Glaucoma is a leading cause of irreversible blindness worldwide. While intraocular pressure (IOP) presents a major risk factor, the underlying pathophysiology still remains largely unclear. The correlation between vascular abnormalities and glaucoma has been deliberated for decades. Evidence for a role played by vascular factors in the pathogenesis of glaucomatous neurodegeneration has already been postulated. In addition, the fact that glaucoma causes both structural and functional changes to retinal blood vessels has been described. This review aims to investigate the published evidence concerning the relationship between vascular abnormalities and glaucoma, and to provide an overview of the “chicken or egg” dilemma in glaucoma. In this study, several biomarkers of glaucoma progression from a vascular perspective, including endothelin-1 (ET-1), nitric oxide, vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs), were identified and subsequently assessed for their potential as pharmacological intervention targets.

Background/Aim The aim of the study was to examine the effect of the COVID-19 pandemic on glaucoma surgical practices within the UK. Methods A cross-sectional online survey was distributed to all consultant glaucoma specialists who are on the UK and Eire Glaucoma Society contact list. Participants were asked specific questions regarding preferences in glaucoma surgical practices and whether these had changed subsequent to the onset of the COVID-19 pandemic. Results Trabeculectomy was the procedure of choice for 61 (87%) glaucoma specialists. A total of 51 (73%) respondents reported performing minimally invasive glaucoma surgery (MIGS) procedures before the COVID-19 pandemic. The most commonly performed MIGS procedure was the iStent inject (51%), followed by XEN 45 (36%) and Preserflo (17%). Forty-three (61%) respondents reported modifying their glaucoma surgery practice subsequent to the onset of the COVID-19 pandemic. Of the glaucoma specialists who modified their surgical practices, 21 (43%) specifically reduced the number of trabeculectomies performed. In combination, diode laser (both micropulse and conventional trans-scleral cyclodiode) was the most common alternative procedure. Glaucoma drainage devices, deep sclerectomy and Preserflo were also commonly chosen alternatives. Conclusion Although trabeculectomy remains the most commonly performed established glaucoma surgery, it is being performed with reduced frequency during the COVID-19 pandemic due to the number of postoperative visits and procedures required. Alternatives such as conventional and micropulse diode laser, glaucoma drainage devices, deep sclerectomy and Preserflo appear to be the favoured alternative procedures.

Background/aims: To evaluate 1-year success rates and safety profile of Preserflo™ Microshunt in glaucoma patients. Methods: Retrospective multicentre cohort study of 100 consecutive eyes (91 patients) from four tertiary-referral glaucoma centres. Four intraocular pressure (IOP) criteria were defined: A: IOP ≤ 21 mmHg+IOP reduction ≥20% from baseline; B: IOP ≤ 18 mmHg+IOP reduction ≥20%; C: IOP ≤ 15 mmHg+IOP reduction ≥25%; D: IOP≤12 mmHg+IOP reduction ≥30%. Success was defined as qualified or complete based on whether reached with or without medication. Primary outcome was success according to the above criteria. Secondary outcomes included: IOP, best-corrected visual acuity (BCVA), medication use, complications, postoperative interventions, and failure-associated factors. Results: Qualified and complete success rates (95% CI) at 12 months were 74%(66–83%) and 58%(49–69%) for criterion A, 72%(63–82%) and 57%(48–68%) for B, 52%(43–63%) and 47%(38–58%) for C, 29%(21–40%) and 26%(19–36%) for D. Overall median (interquartile range (IQR)) preoperative IOP decreased from 21.5(19–28) mmHg to 13(11–16) mmHg at 12 months. BCVA was not significantly different up to 12 months (p = 0.79). Preoperative median (IQR) number of medications decreased from 3 (2–3) to 0 (0–1) at 12 months. Twelve eyes underwent needling, five surgical revision and one device removal due to corneal oedema. There were no hypotony-related complications. Non-Caucasian ethnicity was the only risk factor consistently associated with increased failure. Conclusions: Preserflo™ Microshunt is a viable surgical option in glaucoma patients, with reasonable short-term success rates, decreased medications use, excellent safety profile, smooth postoperative care, and rapid learning curve. Success rates for the most stringent IOP cutoffs were modest, indicating that it may not be the optimal surgery when very low target IOP is required.

To evaluate the central corneal thickness (CCT) of Africans in a glaucoma practice in a university teaching hospital in West Nigeria, Africa, and compare results with similar studies carried out in African American and Afro-Caribbean populations. CCT was measured by means of ultrasound pachymetry (pachymeter used was Micropach 200 P+ Pachymeter; Sonomed) in only African participants with either glaucomatous or healthy eyes. After instillation of topical anesthetic, 3 measurements of corneal thickness were taken, and the average thickness for each was calculated. The relationship between CCT and age was studied using correlation analyses and t tests. A total of 70 eyes were included for analysis. The mean CCT of all participants was 532.00 microm. Glaucoma suspects and patients with glaucoma had corneas thinner than those of normal participants (527.36 and 536.91 microm, respectively); however, the difference was not significant (P = 0.296). Decreasing values of CCT were significantly related to older age (P = 0.002). Men had a significantly higher CCT than women (P = 0.035). CCT values in African populations are less than those of whites. Decreasing values of CCT are significantly related to older age, and men have thicker corneas than women. There is a suggestion that CCT is lower in patients with glaucoma than in nonglaucomatous controls; however, the difference is not statistically significant. Comparing our results to other studies in literature, it seems that average CCT is similar between populations living in sub-Saharan Africa and African Americans and Afro-Caribbeans.

Précis: This prospectively collected case series of 56 eyes having PAUL glaucoma implant (PGI) surgery is the first to demonstrate its medium-term safety and effectiveness in what is essentially an exclusively Caucasian population. Background: To report 2-year outcomes from a single-center cohort undergoing PGI surgery. Methods: Prospectively collected data on patients undergoing PGI surgery at the University Eye Hospital Bonn, Germany, from April 2021 to September 2021. Results: Of 53 patients, 56 eyes were included. Complete and qualified success rates (95% CI) were 52% (37–66) and 89% (80–96) for criterion A ( intraocular pressure [IOP]≤21 mm Hg), 48% (36–61) and 79% (67–88) for criterion B (IOP≤18 mm Hg), 45% (32–57) and 64% (52–77%) for criterion C (IOP≤15 mm Hg) and 27% (16–40) and 38% (25–50) for criterion D (IOP≤12 mm Hg), respectively. Mean IOP decreased from 25.43 mm Hg (7–48 mm Hg) to 11.25 mm Hg (3–24 mm Hg) (reduction of 50%) after 24 months with a reduction of IOP-lowering agents from 3.50 (1–5) to 0.46 (0–3). One eye needed an injection of viscoelastic due to significant hypotony with AC shallowing; 3 eyes received a Descemet membrane endothelial keratoplasty because of persistent corneal decompensation; 9 eyes developed tube exposure which required conjunctival revision with additional pericardial patch graft, with 5 of these eyes eventually needing tube explantation. An intraluminal prolene stent was removed in 24 eyes (42.9%) after a mean time period of 5.67 months (2–15 m). Mean IOP before removal was 21.4 mm Hg (12–40 mm Hg) and decreased to 11.15 mm Hg (6–20 mm Hg). Conclusions: PGI surgery is an effective procedure for reducing IOP and pressure-lowering therapy. The use of an intraluminal prolene stent impedes hypotony in the early postoperative phase and enables further noninvasive IOP lowering during the postoperative course.

Glaucoma is the leading cause of irreversible blindness and is characterized by progressive retinal ganglion cell (RGC) degeneration. Hydrogen sulfide (H₂S) is a potent neurotransmitter and has been proven to protect RGCs against glaucomatous injury in vitro and in vivo. This study is to provide an overall insight of H₂S’s role in glaucoma pathophysiology. Ischemia-reperfusion injury (I/R) was induced in Sprague-Dawley rats (n = 12) by elevating intraocular pressure to 55 mmHg for 60 min. Six of the animals received intravitreal injection of H₂S precursor prior to the procedure and the retina was harvested 24 h later. Contralateral eyes were assigned as control. RGCs were quantified and compared within the groups. Retinal proteins were analyzed via label-free mass spectrometry based quantitative proteomics approach. The pathways of the differentially expressed proteins were identified by ingenuity pathway analysis (IPA). H₂S significantly improved RGC survival against I/R in vivo (p < 0.001). In total 1115 proteins were identified, 18 key proteins were significantly differentially expressed due to I/R and restored by H₂S. Another 11 proteins were differentially expressed following H₂S. IPA revealed a significant H₂S-mediated activation of pathways related to mitochondrial function, iron homeostasis and vasodilation. This study provides first evidence of the complex role that H₂S plays in protecting RGC against I/R.