Temba glaucoma study: a population-based cross-sectional survey in urban South Africa

Impact of race and ethnicity on glaucoma progression detection by perimetry and optical coherence tomography

This study assessed the impact of race and ethnicity on longitudinal test variability and time to detect glaucoma progression using standard automated perimetry (SAP) and optical coherence tomography (OCT). The sample consisted of 47,003 SAP tests from 5402 eyes and 25,480 OCT tests from 4125 eyes, with 20% of participants self-identifying as Black or African American and 80% as White; 29% as Hispanic or Latino and 71% as Not Hispanic or Latino. Variability was measured using standard deviations of residuals from linear regression models for SAP mean deviation (MD) and OCT retinal nerve fiber layer (RNFL) thickness over time. Results showed significantly greater SAP variability in Black or African American (1.80 ± 1.30 dB) compared to White participants (1.56 ± 1.21 dB; P < 0.001) and in Hispanic or Latino (1.81 ± 1.46 dB) compared to Not Hispanic or Latino individuals (1.52 ± 1.10 dB; P < 0.001). OCT variability was higher in Black or African American (2.3 ± 1.5 μm) compared to White (2.1 ± 1.3 μm; P < 0.001) and in Not Hispanic or Latino (2.2 ± 1.3 μm) compared to Hispanic or Latino (2.1 ± 1.2 μm; P = 0.029). Increased SAP variability delayed progression detection, while OCT showed minimal differences. These findings suggest that higher perimetric variability in Black or African American and Hispanic or Latino may affect glaucoma progression detection using SAP.

Impact of Race and Ethnicity on Glaucoma Progression Detection by Perimetry and Optical Coherence Tomography

This study assessed the impact of race and ethnicity on longitudinal test variability and time to detect glaucoma progression using standard automated perimetry (SAP) and optical coherence tomography (OCT). The sample consisted of 47,003 SAP tests from 5,402 eyes and 25,480 OCT tests from 4,125 eyes, with 20% of participants self-identifying as Black or African American and 80% as White; 29% as Hispanic or Latino and 71% as Not Hispanic or Latino. Variability was measured using standard deviations of residuals from linear regression models for SAP mean deviation (MD) and OCT retinal nerve fiber layer (RNFL) thickness over time. Results showed significantly greater SAP variability in Black or African American (1.80±1.30dB) compared to White participants (1.56±1.21dB; P<0.001) and in Hispanic or Latino (1.81±1.46dB) compared to Not Hispanic or Latino individuals (1.52±1.10dB; P<0.001). OCT variability was higher in Black or African American (2.3±1.5μm) compared to White (2.1±1.3μm; P<0.001) and in Not Hispanic or Latino (2.2±1.3μm) compared to Hispanic or Latino (2.1±1.2μm; P=0.029). Increased SAP variability delayed progression detection, while OCT showed minimal differences. These findings suggest that higher perimetric variability in Black or African American and Hispanic or Latino may affect glaucoma progression detection using SAP.

Diagnosing glaucoma in primary eye care and the role of Artificial Intelligence applications for reducing the prevalence of undetected glaucoma in Australia

Glaucoma is the commonest cause of irreversible blindness worldwide, with over 70% of people affected remaining undiagnosed. Early detection is crucial for halting progressive visual impairment in glaucoma patients, as there is no cure available. This narrative review aims to: identify reasons for the significant under-diagnosis of glaucoma globally, particularly in Australia, elucidate the role of primary healthcare in glaucoma diagnosis using Australian healthcare as an example, and discuss how recent advances in artificial intelligence (AI) can be implemented to improve diagnostic outcomes. Glaucoma is a prevalent disease in ageing populations and can have improved visual outcomes through appropriate treatment, making it essential for general medical practice. In countries such as Australia, New Zealand, Canada, USA, and the UK, optometrists serve as the gatekeepers for primary eye care, and glaucoma detection often falls on their shoulders. However, there is significant variation in the capacity for glaucoma diagnosis among eye professionals. Automation with Artificial Intelligence (AI) analysis of optic nerve photos can help optometrists identify high-risk changes and mitigate the challenges of image interpretation rapidly and consistently. Despite its potential, there are significant barriers and challenges to address before AI can be deployed in primary healthcare settings, including external validation, high quality real-world implementation, protection of privacy and cybersecurity, and medico-legal implications. Overall, the incorporation of AI technology in primary healthcare has the potential to reduce the global prevalence of undiagnosed glaucoma cases by improving diagnostic accuracy and efficiency.

Polygenic Risk Scores Driving Clinical Change in Glaucoma

Glaucoma is a clinically heterogeneous disease and the world's leading cause of irreversible blindness. Therapeutic intervention can prevent blindness but relies on early diagnosis, and current clinical risk factors are limited in their ability to predict who will develop sight-threatening glaucoma. The high heritability of glaucoma makes it an ideal substrate for genetic risk prediction, with the bulk of risk being polygenic in nature. Here, we summarize the foundations of glaucoma genetic risk, the development of polygenic risk prediction instruments, and emerging opportunities for genetic risk stratification. Although challenges remain, genetic risk stratification will significantly improve glaucoma screening and management.

Predictors and long-term patterns of medication adherence to glaucoma treatment in Denmark-an observational registry study of 30 100 Danish patients with glaucoma

BACKGROUND

Self-treatment with glaucoma medication (eye drops) has been associated with adherence challenges. Poor adherence results in worse outcomes in terms of visual field loss.

OBJECTIVE

To investigate patterns in medication adherence among Danish patients with glaucoma in relation to selected predictors of adherence, long-term adherence patterns, and long-term societal economic consequences of poor adherence.

METHODS AND ANALYSIS

This register-based study included 30 100 glaucoma patients followed for 10 years between 2000 and 2018. Glaucoma was identified from the Danish national registers by diagnosis of Open Angle Glaucoma and/or by redeemed prescriptions of glaucoma medication. Logistic regression models were applied to estimate patient characteristics related to medical adherence. Diagnosis-related group fees were applied to estimate healthcare costs.

RESULTS

High adherence in the first year(s) of treatment was less likely among men (ORfirst year: 0.78, 95% CI: 0.75 to 0.82), younger individuals and among those with a positive Charlson Comorbidity Index (CCI) score (ORfirst year/CCI≥3: 0.71, 95% CI: 0.63 to 0.80). Adherence in the first year and in the first two years was associated with adherence in the fifth (ORfirst year: 4.55, 95% CI: 4.30 to 4.82/ORfirst two years: 6.47, 95% CI: 6.10 to 6.86) as with adherence in the 10th year with slightly lower estimates. Being medical adherent was related to higher costs related to glaucoma medication after 5 and 10 years comparing with poor adherence, whereas poor adherence was associated with a marked increase in long-term costs for hospital contacts.

CONCLUSION

Increasing age, female sex and low comorbidity score are correlated with better adherence to glaucoma treatment. Adherence in the first years of treatment may be a good predictor for future adherence. In the long term, patients with poor adherence are overall more expensive to society in terms of hospital contacts.

Understanding racial disparities of glaucoma

PURPOSE OF REVIEW

Increased prevalence, earlier onset, and more rapid progression to vision loss from glaucoma has demonstrated racial disparity in numerous studies over decades. Precise etiologies of these important differences among patients of African and Hispanic ancestral background have not been elucidated. This review focuses on currently available epidemiologic/population, genetic, socioeconomic and physiologic studies of racial disparities in this blinding disease.

RECENT FINDINGS

In depth reviews of several landmark studies of glaucoma prevalence in various racial groups have highlighted potential challenges of lack of recruitment of diverse populations in genetic studies and clinical trials, challenges of racial stratification of subjects, and the impact of socioeconomic variables.

SUMMARY

Through a more comprehensive analysis of racial disparities of glaucoma, both clinicians and researchers may provide more effective population screening and management with a holistic approach for individualized patient care to provide improved outcomes. Future studies of interventions in sociodemographic factors and genetic/physiologic variables that influence the prevalence, access, and consequential vision loss from glaucoma will be crucial to minimize/eliminate racial disparities and improve outcomes for all.

Impact of a short online course on the accuracy of non-ophthalmic diabetic retinopathy graders in recognising glaucomatous optic nerves in Vietnam

PURPOSE

To test an online training course for non-ophthalmic diabetic retinopathy (DR) graders for recognition of glaucomatous optic nerves in Vietnam.

METHODS

This was an uncontrolled, experimental, before-and-after study in which 43 non-ophthalmic DR graders underwent baseline testing on a standard image set, completed a self-paced, online training course and were retested using the same photographs presented randomly. Twenty-nine local ophthalmologists completed the same test without the training course. DR graders then underwent additional one-to-one training by a glaucoma specialist and were retested. Test performance (% correct, compared with consensus grades from four fellowship-trained glaucoma experts), sensitivity, specificity, positive and negative predictive value, and area under the receiver operating (AUC) curve, were computed.

RESULTS

Mean age of DR graders (32.6±5.5 years) did not differ from ophthalmologists (32.3±7.3 years, p=0.13). Online training required a mean of 297.9 (SD 144.6) minutes. Graders' mean baseline score (33.3%±14.3%) improved significantly after training (55.8%±12.6%, p<0.001), and post-training score did not differ from ophthalmologists (58.7±15.4%, p=0.384). Although grader sensitivity reduced before [85.5% (95% CI 83.5% to 87.3%)] versus after [80.4% (78.3% to 82.4%)] training, specificity improved significantly [47.8 (44.9 to 50.7) vs 79.8 (77.3 to 82.0), p<0.001]. Grader AUC also improved after training [66.6 (64.9 to 68.3)] to [80.1 (78.5 to 81.6), p<0.001]. Additional one-to-one grader training by a glaucoma specialist did not further improve grader scores.

CONCLUSION

Non-ophthalmic DR graders can be trained to recognise glaucoma using a short online course in this setting, with no additional benefit from more expensive one-to-one training. After 5-hour online training in recognising glaucomatous optic nerve head, scores of non-ophthalmic DR graders doubled, and did not differ from local ophthalmologists. Intensive one-to-one training did not further improve performance.

Glaucoma: Novel antifibrotic therapeutics for the trabecular meshwork

Glaucoma is a chronic and progressive neurodegenerative disease characterized by the loss of retinal ganglion cells and visual field defects, and currently affects around 1% of the world's population. Elevated intraocular pressure (IOP) is the best-known modifiable risk factor and a key therapeutic target in hypertensive glaucoma. The trabecular meshwork (TM) is the main site of aqueous humor outflow resistance and therefore a critical regulator of IOP. Fibrosis, a reparative process characterized by the excessive deposition of extracellular matrix components and contractile myofibroblasts, can impair TM function and contribute to the pathogenesis of primary open-angle glaucoma (POAG) as well as the failure of minimally invasive glaucoma surgery (MIGS) devices. This paper provides a detailed overview of the current anti-fibrotic therapeutics targeting the TM in glaucoma, along with their anti-fibrotic mechanisms, efficacy as well as the current research progress from pre-clinical to clinical studies.

Cell-Specific Expression of Human SIRT1 by Gene Therapy Reduces Retinal Ganglion Cell Loss Induced by Elevated Intraocular Pressure

SIRT1 prevents retinal ganglion cell (RGC) loss in several acute and subacute optic neuropathy models following pharmacologic activation or genetic overexpression. We hypothesized that adeno-associated virus (AAV)-mediated overexpression of SIRT1 in RGCs in a chronic ocular hypertension model can reduce RGC loss, thereby preserving visual function by sustained therapeutic effect. A control vector AAV-eGFP and therapeutic vector AAV-SIRT1 were constructed and optimized for transduction efficiency. A magnetic microbead mouse model of ocular hypertension was optimized to induce a time-dependent and chronic loss of visual function and RGC degeneration. Mice received intravitreal injection of control or therapeutic AAV in which a codon-optimized human SIRT1 expression is driven by a RGC selective promoter. Intraocular pressure (IOP) was measured, and visual function was examined by optokinetic response (OKR) weekly for 49 days following microbead injection. Visual function, RGC survival, and axon numbers were compared among control and therapeutic AAV-treated animals. AAV-eGFP and AAV-SIRT1 showed transduction efficiency of ~ 40%. AAV-SIRT1 maintains the transduction of SIRT1 over time and is selectively expressed in RGCs. Intravitreal injections of AAV-SIRT1 in a glaucoma model preserved visual function, increased RGC survival, and reduced axonal degeneration compared with the control construct. Over-expression of SIRT1 through AAV-mediated gene transduction indicates a RGC-selective component of neuroprotection in multiple models of acute optic nerve degeneration. Results here show a neuroprotective effect of RGC-selective gene therapy in a chronic glaucoma model characterized by sustained elevation of IOP and subsequent RGC loss. Results suggest that this strategy may be an effective therapeutic approach for treating glaucoma, and warrants evaluation for the treatment of other chronic neurodegenerative diseases.

Characteristics of a large, labeled dataset for the training of artificial intelligence for glaucoma screening with fundus photographs

Purpose

Significant visual impairment due to glaucoma is largely caused by the disease being detected too late.

Objective

To build a labeled data set for training artificial intelligence (AI) algorithms for glaucoma screening by fundus photography, to assess the accuracy of the graders, and to characterize the features of all eyes with referable glaucoma (RG).

Design

Cross-sectional study.

Subjects

Color fundus photographs (CFPs) of 113 893 eyes of 60 357 individuals were obtained from EyePACS, California, United States, from a population screening program for diabetic retinopathy.

Methods

Carefully selected graders (ophthalmologists and optometrists) graded the images. To qualify, they had to pass the European Optic Disc Assessment Trial optic disc assessment with ≥ 85% accuracy and 92% specificity. Of 90 candidates, 30 passed. Each image of the EyePACS set was then scored by varying random pairs of graders as "RG," "no referable glaucoma (NRG)," or "ungradable (UG)." In case of disagreement, a glaucoma specialist made the final grading. Referable glaucoma was scored if visual field damage was expected. In case of RG, graders were instructed to mark up to 10 relevant glaucomatous features.

Main Outcome Measures

Qualitative features in eyes with RG.

Results

The performance of each grader was monitored; if the sensitivity and specificity dropped below 80% and 95%, respectively (the final grade served as reference), they exited the study and their gradings were redone by other graders. In all, 20 graders qualified; their mean sensitivity and specificity (standard deviation [SD]) were 85.6% (5.7) and 96.1% (2.8), respectively. The 2 graders agreed in 92.45% of the images (Gwet's AC2, expressing the inter-rater reliability, was 0.917). Of all gradings, the sensitivity and specificity (95% confidence interval) were 86.0 (85.2-86.7)% and 96.4 (96.3-96.5)%, respectively. Of all gradable eyes (n = 111 183; 97.62%) the prevalence of RG was 4.38%. The most common features of RG were the appearance of the neuroretinal rim (NRR) inferiorly and superiorly.

Conclusions

A large data set of CFPs was put together of sufficient quality to develop AI screening solutions for glaucoma. The most common features of RG were the appearance of the NRR inferiorly and superiorly. Disc hemorrhages were a rare feature of RG.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Enhanced glaucomatous damage accompanied by glial response in a new multifactorial mouse model

Introduction

Glaucoma is a complex, multifactorial neurodegenerative disease, which can lead to blindness if left untreated. It seems that, among others, immune processes, elevated intraocular pressure (IOP), or a combination of these factors are responsible for glaucomatous damage. Here, we combined two glaucoma models to examine if a combination of risk factors (IOP and immune response) results in a more severe damage of retinal ganglion cells (RGCs) and the optic nerves as well as an additional glia activation.

Methods

Six-week-old wildtype (WT+ONA) and βB1-Connective Tissue Growth Factor (CTGF) mice (CTGF+ONA) were immunized with 1 mg ONA (optic nerve antigen). A WT and a CTGF control group (CTGF) received sodium chloride instead. IOP was measured before and every two weeks after immunization. After six weeks, electroretinogram (ERG) measurements were performed. Then, retinae and optic nerves were processed for (immuno-) histology. Further, mRNA levels of corresponding genes in optic nerve and retina were analyzed via RT-qPCR.

Results

Six weeks after immunization, the IOP in CTGF and CTGF+ONA mice was increased. The optic nerve of CTGF+ONA animals displayed the most severe cell inflammation, demyelination, and macroglia activation. Fewer numbers of oligodendrocytes were only observed in WT+ONA optic nerves, while more apoptotic cells triggered by the extrinsic pathway could be revealed in all three glaucoma groups. The number of microglia/macrophages was not altered within the optic nerves of all groups. The loss of neuronal cells, especially RGCs was most pronounced in CTGF+ONA retinae in the central part and this was accompanied by an enhanced activation of microglia/macrophages. Also, Müller cell activation could be noted in CTGF and CTGF+ONA retinae.

Discussion

In this new model, an additive degeneration could be noted in optic nerves as well as in the number of RGCs. These results suggest a potential additive role of high IOP and immune factors in glaucoma development, which will aid for understanding this multifactorial disease more precisely in the future.

Factors associated with adherence to treatment in patients with open angle glaucoma in Sierra Leone, West Africa: patient demographics and questionnaire

BACKGROUND

Glaucoma is a significant cause of blindness worldwide. It is more common, presents earlier and is more aggressive in those of African descent. Non-adherence and poor knowledge of glaucoma is a significant barrier to treatment and has been associated with low health literacy. We aim to establish the factors contributing to late presentation, treatment non-adherence and disease progression in glaucoma patients in Sierra Leone. This will help better understand the challenges eye services face, highlight fields requiring development in patient-clinician interaction and identify areas or specific vulnerable patient groups in which resources should be focused.

METHODS

Prospective, consecutive recruitment of 120 patients with POAG attending the Lowell and Ruth Gess Eye Hospital and the Connaught Government Teaching Hospital, Freetown, Sierra Leone between February and April 2020. Data were collected from 3 sources: (1) review of clinical notes since first attendance, (2) semi-structured interviews and (3) assessment of study participant's drop instillation technique using a structured checklist. Descriptive statistics was performed for demographic data and other relevant data points. Logistic regression was used for analysis of target variables.

RESULTS

The average age was 62 years with more males (52.6%). Agricultural workers and informal street traders represented 13.2% of participants' occupation. 25.8% of participants had no formal school, and 47.4% had either a degree or a diploma. This is out of proportion with the general population and may represent a hidden demographic of glaucoma patients. Drop instillation technique was successful in 52% of study participants. Notable responses to the questionnaire were 30% of patients did not know the name of their eye condition and 22% had no knowledge of glaucoma.

CONCLUSION

Investment in a wide-ranging and robust screening programme and public health campaigns targeting these vulnerable groups and high-risk individuals, for example with a positive family history, alongside improved patient education and staff training is required to improve glaucoma care. Support from government, international organisations and the private sector is required to reduce the economic burden of blindness in Sierra Leone.

Determinants for late presentation of glaucoma among adult glaucomatous patients in University of Gondar Comprehensive Specialized Hospital. Case-control study

Introduction

Glaucoma is a disease which causes optic nerve damage and remains a major public health concern worldwide. Late presentation is a major risk factor for glaucoma induced blindness. The aim of this study was to assess determinants for late presentation of glaucoma among adult glaucomatous patients.

Methods

A hospital-based case-control study was conducted among 452 adult glaucomatous patients. Late presenters were glaucoma patients diagnosed with cup to disc ratio (CDR) > 0.8 and mean deviation of greater than -14 decibel in either of the eyes at their first presentation. Study participants were selected among glaucomatous follow-up patients by using systematic random sampling. Data were entered into EPI Info version 7 and exported to SPSS version 22 for analysis. Bivariable and multivariable logistic regression analysis was done to identify determinants. Variables with P-value < 0.05 were considered as statistically significant.

Result

The mean age of participants were 55.1 ± 13.2 years. Being > 60 years of age, 4.51 times (AOR: 4.51; 95% CI: 1.74, 11.67), resided > 53 km away from the hospital 6.02 times (AOR: 6.02; 2.76, 13.14), Presenting IOP > 30 mmHg, 4.49 times (AOR: 4.49, 95% CI: 2.10, 9.12), poor knowledge of glaucoma, 4.46 times (AOR: 4.46, CI: 2.62, 7.58) and absence of regular eye checkup, 2.35 times (AOR: 2.35, 95% CI: 1.09, 5.47) higher odds of being late presenter.

Conclusion

Increasing age, high IOP, poor knowledge of glaucoma, residing far away from the hospital and absence of regular eye checkups were significantly associated with late presentation.

Primary glaucomas in adults: Epidemiology and public health-A review

Glaucoma is a mixed group of optic neuropathies that lead to irreversible visual field loss and blindness if left untreated. It is estimated that 3.5% of the global population aged 40 to 80 years have any glaucoma, being the primary open-angle and the primary angle-closure glaucoma the most prevalent forms. Although the age-standardised prevalence of blindness caused by glaucoma has decreased substantially over the last decades, population growth and ageing impose many challenges in preventing glaucoma-related morbidities on a global level. In addition, difficulties in diagnoses and treatment, along with its chronic and irreversible nature, urge the development and implementation of innovative approaches in confronting the disease. This manuscript reviews recent literature related to the epidemiology of primary glaucomas in adults, the risk factors attributed to the development of the disease, and discuss challenges and potential solutions from a public health perspective.

Prevalence of Open-angle Glaucoma in the Faroese Population

PURPOSE

The Faroe Islands are home to 50,000 genetically isolated people in the North Atlantic. The prevalence of open-angle glaucoma (OAG) in the Faroese population is unknown. Consequently, we conducted a survey to determine the prevalence of OAG in the Faroese population. We also investigated the role of known glaucoma-causing genes in Faroese OAG.

MATERIALS AND METHODS

We conducted a prospective survey of known and newly diagnosed glaucoma patients at the Faroese National Hospital, Landssjukrahusid, Tórshavn between October 1, 2015 to December 31, 2017. In addition we reviewed the only eye care provider in the Faroese Islands by scrutinizing electronic medical records between 2009 and June 15, 2014, October 1, 2015 and the partly overlapping prescriptions for ocular hypotensive medications in 2016 to identify patients with either a diagnosis of glaucoma, a diagnosis of ocular hypertension or a prescription for ocular hypotensive medications. Next, we prospectively confirmed diagnoses with complete eye examinations. Patient DNA samples were tested for variations in known glaucoma-causing genes [myocilin (MYOC), optineurin (OPTN), and TANK binding kinase 1 (TBK1)].

RESULTS

We determined the age-related prevalence of OAG January 1, 2017 in individuals 40 years or older to be 10.7/1000 (1.07%) and highly age-related. A diagnosis of OAG was present in 264 patients, of whom 211 (79.9%) had primary OAG (including normal tension glaucoma), 49 (18.6%) had pseudoexfoliation glaucoma, and 4 (1.5%) had pigmentary glaucoma. Among patients receiving medications for glaucoma, nearly 50% had primary OAG, while the majority of the rest had ocular hypertension or secondary glaucoma. No disease-causing variants were detected in MYOC, OPTN, or TBK1.

CONCLUSIONS

The calculated prevalence of OAG in the Faroe Islands was 1.07%. The absence of MYOC, OPTN, or TBK1 disease-causing variants in Faroese primary OAG patients suggests that a different, potentially unique set of genes may be contributing to the pathogenesis of glaucoma in this population.

Distribution of anterior chamber angle measurements in South African young adults: an optical coherence tomography study

PURPOSE

Assessment of anterior chamber angle (ACA) variables is important to screen, diagnose and monitor ocular anomalies. Even though data on ACA variables, such as angle-opening distance taken at 500 µm (AOD500) and trabecular-iris angle (TIA), are available in the literature, limited information is available about these variables in African sub-populations. The purpose of this study is to describe the distribution of ACA measurements (AOD500 and TIA) in a South African young adult population.

METHODS

In this cross-sectional study, 700 young adults were recruited from a university student population using two-stage random sampling. The Optovue iVue 100 optical coherence tomographer was used to measure the ACA variables. The distribution of the AOD500 and TIA measurements was analysed using descriptive and inferential statistics. Data from only the right eyes were analysed because the ACA measurements in the two eyes showed high levels of interocular symmetry.

RESULTS

The measurements for the nasal and temporal ACAs were asymmetrically distributed (p < 0.001). The median AOD500 measurements in the nasal and temporal angles were 539 µm and 542 µm, respectively. The median TIA measurements were similar (~ 36°) in the two horizontal angles. The temporal ACA measurements were slightly higher than the nasal ACA measurements. Females had higher median ACA measurements than males (p ≥ 0.029).

CONCLUSION

The ACA measurements in South African young adults resemble non-Gaussian curves. The ACA measurements are different from that reported in other sub-populations worldwide and most participants had ACA measurements associated with non-occludable ACAs.

Mitochondrial Dysfunction in Primary Open-angle Glaucoma Characterized by Flavoprotein Fluorescence at the Optic Nerve Head

OBJECTIVE

To investigate the presence of flavoprotein fluorescence (FPF) at the optic nerve head (ONH) rim as a marker of mitochondrial dysfunction in primary open-angle glaucoma (POAG) and control eyes.

DESIGN

Retrospective cross-sectional study, with patients recruited from the New York Eye and Ear Infirmary of Mount Sinai.

SUBJECTS, PARTICIPANTS, AND/OR CONTROLS

A total of 86 eyes (50 eyes of 30 POAG patents and 36 eyes of 20 controls) were enrolled. The presence of POAG was defined by circumpapillary retinal nerve fiber layer thickness below the bottom fifth percentile of the normative database, glaucomatous ONH changes, and visual field defects on 24-2 tests.

METHODS, INTERVENTION, OR TESTING

POAG and control eyes were imaged using the OcuMet Beacon. A 23°x23° infrared scan was obtained, and an FPF scan was performed within a capture field spanning 13 degrees in diameter. The ONH margins on the infrared image were identified by software algorithms. FPF then was measured within an elliptical annulus around the ONH rim, with the inner and outer boundaries corresponding to 0.5 to 1.1 times the ONH rim size.

MAIN OUTCOMES MEASURES

FPF at the OHN rim in POAG and control eyes.

RESULTS

Differences in FPF between POAG and control eyes were characterized through mixed-effects logistic regression, adjusted for age and interocular pressure. FPF was significantly higher in POAG versus control eyes, with a mean±SD of 46.4±27.9 versus 28.0±11.7 (P<0.001), respectively. Evaluation of anatomical quadrants revealed greater FPF in POAG versus control eyes at the temporal (P=0.001), superior (P<0.001), nasal (P=0.002), and inferior (P=0.001) quadrants. Among POAG eyes, FPF showed correlation to visual field mean deviation (P<0.001), visual field pattern standard deviation (P=0.003), and circumpapillary retinal nerve fiber thickness (P=0.001) on linear mixed-effects models.

CONCLUSIONS

Higher FPF in POAG versus control eyes suggests the presence of mitochondrial dysfunction at the ONH rim in eyes with glaucomatous damage. The degree of FPF corresponds to disease severity, as measured by visual field and nerve fiber layer thickness metrics. FPF may thus represent a metabolic indicator of disease status that reveals the extent of injury in glaucoma.

Proteomic Analysis of Retinal Tissue in an S100B Autoimmune Glaucoma Model

Glaucoma is a neurodegenerative disease that leads to damage of retinal ganglion cells and the optic nerve. Patients display altered antibody profiles and increased antibody titer, e.g., against S100B. To identify the meaning of these antibodies, animals were immunized with S100B. Retinal ganglion cell loss, optic nerve degeneration, and increased glial cell activity were noted. Here, we aimed to gain more insights into the pathophysiology from a proteomic point of view. Hence, rats were immunized with S100B, while controls received sodium chloride. After 7 and 14 days, retinae were analyzed through mass spectrometry and immunohistology. Using data-independent acquisition-based mass spectrometry, we identified more than 1700 proteins on a high confidence level for both study groups, respectively. Of these 1700, 43 proteins were significantly altered in retinae after 7 days and 67 proteins revealed significant alterations at 14 days. For example, α2-macroglobulin was found significantly increased not only by mass spectrometry analysis, but also with immunohistological staining in S100B retinae at 7 and 14 days. All in all, the identified proteins are often associated with the immune system, such as heat shock protein 60. Once more, these data underline the important role of immunological factors in glaucoma pathogenesis.

Prevalence and clinical profile of glaucoma patients in rural Nigeria-A hospital based study

PURPOSE

To determine the prevalence and clinical presentation of participants with glaucoma attending a public eye care facility in Nigeria.

METHOD

Hospital based retrospective study of glaucoma participants aged 50 years and above seen over a 5-year period. Descriptive statistics summarized the demographic, clinical characteristics and treatment of the participants and determined the association of variables with gender and age. Prevalence of the glaucoma by type, and their 95% confidence intervals (CI) were also calculated.

RESULT

Of the 5482 case files that were reviewed, 995 (18.15%, 95% Cl 17.15-19.19%) had glaucoma particularly primary open angle glaucoma (11.55%, 95%CI 10.73-12.42%) and were mostly females (564, 56.7%) aged 69 ± 12 years (range, 50-103 years). In contrast to other glaucoma types, the prevalence of primary angle closure glaucoma (3.68, 95%CI 3.22-4.22) increased by 15% over 5 years. The mean intraocular pressure ranged from 15-50 mmHg but higher in females than males (27.8 ± 6.1mmHg versus 26.6 ± 6.0 mmHg, P <0.05) who had comparable VA (0.58 ± 0.4 Log MAR) and cup-disc ratios (P >0.05). On presentation, the glaucoma hemi field test (GHFT) was outside the normal limits in 45.5% and 54.5% of males and females, respectively. The type of visual field defect was associated with glaucoma type (P = 0.047). Arcuate scotoma was most common (35.5%) across glaucoma types, paracentral scotoma more common in Secondary glaucoma while Seidel scotoma was highest in NTG (19.3%). Beta-blocker was the mainstay of management (42.2%) but more likely to be prescribed to males while more females received carbonic anhydrase inhibitors.

CONCLUSIONS

The high prevalence of glaucoma in older people remains a public health problem in Nigeria. The fact that about half of the participants presented with visual field defect suggests there is a need for public health messages to emphasize on early glaucoma screening, detection and management.

Differences in clinical presentation of primary open-angle glaucoma between African and European populations

Purpose

Primary open‐angle glaucoma (POAG) has been reported to occur more frequently in Africans, and to follow a more severe course compared to Europeans. We aimed to describe characteristics of POAG presentation and treatment across three ethnic groups from Africa and one from Europe.

Methods

We ascertained 151 POAG patients from South African Coloured (SAC) and 94 South African Black (SAB) ethnicity from a university hospital in South Africa. In Tanzania, 310 patients were recruited from a university hospital and a referral hospital. In the Netherlands, 241 patients of European ancestry were included. All patients were over 35 years old and had undergone an extensive ophthalmic examination. Patients were diagnosed according to the ISGEO criteria. A biogeographic ancestry analysis was performed to estimate the proportion of genetic African ancestry (GAA).

Results

The biogeographic ancestry analysis showed that the median proportion of GAA was 97.6% in Tanzanian, 100% in SAB, 34.2% in SAC and 1.5% in Dutch participants. Clinical characteristics at presentation for Tanzanians, SAB, SAC and Dutch participants, respectively: mean age: 63, 57, 66, 70 years (p < 0.001); visual acuity in the worse eye: 1.78, 1.78, 0.3, 0.3 LogMAR (p < 0.001); maximum intraocular pressure of both eyes: 36, 34, 29, 29 mmHg (p_anova < 0.001); maximum vertical cup to disc ratio (VCDR) of both eyes: 0.90, 0.90, 0.84, 0.83 (p < 0.001); mean central corneal thickness: 506, 487, 511, 528 μm (p < 0.001). Fourteen percent of Tanzanian patients presented with blindness (<3/60 Snellen) in the better eye in contrast to only 1% in the Dutch.

Conclusion

In this multi‐ethnic comparative study, Sub‐Saharan Africans present at a younger age with lower visual acuity, higher IOP, larger VCDR, than SAC and Dutch participants. This indicates the more progressive and destructive course in Sub‐Saharan Africans.

Effect of papaverine on axonal outgrowth of primary retinal ganglion cells of Sprague Dawley rats

Increasing the level of cyclic adenosine 3, 5'-monophosphate is an important mechanism for axon outgrowth and recovery of central nervous system function. This study aimed to investigate the effects of papaverine, a non-specific phosphodiesterase inhibitor, on axon outgrowth of primary retinal ganglion cells from Sprague Dawley rats. Experiments were performed on primary retinal ganglion cells extracted from Sprague Dawley rat pups within 48-72 h of birth. At 24 h after seeding, immunofluorescence was used to identify and calculate the purity of retinal ganglion cells isolated by an improved two-step immunopanning method developed by author Sujia Ma. The effects of a range of papaverine concentrations on axon outgrowth of primary retinal ganglion cells cultures were observed by immunofluorescence and measured by ImageJ software at three different time points: 24, 48, and 72 h. The ability of papaverine to enable retinal ganglion cells to overcome the inhibitory effects of glial scar component chondroitin sulfate proteoglycans was examined using chondroitin sulfate proteoglycans-coated culture plates. Rp-adenosine 3',5'-cyclic monophosphorothioate triethylammonium salt, a blocking agent of cyclic adenosine 3, 5'-monophosphate, and dibutyryl cyclic adenosine 3, 5'-monophosphate, an analogue of cyclic adenosine 3, 5'-monophosphate, were used to explore the mechanism of papaverine in promoting retinal ganglion cells axon outgrowth. Our study shows 2 μg/mL papaverine concentration significantly promoted axon outgrowth in primary retinal ganglion cells and restored axon outgrowth of these cells on chondroitin sulfate proteoglycans. Axon outgrowth was blocked by Rp-adenosine 3',5'-cyclic monophosphorothioate triethylammonium salt and obviously promoted by dibutyryl cyclic adenosine 3, 5'-monophosphate. Our study is the first to describe the use of papaverine to promote axon outgrowth of retinal ganglion cells. These results may help to expand the application of papaverine, and they provide a cytological basis for papaverine in the treatment of optic nerve injury caused by glaucoma and other diseases.

Drug delivery to the anterior segment of the eye: A review of current and future treatment strategies

Research in the development of ophthalmic drug formulations and innovative technologies over the past few decades has been directed at improving the penetration of medications delivered to the eye. Currently, approximately 90% of all ophthalmic drug formulations (e.g. liposomes, micelles) are applied as eye drops. The major challenge of topical eye drops is low bioavailability, need for frequent instillation due to the short half-life, poor drug solubility, and potential side effects. Recent research has been focused on improving topical drug delivery devices by increasing ocular residence time, overcoming physiological and anatomical barriers, and developing medical devices and drug formulations to increase the duration of action of the active drugs. Researchers have developed innovative technologies and formulations ranging from sub-micron to macroscopic size such as prodrugs, enhancers, mucus-penetrating particles (MPPs), therapeutic contact lenses, and collagen corneal shields. Another approach towards the development of effective topical drug delivery is embedding therapeutic formulations in microdevices designed for sustained release of the active drugs. The goal is to optimize the delivery of ophthalmic medications by achieving high drug concentration with prolonged duration of action that is convenient for patients to administer.

Glaucoma Screening Using an iPad-Based Visual Field Test in a West African Population

PURPOSE

To investigate the performance of the Melbourne Rapid Fields (MRF) for use in clinic-based visual field testing in a low-resource setting.

DESIGN

Prospective cross-sectional study.

PARTICIPANTS

One hundred and three participants (66 patients with glaucoma and 37 control participants) attending a clinical appointment at the Tema Eye Center, Tema, Ghana.

METHODS

Patients with glaucoma and control participants underwent MRF and Humphrey Field Analyzer (HFA) testing.

MAIN OUTCOME MEASURES

Mean deviation (MD), pattern standard deviation (PSD), reliability parameters, sensitivity, specificity, and area under the receiver operating characteristic curve.

RESULTS

Mean MD was less negative and mean PSD was more positive on the MRF than the HFA in both groups (all P < 0.001). False-positive and false-negative rates were comparable between methods (P = 0.09 and P = 0.35, respectively). In patients with glaucoma, MD and PSD from the 2 devices were correlated strongly (r = 0.84; P < 0.001) and moderately (r = 0.61; P < 0.001), respectively. Agreement analysis revealed that MRF tended to generate significantly higher MD (bias, 3.3 ± 4.1 dB; P = 0.03) and PSD (bias, 1.9 ± 2.8 dB; P = 0.03) with wide limits of agreement. For detecting moderate to advanced glaucoma, the sensitivity was 60.9% for the MRF and 78.3% for the HFA (P = 0.10); respective specificities were 86.5% and 83.8% (P = 0.76).

CONCLUSIONS

The MRF underestimated MD and overestimated PSD values compared with the HFA. Agreement biases were significant, suggesting a weak agreement between the 2 devices. However, the MRF showed potential for screening in a low-resource setting, particularly for detecting moderate to advanced glaucoma.

Characteristics of p.Gln368Ter Myocilin Variant and Influence of Polygenic Risk on Glaucoma Penetrance in the UK Biobank

PURPOSE

MYOC (myocilin) mutations account for 3% to 5% of primary open-angle glaucoma (POAG) cases. We aimed to understand the true population-wide penetrance and characteristics of glaucoma among individuals with the most common MYOC variant (p.Gln368Ter) and the impact of a POAG polygenic risk score (PRS) in this population.

DESIGN

Cross-sectional population-based study.

PARTICIPANTS

Individuals with the p.Gln368Ter variant among 77 959 UK Biobank participants with fundus photographs (FPs).

METHODS

A genome-wide POAG PRS was computed, and 2 masked graders reviewed FPs for disc-defined glaucoma (DDG).

MAIN OUTCOME MEASURES

Penetrance of glaucoma.

RESULTS

Two hundred individuals carried the p.Gln368Ter heterozygous genotype, and 177 had gradable FPs. One hundred thirty-two showed no evidence of glaucoma, 45 (25.4%) had probable/definite glaucoma in at least 1 eye, and 19 (10.7%) had bilateral glaucoma. No differences were found in age, race/ethnicity, or gender among groups (P > 0.05). Of those with DDG, 31% self-reported or had International Classification of Diseases codes for glaucoma, whereas 69% were undiagnosed. Those with DDG had higher medication-adjusted cornea-corrected intraocular pressure (IOPcc) (P < 0.001) vs. those without glaucoma. This difference in IOPcc was larger in those with DDG with a prior glaucoma diagnosis versus those not diagnosed (P < 0.001). Most p.Gln368Ter carriers showed IOP in the normal range (≤21 mmHg), although this proportion was lower in those with DDG (P < 0.02) and those with prior glaucoma diagnosis (P < 0.03). Prevalence of DDG increased with each decile of POAG PRS. Individuals with DDG demonstrated significantly higher PRS compared with those without glaucoma (0.37 ± 0.97 vs. 0.01 ± 0.90; P = 0.03). Of those with DDG, individuals with a prior diagnosis of glaucoma had higher PRS compared with undiagnosed individuals (1.31 ± 0.64 vs. 0.00 ± 0.81; P < 0.001) and 27.5 times (95% confidence interval, 2.5-306.6) adjusted odds of being in the top decile of PRS for POAG.

CONCLUSIONS

One in 4 individuals with the MYOC p.Gln368Ter mutation demonstrated evidence of glaucoma, a substantially higher penetrance than previously estimated, with 69% of cases undetected. A large portion of p.Gln368Ter carriers, including those with DDG, have IOP in the normal range, despite similar age. Polygenic risk score increases disease penetrance and severity, supporting the usefulness of PRS in risk stratification among MYOC p.Gln368Ter carriers.

A Review to Populate A Proposed Cost-Effectiveness Analysis of Glaucoma Screening in Sub-Saharan Africa

To populate a proposed cost-effectiveness analysis of glaucoma screening in Sub-Saharan Africa (SSA).A complete search was conducted on PubMed, Medline and African Journals Online (AJOL) to obtain relevant published articles, which were included in this review. All relevant articles on prevalence of glaucoma in SSA and among other African-derived populations, severity of glaucoma, cost of diagnosis and management, clinical effectiveness of glaucoma screening and treatment and the different glaucoma screening strategies in SSA were reviewed.Population screening interventions for glaucoma may be considered as follows: standalone screening for glaucoma, screening for glaucoma during cataract outreach, and screening incorporated with diabetic retinopathy image review using tele-ophthalmology. Our review suggests that cost of glaucoma treatment is relatively low with cost of medical treatment ranging from USD 273 to USD 480 per year/patient and surgical treatment cost of USD 283 per patient as with other developing countries. Compliance with medication is moderate to good in about 50% of glaucoma patients. Prevalence of glaucoma is much higher in SSA and almost 50% of glaucoma patients are blind in at least one eye at presentation in clinics (without outreach screening). Our review suggests a moderate sensitivity and specificity in identifying glaucoma with basic equipment (direct ophthalmoscope, contact tonometer and frequency doubling technology) during outreach screening although about a third or fewer take up glaucoma services in clinics.Our review provides the necessary information to conduct a cost-effective analysis of glaucoma screening in SSA using the decision Markov model.

Differentiating Diagnosed and Undiagnosed Primary Angle-Closure Glaucoma and Open-Angle Glaucoma: A Population-Based Study

PURPOSE

To study and compare factors contributing to the differentiation between diagnosed and undiagnosed primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) in the same population.

DESIGN

Population-based survey.

PARTICIPANTS

All residents 40 years of age and older in Kumejima, Japan.

METHODS

Primary angle-closure glaucoma and POAG were diagnosed according to the criteria of the International Society of Geographical and Epidemiological Ophthalmology. Factors contributing significantly to the differentiation between diagnosed and undiagnosed PACG and POAG were selected from various systemic, ocular, visual function, and fundus planimetric parameters using multivariate logistic regression analysis and were compared between the two diseases.

MAIN OUTCOME MEASURES

Factors contributing significantly to the differentiation between diagnosed and undiagnosed PACG and POAG.

RESULTS

The prevalence rates of PACG and POAG were 2.2% and 4.0%, respectively. A greater proportion of patients with PACG (34.1%) received a diagnosis previously compared with patients with POAG (17.2%; P = 0.004). Worse mean deviation on visual field (VF) testing (odds ratio, 0.869; 95% confidence interval, 0.788-0.959; P = 0.006) and the presence of signs suggestive of previous acute angle closure (odds ratio, 4.35; range, 1.66-11.36; P = 0.003) contributed to a established diagnosis of PACG at the time of screening. A greater vertical cup-to-disc ratio (3.74; range, 1.38-10.17; P = 0.012) contributed with marginal significance to an established diagnosis of POAG at the time of screening.

CONCLUSIONS

Primary angle-closure glaucoma was more likely to have been diagnosed previously than POAG during a screening examination. Examination of the anterior segment and VF may contribute more to the detection of PACG, and disc examination may contribute more to the detection of POAG.

Prevalence of primary open angle glaucoma in the last 20 years: a meta-analysis and systematic review

Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness in the world and is influenced by various sociodemographic factors. This meta-analysis aims to determine the worldwide prevalence of POAG in the adult general population for the last 20 years, and explore variation in prevalence by age, gender and geographical location. An electronic literature search was performed using the PubMed, Embase, and Web of Science databases. Population-based cross-sectional or cohort studies published in the last 20 years (2000–2020) that reported prevalence of POAG were recruited. Relevant studies meeting defined eligibility criteria were selected and reviewed systematically by meta-analysis. The prevalence of POAG was analyzed according to various risk factors. A random effect model was used for the meta-analysis. Fifty publications with a total of 198,259 subjects were included in this meta-analysis. The worldwide overall prevalence of POAG was 2.4% (95% CI 2.0 ~ 2.8%). The prevalence increases with age. Men are found to be more susceptible to POAG than women (RR 1.28, p < 0.01). Africa is found to have the highest prevalence of POAG (4.0%) among all continents. The current estimated global population of POAG is 68.56 million (95% CI 59.99 ~ 79.98). POAG is a worldwide vision threatening disease with high prevalence for the last 20 years. The population-based prevalence of POAG varies widely across individual studies, due to variations in risk factors of age, gender, and population geographic location.

The Potential Role of Small-Molecule PERK Inhibitor LDN-0060609 in Primary Open-Angle Glaucoma Treatment

Primary open-angle glaucoma (POAG) constitutes the most common type of glaucoma. Emerging evidence suggests that Endoplasmic Reticulum (ER) stress and the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-mediated Unfolded Protein Response (UPR) signaling pathway play a key role in POAG pathogenesis. Thus, the main aim of the study was to evaluate the effectiveness of the PERK inhibitor LDN-0060609 in cellular model of glaucoma using primary human trabecular meshwork (HTM) cells. To evaluate the level of the ER stress marker proteins, Western blotting and TaqMan gene expression assay were used. The cytotoxicity was measured by XTT, LDH assays and Giemsa staining, whereas genotoxicity via comet assay. Changes in cell morphology were assessed by phase-contrast microscopy. Analysis of apoptosis was performed by caspase-3 assay and flow cytometry (FC), whereas cell cycle progression by FC. The results obtained have demonstrated that LDN-0060609 triggered a significant decrease of ER stress marker proteins within HTM cells with induced ER stress conditions. Moreover, LDN-0060609 effectively increased viability, reduced DNA damage, increased proliferation, restored normal morphology, reduced apoptosis and restored normal cell cycle distribution of HTM cells with induced ER stress conditions. Thereby, PERK inhibitors, such as LDN-0060609, may provide an innovative, ground-breaking treatment strategy against POAG.

The Global Extent of Undetected Glaucoma in Adults: A Systematic Review and Meta-analysis

TOPIC

Glaucoma is the leading cause of irreversible blindness, despite having good prognosis with early treatment. We evaluated the global extent of undetected glaucoma and the factors associated with it in this systematic review and meta-analysis.

CLINICAL RELEVANCE

Undetected glaucoma increases the risk of vision impairment, which leads to detrimental effects on the quality-of-life and socioeconomic well-being of those affected. Detailed information on the extent and factors associated with undetected glaucoma aid in the development of public health interventions.

METHODS

We conducted a systematic review and meta-analysis of population-based studies published between January 1, 1990, and June 1, 2020. Article search was conducted in online databases (PubMED, Web-of-Science), grey literatures (OpenGrey), and nongovernment organization reports. Our outcome measure was the proportion of glaucoma cases that were undetected previously. Manifest glaucoma included any form of glaucoma reported in the original studies and may include primary open-angle glaucoma (POAG), primary angle-closure-glaucoma, secondary glaucoma, or a combination thereof. Undetected glaucoma was defined as glaucoma cases that were undetected prior to diagnosis in the respective study. Random-effect meta-analysis was used to estimate the pooled proportion of undetected glaucoma. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Meta-analysis of Observational Studies in Epidemiology guidelines in our study.

RESULTS

We identified 61 articles from 55 population-based studies (n = 189 359 participants; n = 6949 manifest glaucoma). Globally, more than half of all glaucoma cases were undetected previously on average in each geographical region. Africa (odds ratio [OR], 12.70; 95% confidence interval [CI], 4.91-32.86) and Asia (OR, 3.41; 95% CI, 1.63-7.16) showed higher odds of undetected glaucoma as compared with Europe. Countries with low Human Development Index (HDI; <0.55) showed a higher proportion of undetected manifest glaucoma as compared with countries of medium to very high HDI (≥0.55; all P < 0.001). In 2020, 43.78 million POAG cases were projected to be undetected, of which 76.7% were in Africa and Asia.

DISCUSSION

Undetected glaucoma is highly prevalent across diverse communities worldwide and more common in Africa and Asia. Strategies to improve detection are needed to prevent excess visual disability and blindness resulting from glaucoma.

An objective structural and functional reference standard in glaucoma

The current lack of consensus for diagnosing glaucoma makes it difficult to develop diagnostic tests derived from deep learning (DL) algorithms. In the present study, we propose an objective definition of glaucomatous optic neuropathy (GON) using clearly defined parameters from optical coherence tomography and standard automated perimetry. We then use the proposed objective definition as reference standard to develop a DL algorithm to detect GON on fundus photos. A DL algorithm was trained to detect GON on fundus photos, using the proposed objective definition as reference standard. The performance was evaluated on an independent test sample with sensitivity, specificity, area under the receiver operating characteristic curve (AUC), and likelihood ratios (LR). The test sample had 2118 fundus photos from 585 eyes of 405 individuals. The AUC to discriminate between GON and normal was 0.92 with sensitivity of 77% at 95% specificity. LRs indicated that the DL algorithm provided large changes in the post-test probability of disease for the majority of eyes. A DL algorithm to evaluate fundus photos had high performance to discriminate GON from normal. The newly proposed objective definition of GON used as reference standard may increase the comparability of diagnostic studies of glaucoma across devices and populations.

Prevalence of Primary Angle Closure Glaucoma in the Last 20 Years: A Meta-Analysis and Systematic Review

Purpose: This meta-analysis aims to investigate the worldwide prevalence of primary angle-closure glaucoma (PACG) and its risk factors in the last 20 years.

Methods: We conducted a systematic review and meta-analysis of 37 population-based studies and 144,354 subjects. PubMed, Embase, and Web of Science databases were searched for cross-sectional or cohort studies published in the last 20 years (2000–2020) that reported the prevalence of PACG. The prevalence of PACG was analyzed according to various risk factors. A random-effects model was used for the meta-analysis.

Results: The global pooled prevalence of PACG was 0.6% [95% confidence interval (CI) = 0.5–0.8%] for the last 20 years. The prevalence of PACG increases with age. Men are found less likely to have PACG than women (risk ratio = 0.71, 95% CI = 0.53–0.93, p < 0.01). Asia is found to have the highest prevalence of PACG (0.7%, 95% CI = 0.6–1.0%). The current estimated population with PACG is 17.14 million (95% CI = 14.28–22.85) for people older than 40 years old worldwide, with 12.30 million (95% CI = 10.54–17.57) in Asia. It is estimated that by 2050, the global population with PACG will be 26.26 million, with 18.47 million in Asia.

Conclusion: PACG affects more than 17 million people worldwide, especially leading a huge burden to Asia. The prevalence of PACG varies widely across different ages, sex, and population geographic variation. Asian, female sex, and age are risk factors of PACG.

Molecular Genetics of Glaucoma: Subtype and Ethnicity Considerations

Glaucoma, the world’s leading cause of irreversible blindness, is a complex disease, with differential presentation as well as ethnic and geographic disparities. The multifactorial nature of glaucoma complicates the study of genetics and genetic involvement in the disease process. This review synthesizes the current literature on glaucoma and genetics, as stratified by glaucoma subtype and ethnicity. Primary open-angle glaucoma (POAG) is the most common cause of glaucoma worldwide, with the only treatable risk factor (RF) being the reduction of intraocular pressure (IOP). Genes associated with elevated IOP or POAG risk include: ABCA1, AFAP1, ARHGEF12, ATXN2, CAV1, CDKN2B-AS1, FOXC1, GAS7, GMDS, SIX1/SIX6, TMCO1, and TXNRD2. However, there are variations in RF and genetic factors based on ethnic and geographic differences; it is clear that unified molecular pathways accounting for POAG pathogenesis remain uncertain, although inflammation and senescence likely play an important role. There are similar ethnic and geographic complexities in primary angle closure glaucoma (PACG), but several genes have been associated with this disorder, including MMP9, HGF, HSP70, MFRP, and eNOS. In exfoliation glaucoma (XFG), genes implicated include LOXL1, CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A. Despite tremendous progress, major gaps remain in resolving the genetic architecture for the various glaucoma subtypes across ancestries. Large scale carefully designed studies are required to advance understanding of genetic loci as RF in glaucoma pathophysiology and to improve diagnosis and treatment options.

Deep learning in glaucoma with optical coherence tomography: a review

Deep learning (DL), a subset of artificial intelligence (AI) based on deep neural networks, has made significant breakthroughs in medical imaging, particularly for image classification and pattern recognition. In ophthalmology, applying DL for glaucoma assessment with optical coherence tomography (OCT), including OCT traditional reports, two-dimensional (2D) B-scans, and three-dimensional (3D) volumetric scans, has increasingly raised research interests. Studies have demonstrated that using DL for interpreting OCT is efficient, accurate, and with good performance for discriminating glaucomatous eyes from normal eyes, suggesting that incorporation of DL technology in OCT for glaucoma assessment could potentially address some gaps in the current practice and clinical workflow. However, further research is crucial in tackling some existing challenges, such as annotation standardization (i.e., setting a standard for ground truth labelling among different studies), development of DL-powered IT infrastructure for real-world implementation, prospective validation in unseen datasets for further evaluation of generalizability, cost-effectiveness analysis after integration of DL, the AI "black box" explanation problem. This review summarizes recent studies on the application of DL on OCT for glaucoma assessment, identifies the potential clinical impact arising from the development and deployment of the DL models, and discusses future research directions.

Contact Lenses as Drug Delivery System for Glaucoma: A Review

Glaucoma is an optical neuropathy associated to a progressive degeneration of retinal ganglion cells with visual field loss and is the main cause of irreversible blindness in the world. The treatment has the aim to reduce intraocular pressure. The first therapy option is to instill drugs on the ocular surface. The main limitation of this is the reduced time of the drug staying on the cornea. This means that high doses are required to ensure its therapeutic effect. A drug-loaded contact lens can diffuse into the post lens tear film in a constant and prolonged flow, resulting in an increased retention of the drug on the surface of the cornea for up to 30 min and thus providing a higher drug bioavailability, increasing the therapeutic efficacy, reducing the amount of administered drug, and thereby provoking fewer adverse events. Several different systems of drug delivery have been studied in recent decades; ranging from more simple methods of impregnating the lenses, such as soaking, to more complex ones, such as molecular imprinting have been proposed. Moreover, different drugs, from those already commercially available to new substances such as melatonin have been studied to improve the glaucoma treatment efficacy. This review describes the role of contact lenses as an innovative drug delivery system to treat glaucoma.

The Genetic and Endoplasmic Reticulum-Mediated Molecular Mechanisms of Primary Open-Angle Glaucoma

Glaucoma is a heterogenous, chronic, progressive group of eye diseases, which results in irreversible loss of vision. There are several types of glaucoma, whereas the primary open-angle glaucoma (POAG) constitutes the most common type of glaucoma, accounting for three-quarters of all glaucoma cases. The pathological mechanisms leading to POAG pathogenesis are multifactorial and still poorly understood, but it is commonly known that significantly elevated intraocular pressure (IOP) plays a crucial role in POAG pathogenesis. Besides, genetic predisposition and aggregation of abrogated proteins within the endoplasmic reticulum (ER) lumen and subsequent activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-dependent unfolded protein response (UPR) signaling pathway may also constitute important factors for POAG pathogenesis at the molecular level. Glaucoma is commonly known as a ‘silent thief of sight’, as it remains asymptomatic until later stages, and thus its diagnosis is frequently delayed. Thereby, detailed knowledge about the glaucoma pathophysiology is necessary to develop both biochemical and genetic tests to improve its early diagnosis as well as develop a novel, ground-breaking treatment strategy, as currently used medical therapies against glaucoma are limited and may evoke numerous adverse side-effects in patients.

Update on the genetics of primary open-angle glaucoma

Affecting nearly 80 million individuals, glaucoma is the number one cause of irreversible blindness in the world. This ocular disease describes a set of optic neuropathies of which primary open angle glaucoma (POAG) is the most common. POAG is associated with progressive visual field deterioration resulting from damage to the optic nerve and loss of retinal ganglion cells. Risk factors for POAG include elevated intraocular pressure, aging, African and Hispanic ancestry, and a positive family history of POAG. Multiple genes have been found to contribute to POAG. Much of POAG genetics and pathology has yet to be explained. Recent genome-wide association studies have identified a large number of novel loci associated with POAG and its endophenotypes. Genomic and proteomic profiling of biofluids has contributed to our knowledge of differential gene expression in POAG. Functional studies both in cell culture and animal models have confirmed the effects of variants and differential gene expression on ocular physiology while in silico analyses have increased our understanding of disease risk and progression so that we might better diagnose and treat this complex genetic illness.

Glaucoma Features in an East African Population: A 6-Year Cohort Study of Older Adults in Nakuru, Kenya

PURPOSE

Glaucoma is a leading cause of blindness in people of African descent. Minimal data is available from African population-based cohort studies. The primary aims of this study were to describe the normative distribution of glaucoma features to enable glaucoma classification and to assess risk factors for those with glaucoma at follow-up among people aged 50 years and above in Kenya.

MATERIALS AND METHODS

Random cluster sampling with probability proportionate to size was used to select a representative cross-sectional sample of adults aged 50 years and above in 2007 to 2008 in Nakuru District, Kenya. A 6-year follow-up was undertaken in 2013 to 2014. Comprehensive ophthalmic examination included visual acuity, digital retinal photography, visual fields, intraocular pressure, optical coherence tomography, and independent grading of optic nerve images. We report glaucoma features, prevalence and predictors for glaucoma based on the International Society for Geographical & Epidemiological Ophthalmology (ISGEO) criteria. Measures were estimated using a Poisson regression model and including inverse-probability weighting for loss to follow-up.

RESULTS

At baseline, 4414 participants aged 50 years and above underwent examination. Anterior chamber optical coherence tomography findings: mean anterior chamber angle of 36.6 degrees, mean central corneal thickness of 508.1 μm and a mean anterior chamber depth of 2.67 mm. A total of 2171 participants were examined at follow-up. The vertical cup to disc ratio distribution was 0.7 and 0.8 at the 97.5th and 99.5th percentiles, respectively. A total of 88 (4.3%, 95% confidence interval, 3.5%-5.9%) of participants at follow-up had glaucoma consistent with ISGEO criteria. A relative afferent pupillary defect and raised intraocular pressure were associated with the diagnosis.

CONCLUSIONS

Glaucoma is a public health challenge in low-resource settings. Research into testing and treatment modalities in Africa is needed.

Severity of Visual Field Loss at First Presentation to Glaucoma Clinics in England and Tanzania

Purpose: To compare severity of visual field (VF) loss at first presentation in glaucoma clinics in England and Tanzania.Methods: Large archives of VF records from automated perimetry were used to retrospectively examine vision loss at first presentation in glaucoma clinics in Tanzania (N = 1,502) and England (N = 9,264). Mean deviation (MD) of the worse eye at the first hospital visit was used as an estimate of detectable VF loss severity.Results: In Tanzania, 44.7% {CI_95%: 42.2, 47.2} of patients presented with severe VF loss (< -20 dB), versus 4.6% {4.1, 5.0} in England. If we consider late presentation to also include cases of advanced loss (-12.01 dB to -20 dB), then the proportion of patients presenting late was 58.1% {55.6, 60.6} and 14.0% {13.3, 14.7}, respectively. The proportion of late presentations was greater in Tanzania at all ages, but the difference was particularly pronounced among working-age adults, with 50.3% {46.9, 53.7} of 18-65-year-olds presenting with advanced or severe VF loss, versus 10.2% {9.3, 11.3} in England. In both countries, men were more likely to present late than women.Conclusions: Late presentation of glaucoma is a problem in England, and an even greater challenge in Tanzania. Possible solutions are discussed, including increased community eye-care, and a more proactive approach to case finding through the use of disruptive new technologies, such as low-cost, portable diagnostic aids.

Prevalence of treatment with glaucoma medication in Scotland, 2010-2017

AIMS

To report the number and demographic distribution of patients receiving intraocular pressure (IOP)-lowering medications across the whole population of Scotland for the years 2010-2017 and, using national census data, show how the observed changes compare with those predicted by the increasing age of the population structure over this period.

METHODS

Data were sourced from the Prescribing Information System of the NHS Information and Statistics Division for Scotland. The number of patients dispensed any IOP-lowering medication from a community pharmacy during each calendar year was collected by gender and by 5-year age bands. National census data were used to model the expected annual increase in treatment numbers due to population ageing.

RESULTS

The number of treated patients in 2017 was 61 249 which represents 1.13% of the whole population (or 2.16% over 40 years of age). The number increased from 48 178 in 2010-an increase over this period of 27.13% (3.88% per year).Prevalence increased with age, reaching 10.67% in those over 90 years. After age adjustment, more men were treated than women (OR 1.26).The expected number treated in 2017 based on census predictions was 54 075 (an increase of 5897 (12.24%) from 2010). The observed growth of 27.13% was 2.22-fold greater than the rate expected by population changes over the period 2010-2017.

CONCLUSION

The number of patients on medication for glaucoma and ocular hypertension in Scotland is increasing. The rate of increase cannot be explained by changes in the size and age structure of the population alone.

Toward International Comparability of Survey Statistics on Visual Impairment: The DISTAB Project

Using data from recent national disability surveys in Australia, Canada, France, the Netherlands, South Africa, and the United States, an international team of researchers coded indicators of several types of disability using the International Classification of Functioning, Disability, and Health. This article discusses the Disability Tabulations (DISTAB) project and presents and evaluates the estimates of the prevalence of visual impairments.

Eight-Year Incidence of Open-Angle Glaucoma in the Tema Eye Survey

PURPOSE

To determine the incidence of open-angle glaucoma (OAG) and its risk factors in the Tema Eye Survey in Ghana, West Africa.

DESIGN

Longitudinal, observational population-based study.

PARTICIPANTS

One thousand two hundred five of 1500 participants 40 years of age or older selected randomly from 5603 participants originally drawn from the population and who had undergone a baseline examination.

METHODS

All participants underwent baseline and follow-up ophthalmologic examinations 8 years apart. Glaucoma diagnosis was determined based on the International Society for Geographical and Epidemiologic Ophthalmology criteria.

MAIN OUTCOME MEASURES

Incidence and odds ratio (OR).

RESULTS

The response rate was 80.3%. Of 1101 nonglaucomatous participants at baseline who had complete follow-up data, 4.6% (95% confidence interval [CI], 3.7%-5.2%) demonstrated OAG over the 8-year period, or 0.58% (95% CI, 0.4%-0.8%) per year. The 8-year incidence increased with age from 3.1% in those 40 to 49 years old to 7.0% in those 60 to 69 years old. Baseline risk factors for incident OAG were male gender (OR, 2.1; 95% CI, 1.1-4.0; P = 0.025), older age relative to those 40 to 49 years old (those 50-50 years old: OR, 2.6; 95% CI, 1.2-5.7; those 60-69 years old: OR, 4.3; 95% CI, 2.0-8.8; and for those 70 years of age and older: OR, 6.3; 95% CI, 2.6-15.4; all P < 0.001), higher intraocular pressure (IOP; OR, 1.4; 95% CI, 1.1-1.8; P < 0.001), larger vertical cup-to-disc ratio (OR, 5.8; 95% CI, 5.2-6.6; P < 0.001), and thinner central cornea (OR, 1.2; 95% CI, 1.03-1.5; P = 0.013). A separate analysis performed with central corneal thickness-based IOP correction did not change the outcome of the associative model of incident glaucoma.

CONCLUSIONS

The incidence of OAG is higher in this population than reported in nonblack populations outside Africa. This is important not only in Ghana and probably other West African countries but also wherever people of the West African diaspora reside. These data enhance our understanding of the epidemiologic factors of OAG in this setting and may serve as reference for public health policy and planning.

Knowledge, attitudes and self-care practices of patients with glaucoma in uThungulu in KwaZulu-Natal

Background: Glaucoma remains one of the leading causes of blindness in South Africa. Early detection, effective treatment and strict compliance with treatment are instrumental to prevent further damage to the optic nerve and thus preserve vision.Aim: The purpose of this study was to assess the knowledge, attitude and self-care practices of patients with glaucoma in KwaZulu-Natal.Setting: The study was conducted in the ophthalmology outpatient department of a public hospital and a private ophthalmology practice in the uThungulu district.Methods: This was an observational, analytic, cross-sectional study. Structured questionnaires assessing knowledge, attitudes and self-care practices were administered to patients presenting for follow-up glaucoma management.Results: The median age of the 384 patients in this study was 60 (interquartile range [IQR] 48.5–69.5) and 59 years (IQR 49.0–66.5) for males and females, respectively (p > 0.05). Two hundred and thirty-eight (62.0%) patients had good knowledge of glaucoma. Age, gender and duration of glaucoma diagnosis were significantly associated with good knowledge of glaucoma. Three hundred and forty-four (89.6%) patients reported having good self-care practices. Patients over the age of 65 years were significantly less likely to have good self-care practices compared to patients aged 26–45 years (odds ratio [OR]: 0.2, confidence interval [CI]: 0.1–0.6, p = 0.01). Good knowledge of glaucoma was significantly associated with good self-care practices of glaucoma (p < 0.001).Conclusion: Elderly patients do not have sufficient knowledge of glaucoma and have poor self-care glaucoma practices. It is important to involve family members of these patients in the education and counselling of glaucoma to facilitate improved disease management.

Exploring gelatin nanoparticles as novel nanocarriers for Timolol Maleate: Augmented in-vivo efficacy and safe histological profile

The use of gelatin has been gaining recognition in ocular delivery for its safety profile and biocompatible properties. Timolol Maleate (TM) is an anti-glaucoma drug possessing poor corneal penetration while causing eye irritation making it an ideal candidate for novel nanoparticulate systems. Timolol Maleate loaded Gelatin Nanoparticles (GNPs) were prepared using the double desolvation method utilizing glutaraldehyde as the crosslinking agent. Optimization of the nanoparticles was achieved through a full-factorial design. An optimum formulation possessing particle size of 205 nm, zetapotential of 12.5 mV and an entrapment efficiency of 74.72% was selected. TEM imaging of the optimized nanoparticles was performed and the stability was tracked over 6 months. The in-vitro release studies showed a burst effect followed by a sustained profile. The selected formulae were tested in-vivo and compared to a Timolol marketed product on albino rabbits and were proven superior regarding intraocular pressure lowering and sustained efficacy. The prepared nanoparticles successfully passed Draize irritancy test and showed normal histology. These data indicate that the prepared GNPs possessed all needed qualities of a successful ocular system; corneal affinity, suitable particle size, high entrapment efficiency, sustained release, good stability, efficient lowering of intraocular pressure, high drug bioavailability and lack of irritancy.

Surgical outcomes of membrane-tube-type glaucoma shunt device in indigenous West Africans

Purpose

The aim of this study was to report the safety and efficacy of the membrane-tube (MT)-type glaucoma shunt device (Finetube MT) in the management of refractory glaucoma in indigenous West Africans.

Methods

The Finetube MT was implanted into 25 eyes of 25 West African patients with refractory glaucoma. These patients had inadequate intraocular pressure (IOP) control despite maximum tolerable IOP-lowering medications with or without previous ocular surgeries. IOP, postoperative complications, interventions, visual acuities, and the number of IOP-lowering medications were analyzed preoperatively and postoperatively.

Results

The mean (standard deviation [SD]) age of the patients was 49.7 (20.9) years. The mean (SD) follow-up duration was 21.0 (10.6) months. Postoperatively, the mean (SD) IOP reduced from a preoperative value of 38.1 (10.3) mmHg to 14.5 (4.6), 16.1 (7.8), and 14.7 (3.0) mmHg at 1, 2, and 3 years postoperatively, respectively, representing 61.9%, 57.7%, and 61.4% reduction from baseline (P<0.01). The mean (SD) number of IOP-lowering medications reduced from 4.1 (1.0) to 0.6 (0.9) at 1 year and 0.9 (1.1) at 2 years after the operation (P<0.01). Using an IOP level between 6 and 21 mmHg and reduced by ≥20% from baseline, the cumulative survival rate (standard error) was 96.0% (3.9%) at 6 months, 89.0% (6.0%) at 18 months, and 81.3% (10.6%) at 3 years after the operation. There was no postoperative ocular hypotony, tube occlusion, or device exposure.

Conclusion

The Finetube MT may effectively control IOP with minimal risk of postoperative complications in indigenous West Africans.

South African Eye Study (SAES): ethnic differences in central corneal thickness and intraocular pressure

PurposeGlaucoma is the leading cause of irreversible blindness worldwide. South Africa has a diverse population but there is a lack of published ethnic specific normative data. The purpose of the study is to determine the distribution of intraocular pressure (IOP) and central corneal thickness (CCT) values in a multi-ethnic South African population and to determine additional systemic and ocular factors that influence IOP and CCT.Patients and methodsThis cross-sectional study included a total of 402 participants with 706 eyes aged 18-94 years. Participants underwent a standardized interviewer-administered questionnaire for risk factor assessment followed by a full ophthalmic examination. The averages of six IOP readings were measured with an Icare PRO tonometer and CCT was measured with a Pentacam.ResultsThe mean CCT readings in the African, Mixed ethnicity, and Caucasian participants were 514.77±31.86, 531.77±35.17, and 549.97±30.51 μm (P<0.001). The mean IOP in the African, Mixed ethnicity, and Caucasian participants were 15.51±2.49, 15.09±2.12, and 15.13±2.53 mm Hg (P=0.07). Africans had significantly higher IOP than Mixed ethnicity (P=0.034) and Caucasians (P=0.011). Hypertensives had a higher IOP (P=0.03). Age and pseudophakia were associated with a lower IOP (P<0.001) and higher CCT (P<0.001). There was a strongly positive correlation between CCT and IOP (β=0.021; P<0.001).ConclusionsIn the South African Eye Study (SAES), Africans had the thinnest corneas and highest IOP followed by Mixed ethnicity and Caucasians. Including systemic and ocular factors that influence IOP specific to each population and ethnic group, will lead to a more accurate clinical risk stratification in glaucoma management.

Variants in the PRPF8 Gene are Associated with Glaucoma

Glaucoma is the cause of irreversible blindness worldwide. Mutations in six genes have been associated with juvenile- and adult-onset familial primary open angle glaucoma (POAG) prior to this report but they explain only a small proportion of the genetic load. The aim of the study is to identify the novel genetic cause of the POAG in the families with adult-onset glaucoma. Whole exome sequencing (WES) was performed on DNA of two affected individuals, and predicted pathogenic variants were evaluated for segregation in four affected and three unaffected Dutch family members by Sanger sequencing. We identified a pathogenic variant (p.Val956Gly) in the PRPF8 gene, which segregates with the disease in Dutch family. Targeted Sanger sequencing of PRPF8 in a panel of 40 POAG families (18 Pakistani and 22 Dutch) revealed two additional nonsynonymous variants (p.Pro13Leu and p.Met25Thr), which segregate with the disease in two other Pakistani families. Both variants were then analyzed in a case-control cohort consisting of Pakistani 320 POAG cases and 250 matched controls. The p.Pro13Leu and p.Met25Thr variants were identified in 14 and 20 cases, respectively, while they were not detected in controls (p values 0.0004 and 0.0001, respectively). Previously, PRPF8 mutations have been associated with autosomal dominant retinitis pigmentosa (RP). The PRPF8 variants associated with POAG are located at the N-terminus, while all RP-associated mutations cluster at the C-terminus, dictating a clear genotype-phenotype correlation.