F, one-way ANOVA, p < 0.0001). In a subcohort of deep sclerectomy blebs augmented by intraoperative Mitomycin-C, the trabeculo-Descemet window was significantly longer in the complete success compared to the qualified success group (613.7 vs. 378.1 vs. 450.8 µm in CS vs. QS vs. F, p = 0.004). The scleral flap length, thickness, and width were otherwise similar across the three outcome groups. The quantification of surgical parameters that influence aqueous outflow in non-penetrating GFS can help surgeons better understand the influence of these structures on aqueous outflow and improve surgical outcomes.

Dislocation of the PreserFlo MicroShunt During a Postsurgical Needling Procedure

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.

Clinical and Optical Coherence Tomography Evidence of Aqueous Humor Flow from the Suprachoroidal Space to Conjunctival Lymphatics

A surgical technique was developed to enhance aqueous humor (AH) flow through the non-trabecular outflow pathway by rerouting it from the anterior chamber (AC) to the suprachoroidal space (SCS) without detaching the ciliary body from the scleral spur. Medium- and long-term surgical outcomes were retrospectively analyzed in a case series of 58 glaucoma patients. At 6, 12, and 24 months, the mean IOP decreased from 27.8 ± 8.3 to 14.9 ± 5.0 mmHg, median 15.0 (25th percentile (p25)13.0; 75th percentile (p75) 18.0) and 15.2 ± 3.3 mmHg, and hypotensive medication use reduced from a median (p25; p75) of 3 (2; 3) to 0 (0; 2), 0 (0; 2), and 0 (0; 1.5), respectively. Intra- and postoperative complications were few and manageable. Following surgery, no bleb formation occurred in any of the cases (as confirmed by optical coherence tomography). Conjunctival lymphatic vessels (CLVs) developed in 50% of eyes (29/58). Clinically, they developed directly from sclera and had no connection to the surgical site. Analysis further showed that the development of CLVs and their longer visibility period had poor prognostic value for IOP control. If the fluid flow from the SCS to CLVs was resistance-free, no CLV development was evident. However, if any resistance existed in the flow, the fluid accumulated in lymphatics, resulting in their engorgement. The proposed technique was safe and effective in decreasing IOP in glaucoma patients by enhancing AH flow from the SCS to CLVs via connecting intrascleral microchannels.

Slow Interstitial Fluid Flow Activates TGF-β Signaling and Drives Fibrotic Responses in Human Tenon Fibroblasts

BACKGROUND

Fibrosis limits the success of filtering glaucoma surgery. We employed 2D and 3D in vitro models to assess the effects of fluid flow on human tenon fibroblasts (HTF).

METHODS

HTF were exposed to continuous or pulsatile fluid flow for 48 or 72 h, at rates expected at the transscleral outflow site after filtering surgery. In the 2D model, the F-actin cytoskeleton and fibronectin 1 (FN1) were visualized by confocal immunofluorescence microscopy. In the 3D model, mRNA and whole cell lysates were extracted to analyze the expression of fibrosis-associated genes by qPCR and Western blot. The effects of a small-molecule inhibitor of the TGF-β receptor ALK5 were studied.

RESULTS

Slow, continuous fluid flow induced fibrotic responses in the 2D and 3D models. It elicited changes in cell shape, the F-actin cytoskeleton, the deposition of FN1 and activated the intracellular TGF-β signaling pathway to induce expression of fibrosis-related genes, such as CTGF, FN1 and COL1A1. ALK5-inhibition reduced this effect. Intermittent fluid flow also induced fibrotic changes, which decreased with increasing pause duration.

CONCLUSIONS

Slow interstitial fluid flow is sufficient to induce fibrosis, could underlie the intractable nature of fibrosis following filtering glaucoma surgery and might be a target for antifibrotic therapy.

Disparities in Glaucoma Surgery: A Review of Current Evidence and Future Directions for Improvement

There is a need to understand existing disparities in glaucoma surgery and to create strategies to eliminate these disparities. Disparities can exist in several aspects of glaucoma surgical management, including patient selection and timing of surgery, type of surgery performed, intra-operative and postoperative surgical complications, follow-up surgical care, and long-term surgical outcomes. Additionally, multiple types of disparities can exist within each of these realms, including disparities by race and ethnicity, age, gender, insurance type, people with disabilities, and other social, economic, and demographic factors. Disparities in glaucoma surgery have been examined in large scale datasets, retrospective clinical studies, and clinical trials, and several studies have identified likely racial and ethnic disparities in glaucoma surgical incidence and outcomes. We present existing literature on disparities in glaucoma surgery, analyze the advantages and limitations of various study designs for the investigation of these disparities, and propose directions for future research and interventions to identify and eliminate disparities in surgical glaucoma care.

Ocular surface and glaucoma, a mutual relationship. Practical suggestions for classification and management

The chronic use of glaucoma medications could improve the development of an ocular comorbidity, the glaucoma therapy-related ocular surface disease. This could be related to the exposure of the conjunctiva to preservatives, but also active compounds such as prostaglandin analogues may improve the risk of ocular surface inflammation. Inflammation has a negative impact on tolerability and adherence to eyedrops and to the outcome of filtration surgery as well. A stratification of glaucoma patients based not only on visual field progression but also on glaucoma therapy-related ocular surface disease would be desirable for a strategic management. Early diagnosis, individualized treatment, and safe surgical management should be the hallmarks of glaucoma treatment. One of the main issues for the proper and successful management of patients is the right timing, effectiveness and safety for both medical and surgical treatment options leading to a precision medicine in glaucoma disease as the best modern treatment.

Cyclodialysis Cleft and Hypotony Following Combined Phacoemulsification and Excisional Goniotomy with the Kahook Dual Blade

A 69-year-old woman with bilateral primary open-angle glaucoma who underwent cataract extraction with intraocular lens implantation and excisional goniotomy with the Kahook Dual Blade (KDB; New World Medical, Rancho Cucamonga, CA, USA) in both eyes one year prior was referred for evaluation of significant visual acuity loss and pain in the left eye. On initial examination, intraocular pressure in the left eye was 3 mmHg and slit lamp examination revealed normal anterior chamber depth. Gonioscopy revealed a cyclodialysis cleft that was confirmed by anterior segment optical coherence tomography. Prominent chorioretinal folds suggestive of long-standing hypotony maculopathy were observed during fundoscopic examination. The cyclodialysis cleft, thought to be created inadvertently during the KDB goniotomy, resolved after three sessions of argon laser photocoagulation and the patient's symptoms and visual acuity partially improved.