Epidemiology of glaucoma in sub-saharan Africa: prevalence, incidence and risk factors

Novel ancestry-specific primary open-angle glaucoma loci and shared biology with vascular mechanisms and cell proliferation

Primary open-angle glaucoma (POAG), a leading cause of irreversible blindness globally, shows disparity in prevalence and manifestations across ancestries. We perform meta-analysis across 15 biobanks (of the Global Biobank Meta-analysis Initiative) (n = 1,487,441: cases = 26,848) and merge with previous multi-ancestry studies, with the combined dataset representing the largest and most diverse POAG study to date (n = 1,478,037: cases = 46,325) and identify 17 novel significant loci, 5 of which were ancestry specific. Gene-enrichment and transcriptome-wide association analyses implicate vascular and cancer genes, a fifth of which are primary ciliary related. We perform an extensive statistical analysis of SIX6 and CDKN2B-AS1 loci in human GTEx data and across large electronic health records showing interaction between SIX6 gene and causal variants in the chr9p21.3 locus, with expression effect on CDKN2A/B. Our results suggest that some POAG risk variants may be ancestry specific, sex specific, or both, and support the contribution of genes involved in programmed cell death in POAG pathogenesis.

Determinants of participation in glaucoma genomic research in South East Nigeria: A cross-sectional analytical study

BACKGROUND

Genomic research advances the understanding of human health and disease. It also drives both the discovery of salient genetic association(s) as well as targeted screening, diagnostic and therapeutic strategies. Human subject participation is crucial for the success of genomic research.

METHODS

This is a cross sectional analytical study conducted at two tertiary centers in Enugu Southeast Nigeria. Semi structured questionnaires were administered to eligible consenting participants. Data on their demographics, willingness to participate in genomic research and motivation for participation were obtained. Data was analyzed using Stata version 17 and summarized using median, frequencies and interquartile range(IQR). Associations between covariates were evaluated with Chi square test and multivariable logistic regression.

RESULTS

Among 228 glaucoma subjects who participated in our study,119(52.2%) were female and 109(47.8%) were male. The median age was 64 years(IQR = 50-76). Although 219 (96.0%) participants expressed willingness to participate in a glaucoma genetic study, only 27(11.9%) of them will be willing to participate if there will not be feedback of results to participants (χ2 = 18.59, P<0.001). No participant expressed willingness to submit ocular tissue samples. Majority (96.2%) of subjects will not participate if the intended research required submission of body samples after death. Desire to know more about glaucoma (63%) was the most common reason for participation. In a multivariable logistic model, subjects between 61-90 years (p = 0.004, OR = 7.2) were 7 times more likely to express willingness to participate in glaucoma genetic research after adjusting for other covariates when compared to subjects aged 41-60 years. Other covariates did not influence participants' willingness.

CONCLUSION

Glaucoma subjects are more likely to be willing to participate in genetic research, if they would receive feedback of results. Willingness to participate in genetic research is significantly associated with age.

LIMITATIONS

We did not evaluate the salient options for feedback of results to participants in our study.

Comparative Evaluation of Activities of Daily Living Using Virtual Reality Simulation in Glaucoma and Non-Glaucoma Patients

Purpose

To compare the performance of activities of daily living (ADL) in Primary open-angle glaucoma patients and non-glaucoma normal controls using virtual reality (VR) simulation at the Lagos State University Teaching Hospital.

Materials and Methods

This was a comparative clinical analysis involving primary open-angle glaucoma (POAG) patients. A total of 86 patients were enrolled (43 cases and 43 normal non-glaucoma). Each participant completed four VR simulation tasks. Chi-square/Fisher exact test was used to compare variables. The confidence interval was set at 95% for all statistical tests, and a P value of <0.05 was considered significant.

Results

The mean age of participants in the glaucoma group was 60.3 years, and the mean age in the normal non-glaucoma group was 56.5 years. The number of clicks in the driving task in the normal non-glaucoma and glaucoma group differed by 4.84 clicks (mean normal 21.00, confidence interval [CI], 19.96-22.14, mean glaucoma 16.16, CI, 14.30-18.03, P < 0.001). The number of newspapers seen differed by 0.88 (mean normal 9.74, CI, 9.40-10.09; mean glaucoma 8.86, CI, 8.21-9.51, P = 0.020). The mean time taken to complete the bus stop simulation task differed by 41.23 s (mean normal 29.72 s, CI, 25.02-34.42; mean glaucoma, 70.95 s, CI, 53.26-88.65, P < 0.001). The mean time taken to complete the best dress task differed by 14.39 s (mean normal 9.49, CI, 8.18-10.80; mean glaucoma 23.88, CI, 10.03-37.74, P = 0.038). Patients with advanced and severe stages of glaucoma took longer to complete the VR task than those with early glaucoma.

Conclusions

The VR simulation used in assessing the performance of ADL among POAG participants highlights limitations that vary with varying severity of glaucoma. The conventional clinical investigation used in assessing glaucoma severity might not define the real-time social effect of the disease.

Adherence to Ocular Hypotensive Medication in Patients With Primary Open Angle Glaucoma in Ghana

PRCIS

There is a high rate of nonadherence to ocular hypotensive medications in a highly prevalent glaucoma setting, which warrants the attention of caregivers so as to inform their discussion of the possible barriers to adherence with their patients.

PURPOSE

To assess adherence to ocular hypotensive medication objectively among glaucoma patients in Ghana and to identify factors associated with adherence.

MATERIALS AND METHODS

The prospective, observational cohort study included consecutive patients with primary open angle glaucoma treated with Timolol at the Christian Eye Centre, Cape Coast, Ghana. Adherence was assessed using Medication Event Monitoring System (MEMS) for a period of 3 months. MEMS adherence was defined as the number of doses taken divided by the number of doses prescribed, expressed in percent. Patients with adherence of 75% or less were classified as nonadherent. Associations with glaucoma medication self-efficacy, eyedrop-taking behaviors, and health beliefs were also assessed.

RESULTS

Of the 139 patients (mean age, 65 y [SD, 13 y]) included in the study, 107 (77.0%) were nonadherent when assessed with MEMS, compared with only 47 (33.8%) who self-reported being nonadherent. Overall, mean adherence was 48.5%±29.7. In univariate analysis, MEMS adherence was significantly associated with educational level ( χ2 =9.18, P =0.01) and the number of systemic comorbidities ( χ2 =6.03, P =0.049).

CONCLUSION

Overall, mean adherence was low, and adherence was associated with educational level and number of systemic comorbidities in univariate analysis.

Profiling and factors associated with glaucoma diagnostic practice in sub-Saharan Africa-a cross sectional study of Nigerian and Ghanaian optometrists

BACKGROUND

Ghana and Nigeria are the two countries in Africa that currently run the Doctor of Optometry (OD) program in sub-Saharan Africa (SSA). Optometrists in these countries are licensed to provide glaucoma care. Despite the clinically relevant practice guidelines for glaucoma, there is no data on the practice patterns for glaucoma eye care in SSA, a region with the highest prevalence of glaucoma. This study aimed to profile glaucoma diagnosis adherence to practice guidelines among optometrists in two neighbouring anglophone countries (Nigeria and Ghana).

METHODS

A web-based cross-sectional survey of practising optometrists was conducted in both countries. Each country data was weighted to reflect the total number of licensed and practising optometrists at the time of this survey. Descriptive analyses were performed against demography and practice factors using survey commands to adjust for sampling weights when estimating confidence intervals (CI) around prevalence estimates. Simple and multiple logistic regression analyses were performed to identify factors associated with glaucoma diagnosis.

RESULTS

A total of 493 optometrists (238, 48.3% and 255, 51.7%) from Ghana and Nigeria respectively, responded to the survey-the first to document and compare the glaucoma diagnostic criteria between optometrists in Ghana and Nigeria. More Ghanaian than Nigerian optometrists diagnosed glaucoma and over 90% in both countries reported that they frequently performed either tonometry, visual field testing, or fundus examination during glaucoma diagnosis. Ghanaian optometrists were significantly more likely to diagnose glaucoma than Nigerian optometrists (adjusted odd ratio, AOR = 6.15, 95%CI:1.63-23.15, P = .007). Optometrists who have practiced for more than 10 years (AOR = 7.04; 95%CI:1.74-28.47, P = .006) and private practice optometrists (AOR = 3.33; 95%CI:1.13-9.83, P = .03) were more likely to diagnose glaucoma.

CONCLUSIONS

The study provides information for evaluating glaucoma assessment for optometrists in both countries. Optometrists in both countries are reasonably well-equipped to diagnose glaucoma and are practicing at an adequate level, but with room for improvement.

The Effect of Early Posttrabeculectomy Bleb Leakage on Surgical Outcome: A Prospective Cohort Study

Purpose

To evaluate the effect of early posttrabeculectomy bleb leakage on trabeculectomy surgery outcomes and success rate.

Methods

The present prospective cohort study was conducted on 203 eyes of 203 patients who underwent trabeculectomy at Torfeh and Imam Hossein Medical Centers, Tehran, Iran, between 2016 and 2021. Patients were divided into two groups: those with early bleb leakage (within the 1st month of surgery) and those without bleb leakage. The success rate of surgery was compared 12, 18, and 24 months after surgery in the two groups. The average intraocular pressure (IOP) and the need for medications in patients 1, 3, 6, 9, 12, 18, and 24 months after the trabeculectomy were also compared.

Results

Bleb leakage was detected in 33 eyes during the 1st month after a trabeculectomy (16.3%). The mean decrease in IOP in the group with leakage was significantly lower than in patients without leakage at 1, 6, 9, 12, 18, and 24 months after surgery (P < 0.05). The need for antiglaucoma medication was significantly higher among patients with bleb leakage at 3 months (P = 0.04) and 9 months (P = 0.047) after surgery (P < 0.05). The success rate at 12, 18, and 24 months after surgery was significantly lower in the group with leakage than the group without.

Conclusions

The results of our study suggest that early posttrabeculectomy bleb leakage negatively impacts surgery success. Furthermore, IOP reduction was lower in patients with early leakage.

Unfulfilled Needs in the Detection, Diagnosis, Monitoring, Treatment, and Understanding of Glaucoma in Blacks Globally

Glaucoma is an ophthalmic disorder that affects a significant number of Blacks globally. A leading cause of this condition is an age-related enlargement of the lens and increased intraocular pressure. Although Blacks are affected by glaucoma at a higher rate than their Caucasian counterparts, there remains a lack of emphasis placed on the detection, diagnosis, monitoring, and treatment of glaucoma in this population. Education regarding glaucoma in the African and African American populations is essential to reducing rates of glaucoma-related visual impairment and improving treatment success. In this article, we highlight specific issues and limitations to the management of glaucoma, which affects Blacks at a higher rate. In addition, we also review the backgrounds of Blacks globally and examine historical events that have contributed to financial inequality and wealth/health disparities affecting glaucoma management. Lastly, we suggest reparations and solutions that health care professionals can use to improve glaucoma screening and management.

Advances in Polysaccharide- and Synthetic Polymer-Based Vitreous Substitutes

The vitreous humour is a gel-like structure that composes the majority of each eye. It functions to provide passage of light, be a viscoelastic dampener, and hold the retina in place. Vitreous liquefaction causes retinal detachment and retinal tears requiring pars plana vitrectomy for vitreous substitution. An ideal vitreous substitute should display similar mechanical, chemical, and rheological properties to the natural vitreous. Currently used vitreous substitutes such as silicone oil, perfluorocarbon liquids, and gases cannot be used long-term due to adverse effects such as poor retention time, cytotoxicity, and cataract formation. Long-term, experimental vitreous substitutes composed of natural, modified and synthetic polymers are currently being studied. This review discusses current long- and short-term vitreous substitutes and the disadvantages of these that have highlighted the need for an ideal vitreous substitute. The review subsequently focuses specifically on currently used polysaccharide- and synthetic polymer-based vitreous substitutes, which may be modified or functionalised, or employed as the derivative, and discusses experimental vitreous substitutes in these classes. The advantages and challenges associated with the use of polymeric substitutes are discussed. Innovative approaches to vitreous substitution, namely a novel foldable capsular vitreous body, are presented, as well as future perspectives related to the advancement of this field.

The Impact of Simulation-Based Trabeculectomy Training on Resident Core Surgical Skill Competency

PRCIS

Simulation-based surgical education shows a positive, immediate, and sustained impact on core surgical skill competency in trabeculectomy among resident ophthalmologists in training.

PURPOSE

To measure the impact of trabeculectomy, surgical simulation training on core surgical skill competency in resident ophthalmologists.

MATERIALS AND METHODS

This is a post hoc analysis of the GLAucoma Simulated Surgery trial, which is a multicenter, multinational randomized controlled trial. Resident ophthalmologists from 6 training centers in sub-Saharan Africa (in Kenya, Uganda, Tanzania, Zimbabwe, and South Africa) were recruited according to the inclusion criteria of having performed zero surgical trabeculectomies and assisted in <5. Participants were randomly assigned to intervention and control arms using allocation concealment. The intervention was a 1-week intensive trabeculectomy surgical simulation course. Outcome measures were mean surgical competency scores in 8 key trabeculectomy surgical skills (scleral incision, scleral flap, releasable suturing, conjunctival suturing, sclerostomy, tissue handling, fluidity, and speed), using a validated scoring tool.

RESULTS

Forty-nine residents were included in the intention-to-treat analysis. Baseline characteristics were balanced between arms. Median baseline surgical competency scores were 2.88/16 [interquartile range (IQR): 1.75-4.17] and 3.25/16 (IQR: 1.83-4.75) in the intervention and control arms, respectively. At primary intervention, median scores increased to 11.67/16 (IQR: 9.58-12.63) and this effect was maintained at 3 months and 1 year ( P =0.0001). Maximum competency scores at primary intervention were achieved in the core trabeculectomy skills of releasable suturing (n=17, 74%), scleral flap formation (n=16, 70%), and scleral incision (n=15, 65%) compared with scores at baseline.

CONCLUSIONS

This study demonstrates the positive impact of intensive simulation-based surgical education on core trabeculectomy skill development. The rapid and sustained effect of resident skill acquisition pose strong arguments for its formal integration into ophthalmic surgical education.

Effectiveness of community outreach screening for glaucoma in improving equity and access to eye care in Nigeria

PURPOSE

To determine the effectiveness of community outreach screening for glaucoma in improving equity and access to eye care in Nigeria.

METHODOLOGY

This was a prospective study in which two cohort of participants were recruited in Nigeria: 1 from 24 outreach screenings and another from consecutive patients presenting spontaneously to a tertiary eye clinic in Nigeria. Sociodemographic and clinical data were obtained from participants and compared.

RESULTS

Our sample consisted of 120 patients with glaucoma or suspected glaucoma (6.38% of 1881 screenees) recruited from the 24 outreach screenings, and another 123 patients with glaucoma who presented spontaneously at the eye clinic. Participants from the screenings were significantly older (p=0.012), less educated (p<0.001), had lower incomes (p<0.001), lower glaucoma knowledge scores and were less aware of their glaucoma (both p<0.001) and were more likely to be dependent on relations and children (p=0.002) compared with clinic participants. Of the 120 patients identified at the screenings and referred to the clinic for definitive care, 39 (32.5%) presented at the clinic within 3 months. Reasons for poor uptake of referral services were lack of a felt need and lack of money for transportation. Considering only patients who accepted referral, they were still less educated (p<0.001), poorer (p=0.001) and less knowledgeable about glaucoma (p=0.003) than spontaneous clinic presenters.

CONCLUSION

Outreach screening improved equity of access but its effects were somewhat reduced by poor uptake of referral care. Interventions such as free transportation and educational efforts may improve the uptake of referral services and maximise equity gains.

Development and Evaluation of a Rules-based Algorithm for Primary Open-Angle Glaucoma in the VA Million Veteran Program

The availability of electronic health record (EHR)-linked biobank data for research presents opportunities to better understand complex ocular diseases. Developing accurate computable phenotypes for ocular diseases for which gold standard diagnosis includes imaging remains inaccessible in most biobank-linked EHRs. The objective of this study was to develop and validate a computable phenotype to identify primary open-angle glaucoma (POAG) through accessing the Department of Veterans Affairs (VA) Computerized Patient Record System (CPRS) and Million Veteran Program (MVP) biobank. Accessing CPRS clinical ophthalmology data from VA Medical Center Eye Clinic (VAMCEC) patients, we developed and iteratively refined POAG case and control algorithms based on clinical, prescription, and structured diagnosis data (ICD-CM codes). Refinement was performed via detailed chart review, initially at a single VAMCEC (n = 200) and validated at two additional VAMCECs (n = 100 each). Positive and negative predictive values (PPV, NPV) were computed as the proportion of CPRS patients correctly classified with POAG or without POAG, respectively, by the algorithms, validated by ophthalmologists and optometrists with access to gold-standard clinical diagnosis data. The final algorithms performed better than previously reported approaches in assuring the accuracy and reproducibility of POAG classification (PPV >83% and NPV >97%) with consistent performance in Black or African American and in White Veterans. Applied to the MVP to identify cases and controls, genetic analysis of a known POAG-associated locus further validated the algorithms. We conclude that ours is a viable approach to use combined EHR-genetic data to study patients with complex diseases that require imaging confirmation.

Intraocular pressure screening during high-volume cataract surgery outreach in Ethiopia

Introduction

Glaucoma is the leading cause of irreversible blindness worldwide and is often undetected in resource-limited settings. Early screening and treatment of elevated intraocular pressure (IOP) reduces both the development and progression of visual field defects. IOP screening in developing countries is limited by access to ophthalmic equipment, trained ophthalmic staff, and follow up. High-volume cataract surgery outreaches in resource-limited countries provide ample opportunity for glaucoma screening, intervention and follow up.

Methods

This prospective cross-sectional study took place during a cataract outreach campaign sponsored by the Himalayan Cataract Project (HCP) in partnership with Felege Hiwot Hospital in Bahir Dar, Ethiopia, during April 5th – April 10th 2021. IOP was measured on the surgical eye of patients before undergoing small incision cataract surgery (SICS) using rebound tonometry with an iCare tonometer model IC100.

Results

Intraocular pressure (IOP) was measured in 604 eyes of 595 patients who received SICS. Mean IOP was 12.1 mmHg (SD = 5.0 mmHg). A total of 29 patients had an IOP greater than 21 mmHg representing 4.8% of total IOP measurements. A total of 17 patients received oral acetazolamide prior to surgery to acutely lower IOP. Six of these patients had their surgery delayed due to elevated IOP and 9 patients received excisional goniotomy at the time of SICS. A temporal approach during SCIS was taken for all patients with elevated IOP to allow for possible trabeculectomy at a future date.

Discussion

IOP screening during high-volume cataract outreach campaigns can be performed safely, accurately and on a large scale with minimal resources and supplemental training. Pre-operative IOP measurement can improve surgical care at the time of cataract surgery as well as help establish long-term follow up for patients with glaucoma.

A Survey on Patients' Opinions of Alternative Drug Delivery Systems for the Treatment of Glaucoma in South-South Nigeria

PURPOSE

Despite the human ocular surface being easily accessible, ocular drug delivery can be challenging. When applied improperly, topical medications, the most popular first-line treatment used to treat glaucoma, can have a very brief contact time with the ocular surface and may not have the desired therapeutic impact. Drug delivery devices are gadgets that can address some of these problems. This study aims to determine patients' opinions on ocular drug delivery devices used in the treatment of primary open-angle glaucoma (POAG).

METHODS

A pretested interviewer-administered questionnaire was used in a cross-sectional study of 115 POAG patients recruited from outpatient clinics in two Nigerian tertiary health institutions. Participants were asked about their understanding and acceptance of five Ocular drug delivery systems (ODD), namely drug-emitting contact lenses (CL), punctual plugs, subconjunctival injections, intracameral implants, and trabecular meshwork micro-stents, for the treatment of POAG.

RESULTS

Sixty (52.2%) participants, whose average age was 50 ± 9.8 years, were men. Self-pay was used for eye health treatments by 65% of participants. Of the participants, 68.7% admitted to using eye drops on their own. 57% of people were said to take their glaucoma medications consistently. CL and subconjunctival implants were seen to be most acceptable according to 39% and 30% of participants, respectively. Major factors determining the acceptability of ODD for POAG treatment were observed to be cost and effectiveness.

CONCLUSION

Patients in our cohort who are being treated for POAG have a fairly positive attitude towards ODD. The prospective use of these devices for POAG treatment in Nigeria will depend on their efficacy and cost, as well as how ophthalmologists will weigh ODD options.

Awareness and Knowledge of Glaucoma among Health Workers in Butajira General Hospital, South Ethiopia

Background

Raising awareness and knowledge of glaucoma is a key means of enhancing people alertness, increasing regular eye screening practice, and the chance of identifying undetected cases. Health professionals other than ophthalmologists are often the first point of contact when patients seek medical advice. However, little is known about the awareness and knowledge of glaucoma among health care professionals in Ethiopia. The objective of this study was to determine general awareness and knowledge of glaucoma among health workers in Butajira General Hospital.

Methods

Hospital-based cross-sectional study was conducted at Butajira Hospital in September and October 2021 among health care providers. All health workers except those on leave and the staff in the department of Ophthalmology were included in the study. The awareness and knowledge were assessed using a self-administered questionnaire. Descriptive statistics was computed to describe the study variable, and logistic regression was conducted to see associations between dependent and independent variables. Significant associations were declared at p-values <0.05.

Result

This study showed that 184 (91.1%) had an awareness of glaucoma among the study participants, whereas 8.9% had never heard about glaucoma. Of those who were aware, only 42% have good knowledge. Professionals who had a history of eye examinations and family history of glaucoma were about 3.0 times more likely to have good knowledge.

Conclusions

Fifty-eight percent of clinical professionals from Butajira Hospital had no awareness at all or had poor knowledge about glaucoma. Being a physician, history of eye examinations, and having a family history of glaucoma were factors related to glaucoma knowledge.

Predictors for elevation of Intraocular Pressure (IOP) on glaucoma patients; a retrospective cohort study design

OBJECTIVE

Because of the increase in the number of cases, currently, glaucoma is a significant public health issue that it leads to optic nerve damage and vision loss. High Intraocular Pressure reading indicates that the treatment given to a glaucoma patient is not sufficient/ adequate. Hence, the elevation of intraocular pressure is one of the indicators that, the therapy given to glaucoma patients under treatment is inadequate. Therefore, the main objective of the current study was to investigate predictors for the variation of elevation of IOP readings on glaucoma patients.

MATERIALS AND METHODS

A retrospective cohort study design was conducted on 1254 glaucoma patients, whose followed-ups were from September 2015 to August 2016 at Felege Hiwot Teaching and Specialized Hospital, North West Ethiopia. Data analysis was conducted using Statistical Analysis of Systems (SAS) software version 9.2 and AMOS software. The parameter estimation was conducted using the maximum likelihood estimation technique.

RESULTS

Main effects like age (β = 0.01, t-value = 0.15, p-value = 0.018), patients with normal blood pressure (β = -3.35, t-value = -2.28, p-value = 0.0263), patients without diabetics (β = -3.79, t-value = -2.47, p-value = 0.014), visiting times (β = -6.00, t-value = -5.02, p-value = 0.0001), farmer glaucoma patients (β = -6.04, t-value = 3.87, p-value = 0.0001) had significant and indirect effect for the variation of elevation of IOP on glaucoma patients. Interaction effects like visiting time with existence of diabetes, visiting time with cataract surgery significantly effected on the variable of interest. Hence, both main and interaction effects had significant effects on the variable of interest. This study had identified socio-demographic characteristics, personal/individual behaviors, and clinical factors for the variation of elevation of IOP. The findings, in the current investigation, help health staff to conduct health-related education for awareness creation. Health-related education, about the progression of glaucoma, should be conducted on patients.

Vision-related Quality of Life in Congolese Patients with Glaucoma

Purpose

Methods

Results

Conclusion

How to cite this article

COVID-19 and the Rationale for Primary Selective Laser Trabeculoplasty and Diode Laser Transscleral Cyclophotocoagulation in Africa

The recent COVID-19 pandemic has affected ophthalmologists' practices worldwide. Consequent global drug shortages and the limitations of medical glaucoma treatments in sub-Saharan Africa have highlighted the need for innovation in global ophthalmology to provide accessible, affordable, and effective glaucoma care. The role of lasers rather than medications for glaucoma patients in developing nations is emerging. Since lasers are easier to master than glaucoma surgery, it is pertinent to discuss the primary use of lasers in treating glaucoma in such nations. In particular, selective laser trabeculoplasty and diode laser transscleral cyclophotocoagulation seem to present a promising future for the treatment of glaucoma in Africa. In this report, we provide an evidence-based discussion exploring the emerging role of lasers in Africa.

Gessesse G. Knowledge and practice towards glaucoma among glaucoma patients at University of Gondar Tertiary Eye Care and Training Center

Background

For better treatment outcome, exploring the knowledge of glaucoma and practices among glaucomatous patients is much more important.

Objective

The aimed of this study was to determine the knowledge and self-care practice and their associated factors towards glaucoma and its medications among glaucoma patients.

Methods

Cross section design study was conducted between May and July, 2017. The data was collected from glaucoma patients. Descriptive statistics was done to summarize socio demography data and associated factors with good knowledge and good practice were determined using binary logistic regression. Statistically significant variables were generated by considering p-value < 0.05.

Results

A total of 360 glaucoma patients were participated in this survey. The median age of the participant was 65 years. About 177 (49.25%) (95%CI: 43.9, 54.4) had good knowledge and a total of 197 or 54.7% (95%CI: 49.4, 59.7) had good practice about glaucoma and its medical treatments. The factors such as residence, marital status, educational status and stages of glaucoma of study participants were independently associated with having good knowledge. With respect to practice, educational status, duration of glaucoma, laterality and frequency of follow up were significantly associated with practice status of study participants.

Conclusion

In this study among glaucoma patients in a tertiary hospital, only half of patients have good knowledge about the disease and good practice pattern. Those with urban residence, higher education status and advanced stage of glaucoma were more likely to have good knowledge.

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.

Prevalence of blindness and its major causes in sub-Saharan Africa in 2020: A systematic review and meta-analysis

Background:

Global studies show that the prevalence of visual impairment and blindness continued to rise despite the implementation of strategies outlined in the Global Action Plan, aimed at reducing these by the year 2020. Vision impairment impacts negatively on one’s independence, opportunities, and quality of life. Therefore, knowledge of the prevalence, and the major causes of blindness impairment in any population, is vital in designing strategies to address this public health challenge.

Methods:

Literature mapping evidence of vision impairment was searched for on PubMed, Google Scholar, and EBSCOhost databases MEDLINE, Health Source: Nursing/Academic Edition, Health Source – Consumer Edition, CINAHL, and Academic Search Complete. Studies that were searched for included peer-reviewed and grey literature published in English from various countries in sub-Saharan Africa (SSA).

Results:

Only 77 studies with 191,173 participants, contributing data from 26 countries within SSA, met the inclusion criteria for the final review. The overall pooled prevalence estimate (PPE) of blindness from the selected studies was 10% (95% confidence interval [CI]: 8.0% – 11.0%). West Africa and East Africa had the highest prevalence. The identified leading causes of blindness were cataracts (46%; 95% CI: 40% – 52%), followed by glaucoma (14%; 95% CI: 11% – 18%). There was a high level of heterogeneity in most pooled estimates (I2 ˃ 80%, p < .001).

Conclusion:

The prevalence of blindness in SSA has increased in all four regions with most cases being avoidable. Policymakers should prioritise blindness prevention programmes, ensure enabling health systems, and provide the necessary resources towards reducing blindness in SSA.

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.

HPLC-MS/MS studies of brimonidine in rabbit aqueous humor by microdialysis

Aim: The pharmacokinetic study of the brimonidine tartrate in situ gel in the anterior chamber of the rabbit eye was studied by microdialysis technique, and samples were analyzed by HPLC-MS/MS. Materials & methods: It was monitored in ESI mode at transition 291.9→212.0 and 296.0→216.0 for brimonidine and internal standard, respectively. Acetonitrile and 0.1% aqueous formic acid (50:50, v/v) were used as the mobile phase at 0.4 ml/min. Results & conclusion: It showed a good linear correlation between 5 and 5000 ng/ml in microdialysis solution, and the inter- and intra-day precision (relative standard deviation) was less than 4.0%. The pharmacokinetic study showed that the AUC_(0-t) of in situ gel was 3.5-times than that of eyedrops, which significantly improve the bioavailability of brimonidine.

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.

Clinical and sociodemographic characteristics of glaucoma patients at a tertiary referral facility in Zimbabwe

Purpose

To evaluate the clinical and socio-demographic profile of patients living with glaucoma and receiving care in a tertiary eye center in Zimbabwe.

Method

A hospital-based retrospective study of clinical records of glaucoma patients from January 2014 to December 2018. The study involved collating demographic information of patients, visual acuities, (VA) intraocular pressure, (IOP), cup-to-disc ratios, (CDRs), average retinal nerve fibers thickness, (RNFL), cup volume, cup-to-disc area, vertical cup-to-disc ratio, (VCDR), rim area, disc area, glaucoma hemifield test, visual field indices and the management of glaucoma.

Results

Nine thousand one hundred and eighty-five (9,185) folders were retrieved. Out of these, 432 (4.7%) qualified for the study and were analyzed. There were 267 (61.8%) males and 165 (38.2%) females. The mean age (± Standard deviation, SD) of the patients was 62.66 ± 15.94 years, (range 10 - 110 years). The means visual acuity (VA): OD =1.30 ± 1.06 Logarithm of the Minimum Angle of Resolution, (logMAR), OS = 1.33 ± 1.06 logMAR; IOP: OD = 29.51 ± 12.89 mmHg, OS: 29.17 ± 12.59 mmHg; CDRs: OD = 0.91 ± 0.14 D, OS = 0.92 ± 0.14 D; and the average RNFL thickness was 72.76 ± 18.26 µm and 71.24 ± 23.17 µm in the right and left eye respectively. The mainstay of treatment was medication only.

Conclusion

There were more males than females receiving glaucoma care at the tertiary level. Glaucoma cases included juveniles but the mean age was mostly the elderly. It was characterized by high IOPs, large CDRs, and thin RNFL suggestive of late presentation.

The Effect of Ocular Perfusion Pressure on Retinal Thickness in Young People with Presumed Systemic Hypotension

Low ocular perfusion pressure (OPP) may increase the risk of optic neuropathy. This study investigated the effects of OPP on the ganglion cell complex (GCC) and optic nerve head-retinal nerve fibre layer (ONH-RNFL) thickness in presumed systemic hypotensives (PSH). Fifteen participants with PSH and 14 controls underwent automated sphygmomanometry and Icare tonometry to calculate OPP: mean OPP (MOPP), systolic OPP (SOPP), and diastolic OPP (DOPP). ONH-RNFL and macula GCC thickness were evaluated using the Optovue iVue optical coherence tomographer. Statistical analysis comprised independent t-tests, the Mann-Whitney U test and binary logistic regression analysis. There was no significant difference when comparing ONH-RNFL and macula GCC thickness between both groups. Increased MOPP (OR = 0.51; 95% CI: 0.27-0.97; p = 0.039) and SOPP (OR = 0.79; 95% CI: 0.64-0.98; p = 0.035) were significantly associated with a decreased risk of reductions in GCC total thickness. Increased SOPP (OR = 0.11; 95% CI: 0.01-0.89; p = 0.027) was significantly associated with a decreased risk of reductions in the average ONH-RNFL thickness. The study found no significant retinal thickness changes in PSH's, in comparison to the controls. The study established that, by increasing MOPP and SOPP, there was a decreased risk of reductions in the total GCC thickness and average ONH-RNFL thickness. Higher SOPP may decrease the possibility of retinal thinning of the GCC and ONH-RNFL. However, higher MOPP may decrease the odds of thinning of the GCC before ONH-RNFL changes.

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.

A review on the use of telemedicine in glaucoma and possible roles in COVID-19 outbreak

We review the use of telemedicine in glaucoma and its possible roles in the COVID-19 outbreak. We performed a literature search of published human studies on teleglaucoma on May 12, 2020, using search terms including “telemedicine” and “glaucoma” that were in English and published over the prior 10 years. This search strategy yielded a total of 14 relevant articles after manual curation. Of the 14 articles, 4 were from the same randomized control trial, 7 were prospective studies, 2 were retrospective studies, 1 was descriptive analysis, and 1 was cost-effective analysis. Seven discussed the common ophthalmologic measurements used in teleglaucoma. Four demonstrated the cost effectiveness of the use of teleglaucoma, and 3 articles investigated patient satisfaction with the use of teleglaucoma. Three articles investigated the correlation between teleglaucoma and face-to-face clinics. Five articles discussed the current use and opportunities of teleglaucoma.

When compared to in-person care, teleglaucoma is more time and cost-effective, shows high patient satisfaction and fair to good agreement with in-person care; however, there is great variation in the reported sensitivity of glaucoma screening, warranting further studies to establish its efficacy. For glaucoma management, both the sensitivity and specificity must be further improved before it could be put into extensive use. Nevertheless, it is worthwhile to explore the possible extensive application of teleglaucoma in monitoring “glaucoma suspects” and maintaining glaucoma follow-up during a pandemic outbreak to reduce the risk of transmission of infection.

Exploiting biomaterial approaches to manufacture an artificial trabecular meshwork: A progress report

Glaucoma is the second leading cause of irreversible blindness worldwide. Glaucoma is a progressive optic neuropathy in which permanent loss of peripheral vision results from neurodegeneration in the optic nerve head. The trabecular meshwork is responsible for regulating intraocular pressure, which to date, is the only modifiable risk factor associated with the development of glaucoma. Lowering intraocular pressure reduces glaucoma progression and current surgical approaches for glaucoma attempt to reduce outflow resistance through the trabecular meshwork. Many surgical approaches use minimally invasive glaucoma surgeries (MIGS) to control glaucoma. In this progress report, biomaterials currently employed to treat glaucoma, such as MIGS, and the issues associated with them are described. The report also discusses innovative biofabrication approaches that aim to revolutionise glaucoma treatment through tissue engineering and regenerative medicine (TERM). At present, there are very few applications targeted towards TM engineering in vivo, with a great proportion of these biomaterial structures being developed for in vitro model use. This is a consequence of the many anatomical and physiological attributes that must be considered when designing a TERM device for microscopic tissues, such as the trabecular meshwork. Ongoing advancements in TERM research from multi-disciplinary teams should lead to the development of a state-of-the-art device to restore trabecular meshwork function and provide a bio-engineering solution to improve patient outcomes.

[Preliminary selective laser trabeculoplasty (SLT) intraocular pressure results in glaucoma patients in Burkina Faso]

INTRODUCTION

Glaucoma is the leading cause of irreversible blindness in the world. The purpose of our study was to evaluate the tonometric results of SLT treatment in patients with glaucoma.

MATERIALS AND METHODS

This was a prospective study of patients with glaucoma who were seen from October 1, 2017 to July 31, 2018. All patients underwent SLT of the inferior 180°. Intraocular pressure (IOP) was measured before and then at 1, 15, 30, 60, 90 and 120days after treatment.

RESULTS

We studied 35 eyes of 31 patients. The mean age was 59.3 (±8.4years), range 43-77years. The mean IOP prior to SLT was 20.1mmHg (±7mmHg). One day after the laser, this decreased to 17.6mmHg (±8.4), for a percentage of drop of 12.4%. At 30days, it was 15.3mmHg (±5.4mmHg), i.e. a 23.9% decrease. After 60 and 90days, there was a drop of 13.9% and 15.4%, respectively. At 120days, 43.3% of treated eyes had a decrease of at least 20%. The main complication was increased IOP in 14.2% of cases.

CONCLUSION

SLT reduces IOP and the number of glaucoma medications in patients. It appears to be a viable alternative in our countries. These results should be confirmed with a larger cohort and longer follow-up.

Epidemiology and clinical presentation of glaucoma in a referral facility in Ghana: Any lessons for public health intervention?

The purpose of this study was to evaluate the epidemiological and clinical profile of patients living with glaucoma and receiving care in a tertiary eye center in Ghana. This was a hospital-based retrospective study of clinical records of glaucoma patients from January 2010 to December 2019. The study involved collating demographic information of patients, clinical presentation, and the management of glaucoma. A total of nineteen thousand (19,000) charts were retrieved from the eye center's archives. Out of these, 660 (3.5%) records of patients qualified for the study and were analyzed. There were 398 (60.3%) males and 262 (39.7%) females. Their ages ranged from 9 to 86 years (mean age = 47.30; SD ± 16.86 years). The averages of ocular parameters of 1,320 eyes (660 patients) were visual acuity = 0.26 ± 0.55 logMAR; intraocular pressure: 17.31 ± 6.11 mmHg; cup-to-disc ratios: 0.67 ± 0.17 D; and the average retinal nerve fibers thickness was 95.03 ± 21.74 μm. The mainstay of treatment was the sole use of medication. Males were the major group receiving glaucoma care at the tertiary level. Glaucoma cases included juveniles but the mean age suggests most were of adult-onset. Socio-demographic characteristics affected the diagnosis and management of glaucoma among patients receiving care at a referral center. Public health, stakeholders, and policymakers' interventions can help identify individuals with glaucoma.

A multiethnic genome-wide analysis of 44,039 individuals identifies 41 new loci associated with central corneal thickness

Central corneal thickness (CCT) is one of the most heritable human traits, with broad-sense heritability estimates ranging between 0.68 to 0.95. Despite the high heritability and numerous previous association studies, only 8.5% of CCT variance is currently explained. Here, we report the results of a multiethnic meta-analysis of available genome-wide association studies in which we find association between CCT and 98 genomic loci, of which 41 are novel. Among these loci, 20 were significantly associated with keratoconus, and one (RAPSN rs3740685) was significantly associated with glaucoma after Bonferroni correction. Two-sample Mendelian randomization analysis suggests that thinner CCT does not causally increase the risk of primary open-angle glaucoma. This large CCT study explains up to 14.2% of CCT variance and increases substantially our understanding of the etiology of CCT variation. This may open new avenues of investigation into human ocular traits and their relationship to the risk of vision disorders.

Demographic and clinical characteristics of patients with glaucoma in a tertiary eye facility in Ghana

Background: Ghana has been reported to have the second highest prevalence of glaucoma worldwide.Aim: Because of glaucoma causing numerous cases of irreversible blindness, there is the need for baseline data for glaucoma characteristics among Ghanaians. This study was conducted to determine the demographic and clinical characteristics of glaucoma patients in a tertiary eye centre.Setting: The setting for this study is the eye clinic of the Agogo Presbyterian Hospital, which is situated in the Ashanti Region of Ghana.Methods: The medical records of patients who attended the eye centre from January 2013 to December 2017 were reviewed. The data collected included the demographic variables and clinical characteristics of patients diagnosed with glaucoma.Results: Of the 1100 medical records reviewed, 311 were diagnosed with glaucoma. Of the 311 patients, 159 (51.1%) were males and 152 (48.9%) were females, with their ages ranging from 11 to 104 years (mean = 60 ± 18.1 years). Primary open-angle, secondary, juvenile and primary angle-closure glaucomas accounted for 81.6%, 11%, 3.8% and 3.6%, respectively, of all cases of glaucoma. The average intra-ocular pressure was 28.2 ± 11 mmHg. The cup-to-disc ratio and visual acuity varied significantly among the various ethnic groups (p 0.05), while the average intra-ocular pressure did not (p 0.05). Timolol was the first line of treatment for 91.4% cases of glaucoma.Conclusion: Primary open-angle glaucoma is the predominant type in this population, with the clinical characteristics of visual acuity and cup-to-disc ratio varying among the different Ghanaian ethnic groups. There is a need for population-based epidemiologic studies to validate the data collected in this hospital-based study.

Awareness of Glaucoma and Associated Factors Among Adults in Gish Abay Town, Northwest Ethiopia

PURPOSE

The purpose of this study was to determine the awareness of glaucoma and associated factors among adults living in Gish Abay town, Northwest Ethiopia.

METHODS

A population-based cross-sectional study was conducted on 594 adults who were selected using systematic random sampling from April to May 2018. Data were entered into Epi Info version 7 and were analyzed by SPSS version 23. Binary and multivariable logistic regression was used to determine factors associated with awareness. Variables with P-value < 0.05 were considered statistically significant.

RESULTS

The proportion of awareness of glaucoma was 24.4% [95% CI; 21.0, 28.1]. It was positively associated with educational status, primary education [AOR: 3.15; 1.72, 5.77], secondary education [AOR; 3.11: 1.66, 5.84], college and above [AOR; 6.10; 2.80, 13.27], history of eye examination [AOR: 6.52; 3.46, 12.25], income level >2000 Ethiopian birr [4.65; 2.59, 8.37] and history of chronic diseases [AOR; 2.93: 1.25, 6.85].

CONCLUSION

The status of glaucoma awareness in Gish Abay town can be said to be low as compared to studies. Higher educational status, eye examination, history of chronic diseases and better income level were significantly associated with awareness of glaucoma.

Normative Values of Retinal Nerve Fibre Layer Thickness and Optic Nerve Head Parameters and Their Association with Visual Function in an African Population

Purpose

To determine normative values of retinal nerve fibre layer thickness (RNFL) and optic nerve head (ONH) parameters and their association with routine clinical tests such as refractive error (RE), stereoacuity (SA), and contrast sensitivity (CS) in an African population.

Methods

In a cross-sectional observational study, 100 normal subjects aged 20 to 78 years were evaluated using the Cirrus HD-OCT 5000 and matched with 200 glaucoma patients.

Results

Average (±SD) RNFL thickness for normal subjects was found to be 102.37 ± 7.45 (range, 82–119 microns) compared with 90.74 ± 14.50 found for glaucoma subjects. Females had higher average RNFL values (104.84 ± 6.90) compared with males (99.80 ± 7.18). Significant associations were calculated between quadrant RNFL thickness and SA, SE, and CS (all p < 0.05). The mean cup to disc ratio (CDR) was 0.49 ± 0.12, and mean optic disc area (DA) was 2.08 mm² ± 0.40. Smaller DA was recorded for participants aged 60+ years (1.86 ± 0.25), followed by 40–59 age group (2.01 ± 0.41) and then 20–39 age group (2.19 ± 0.41). Significant associations were calculated between SA and ONH parameters, except rim area (all p < 0.05). The mean cup to disc ratio (CDR) was 0.49 ± 0.12, and mean optic disc area (DA) was 2.08 mm² ± 0.40. Smaller DA was recorded for participants aged 60+ years (1.86 ± 0.25), followed by 40–59 age group (2.01 ± 0.41) and then 20–39 age group (2.19 ± 0.41). Significant associations were calculated between SA and ONH parameters, except rim area (all p < 0.05). The mean cup to disc ratio (CDR) was 0.49 ± 0.12, and mean optic disc area (DA) was 2.08 mm² ± 0.40. Smaller DA was recorded for participants aged 60+ years (1.86 ± 0.25), followed by 40–59 age group (2.01 ± 0.41) and then 20–39 age group (2.19 ± 0.41). Significant associations were calculated between SA and ONH parameters, except rim area (all

Conclusion

RNFL thickness in healthy black Ghanaian population was significantly higher than that reported in other races. The values and associations reported in this study can inform clinical decision on the normal variation in RNFL and optic disc parameters.

Knowledge of glaucoma and associated factors among adults in Gish Abay town, Northwest Ethiopia

BACKGROUND

Glaucoma is a global public health problem and it is the leading cause of irreversible blindness worldwide. Even though public knowledge of glaucoma is a key for early case identification and prevention of blindness, it is unknown in the study area, making provision of interventions difficult. Therefore, this study was intended to assess knowledge of glaucoma and associated factors among adults in Gish Abay town, Northwest Ethiopia, 2018.

METHODS

A Community based cross - sectional design study with systematic random sampling technique was used to select 630 adults. The study was conducted from April to May, 2018. Data was entered into Epi Info version 7 and was analysed by Statistical Package for Social Sciences version 23. Binary logistic regression model and adjusted odds ratio with 95% confidence level was used to identify the significant factors associated with knowledge of glaucoma. Variables with P-value ≤0.05 was considered statistically significant.

RESULTS

About 594 adults were participated with a response rate of 94%. Above half of (52%) the participants were females with median age of 28 years. The proportion of good knowledge was demonstrated in 16.8% [95% CI; 14.0, 19.9]. Educational status: primary education [AOR; 2.89: 1.41, 5.90], secondary education [AOR; 3.03: 1.47, 6.24] college and above [AOR; 5.18: 2.21, 12.13], history of eye examination [AOR; 6.52: 3.37, 12.63]; family history of glaucoma [AOR; 12.08: 4.13, 35.30] and higher income level [AOR; 3.11: 1.55, 6.25] were positively associated with good knowledge of glaucoma.

CONCLUSIONS

The proportion of good knowledge of glaucoma was low. Higher educational status, positive family history of glaucoma, eye examination and higher income level were significantly associated with knowledge of glaucoma.

Adherence with Medical Therapy for Primary Open-Angle Glaucoma in Kenya - A Pilot Study

BACKGROUND/OBJECTIVES

Adherence is a major challenge in topical glaucoma therapy, particularly in an African context. We report a pilot study assessing adherence independently for the first time in an African context.

SUBJECTS/METHODS

Participants with newly diagnosed open-angle glaucoma received a weighed bottle of Lumigan 0.01% with counselling on therapy. The bottles were returned monthly for renewal and weighed on return to estimate drops taken during the period. Data collection was for one year with a short compliance questionnaire.

RESULTS

11 patients participated. 5 (45%) failed to complete one full year of topical therapy. The overall mean number of drops per eye per day was 1.74 (SD 0.69) for the 6 with one year of monthly returned bottles and controlled IOPs at each visit. Self-perception of compliance in these patients was good.

CONCLUSION

The signs of poor adherence based on both self-report (previous literature), and in this small-scale study of an objective measure suggest medication may not be the first-line treatment of choice in this environment. Our report does, however, raise the possibility that those patients who return for repeat prescriptions and review are indeed adhering to their treatment regimens.

Proportion of Glaucoma among Voluntary People Coming for Glaucoma Screening Program at Jimma University Department of Ophthalmology, Jimma, Ethiopia

Background

Glaucoma is the second leading cause of blindness worldwide. Glaucoma screening has been controversial, and much of the controversy has centered on the value of mass or community screening.

Methods

The aim of this study was to determine the proportion of glaucoma among volunteer adults who were screened in Jimma University Department of Ophthalmology. A cross-sectional study was conducted among 459 volunteer residents of Jimma town and surrounding areas. The study subjects were aged 40 years and above, who came for community screening program after media announcement during the four consecutive weekends of November 2014. Comprehensive eye examination was done including best corrected visual acuity, intra-ocular pressure measurement, stereoscopic optic nerve evaluation, angle structure evaluation and visual field testing. Three diagnostic criteria for glaucoma were employed for all cases.

Results

Of all adults who came for screening, 47(10.24%) were diagnosed to have glaucoma, 59(12.85%) were glaucoma suspects, and 8(1.74%) had ocular hypertension. The proportion of glaucoma increased with increasing age, (P value= 0.001 (99%CI)). Primary open angle glaucoma was the most common form (42.55%) of all new cases while 4.4% of all screened adults were followed by normal tension glaucoma (29.79%), pseudoexfoliative glaucoma (19.15%), and primary angle closure glaucoma (6.38%) Around 5.7% of all glaucoma cases were found to be blind.

Conclusion

The proportion of glaucoma in this community screening program in Southwest Ethiopia was 10.24% with primary open angle glaucoma being the commonest subtype. Glaucoma community screening should be promoted for early diagnosis and intervention to prevent irreversible blindness.

Association of Long-term Ambient Black Carbon Exposure and Oxidative Stress Allelic Variants With Intraocular Pressure in Older Men

Importance

Elevated intraocular pressure is a major risk factor for glaucoma, a leading cause of irreversible blindness worldwide. Environmental air pollution has been suggested as a potential contributor to elevated intraocular pressure; however, no studies have demonstrated such an association to date.

Objective

To investigate the association of long-term ambient black carbon exposure with intraocular pressure in community-dwelling older adults.

Design, Setting, and Participants

This population-based analysis, conducted from October 18, 2017, through March 22, 2018, used data from the all-male, New England-based Normative Aging Study of the US Department of Veterans Affairs. The analysis included 419 older men with a total of 911 follow-up study visits between January 1, 2000, and December 30, 2011. Intraocular pressure was measured by Goldmann applanation tonometry during the study visits. Validated spatiotemporal models were used to generate 1-year black carbon exposure levels at the addresses of the participants.

Main Outcomes and Measures

An independently developed genetic score approach was used to calculate allelic risk scores for 3 pathways associated with black carbon toxicity: endothelial function, oxidative stress, and metal processing. The associations among black carbon exposure, allelic risk scores, and intraocular pressure were explored using linear mixed-effects models.

Results

All 419 participants were men with a mean (SD) age of 75.3 (6.9) years. The mean (SD) 1-year black carbon exposure was 0.51 (0.18) μg/m3, and the mean (SD) intraocular pressure for the left eye was 14.1 (2.8) mm Hg and for the right eye was 14.1 (3.0) mm Hg. Of the 911 visits, 520 (57.1%) had a high endothelial function allelic risk score, 644 (70.7%) had a high metal-processing allelic risk score, and 623 (68.4%) had a high oxidative stress allelic risk score. In fully adjusted linear mixed-effects models, the association of black carbon with intraocular pressure was greater in individuals with a high oxidative stress allelic score (β = 0.36; 95% CI, 0.003-0.73) compared with individuals with a low score (β = -0.35; 95% CI, -0.86 to 0.15).

Conclusions and Relevance

Ambient black carbon exposure may be a risk factor for increased intraocular pressure in individuals susceptible to other biological oxidative stressors. If additional studies confirm these results, monitoring ambient black carbon exposure and physiological oxidative stress may prevent the development and progression of intraocular pressure-related disease.

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.

Clinical implications of recent advances in primary open-angle glaucoma genetics

Over the last decade, genetic studies, including genome-wide association studies (GWAS), have accelerated the discovery of genes and genomic regions contributing to primary open-angle glaucoma (POAG), a leading cause of irreversible vision loss. Here, we review the findings of genetic studies of POAG published in English prior to September 2019. In total, 74 genomic regions have been associated at a genome-wide level of significance with POAG susceptibility. Recent POAG GWAS provide not only insight into global and ethnic-specific genetic risk factors for POAG susceptibility across populations of diverse ancestry, but also important functional insights underlying biological mechanisms of glaucoma pathogenesis. In this review, we also summarize the genetic overlap between POAG, glaucoma endophenotypes, such as intraocular pressure and vertical cup-disc ratio (VCDR), and other eye disorders. We also discuss approaches recently developed to increase power for POAG locus discovery and to predict POAG risk. Finally, we discuss the recent development of POAG gene-based therapies and future strategies to treat glaucoma effectively. Understanding the genetic architecture of POAG is essential for an earlier diagnosis of this common eye disorder, predictive testing of at-risk patients, and design of gene-based targeted medical therapies none of which are currently available.

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.

Association of MTHFR C677T and A1298C Polymorphisms with Glaucoma Risk: a Systematic Review Meta-Analysis based 42 Case-Control Studies

Aim: Several epidemiological studies have been performed to explore the association of MTHFR polymorphisms with glaucoma risk. However, the results were inconsistent or even inconclusive. Hence, we performed a meta-analysis to evaluate the association of MTHFR C677T and A1298C polymorphisms with glaucoma risk. Methods: A comprehensive literature search on PubMed, Google Scholar, EMBASE, and CNKI databases was performed to find all eligible studies up to January 30, 2019. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of such association. Results: A total of 42 case-control studies including 33 studies for MTHFR C677T and nine studies for A1298C polymorphism were selected. Pooled results showed that there was no significant association between the MTHFR C677T polymorphism and glaucoma risk. Similarly, no associations were found in subgroup analysis based on ethnicity and glaucoma type. However, there was a significant association between the A1298C polymorphism and the increased risk of glaucoma under heterozygote model (OR=0.765, 95% CI=0.626-0.935, P=0.009). Moreover, the significant association between MTHFR A1298C polymorphism and glaucoma were found by ethnicity and primary open angle glaucoma (POAG). Conclusions: The present meta-analysis revealed that MTHFR A1298C polymorphism is significantly associated with the increased risk of glaucoma, but not MTHFR C677T polymorphism.

The Rationale for Selective Laser Trabeculoplasty in Africa

Glaucoma is the leading cause of irreversible blindness in Africa. The condition is treatable but not curable. There are numerous obstacles to glaucoma care in Africa, including availability, accessibility and affordability of treatments, as well as medication nonadherence among patients. Medical therapy is costly relative to the average income in Africa and it requires daily self-dosing by patients. Surgery is of limited availability in many regions in Africa, and a high proportion of patients refuse surgery because it is expensive. Selective laser trabeculoplasty (SLT) proves to be a favorable alternative to medical or surgical care, as it is highly effective and safe in people of African descent, more cost-effective than medical therapy, quick and easy to perform, and portable. The procedure also requires no postoperative care, thus obviates the issue of nonadherence. In uncontrolled studies, SLT has a high response rate and it lowers intraocular pressure by 30% to 40%, which exceeds the goal in international guidelines for initial therapies. The African Glaucoma Consortium (AGC), a member-driven stakeholder collective, has been formed in part to develop the infrastructure for continent-wide improvements in glaucoma care. It embraces SLT as a potential key tool in their development plans. The mission of AGC includes improving clinical care by educating existing and new health care professionals to expand the provider network, by conducting trials to identify optimal care strategies for glaucoma in Africa, and by facilitating the development of an integrated network of Centers of Excellence to bring SLT and other crucial glaucoma therapies to communities throughout Africa.

Genome-wide association study of primary open-angle glaucoma in continental and admixed African populations

Primary open angle glaucoma (POAG) is a complex disease with a major genetic contribution. Its prevalence varies greatly among ethnic groups, and is up to five times more frequent in black African populations compared to Europeans. So far, worldwide efforts to elucidate the genetic complexity of POAG in African populations has been limited. We conducted a genome-wide association study in 1113 POAG cases and 1826 controls from Tanzanian, South African and African American study samples. Apart from confirming evidence of association at TXNRD2 (rs16984299; OR_[T] 1.20; P = 0.003), we found that a genetic risk score combining the effects of the 15 previously reported POAG loci was significantly associated with POAG in our samples (OR 1.56; 95% CI 1.26–1.93; P = 4.79 × 10⁻⁵). By genome-wide association testing we identified a novel candidate locus, rs141186647, harboring EXOC4 (OR_[A] 0.48; P = 3.75 × 10⁻⁸), a gene transcribing a component of the exocyst complex involved in vesicle transport. The low frequency and high degree of genetic heterogeneity at this region hampered validation of this finding in predominantly West-African replication sets. Our results suggest that established genetic risk factors play a role in African POAG, however, they do not explain the higher disease load. The high heterogeneity within Africans remains a challenge to identify the genetic commonalities for POAG in this ethnicity, and demands studies of extremely large size.

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.

B-mode sonographic evaluation of optic nerve sheath diameter and lens thickness in Nigerian adults with glaucoma

Objective

This study was done to investigate the effect(s) of glaucoma on the ocular optic nerve sheath diameter and lens thickness using B-mode ultrasonography.

Materials and methods

One hundred and twenty study participants were recruited; 60 subjects with glaucoma and 60 age- and sex-matched controls without glaucoma. The optic nerve sheath diameter and lens thickness of both eyes were measured using a linear high frequency transducer with frequency of 6.5–12MHz.

Results

The mean optic nerve sheath diameter of the glaucomatous eyes (3.57 ± 0.19mm and 3.59 ± 0.33mm on the right and left, respectively) were significantly thinner than that of controls (4.23 ± 0.34 mm and 4.26 ± 0.30 mm on the right and left, respectively; p < 0.001). There is increased mean lens thickness in the glaucomatous eyes (4.15 ± 0.43mm and 4.18 ± 0.46mm on the right and left, respectively) than in the controls (4.01 ± 0.56mm and 3.99 ± 0.45mm on the right and left, respectively) with a statistically significant difference seen in the left eye (p = 0.024).

Conclusion

B-mode ultrasound is a reliable tool of assessing the nerve sheath diameter and lens thickness in glaucoma. Optic nerve sheath diameter is reduced in glaucoma

Safety and effectiveness of primary transscleral diode laser cyclophotoablation for glaucoma in Nigeria

Importance

To investigate the safety, effectiveness and follow‐up rates after transscleral diode laser cyclophotocoagulation as primary treatment for seeing eyes with primary open angle glaucoma in Bauchi, Nigeria.

Background

There is a high prevalence of primary open angle glaucoma in Africa where adherence to medical treatment and acceptance of surgery are poor.

Design

Prospective case series.

Participants

New glaucoma patients where surgical intervention was recommended.

Methods

A diode 810 nm laser G‐probe was used under retrobulbar anaesthesia to deliver approximately 20 shots for 2000 ms, titrating the power. If both eyes were treated the first was the study eye. Repeat treatment offered if the intraocular pressure (IOP) was >21 mmHg on two consecutive visits.

Main Outcome Measures

IOP < 22 mmHg, change in ≥2 lines of Snellen visual acuity (VA), and complications.

Results

201 out of 204 eyes with complete data analysed. Mean age 52 years, 17 (8.3%) eyes were re‐treated. Mean pre‐treatment IOP was 39 (SD 11) mmHg. 106 (53%) attended at 12 months when the mean IOP was 19 (7–45) mmHg; 77 (73%) had IOP < 22 mmHg. VAs were better in 13 (12.3%) and worse in 23 (21.7%) eyes. Postoperative complications included mild uveitis (5.5%), corneal oedema (2.5%), severe uveitis (0.5%) and transient hypotony (2.0%). No hypotony at 12 months.

Conclusions and Relevance

Transscleral diode laser cyclophotocoagulation controlled IOP in almost three quarters of eyes at 12 months with short‐term preservation of vision and minimal complications. Poor follow‐up in this setting highlights the need for an effective, safe and acceptable treatment where regular follow‐up is less critical.