Interplay Between Ocular Ischemia and Glaucoma: An Update

Glaucoma is a main cause of irreversible blindness worldwide, with a high impact on productivity and quality of life. The mechanical and ischemic theories are currently the most recognized pathophysiological pathways that explain the neurodegeneration of retinal nerve fibers in glaucoma. In this narrative review, aspects of ischemia in glaucoma are discussed, including vascular dysregulation, retinal ischemia signaling pathways, roles of vascular endothelial growth factors, and future research and therapeutic directions. In conclusion, a better understanding of the ischemic processes in glaucoma may lead to innovative treatment options and improved management and follow-up of our patients.

Primary Congenital and Childhood Glaucoma-A Complex Clinical Picture and Surgical Management

Childhood glaucoma encompasses a group of rare but severe ocular disorders characterized by increased intraocular pressure (IOP), posing significant risks to vision and quality of life. Primary congenital glaucoma has a prevalence of one in 10,000-68,000 people in Western countries. More worryingly, it is responsible for 5-18% of all childhood blindness cases. According to the Childhood Glaucoma Research Network (CGRN), this spectrum of disease is classified into primary glaucoma (primary congenital glaucoma and juvenile open-angle glaucoma) and secondary glaucomas (associated with non-acquired ocular anomalies, non-acquired systemic disease, acquired conditions, and glaucoma after cataract surgery). They present very specific ocular characteristics, such as buphthalmos or progressive myopic shift, corneal modifications such as Haab striae, corneal edema or increased corneal diameter, and also glaucoma findings including high intraocular pressure, specific visual fields abnormalities, and optic nerve damage such as increased cup-disc ratio, cup-disc ratio asymmetry of at least 0.2 and focal rim thinning. Surgical intervention remains the cornerstone of treatment, and initial surgical options include angle surgeries such as goniotomy and trabeculotomy, aimed at improving aqueous outflow. For refractory cases, trabeculectomy and glaucoma drainage devices (GDDs) serve as second-line therapies. Advanced cases may require cyclodestructive procedures, including transscleral cyclophotocoagulation, reserved for eyes with limited visual potential. All in all, with appropriate management, the prognosis of PCG may be quite favorable: stationary disease has been reported in 90.3% of cases after one year, with a median visual acuity in the better eye of 20/30. Immediate recognition of the specific signs and symptoms by caregivers, primary care providers, and ophthalmologists, followed by prompt diagnosis, comprehensive surgical planning, and involving the caregivers in the follow-up schedule remain critical for optimizing outcomes in childhood glaucoma management.

Characterising information gains and losses when collecting multiple epidemic model outputs

BACKGROUND

Collaborative comparisons and combinations of epidemic models are used as policy-relevant evidence during epidemic outbreaks. In the process of collecting multiple model projections, such collaborations may gain or lose relevant information. Typically, modellers contribute a probabilistic summary at each time-step. We compared this to directly collecting simulated trajectories. We aimed to explore information on key epidemic quantities; ensemble uncertainty; and performance against data, investigating potential to continuously gain information from a single cross-sectional collection of model results.

METHODS

We compared projections from the European COVID-19 Scenario Modelling Hub. Five teams modelled incidence in Belgium, the Netherlands, and Spain. We compared July 2022 projections by incidence, peaks, and cumulative totals. We created a probabilistic ensemble drawn from all trajectories, and compared to ensembles from a median across each model's quantiles, or a linear opinion pool. We measured the predictive accuracy of individual trajectories against observations, using this in a weighted ensemble. We repeated this sequentially against increasing weeks of observed data. We evaluated these ensembles to reflect performance with varying observed data.

RESULTS

By collecting modelled trajectories, we showed policy-relevant epidemic characteristics. Trajectories contained a right-skewed distribution well represented by an ensemble of trajectories or a linear opinion pool, but not models' quantile intervals. Ensembles weighted by performance typically retained the range of plausible incidence over time, and in some cases narrowed this by excluding some epidemic shapes.

CONCLUSIONS

We observed several information gains from collecting modelled trajectories rather than quantile distributions, including potential for continuously updated information from a single model collection. The value of information gains and losses may vary with each collaborative effort's aims, depending on the needs of projection users. Understanding the differing information potential of methods to collect model projections can support the accuracy, sustainability, and communication of collaborative infectious disease modelling efforts.

Challenges of Secondary Glaucoma Management Following Congenital Cataract Surgery, Penetrating Keratoplasty and Vitreoretinal Surgery

Glaucoma is one of the world's leading causes of irreversible vision loss. It is often asymptomatic until it reaches an advanced stage, which can have a significant impact on patients' daily lives. This paper describes the case of a 50-year-old female patient who presented with acute onset of ocular pain, photophobia, and loss of visual acuity in her right eye (RE). The patient's medical history includes congenital cataracts, surgical aphakia, nystagmus, strabismus, amblyopia, and secondary glaucoma. Ophthalmological examination showed BCVA RE-hand movement, left eye (LE)-0.08 with an intraocular pressure (IOP) of 30 mmHg in RE and 16 mmHg in LE. Biomicroscopic examination of RE showed corneal graft, epithelial and endothelial edema, endothelial precipitates, corneal neovascularization, aphakia, and Ahmed valve superotemporally. Despite maximal topical and systemic treatment, Ahmed valve, and trabeculectomy, secondary glaucoma in the right eye remained refractory. Reimplantation of an Ahmed valve was performed. This resulted in a favorable outcome with increased visual acuity and controlled intraocular pressure. The combination of aphakia, penetrating keratoplasty, and secondary glaucoma is a challenge for any surgeon. It is important that both the perioperative risks and the possible complications are carefully assessed in each patient, especially if associated pathology is present.

Systematic Review and Meta-Analysis on the Association Between Daily Niacin Intake and Glaucoma

BACKGROUND

Glaucoma is a progressive optic neuropathy, characterised by a complex pathophysiology, with mitochondrial dysfunction playing a significant role in the cellular damage and apoptosis of ganglion cells. Niacin is a precursor to several molecules acting as coenzymes in the mitochondrial production of ATP, in DNA repair and in the reduction of reactive oxygen species. The objective of this systematic review is to assess the impact of daily niacin intake on glaucoma.

METHODS

Case-control and cohort studies regarding niacin and glaucoma, indexed in PubMed, Web of Science, Cochrane and Scopus, were included. Other study methodologies, studies regarding niacin in other ocular disease or other nutrients in glaucoma were excluded. Bias was assessed using the Newcastle-Ottawa Scale. The study protocol was registered in the PROSPERO database (no. CRD42024578889).

RESULTS

Five case-control studies were included. In the pooled analysis, a significantly higher proportion of patients with high niacin consumption was found in the group without glaucoma compared to those with glaucoma as defined by ISGEO criteria (p-value < 0.00001; OR = 0.66, 95% CI 0.55-0.79) or as defined by retinal imaging (p-value = 0.02; OR = 0.63, 95% CI 0.43-0.94).

CONCLUSIONS

Daily dietary intake of niacin is significantly lower in patients with glaucoma compared to the general population. Given different average daily intakes of niacin in these populations, different glaucoma definitions and several confounding variables which weaken the associations, large sample, standardised randomised controlled trials are needed to confirm the potential benefits of niacin in glaucoma.

Secondary Angle Closure Glaucoma in Weill-Marchesani Syndrome

We report a case of a 16-year-old girl presenting to our clinic with decreased visual acuity and increased intraocular pressure in both eyes. The ophthalmological examination revealed best-corrected visual acuity (BCVA) of 0.3 in the right eye (R.E.) and 0.4 in the left eye (L.E.) and intraocular pressure (IOP) of 46 mmHg in the R.E. and 42 mmHg in the L.E., with a 360° closed angle on gonioscopy, pupillary block due to bulging, a hyper-spherical lens and high corneal thickness, without ectopia lentis or cataract. The eyes responded poorly to pharmacological mydriasis; therefore, the lens equator could not be visualised. The patient had a history of pulmonary stenosis, short stature and no significant cognitive deficits. These elements point to the diagnosis of Weill-Marchesani syndrome, and the ophthalmological management was surgical, including lens extraction and the installation of a capsular tension ring, an intraocular lens and a Shunt ExPress implantation. Evolution was favourable, with improved BCVA of 0.7 in the R.E. and 0.63 in the L.E. and IOP of 14 mmHg in the R.E. and 13 mmHg in the L.E., without topical or systemic treatment at the 6-month follow-up. Weill-Marchesani syndrome has a complex presentation, with ophthalmological, musculoskeletal, cardiac and psychiatric manifestations. Usually, this leads to a need for a multidisciplinary approach. The ophthalmologic symptoms are often the cause of presentation to a specialist, and glaucoma is the most threatening of the ocular pathologies, with possible evolution into irreversible blindness; therefore, prompt surgery and careful follow-up become key components of the treatment plan. As a take-home message, we encourage a high degree of suspicion of Weill-Marchesani syndrome in such cases.

The Mirror Theory: Parallels between Open Angle and Angle Closure Glaucoma

Glaucoma is a widespread ophthalmological disease, with a high impact and frequent visual morbidity. While the physiopathology of the two types of primary glaucoma (open angle and angle closure) has been studied, there seems to be little relationship between the two. In this study, we gather clinical and preclinical data to support the idea that the two primary glaucomas are "mirrored" in terms of morphological parameters and disease physiopathology. In short, primary angle closure glaucoma (PACG) is associated with hyperopia and low axial length, and primary open angle glaucoma (POAG) is associated with myopia and high axial length. Moreover, in PACG and in primary angle closure or primary angle closure suspect cases, while there is extensive iridotrabecular contact, the intraocular pressure (IOP) is still maintained in the lower half of the normal range throughout the evolution of the disease, which suggests a baseline trabecular hyperfiltration in PACG. In the opposite case, myopic eyes with open angles and a higher risk of developing POAG often have a baseline IOP in the upper half of the normal range, suggesting a baseline trabecular hypofiltration. As we explore clinical, genetic and animal model data regarding these opposing aspects, we hypothesize the existence of a mirroring relationship between PACG and POAG. Defining the relationship between the two potentially blinding diseases, with a high prevalence worldwide, may aid in understanding the mechanisms better and refining diagnosis and treatment. Thus, our theory has been named the Mirror Theory of Primary Glaucomas.