Rapid Assessment of Avoidable Blindness and Diabetic Retinopathy in Chiapas, Mexico

Prevalence and incidence of diabetic retinopathy in patients with diabetes of Latin America and the Caribbean: A systematic review and meta-analysis

OBJECTIVES

This systematic review aimed to assess the prevalence and incidence of diabetic retinopathy in patients with diabetes of Latin America and the Caribbean.

METHODS

We searched Web of Science (WoS)/Core Collection, WoS/MEDLINE, WoS/Scielo, Scopus, PubMed/Medline and Embase databases until January 16, 2023. We meta-analyzed prevalences according to type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM).

RESULTS

Forty-three prevalence studies (47 585 participants) and one incidence study (436 participants) were included. The overall prevalence of retinopathy in patients with T1DM was 40.6% (95% CI: 34.7 to 46.6; I2: 92.1%) and in T2DM was 37.3% (95% CI: 31.0 to 43.8; I2: 97.7), but the evidence is very uncertain (very low certainty of evidence). In meta-regression, we found that age (T1DM) and time in diabetes (T2DM) were factors associated with the prevalence. On the other hand, one study found a cumulative incidence of diabetic retinopathy of 39.6% at 9 years of follow-up.

CONCLUSIONS

Two out of five patients with T1DM or T2DM may present diabetic retinopathy in Latin America and the Caribbean, but the evidence is very uncertain. This is a major public health problem, and policies and strategies for early detection and opportunely treatment should be proposed.

Present and future screening programs for diabetic retinopathy: a narrative review

Diabetes is a prevalent global concern, with an estimated 12% of the global adult population affected by 2045. Diabetic retinopathy (DR), a sight-threatening complication, has spurred diverse screening approaches worldwide due to advances in DR knowledge, rapid technological developments in retinal imaging and variations in healthcare resources.Many high income countries have fully implemented or are on the verge of completing a national Diabetic Eye Screening Programme (DESP). Although there have been some improvements in DR screening in Africa, Asia, and American countries further progress is needed. In low-income countries, only one out of 29, partially implemented a DESP, while 21 out of 50 lower-middle-income countries have started the DR policy cycle. Among upper-middle-income countries, a third of 59 nations have advanced in DR agenda-setting, with five having a comprehensive national DESP and 11 in the early stages of implementation.Many nations use 2-4 fields fundus images, proven effective with 80-98% sensitivity and 86-100% specificity compared to the traditional seven-field evaluation for DR. A cell phone based screening with a hand held retinal camera presents a potential low-cost alternative as imaging device. While this method in low-resource settings may not entirely match the sensitivity and specificity of seven-field stereoscopic photography, positive outcomes are observed.Individualized DR screening intervals are the standard in many high-resource nations. In countries that lacks a national DESP and resources, screening are more sporadic, i.e. screening intervals are not evidence-based and often less frequently, which can lead to late recognition of treatment required DR.The rising global prevalence of DR poses an economic challenge to nationwide screening programs AI-algorithms have showed high sensitivity and specificity for detection of DR and could provide a promising solution for the future screening burden.In summary, this narrative review enlightens on the epidemiology of DR and the necessity for effective DR screening programs. Worldwide evolution in existing approaches for DR screening has showed promising results but has also revealed limitations. Technological advancements, such as handheld imaging devices, tele ophthalmology and artificial intelligence enhance cost-effectiveness, but also the accessibility of DR screening in countries with low resources or where distance to or a shortage of ophthalmologists exists.

Identification of Genetic Variants for Diabetic Retinopathy Risk Applying Exome Sequencing in Extreme Phenotypes

Background

Diabetic retinopathy (DR) risk has been shown to vary depending on ethnic backgrounds, and thus, it is worthy that underrepresented populations are analyzed for the potential identification of DR-associated genetic variants. We conducted a case-control study for the identification of DR-risk variants in Mexican population.

Methods

We ascertained 60 type 2 diabetes mellitus (T2DM) patients. Cases (n = 30) were patients with advanced proliferative DR (PDR) with less than 15 years after a T2DM diagnosis while controls (n = 30) were patients with no DR 15 years after the diagnosis of T2DM. Exome sequencing was performed in all patients, and the frequency of rare variants was compared. In addition, the frequency of variants occurring in a set of 169 DR-associated genes were compared.

Results

Statistically significant differences were identified for rare missense and splice variants and for rare splice variants occurring more than once in either group. A strong statistical difference was observed when the number of rare missense variants with an aggregated prediction of pathogenicity and occurring more than once in either group was compared (p = 0.0035). Moreover, 8 variants identified more than once in either group, occurring in previously identified DR-associated genes were recognized. The p.Pro234Ser KIR2DS4 variant showed a strong protective effect (OR = 0.04 [0.001-0.36]; p = 0.04).

Conclusions

Our study showed an enrichment of rare splice acceptor/donor variants in patients with PDR and identified a potential protective variant in KIR2DS4. Although statistical significance was not reached, our results support the replication of 8 previously identified DR-associated genes.

Diabetic Retinopathy Screening Using Smartphone-Based Fundus Photography and Deep-Learning Artificial Intelligence in the Yucatan Peninsula: A Field Study

BACKGROUND

To compare the performance of Medios (offline) and EyeArt (online) artificial intelligence (AI) algorithms for detecting diabetic retinopathy (DR) on images captured using fundus-on-smartphone photography in a remote outreach field setting.

METHODS

In June, 2019 in the Yucatan Peninsula, 248 patients, many of whom had chronic visual impairment, were screened for DR using two portable Remidio fundus-on-phone cameras, and 2130 images obtained were analyzed, retrospectively, by Medios and EyeArt. Screening performance metrics also were determined retrospectively using masked image analysis combined with clinical examination results as the reference standard.

RESULTS

A total of 129 patients were determined to have some level of DR; 119 patients had no DR. Medios was capable of evaluating every patient with a sensitivity (95% confidence intervals [CIs]) of 94% (88%-97%) and specificity of 94% (88%-98%). Owing primarily to photographer error, EyeArt evaluated 156 patients with a sensitivity of 94% (86%-98%) and specificity of 86% (77%-93%). In a head-to-head comparison of 110 patients, the sensitivities of Medios and EyeArt were 99% (93%-100%) and 95% (87%-99%). The specificities for both were 88% (73%-97%).

CONCLUSIONS

Medios and EyeArt AI algorithms demonstrated high levels of sensitivity and specificity for detecting DR when applied in this real-world field setting. Both programs should be considered in remote, large-scale DR screening campaigns where immediate results are desirable, and in the case of EyeArt, online access is possible.

National sex- and age-specific burden of blindness and vision impairment by cause in Mexico in 2019: a secondary analysis of the Global Burden of Disease Study 2019

Background

Reliable national estimations for blindness and vision impairment are fundamental to assessing their burden and developing public health policies. However, no comprehensive analysis is available for Mexico. Therefore, in this observational study we describe the national burden of blindness and vision loss by cause and severity during 2019.

Methods

Using public data from the Global Burden of Disease (GBD) study 2019, we present national prevalence and years lived with disability (YLDs) counts and crude and age-standardized rates (per 100,000 people) of total, severity- and cause-specific blindness and vision impairment with 95% uncertainty intervals (UIs) by sex and age group.

Findings

In Mexico, the burden of blindness and vision impairment was estimated at 11.01 million (95% UI, 9.25-13.11) prevalent cases and 384.96 thousand (259.57-544.24) YLDs during 2019. Uncorrected presbyopia caused the highest burden (6.06 million cases, 4.36-8.08), whereas severe vision loss and blindness affected 619.40 thousand (539.40-717.73) and 513.84 thousand (450.59-570.98) people, respectively. Near vision loss and refraction disorders caused 78.7% of the cases, whereas neonatal disorders and age-related macular degeneration were among the least frequent. Refraction disorders were the main cause of moderate and severe vision loss (61.44 and 35.43%), and cataracts were the second most frequent cause of blindness (26.73%). Females suffered an overall higher burden of blindness and vision impairment (54.99% and 52.85% of the total cases and YLDs), and people >50 years of age suffered the highest burden, with people between 70 and 74 years being the most affected.

Interpretation

Vision loss represents a public health problem in Mexico, with women and older people being the most affected. Although the causes of vision loss contribute differentially to the severity of visual impairment, most of the impairment is avoidable. Consequently, a concerted effort at different levels is needed to alleviate this burden.

Funding

This study received no funding.

Inclusion of diabetic retinopathy screening strategies in national-level diabetes care planning in low- and middle-income countries: a scoping review

BACKGROUND

Diabetes is a major public health concern, with approximately 80% of the burden falling on low- and middle-income countries (LMICs). Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes, and early detection through diabetic eye screening programmes is essential to prevent visual impairment and blindness. Careful planning at a national level is crucial for effective implementation of such programmes.

METHODS

A scoping review was conducted, and the protocol was published previously to explain the methods in detail. Data were collected from databases and searches, including grey literature. Furthermore, consultations were conducted with key informants from LMICs.

RESULTS

Lower-middle-income countries (29/50, 58%) and upper-middle-income countries (27/59, 45.8%) are making more progress than low-income countries (4/29, 13.8%) in terms of DR policy planning. However, no identified data for published policies have actually implemented national DR policies. Compared to low-income and lower-middle-income countries, upper-middle-income countries are making the most progress in implementing national diabetic eye screening programmes; however, their progress is still slow, with only 5/59 (8.5%) having such programmes.

CONCLUSION

There are significant gaps in the literature, with no data reported for 78/138 (56.5%) LMICs. Further research is clearly needed to support and document DR policy development in LMICs.

Serum Ang-1/Ang-2 ratio may be a promising biomarker for evaluating severity of diabetic retinopathy

PURPOSE

To investigate the predictive role of serum angiopoietin-1 and angiopoietin-2 (Ang-1/Ang-2) in evaluating the severity of diabetic retinopathy (DR).

METHODS

A total of 101 outpatients with type 2 diabetes mellitus (T2DM) were recruited and were further divided into the following five groups: T2DM without DR (non-DR), mild non-proliferative DR (NPDR), moderate NPDR, severe NPDR and proliferative DR (PDR) in accordance with the International Clinical Diabetic Retinopathy Guidelines. Furthermore, 101 serum samples were included in the further analysis using enzyme-linked immunosorbent assays. A receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic value of each index.

RESULTS

The expression of Ang-1 in the PDR group was significantly lower than that in the non-DR group, while Ang-2 showed an opposite upward trend (p < 0.05). The Ang-1/Ang-2 ratio of the non-DR group was significantly lower than that of the moderate NPDR, severe NPDR and PDR (p < 0.05, p < 0.01 and p < 0.01, respectively). Differences in the Ang-1/Ang-2 ratio were observed earlier than those in the individual Ang-1 and Ang-2 measurements. The maximal Youden index was 0.512 with a calculated area under the curve (AUC) value of 0.734 (p < 0.01).

CONCLUSIONS

The Ang-1/Ang-2 ratio was helpful in assessing the severity of DR and may provide potential clinical benefits as a biomarker and early warning signs for DR diagnosis.

Importance of Early Spotting of Diabetic Retinopathy in Type 2 Diabetes Patients by Family Medicine Physicians and Ophthalmologists: A Study in Jordan

BACKGROUND

Diabetes mellitus is a long-standing progressive disorder. Diabetic retinopathy is the primary cause of blindness among adults suffering from diabetes. Diabetic retinopathy is found to be dependent on the length of the period affected by diabetes, glucose control, blood pressure, and lipid profile while age, sex, and type of medical therapy were not found to be risk factors.  Aim: This study attempts to determine the importance of early spotting of diabetic retinopathy in Jordanian type 2 diabetes mellitus (T2DM) subjects by family medicine and ophthalmologist physicians, which will help us achieve better health outcomes.  Methods: Our retrospective investigation recruited 950 working-age subjects, of both sexes and with T2DM at three hospitals in Jordan, from September 2019 to June 2022. Early spotting of diabetic retinopathy was done by family medicine physicians and confirmation was done by ophthalmologists using direct ophthalmoscopy. Evaluation of the fundus by pupillary dilation was performed to assess the degree of diabetic retinopathy, macular edema, and the number of patients with diabetic retinopathy. The level of severity for diabetic retinopathy at confirmation was done using the classification for diabetic retinopathy produced by the American Association of Ophthalmology (AAO). Continuous parameters and independent t-tests were used to assess the average discrepancy in the degree of retinopathy among subjects. Categorical parameters were mentioned in numbers and percentages and chi-square tests were done to determine discrepancies in proportion among patients.   Results: Early spotting of diabetic retinopathy was recorded by family medicine physicians in 150 (15.8%) of 950 patients with T2DM of whom 56.7% (85/150) were women with an average age of 44 years. Of these 150 subjects with T2DM, who were presumed to have diabetic retinopathy, ophthalmologists diagnosed diabetic retinopathy in 35 patients (35/150; 23.3%). Of these, 33 (94.3%) had non-proliferative diabetic retinopathy and two (5.7%) had proliferative diabetic retinopathy. Of the 33 patients with non-proliferative diabetic retinopathy, 10 had mild non-proliferative diabetic retinopathy, 17 had moderate non-proliferative diabetic retinopathy, and six had severe non-proliferative diabetic retinopathy. Subjects aged more than 28 years had a 2.5 times increased risk of experiencing diabetic retinopathy. Awareness and lack of awareness values differed significantly (316 (33.3%), 634 (66.7%); P<0.05, respectively).  Conclusions: Early spotting of diabetic retinopathy by family medicine physicians shortens the delay of diagnosis confirmation by ophthalmologists.

Evaluation of a remote telemedicine platform using a novel handheld fundus camera: Physician and patient perceptions from real-world experience

BACKGROUND

Although teleophthalmology has gained traction in recent years, it is at the center of the coronavirus disease pandemic. However, most hospitals are not ready owing to a severe lack of real-world experience. Furthermore, a limited number of studies have evaluated telemedicine applications on remote islands. This study aimed to evaluate real-world clinical and referral accuracy, image quality, physician-perceived diagnostic certainty, and patient satisfaction with telemedicine eye screening using a novel handheld fundus camera in a rural and medically underserved population.

METHODS

This prospective study included 176 eyes from a remote island. All participants underwent a comprehensive ophthalmic examination. Nonmydriatic retinal images obtained using a handheld fundus camera were reviewed by two retinal specialists to determine image quality, diagnosis, and need for referrals. The agreement of diagnosis between image-based assessments was compared with that of binocular indirect ophthalmoscopic assessments.

RESULTS

Image quality of fundus photographs was considered acceptable or ideal in 97.7% and 95.5% of eyes assessed by two reviewers, respectively. There was considerable agreement in diagnosis between the indirect ophthalmoscopic assessment and image-based assessment by two reviewers (Cohen's kappa = 0.80 and 0.78, respectively). Likewise, substantial agreement was achieved in the referrals. The sensitivity for referable retinopathy from the two reviewers was 78% (95% confidence interval [CI], 57%-91%) and 78% (95% CI, 57%-91%), whereas specificity was 99% (95% CI, 95%-99%] and 98% (95% CI, 93%-99%), respectively. For physicians' perceived certainty of diagnosis, 93.8% and 90.3% were considered either certain or reliable. Overall, 97.4% of participants were satisfied with their experiences and greatly valued the telemedicine services.

CONCLUSION

Novel fundus camera-based telemedicine screening demonstrated high accuracy in detecting clinically significant retinopathy in real-world settings. It achieved high patient satisfaction and physician-perceived certainty in diagnosis with reliable image quality, which may be scaled internationally to overcome geographical barriers under the global pandemic.

Altered spontaneous brain activity patterns in patients with diabetic retinopathy using amplitude of low-frequency fluctuation

BACKGROUND

Diabetes mellitus is a metabolic disorder characterized by prolonged elevation of blood glucose due to various causes. Currently, the relationship between diabetic retinopathy (DR) and altered connectivity of brain function is unclear.

AIM

To investigate the relationship between this brain activity and clinical manifestations and behaviors of DR patients by using the amplitude of low-frequency fluctuation (ALFF) technique.

METHODS

Twenty-four DR patients and 24 healthy controls (HCs) matched for age and gender were enrolled. We measured and recorded average ALFF values of DR patients and HCs and then classified them using receiver operating characteristic (ROC) curves.

RESULTS

ALFF values of both left and right posterior cerebellar lobe and right anterior cingulate gyrus were remarkably higher in the DR patients than in the HCs; however, DR patients had lower values in the bilateral calcarine area. ROC curve analysis of different brain regions demonstrated high accuracy in the area under the curve analysis. There was no significant relationship between mean ALFF values for different regions and clinical presentations in DR patients. Neuronal synchronization abnormalities in some brain regions of DR patients were associated with cognitive and visual disorders.

CONCLUSION

Abnormal spontaneous brain activity was observed in many areas of DR patients’ brains, which may suggest a possible link between clinical manifestations and behaviors in DR patients.

Cluster-randomised trial of community-based screening for eye disease in adults in Nepal: the Village-Integrated Eye Worker Trial II (VIEW II) trial protocol

INTRODUCTION

The majority of blindness worldwide could be prevented or reversed with early diagnosis and treatment, yet identifying at-risk and prevalent cases of eye disease and linking them with care remain important obstacles to addressing this burden. Leading causes of blindness like glaucoma, diabetic retinopathy and age-related macular degeneration have detectable early asymptomatic phases and can cause irreversible vision loss. Mass screening for such diseases could reduce visual impairment at the population level.

METHODS AND ANALYSIS

This protocol describes a parallel-group cluster-randomised trial designed to determine whether community-based screening for glaucoma, diabetic retinopathy and age-related macular degeneration reduces population-level visual impairment in Nepal. A door-to-door population census is conducted in all study communities. All adults aged ≥60 years have visual acuity tested at the census visit, and those meeting referral criteria are referred to a local eye care facility for further diagnosis and management. Communities are subsequently randomised to a community-based screening programme or to no additional intervention. The intervention consists of a single round of screening including intraocular pressure and optical coherence tomography assessment of all adults ≥60 years old with enhanced linkage to care for participants meeting referral criteria. Four years after implementation of the intervention, masked outcome assessors conduct a repeat census to collect data on the primary outcome, visual acuity. Individuals with incident visual impairment receive a comprehensive ophthalmological examination to determine the cause of visual impairment. Outcomes are compared by treatment arm according to the originally assigned intervention.

ETHICS AND DISSEMINATION

The trial has received ethical approval from the University of California San Francisco Institutional Review Board, Nepal Netra Jyoti Sangh and the Nepal Health Research Council. Results of this trial will be disseminated through publication in peer-reviewed journals and presentation at local and international meetings.

TRIAL REGISTRATION NUMBER

NCT03752840.

Current State of Diabetes Mellitus Prevalence, Awareness, Treatment, and Control in Latin America: Challenges and Innovative Solutions to Improve Health Outcomes Across the Continent

PURPOSE OF REVIEW

Latin America is the scenario of great inequalities where about 32 million human beings live with diabetes. Through this review, we aimed at describing the current state of the prevalence, awareness, treatment, and control of diabetes mellitus and completion of selected guidelines of care across Latin America and identify opportunities to advance research that promotes better health outcomes.

RECENT FINDINGS

The prevalence of diabetes mellitus has been consistently increasing across the region, with some variation: higher prevalence in Mexico, Haiti, and Puerto Rico and lower in Colombia, Ecuador, Dominican Republic, Peru, and Uruguay. Prevalence assessment methods vary, and potentially underestimating the real number of persons with diabetes. Diabetes unawareness varies widely, with up to 50% of persons with diabetes who do not know they may have the disease. Glycemic, blood pressure, and LDL-C control and completion of guidelines to prevent microvascular complications are not consistently assessed across studies, and the achievement of control goals is suboptimal. On the other hand, multiple interventions, point-of-care/rapid assessment tools, and alternative models of health care delivery have been proposed and tested throughout Latin America. The prevalence of diabetes mellitus continues to rise across Latin America, and the number of those with the disease may be underestimated. However, some local governments are embedding more comprehensive diabetes assessments in their local national surveys. Clinicians and public health advocates in the region have proposed and initiated various multi-level interventions to address this enormous challenge in the region.

Relationship between diabetes mellitus and cataract in Hungary

AIM

To examine the coexistence of diabetes mellitus (DM) and cataract in Hungary. The effects of DM on the cataract surgical results were also in the focus of analysis.

METHODS

Statistical data analysis of the results of the Rapid Assessment of Avoidable Blindness with Diabetic Retinopathy (RAAB+DR) module conducted in Hungary in 2015. This cross-sectional, population-based, national survey included 3523 people aged 50 years and over. Participants of the survey were examined on-site. Visual acuity, main cause for visual impairment (using direct and indirect ophthalmoscopes), in case of best corrected visual acuity (BCVA) ≤0.5 and blood glucose level (random test with glucometer) were examined.

RESULTS

The prevalence of cataract was 23.4%, and DM was 20.0%. The occurrence of cataract steadily increased with age. Among the examined participants with DM, the prevalence of cataract was significantly (P=0.012) higher (+35%) than that in non-diabetic subjects (29.5% vs 21.8%). Following aging (OR=15.2%, P<0.001), DM proved to be the most independent influencing risk factor (OR=49.9%, P<0.001). The presence of DM was neither an influencing factor for complications of cataract surgery, nor for postoperative visual acuity.

CONCLUSION

DM appears to be one of the main risk factors for developing cataract. Other risk factors, such as age, sex and environment also play an influencing role. Diabetes does not seem to affect the occurrence of cataract surgical complications.

Diagnostic Accuracy of Rapid Assessment of Avoidable Blindness: A Population-based Assessment

OBJECTIVES

To evaluate the diagnostic accuracy of rapid assessment of avoidable blindness (RAAB).

DESIGN

Population-based diagnostic accuracy study.

METHODS

A total of 2145 (95.3%, 2145/2250) subjects aged 50 years and older who participated in the RAAB survey were included. All the recruited participants underwent ophthalmic examination according to the RAAB protocol and then were reexamined with instruments in a mobile eye clinic set up in a village center on the same day. Examination in the mobile clinic included standardized visual acuity (VA) tests using logMAR charts, refraction, slit-lamp biomicroscopy, and dilated fundal examination with a binocular indirect ophthalmoscope. Blindness and economic blindness were defined as VA in the better-seeing eye <3/60 and <6/60, respectively. Visual impairment (VI) was defined as VA <6/18 in the better eye. The primary cause of blindness and VI was defined according to the cause of VI in the participant's better eye.

MAIN OUTCOME MEASURES

The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and area under the curve (AUC) of receiver operating characteristics of RAAB for detection of blindness and the principal causes of VI.

RESULTS

A total of 1816 subjects (84.7%), including 686 men (37.8%) and 1130 women (62.2%), underwent ophthalmic examination in the mobile eye clinic. The mean (±standard deviation) age was 64.4 ± 9.6 years. The sensitivities, specificities, AUC, PLR, and NLR of RAAB were 90.3%, 99.3%, 0.948, 124.0, and 0.10, respectively, for detection of blindness (presenting visual acuity, PVA <3/60); 89.5%, 98.7%, 0.940, 69.2, and 0.11, respectively, for detection of economic blindness (PVA <6/60); and 90.3%, 97.7%, 0.940, 38.7, and 0.10, respectively, for detection of VI (PVA <6/18). The sensitivities, specificities, AUC, PLR, and NLR were 90.5%, 98.1%, 0.943, 48.1, and 0.10; and 60.4%, 98.7%, 0.796, 46.4, and 0.40 for detection of VI (PVA <6/18) owing to cataract and refractive error, respectively.

CONCLUSION

The diagnostic performances of RAAB were high for detecting the prevalence of blindness, VI, and VI owing to cataract.

Prevalence and associated risk factors of diabetic retinopathy and macular oedema in patients recently diagnosed with type 2 diabetes

Objective

To determine the prevalence of diabetic retinopathy (DR) and diabetic macular oedema (DME) and their associated risk factors in patients recently diagnosed with type 2 diabetes.

Methods and analysis

We carried out a cross-sectional study from April 2014 to August 2017. We included patients aged ≥18 years. Diabetes was defined as fasting plasma glucose of >7.8 mmol/L or 2-hour postload plasma glucose of >11.1 mmol/L. Non-mydriatic fundus examination with a digital-fundus camera was performed. Three images centred in the macula, optic disc and temporal to the macula were obtained and graded according to the Scottish Scale Classification of Diabetic Retinopathy.

Results

1232 patients (mean age 51.5 years) with a diabetes duration of 0–5 years were examined. Age-adjusted and sex-adjusted prevalence of DR and DME was 17.4% (95% CI 15.3% to 19.6%) and 6.6% (95% CI 5.4% to 8.2%), respectively. DR was associated with diabetes duration (OR per year=1.20, p<0.001), haemoglobin A1c (HbA1c) from 7.0 to 8.9 (OR=2.19, p<0.001), HbA1c≥9 (OR=2.98, p<0.001) and systolic blood pressure (SBP) (OR=1.16 per 5 mm Hg, p<0.001). DME was associated with diabetes duration (OR per year=1.26, p<0.01), HbA1c from 7.0 to 8.9 (OR=2.26, p<0.05), HbA1c≥9 (OR=2.38, p<0.01), SBP (OR per mm Hg=1.15, p<0.001) and albuminuria (OR=2.45, p<0.01).

Conclusion

Our study contributes to the evidence of progressive increase in DR and DME risk in early stages of diabetes, supporting the urgent need for early screening.

Adults visual impairment and blindness - An overview of prevalence and causes in Saudi Arabia

BACKGROUND

A major socio-economic development in Saudi Arabia affected the pattern and causes of visual impairment for the past 40 years. Moreover, an up-to-date summary of available data is vital for planning, monitoring, and evaluating national blindness prevention program.

AIM

This study conducted to provide a summary overview of prevalence, causes, and changes in the pattern of blindness and visual impairment for the past 40 years among Saudi adults, with brief discussion of the related socio-economic and ecological factors.

METHODS

The review was confined to the published epidemiological studies performed in Saudi Arabia covering the age group 18 year and older from 1985 onwards.

RESULTS

Six epidemiological studies were included from 1985 onwards. In1986, the prevalence of blindness and visual impairment in Saudi Arabia were 1.5% and 7.8%, respectively which is 20 times the magnitude of blindness in the United States. Multiple regional population based studies conducted later in areas with disparate ecological and socio-economical determinants at different time intervals showed variable prevalence of blindness 3.3% Eastern Province 1986, 0.7% Bisha 1993. Recently, in older than 50 year population the reported prevalence was 2.6% Taif 2012 and 5.7% Jazan 2015 and 6.4% in Ahsa. Since 1986, the single leading cause of adult blindness in Saudi Arabia is cataract. Although, Trachoma reported to be the second primary cause of blindness on 1986, its burden is reduced in Jizan (2015) and minimal in Taif (2012) which is replaced by chronic diseases related etiologies i.e Diabetic Retinopathy.

CONCLUSION

Ecological and socio-economical determinants play critical role in the magnitude and causes of blindness and visual impairment in Saudi Arabia. Significant data gaps obscure monitoring and evaluation of the eye health. Eye health indicators should be integrated into the national health information system for dynamic monitoring and evaluation.

Teleophthalmology: a strategy for timely diagnosis of sight-threatening diabetic retinopathy in primary care, Concepción, Chile

AIM

To estimate the prevalence of diabetic retinopathy (DR) in a diabetic population of the public health system.

METHODS

This non-experimental, descriptive and cross-sectional study, with no direct control over the variables analysed, was carried out by the Telemedicine Unit of the University of Concepción (TELMED) and the Family Health Centers (CESFAM) of the Health Service Concepción, Chile, among a population of 7382 diabetic patients of the public health system, from October 2014 to June 2015. Two digital images for each patient's eyes were obtained and uploaded to the TELMED tele-ophthalmology platform. The images were remotely evaluated by a retina expert ophthalmologist for diagnosis. Treatment and a referral (if required) were recommended, and an individualised report for each patient was sent to the place of origin.

RESULTS

The prevalence of DR in this study was 14.9%. Of these, 48.7% had mild non-proliferative DR (NPDR), 30.8% moderate NPDR, 15.9% severe NPDR, and 4.6% proliferative DR. Of the patients with DR, 17.8% were referred for fluorescein angiography, 4.3% for panretinal photocoagulation, 1.2% for vitrectomy, and 0.4% for cataract surgery.

CONCLUSION

The use of telemedicine allowed an increased screening coverage for DR in diabetic patients. The different types of DR were detected in a timely manner, decreasing waiting times due to the lack of specialists in ophthalmology in the public health system.

Generating evidence for planning eye care service delivery in an urban underprivileged population setting in Pune, Western India

Purpose

To estimate prevalence of blindness, diabetic retinopathy and causes of blindness through rapid assessment of avoidable blindness (RAAB) survey in Pune, India to develop an evidence base for planning urban eye care services.

Methods

‘Rapid assessment of avoidable blindness and diabetic retinopathy’ methodology was used. Compact segment sampling was used in each of the 60 selected electoral wards identified through cluster selection module of the RAAB software using probability proportionate to size method. Persons >50 years of age were enumerated from selected segments to achieve cumulative target of 60/day by two teams. Participants underwent presenting and pinhole visual acuity (VA) testing in each eye. A torch light examination and direct ophthalmoscopy established cause of visual impairment/blindness if present. Data were entered into and analysed using RAAB software.

Results

The response rate was 89.5% (3221/3600), and 55.3% were women. Results of only RAAB module are presented in this paper. Age-standardised and sex-standardised prevalence of blindness was 1.3% (95% CI 0.9 to 1.8). Cataract was the most common cause of blindness (45.7%) followed by overall posterior segment disorders (39.1%). Cataract surgical outcome was good (VA>6/18) or very good (VA>6/12) in 805/1190 (67.6%) cases. Cataract surgical coverage was 96.7%. ‘Need not felt’ (36.6%) and ‘cost’ (31.7%) were the most common barriers for cataract surgery.

Conclusion

Prevalence of blindness is showing declining trend in urban India. Cataract remains a major cause of blindness followed by posterior segment disorders. Social marketing, and referral linkages between community and service providers were planned after this survey.

Rural–urban disparities in the prevalence of diabetes and diabetic eye complications in Hungary

Background

To examine the rural–urban differences in the prevalence of diabetes mellitus (DM) and diabetic retinopathy (DR) in the population aged 50 years and older in Hungary.

Methods

105 clusters of 35 people aged 50 years or older were randomly selected. Standardized rapid assessment of avoidable blindness (RAAB) with the diabetic retinopathy module was performed. Participants were classified as diabetic if they had a previous diagnosis of DM or a random blood glucose level ≥200 mg/dl. Each individual with DM who agreed underwent dilated fundus examination and DR grading.

Results

The prevalence of DM was higher in rural (21.8%) than in urban (18.6%) areas (p = 0.016). The prevalence of DR did not differ significantly between rural and urban areas in DM cases. Blindness (0.9% vs. 0.1%; p = 0.048) and blindness due to DM (0.3% vs. 0.0%; p = 0.021) in diabetic participants was significantly more common in rural than in urban areas. Diabetic eye screening coverage was significantly lower in rural than in urban areas (p ≤ 0,007).

Conclusion

Based on our results and the high rate of blindness and blindness due to DR in rural areas, primary eye care should be improved and a telemedical eye screening program should be undertaken, especially concentrating on rural areas.

Rapid Assessment of Avoidable Blindness: looking back, looking forward

The Rapid Assessment of Avoidable Blindness, or RAAB, is a relatively simple and low-cost survey methodology to provide data on the prevalence and causes of visual loss. The aim of this article is to reflect on the achievements and challenges of RAAB, and to describe the future developments that are needed to ensure that it remains a relevant and widely used tool. To date, at least 331 RAABs have been undertaken in 79 countries, and these surveys provide an important source of information on visual loss at both the local and global level. A RAAB repository has been developed which includes the site and date of RAABs undertaken, and, where authors have agreed, the core indicators, reports or even raw data from the survey. This dataset has already been used for meta-analyses, and there are further opportunities for its use. Despite these achievements, there are core areas in which RAAB needs to be strengthened so that the full benefits of undertaking the survey can be reaped. Key developments of RAAB are underway, and will include greater use of mobile technologies using a cloud-based platform to enable both digital data collection, real-time survey reviews, reporting and analysis, and a greater emphasis on using the data for planning.

Elevated plasma and vitreous levels of leucine-rich-α2-glycoprotein are associated with diabetic retinopathy progression

PURPOSE

To investigate the association of plasma and vitreous leucine-rich-α2-glycoprotein (LRG1) with diabetic retinopathy (DR) progression.

METHODS

A total of 86 outpatients and 33 inpatients were recruited. Outpatients with type 2 diabetes mellitus (T2DM) were classified as T2DM without DR (n = 22), nonproliferative DR (NPDR) (n = 20) and proliferative DR (PDR) (n = 22) based on international clinical DR severity scales. A total of 86 plasma and 33 vitreous samples were collected and subjected to enzyme-linked immunosorbent assay. The diagnostic value of plasma LRG1 was tested using receiver operating characteristic (ROC) curves.

RESULTS

Plasma LRG1 in PDR patients (9025 ± 1870 pg/ml) was significantly increased as compared with controls (5975 ± 2022 pg/ml), T2DM without DR (6550 ± 2359 pg/ml) and NPDR patients (6550 ± 2359 pg/ml) (p < 0.0001). Vitreous LRG1 in PDR patients was elevated by approximately 4.3-fold than that in controls (562.1 ± 273.5 ng/ml versus 130.0 ± 102.8 ng/ml, p = 0.000). The area under the ROC curve value for plasma LRG1 was 0.786 (p < 0.0001). The maximal Youden index was 0.4372 and the optimal cut-off value of LRG1 was 7357.043 pg/ml with 81.82% sensitivity and 61.90% specificity.

CONCLUSION

Plasma and vitreous LRG1 levels were elevated in patients with PDR. Leucine-rich-α2-glycoprotein (LRG1) might be a potential risk-warning marker for PDR.

Estimating the magnitude of diabetes mellitus and diabetic retinopathy in an older age urban population in Pune, western India

Objective

To estimate magnitude of diabetes mellitus (DM) and diabetic retinopathy (DR) in a high risk population in Pune, western India.

Methods

DR module in rapid assessment of avoidable blindness (RAAB) survey methodology was used. Sample size of 3527 was calculated based on estimates from previous studies in India. A certified RAAB trainer conducted a training of survey teams. Random cluster sampling with probability proportionate to size was adapted to select 60 clusters consisting of 60 individuals each. Two teams visited door to door until they finished visiting 60 persons each day. Visual acuity testing, torch light examination, red glow test were carried out to determine persons with visual impairment and its cause. Every participant then underwent a random blood sugar level testing. All diabetics (known and newly detected) underwent dilated retina evaluation with indirect ophthalmoscopy to determine their DR status. Data were entered into RAAB6 software and descriptive statistics generated.

Results

Response rate was 89.5 % (3221/3600), females (55.3%). The prevalence of DM in the sample was (706/3221) 21.9 %(95 CI 20.1 to 23.7). Prevalence of DR was 14.3 % (95% CI 11.7 to 16.9). Most diabetics (401/579, 69.3%) never had an eye examination for DR in the past. Cataract was the principal cause of blindness (50 % cases) among diabetics.

Conclusion

DM affects over fifth of persons above 50 years of age in western India. Nearly seventh of the diabetics have DR, but coverage of screening is poor in Pune.

Diabetes and blindness in people with diabetes in Hungary

INTRODUCTION:

The purpose of the study was to estimate the number of people with diabetes mellitus, the prevalence of diabetes mellitus and the prevalence of blindness and severe visual impairment among people with diabetes mellitus in Hungary based on our recent national representative survey.

METHODS:

Altogether 105 clusters of 35 people aged 50 years or older were randomly selected. Standardized rapid assessment of avoidable blindness with the diabetic retinopathy module was used. Each individual received a visual acuity assessment, and every person with diabetes mellitus underwent dilated fundus examination.

RESULTS:

The estimated number of people with diabetes mellitus was 807,885 in the adult (⩾18 years) population in Hungary with 9.9% prevalence. Diabetic retinopathy exhibited an increasing tendency with age. The prevalence rates of blindness and severe visual impairment in people with diabetes mellitus aged ⩾50 years were 1.0% and 0.9%, respectively. Diabetic retinopathy was responsible for 28% of blindness and 50% of severe visual impairment among participants aged ⩾50 years with diabetes mellitus.

CONCLUSION:

The estimated number of people with diabetes mellitus and prevalence of diabetes mellitus were lower than those recently reported. However, if we extend our estimation, prevalence of undiagnosed diabetes mellitus may be higher and thus prevalence of diabetes mellitus may reach a higher value (between 9.9% and 13.4%). Because of the high number of ophthalmologically uncontrolled diabetic eyes and high rate of blindness due to diabetic retinopathy, primary eye care should be improved, and a nationwide telemedical eye-screening programme should be undertaken.

Rapid assessment of avoidable blindness and diabetic retinopathy in people aged 50 years and older in the National Capital District of Papua New Guinea

BACKGROUND/AIMS

To conduct an assessment of avoidable blindness, diabetes mellitus and diabetic retinopathy (DR) in adults aged 50 years and older in the National Capital District (NCD) region of Papua New Guinea (PNG).

METHODS

A cross-sectional population-based survey was performed for which 25 clusters of 50 people aged ≥50 years were randomly selected from the NCD region. The standardised rapid assessment of avoidable blindness (RAAB) with diabetic retinopathy (+DR) methodology was used. Blindness was defined as presenting visual acuity <3/60 in the better eye. Participants were classified as having diabetes if they were known to have diabetes or if their random blood glucose level was ≥200 mg/dL. Dilated fundus examination and Scottish DR grading were performed.

RESULTS

In total, 1192 out of 1250 eligible participants (95.4%) were examined. Of these, 7.8% had known or newly diagnosed diabetes. Seventy-one per cent of participants with known diabetes had a blood glucose level ≥200 mg/dL, and 82.9% had never had an ophthalmological examination for DR. Prevalence of DR and/or maculopathy was 46.4%. The age-adjusted and sex-adjusted prevalence of diabetes was estimated at 8.1% (95% CI 5.7% to 10.4%) in the population aged 50 years or older in the NCD region of PNG.

CONCLUSIONS

Prevalence of diabetes in adults aged 50 years and older was lower than reported elsewhere in the region, and lower than other RAAB+DR surveys. Despite this, the prevalence of DR is high compared with other RAAB+DR surveys and demonstrates the need for increased awareness and accessibility to eye services for people with diabetes.

Visual impairment and blindness in Hungary

AIM

The aim of this study was to estimate the prevalence and causes of blindness, severe visual impairment (SVI), moderate visual impairment (MVI), and early visual impairment (EVI) and its causes in an established market economy of Europe.

DESIGN

A cross-sectional population-based survey.

METHODS

A sample size of 3675 was calculated using the standard Rapid Assessment of Avoidable Blindness (RAAB) software in Hungary. A total of 105 clusters of 35 people aged 50 years or older were randomly selected with probability proportionate to size by the Hungarian Central Statistical Office. Households within the clusters were selected using compact segment sampling. Visual acuity (VA) was assessed with a Snellen tumbling E-chart with or without a pinhole in the households.

RESULTS

The adjusted prevalences of bilateral blindness, SVI, MVI and EVI were 0.9% (95% CI: 0.6-1.2), 0.5% (95% CI: 0.2-0.7), 5.1% (95% CI: 4.3-5.9) and 6.9% (95% CI: 5.9-7.9), respectively. The major causes of blindness in Hungary were age-related macular degeneration (AMD; 27.3%) and other posterior segment diseases (27.3%), cataract (21.2%) and glaucoma (12.1%). Cataract was the main cause of SVI, MVI and EVI. Cataract surgical coverage (CSC) was 90.7%. Of all bilateral blindness in Hungary, 45.5% was considered avoidable.

CONCLUSION

This study proved that RAAB methodology can be successfully conducted in industrialized countries, which often lack reliable epidemiologic data. The prevalence of blindness was relatively low, with AMD and other posterior segment diseases being the leading causes, and cataract is still a significant cause of visual impairment.

Feasibility of the rapid assessment of avoidable blindness with diabetic retinopathy module (RAAB+DR) in industrialised countries: challenges and lessons learned in Hungary

PURPOSE

To present experiences gained during the planning, implementation, and practical performance of the rapid assessment of avoidable blindness with diabetic retinopathy module (RAAB+DR) in an established market economy.

METHODS

A total of 3523 people aged 50 years or older were examined at their homes in 105 randomly selected clusters in Hungary. During the 4-month-long field work, five teams visited the clusters. Each team was composed of a senior ophthalmic resident or eye specialist, a nurse, an assistant, a driver, and a local guide. The local guides were found through local mayors of the towns or villages or other local leaders.

RESULTS

Of all 105 clusters, 41% were completed in 1 day and 59% required a longer stay. The shortest daily examination time was 3.5 hours and the longest was 10 hours. Altogether, 7.6% of the enumeration areas needed revisit, mainly due to insufficient preparatory work and absence of the subjects. The best local guides were the local government workers, health visitors, and general practitioner (GP) nurses. Refusal of pupillary dilatation was relatively high and varied greatly among the study groups (7.7-43.8%).

CONCLUSION

The performance of a RAAB+DR study in a well-industrialised country is difficult, but may be successful. The most critical factor for success is an excellent local guide who is able to achieve participation of the people. The results of the RAAB are a solid basis for the development of a national programme for universal eye health and to prepare active media campaigns.

Diabetic Retinopathy in the Asia-Pacific

Diabetic retinopathy (DR), the most common complication of diabetes mellitus, is the leading cause of new cases of blindness in middle-aged and elderly in the Asia-Pacific. It has been estimated that 51% of all those with blindness due to DR globally (n = 424,400) and 56% of those with visual impairment due to DR (2.1 million) come from the Asia-Pacific. Prevalence of DR among those with diabetes ranged from 10% in India to 43% in Indonesia within the Asia-Pacific. Awareness of DR among persons with diabetes ranged from 28% to 84%. Most common modifiable risk factors for DR in the Asia-Pacific were hyperglycemia, blood pressure, dyslipidemia, and obesity. Implementation of systematic screening programs for DR and advancement in telemedicine screening methods have increased patient coverage and cost-effectiveness, though there are still numerous factors impeding screening uptake in the low-middle income regions of the Asia-Pacific. Management and treatment of DR in the Asia-Pacific is mainly limited to traditional laser retinopexy, but it is suboptimal despite new clinical approaches such as use of intravitreal anti.vascular endothelial growth factor and steroids due to limited resources. Further research and data are required to structure a more cost-effective public healthcare program and more awareness-building initiatives to increase the effectiveness of DR screening programs.

A Diabetic Retinopathy Screening Tool for Low-Income Adults in Mexico

INTRODUCTION

A national diabetic retinopathy screening program does not exist in Mexico as of 2017. Our objective was to develop a screening tool based on a predictive model for early detection of diabetic retinopathy in a low-income population.

METHODS

We analyzed biochemical, clinical, anthropometric, and sociodemographic information from 1,000 adults with diabetes in low-income communities in Mexico (from 11,468 adults recruited in 2014-2016). A comprehensive ophthalmologic evaluation was performed. We developed the screening tool through the following stages: 1) development of a theoretical predictive model, 2) performance assessment and validation of the model using cross-validation and the area under the receiver operating characteristic curve (AUC ROC), and 3) optimization of cut points for the classification of diabetic retinopathy. We identified points along the AUC ROC that minimized the misclassification cost function and considered various scenarios of misclassification costs and diabetic retinopathy prevalence.

RESULTS

Time since diabetes diagnosis, high blood glucose levels, systolic hypertension, and physical inactivity were considered risk factors in our screening tool. The mean AUC ROC of our model was 0.780 (validation data set). The optimized cut point that best represented our study population (z = -0.640) had a sensitivity of 82.9% and a specificity of 61.9%.

CONCLUSION

We developed a low-cost and easy-to-apply screening tool to detect people at high risk of diabetic retinopathy in Mexico. Although classification performance of our tool was acceptable (AUC ROC > 0.75), error rates (precision) depend on false-negative and false-positive rates. Therefore, confirmatory assessment of all cases is mandatory.

Field Testing Project to Pilot World Health Organization Eye Health Indicators in Latin America

PURPOSE

To develop and implement mechanisms to collect, report, and assess the World Health Organization (WHO) core eye health indicators in Chile, Honduras, Mexico, Peru, and Uruguay.

METHODS

Simple templates for a situational analysis (of data collection and reporting processes), a national data collection strategy, and a national work plan to implement the core eye health indicators were developed. Public and private sector representatives from the ministries of health (MOHs), national vision committees, and national societies of ophthalmology of each country used these tools with 2013 baseline data to improve their data collection processes and collected 2015 data. Final analysis and cross-validation were performed using intraocular lens sales data and last observation carried forward imputation.

RESULTS

Study tools were effectively implemented in all five countries and resulted in improved intersectoral stakeholder collaboration and communications, which improved the data collection and reporting processes. More complete and accurate data were reported by 2015 compared to the 2013 baseline.

CONCLUSIONS

Multisectoral stakeholders, including national professional societies and national vision committees, should collaborate with MOHs to improve the quality of data that are reported to WHO. This study involved these stakeholders in the data collection processes to better understand the realities of indicator implementation, better manage their expectations, and improve data quality. WHO Member States across the globe can feasibly adapt the study tools and methodologies to strengthen their data collection processes. Overall, the reliability and validity of the indicators is hampered with limitations that prevent fully accurate data from being collected.

Prevalence of visual impairment and outcomes of cataract surgery in Chaonan, South China

Purpose

To estimate the prevalence and causes of blindness and visual impairment (VI), and report the outcomes of cataract surgery in Chaonan Region, Guangdong Province, southern China

Design

Cross-sectional population-based survey

Participants

A total of 3484 participants including 1397 men (40.1%) and 2087 women (59.9%) aged ≥50 years were examined (94.2% response rate).

Method

A two-stage cluster sampling procedure was used to select 3700 participants aged ≥50 years from 74 clusters of Chaonan Region. Participants were examined according to the Rapid Assessment of Avoidable Blindness (RAAB) method. Blindness and visual impairment (VI) were defined by the World Health Organization criteria. Participants with visual acuity (VA) < 6/18 in either eye were examined by ophthalmologists. The primary causes of blindness and VI were reported with reference to the participant’s better eye.

Main outcome measures

Prevalence and main causes of blindness, severe visual impairment (SVI), VI and the outcomes of cataract surgery

Results

The standardized prevalence rates of blindness, SVI, and VI were 2.4% (95% confidence interval [CI], 1.9–2.9%), 1.0% (95% CI, 0.7–1.4%), and 6.4% (95% CI, 5.6%– 7.1%), respectively. The principal cause of blindness and SVI was cataract, accounting for 67.1% and 67.6% respectively, and the principal cause of VI was refractive error (46.9%). One hundred and fifty five out of 3484 (4.4%) people (211 eyes) had cataract surgery. Of the 211 eyes that had cataract surgery, 96.7% were pseudophakic. 67.2% of the 211 operated eyes had a presenting visual acuity (PVA) of 6/18 or better.

Conclusions

The prevalence of blindness, SVI, and VI was high among rural residents in Chaonan. Cataract remained the leading cause of avoidable blindness. Outcomes of cataract surgery performed in rural private clinics were suboptimal. Quality-control initiatives such as hands-on training program should be introduced to improve cataract surgery outcomes.

Rapid Assessment of Avoidable Blindness and Diabetic Retinopathy in Gilan Province, Iran

PURPOSE

To conduct an assessment of avoidable blindness and diabetic retinopathy (DR) in Gilan, 2014.

METHODS

A cross-sectional population-based survey was performed on a representative sample of urban and rural individuals aged ≥50 years of the province. Blindness was defined as presenting visual acuity (PVA) <3/60 in the better eye. Moderate visual impairment (MVI) and severe visual impairment (SVI) were defined as 6/60 ≤ PVA <6/18 and 3/60 ≤ PVA <6/60 in the better eye, respectively. Diabetes mellitus (DM) was determined based on random blood sugar (RBS) levels ≥200 mg/dL or a previous diagnosis. We used the Scottish grading system to grade DR.

RESULTS

We invited 2975 individuals from 85 clusters. Age- and sex-adjusted prevalence and 95% confidence interval (CI) of blindness, SVI, MVI, and DM in 2587 participants (response rate: 86.9%) were 1.5% (95% CI: 1.1-2.0), 1.5% (95% CI: 0.9-2.0), 11.3% (95% CI: 9.9-12.7) and 21.4% (95% CI: 19.2-23.7), respectively. The leading causes of blindness were cataract (47.1%), age-related macular degeneration (14.7%) and DR (8.8%). Cataract surgery (CS) coverage was 69.3%. The main challenges for CS were cost and unawareness. The outcome of CS was good in 66.9% of operated eyes. Any DR and/or maculopathy were observed in 25.3% (95% CI: 21.0-29.5) of subjects including 12.6% (95% CI: 9.7-15.6) sight-threatening DR. In previously known DM cases, 215 (41.7%) had never undergone an eye examination for DR.

CONCLUSION

The proportion of avoidable blindness and DR is considerable in Gilan Province.

Prevalence and causes of blindness and diabetic retinopathy in Southern Saudi Arabia

Objectives:

To determine the prevalence and causes of blindness and diabetic retinopathy (DR) in Jazan district, Southern Saudi Arabia.

Methods:

Using the standardized Rapid Assessment for Avoidable Blindness (RAAB) and DR cross-sectional methodology, 3800 subjects were randomly selected from the population of ≥50 years of age in Jazan, Saudi Arabia between November 2011 and January 2012. Participants underwent screening comprised of interview, random blood glucose test, and ophthalmic assessment including visual acuity (VA) and fundus examination. Among participants with VA <6/18 in either eye, the cause(s) of visual impairment was determined. Participants were classified as diabetic if they had previous diagnoses of diabetes, or random blood glucose >200 mg/dl. Diabetic participants were assessed for DR using dilated fundus examination. All data were recorded using the RAAB + DR standardized forms.

Results:

The prevalence of bilateral blindness <3/60 was 3.3% (95% confidence interval [CI]: 2.74 - 3.90). Cataract was the leading cause of blindness (58.6%); followed by posterior segment diseases (20%), which included DR (7; 3.3%). The prevalence of diabetes mellitus (DM) was 22.4%, (95% CI: 21.09 - 23.79), among them; 27.8% had DR. The prevalence of sight-threatening DR was 5.7%.

Conclusion:

The prevalence of DM and the corresponding proportion of DR in this region is lower than that reported in other regions of Saudi Arabia. However, the prevalence of blindness not related to DR is relatively higher than the other studies.

Outcomes of Cataract Surgery in Urban and Rural Population in the South Indian State of Andhra Pradesh: Rapid Assessment of Visual Impairment (RAVI) Project

OBJECTIVE

To assess the visual outcomes after cataract surgery among urban and rural population aged ≥40 years in the South India state of Andhra Pradesh.

METHODS

A population based cross-sectional study was conducted in which 7800 subjects were sampled from two rural and one urban location. Visual Acuity was assessed and eye examination were performed by trained personnel. A questionnaire was used to collect personal and demographic information, and history of cataract surgery. Blindness and moderate Visual Impairment (MVI) was defined as presenting VA <6/60 and <6/18 to 6/60 in the better eye respectively.

RESULTS

In total, 7378 (94.6%) were examined. Of these, 1228 eyes of 870 individuals were operated for cataract. The mean age of operated subjects was 63.7 years (SD: 10.7 years). Overall, 56.3% of those operated were women, 76% were illiterate and 42% of them were using spectacles after cataract surgery. Even after surgery, 12.2% of the operated eyes had MVI and blindness was seen in 14.7% of the eyes. A significantly higher proportion of subjects in urban area had good outcome as compared to those in the rural area (p = 0.01). Uncorrected refractive error (58.7%) was the leading cause of MVI, and posterior segment disease (34.3%) was the leading cause of blindness. On applying multiple logistic regression, risk factors for poor outcomes were age ≥ 70 years (OR: 1.9, 95% CI: 1.3-2.8), rural residence (OR: 1.3, 95% CI:1.0-1.8) and presence of aphakia (OR: 8.9, 95% CI: 5.7-13.8).

CONCLUSIONS

Post cataract surgery, refractive errors remain an important correctable cause of MVI, in the south Indian state of Andhra Pradesh. The correction of refractive errors is required to provide good visual recovery and achieve the benefit of cataract surgery.

Diabetes and diabetic retinopathy in people aged 50 years and older in Hungary

BACKGROUND/AIMS

The purpose of this study was to estimate the prevalence of diabetes mellitus (DM) and diabetic retinopathy (DR) in the population aged 50 years and older in Hungary, and to assess the coverage of diabetic eye care services.

METHODS

In total, 105 clusters of 35 people aged 50 years or older were randomly selected. The standardised rapid assessment of avoidable blindness (RAAB) with the diabetic retinopathy module (DRM) was used. Participants were classified as having DM if they were known to have DM or if their random blood glucose level was ≥200 mg/dL. Dilated fundus examination and Scottish DR grading were performed.

RESULTS

In total, 3523 (95.9%) out of 3675 eligible subjects were examined. And 705 (20.0%) out of 3523 had known (661) or newly diagnosed DM (44). Twenty per cent of participants with known DM had a blood glucose level ≥200 mg/dL, and 27.4% had never had an ophthalmological examination for DR. Prevalence of DR and/or maculopathy was 20.7% and prevalence of sight-threatening DR (STDR) was 4.3% in one or both eyes among participants with DM.

CONCLUSIONS

Prevalence of DM was in line with findings of other RAAB+DRM surveys and slightly lower than the unpublished earlier age-matched Hungarian estimate. Prevalence of DR was slightly lower than expected. The prevalence of STDR was low in people aged 50 years and older in Hungary compared with the results of other RAAB with DRM surveys. DR screening coverage was low. To prevent severe complications of DM and possible concomitant visual loss, the coverage of ophthalmic examinations in patients with DM should be increased.

Diabetes and diabetic retinopathy in people aged 50 years and older in the Republic of Suriname

BACKGROUND/AIMS

Population-based surveys on diabetes and diabetic retinopathy (DR) are necessary to increase awareness and develop screening and therapeutic programmes. The aim was to estimate the prevalence of DR in older adults of different ethnic backgrounds in Suriname.

METHODS

Fifty clusters of 60 people aged ≥50 years were randomly selected with a probability proportional to the size of the population unit. Eligible people were randomly selected through compact segment sampling and examined using the Rapid Assessment of Avoidable Blindness plus Diabetic Retinopathy (RAAB + DR) protocol. Participants were classified as having diabetes if they: were previously diagnosed with diabetes; were receiving treatment for glucose control; had a random blood glucose level >200 mg/dL. These participants were dilated for funduscopy, assessed for DR following the Scottish DR grading protocol and evaluated for ethnicity and DR ophthalmic screening frequencies.

RESULTS

A total of 2806 individuals was examined (response 93.6%). The prevalence of diabetes was 24.6%. In these patients any type of DR and/or maculopathy occurred in 21.6% and sight-threatening DR in 8.0%. Of the known diabetics, 34.2% never had an eye examination for DR and in 13.0% the last examination was >24 months ago. The prevalence of diabetes was significantly higher in Hindustani people compared with other major ethnic groups.

CONCLUSIONS

The prevalence of diabetes and diabetics without regular DR control in people aged ≥50 years in Suriname was higher than expected. The uptake for special services for DR has to be expanded to decrease patient delay and DR-induced blindness.

High prevalence of diabetic retinopathy and lack of association with integrin α2 gene polymorphisms in patients with type 2 diabetes from Northeastern Mexico

Diabetic retinopathy (DR) is one of the primary causes of blindness in the working age population and is characterized by angiogenesis in the retina. Platelets have been suggested to be involved in the pathogenesis of diabetic microvascular complications. The integrin receptor for collagen/laminin, α2β1, mediates platelet primary adhesion to subendothelial tissues, which is an essential first step in thrombus formation. The gene encoding the α2 subunit of α2β1 integrin has ≥8 polymorphisms, including a BglII/NdeI restriction fragment length polymorphism. To explore the prevalence of DR in a population from Northeastern Mexico, unrelated, hospitalized patients who had received a diagnosis of type 2 diabetes mellitus (DM2) at least 10 years previously were recruited (n=177). DR was diagnosed in a masked manner by independent ophthalmologists using fundus images captured using a non-mydriatic retinal camera. A total of 121 patients with DM2 (68%) had some degree of DR development (DR patients), and 56 patients with DM2 (32%) did not exhibit any sign of DR (No-DR patients). The results showed that after 15 years of DM2 progression, there is an increased risk of DR (P=0.0497; odds ratio, 1.993). In addition, insulin therapy and family history of DM2 were significantly associated with DR. In order to detect a possible association between DR and BglII/NdeI α2 gene polymorphisms, a comparative cross-sectional study between DR and No-DR patients was conducted. The α2 gene was genotyped by polymerase chain reaction-restriction fragment length polymorphism assay. Statistical analysis revealed no association between BglII/NdeI genotypes and the development of DR in this group of patients. In conclusion, the present data indicate a high prevalence of DR in the Mexican population and suggest that the damage in DR is due to other factors, such as the duration of the DM2, and is not linked to BglII/NdeI α2 gene polymorphisms.

Prevalence of blindness and diabetic retinopathy in northern Jordan

PURPOSE

To estimate the prevalence of blindness, visual impairment, diabetes, and diabetic retinopathy in north Jordan (Irbid) using the rapid assessment of avoidable blindness and diabetic retinopathy methodology.

METHODS

A multistage cluster random sampling technique was used to select participants for this survey. A total of 108 clusters were selected using probability proportional to size method while subjects within the clusters were selected using compact segment method. Survey teams moved from house to house in selected segments examining residents 50 years and older until 35 participants were recruited. All eligible people underwent a standardized examination protocol, which included ophthalmic examination and random blood sugar test using digital glucometers (Accu-Chek) in their homes. Diabetic retinopathy among diabetic patients was assessed through dilated fundus examination.

RESULTS

A total of 3638 out of the 3780 eligible participants were examined. Age- and sex-adjusted prevalence of blindness, severe visual impairment, and visual impairment with available correction were 1.33% (95% confidence interval [CI] 0.87-1.73), 1.82% (95% CI 1.35-2.25), and 9.49% (95% CI 8.26-10.74), respectively, all higher in women. Untreated cataract and diabetic retinopathy were the major causes of blindness, accounting for 46.7% and 33.2% of total blindness cases, respectively. Glaucoma was the third major cause, accounting for 8.9% of cases. The prevalence of diabetes mellitus was 28.6% (95% CI 26.9-30.3) among the study population and higher in women. The prevalence of any retinopathy among diabetic patients was 48.4%.

CONCLUSIONS

Cataract and diabetic retinopathy are the 2 major causes of blindness and visual impairment in northern Jordan. For both conditions, women are primarily affected, suggesting possible limitations to access to services. A diabetic retinopathy screening program needs to proactively create sex-sensitive awareness and provide easily accessible screening services with prompt treatment.

Rapid assessment of avoidable blindness and diabetic retinopathy in Republic of Moldova

OBJECTIVE

To evaluate the prevalence and causes of blindness and visual impairment, the prevalence of diabetes mellitus and diabetic retinopathy among people aged ≥50 years in the Republic of Moldova using Rapid Assessment of Avoidable Blindness plus Diabetic Retinopathy ('RAAB+DR') techniques.

MATERIALS AND METHODS

111 communities of people aged ≥50 years were randomly selected. In addition to standard RAAB procedures in all people with diabetes (previous history of the disease or with a random blood glucose level >11.1 mm/L (200 mg/dL)), a dilated fundus examination was performed to assess the presence and the degree of diabetic retinopathy using the Scottish DR grading system.

RESULTS

3877 (98%) people out of the 3885 eligible people were examined. The prevalence of blindness was 1.4% (95% CI 1.0% to 1.8%). The major causes of blindness and severe visual impairment were untreated cataract (58.2%), glaucoma (10.9%), and other posterior segment causes (10.9%). The estimated prevalence of diabetes was 11.4%. Among all people with diabetes, 55.9% had some form of retinopathy, and sight threatening diabetic retinopathy affected 14.6%.

CONCLUSIONS

The RAAB+DR survey in the Republic of Moldova established that untreated cataract is the major cause of avoidable blindness in rural areas. This needs to be tackled by expanding the geographical coverage of cataract surgical services.

Prevalence and risk factors for diabetes and diabetic retinopathy: results from the Nigeria national blindness and visual impairment survey

BACKGROUND

In Nigeria, urbanisation and increasing life expectancy are likely to increase the incidence of non-communicable diseases. As the epidemic of diabetes matures, visual loss from diabetic retinopathy (DR) will increase unless mechanisms for early detection and treatment improve, and health systems respond to the growing burden of non-communicable diseases.

METHODS

A nationally-representative population-based sample of 13,591 participants aged ≥40 years selected by multistage-stratified-cluster-random-sampling with probability-proportional-to-size procedures were examined in 305 clusters in Nigeria between January 2005 to June 2007. All were asked about history of diabetes and underwent basic eye examination. Visual acuity (VA) was measured using logMAR E-chart. Participants with VA<6/12 and/or DR detected underwent detailed eye examination including dilated retinal examination and retinal photography. Systematic sampling of 1-in-7 gave a subsample (n=1759) examined in detail regardless of VA; and had random blood glucose (RBG) testing. Images were graded by Moorfields Eye Hospital Reading Centre. Participants were defined as having diabetes if they were previously diagnosed or RBG>11.1mmol/l or had DR. Data in the subsample were used to estimate the prevalence and to analyse risk factors for diabetes and DR using multivariable logistic regression. Additional information on the types of DR was obtained from participants not in the subsample.

RESULTS

In the subsample, 164 participants were excluded due to missing data; and 1,595 analysed. 52/1,595 had diabetes, a prevalence of 3.3% (95%CI 2.5-4.3%); and 25/52(48%) did not know. Media opacity in 8/52 precluded retinal examination. 9/44(20.5%) had DR. Higher prevalence of diabetes was associated with urban residence (Odds ratio [OR]1.87) and overweight/obesity (OR3.02/4.43 respectively). Although not statistically significant, DR was associated with hypertension (OR3.49) and RBG>15.0mmol/L (OR8.10). Persons with diabetes had 3 times greater odds of blindness. Of 11,832 other participants in the study sample, 175(1.5%) had history of diabetes; 28 had DR. Types of DR (total=37) included 10.8% proliferative, 51.4% macular oedema.

CONCLUSION

The age-adjusted prevalence of diabetes in Nigeria was 3.25% (95%CI 2.50-4.30) and over 10% of people with diabetes aged ≥40 years had sight-threatening-DR. These data will enable the development of better public health strategies for the control of diabetes and planning services for DR to prevent vision loss.

Sight-threatening diabetic retinopathy at presentation to screening services in Fiji

PURPOSE

To report the spectrum of retinopathy at first presentation to photoscreening services, to determine the proportion of patients that present with sight-threatening diabetic retinopathy (STDR), and to raise awareness of the burden of diabetic eye disease in Fiji.

METHODS

This retrospective observational cohort study used data from the initial visit of all new patients presenting to the diabetes retinal screening service at the Pacific Eye Institute in Fiji over the 3-month period between July and September 2012. Patients were assessed using a detailed questionnaire regarding diabetes type, duration of disease, medications, complications and co-morbidities, and blood sugar control. Patients subsequently underwent non-mydriatic fundus photography according to Pacific diabetes retinal screening guidelines. Images were graded at the time of acquisition, and data were entered onto a computerized database. For the purposes of this study, information regarding retinopathy grading, visual acuity and patient demographics was used.

RESULTS

A total of 522 new patients were screened over the 3-month period. STDR was observed in 27% of patients, with 15% observed to have bilateral STDR. Diabetes control was generally poor. Blindness and visual impairment were observed in 2.7% and 6.7% of the cohort, respectively.

CONCLUSION

Severe and advanced diabetic retinopathy was present in this population presenting to screening. This was observed 4 years after the formal expansion of the screening services and reflects the high prevalence of diabetes in the population. The need for increased public awareness and greater resource allocation into diabetes and its complications is emphasized.

The cataract situation in Latin America: barriers to cataract surgery

PURPOSE

To provide an update of cataract data and barriers to cataract surgery in Latin America.

DESIGN

Review and longitudinal study.

METHODS

Cataract surgery rates and other related indicators that have been reported to the VISION 2020 Latin America program since 2005 were reviewed. PubMed was searched for publications concerning regional epidemiologic studies related to cataract, cataract surgery, barriers, outcomes, and cataract prevalence between January 2012 and October 2013 to obtain the most up-to-date data from 19 countries.

RESULTS

The weighted mean regional cataract surgery rate has increased by an impressive 70% since 2005, from 1562 to 2672 cataract surgeries per 1 million inhabitants. The weighted mean number of ophthalmologists per 1 million inhabitants in the region is approximately 62. Cataract surgery coverage varies widely in Latin America, from a meager 15% in El Salvador to a more satisfactory 77% in Uruguay. Five recent surveys indicate that lack of awareness of cataract and the surgery treatment option as well as the cost of the surgery are the main barriers to cataract surgery.

CONCLUSIONS

In spite of the increasing rates of cataract surgery and the more-than-adequate number of ophthalmologists in Latin America, it is not known how many ophthalmologists actually perform surgery. Coverage remains less than satisfactory across the region. Barriers to cataract surgery hinder the efforts of eye care programming. More comprehensive eye care programs and training centers are needed so that they can focus on reaching the underserved and unaware communities, increase surgery output and uptake, and improve outcomes.

Foldable vs rigid lenses after phacoemulsification for cataract surgery: a randomised controlled trial

PURPOSE

To compare the outcomes of phacoemulsification with either a 2.5-mm clear corneal incision and a foldable intraocular lens (IOL) or a 5-mm sclerocorneal tunnel incision and a rigid polymethyl methacrylate (PMMA) IOL.

METHODS

In a prospective, randomised clinical trial of phacoemulsification cataract surgery, 1200 patients received either a foldable hydrophilic acrylic IOL through a 2.5-mm corneal incision or an inexpensive rigid PMMA IOL via a 5-mm sclerocorneal tunnel. Intra- and post-operative data and visual acuity at discharge, 6 weeks, and 1 year follow-up were analysed.

RESULTS

At 1 year after surgery, 996 (83.0%) patients were followed up with an uncorrected visual acuity of 6/18 or better in 90.3% of the foldable and 94.3% in the rigid IOL group (risk ratio (RR) 0.96, 95% confidence intervals (CI) 0.92-0.99). Poor outcome (best-corrected acuity 6/60 or worse) occurred in 1.0% and 0.4%, respectively (RR 4.28, 95% CI 0.48-38.18). The surgical cost of consumables and overall surgical time were similar in both groups; however, the cost of the foldable IOL was eight times higher than the PMMA IOL. Posterior capsule opacification was more common in the rigid IOL group at 12 months (36.1% vs 23.3%); however, this did not affect post-operative vision.

CONCLUSION

In the hands of experienced cataract surgeons, phacoemulsification with implantation of a foldable or a rigid IOL gives excellent results. Using an inexpensive rigid PMMA IOL will make phacoemulsification more affordable for poor patients in low- and middle-income countries.

Prevalence of diabetic retinopathy in Type 2 diabetes in developing and developed countries

BACKGROUND

As the global prevalence of diabetes increases, so will the numbers of people with diabetic retinopathy. Our review aimed to provide a comprehensive picture of available studies of diabetic retinopathy and how prevalence varies around the developed and developing world.

METHODS

A detailed literature search using PubMed was undertaken. The following search term was used: 'diabetic retinopathy AND prevalence'. The titles and abstracts of all publications identified by the search were reviewed and 492 studies were retrieved. Inclusion and exclusion criteria were applied.

RESULTS

A total of 72 articles from 33 countries were included. There were only 26 population-based studies using fundus photography (12 in developing countries), of which only 16 (eight in developing countries) were published since 2000. Prevalence estimates varied from as low as 10% to as high as 61% in persons with known diabetes and from 1.5 to 31% in newly diagnosed diabetes. Across all the studies, the median (interquartile range) prevalence of any diabetic retinopathy in known diabetes was 27.9% (22-37%) and 10.5% (6-16%) in newly diagnosed diabetes. Prevalence of diabetic retinopathy was higher in developing countries.

CONCLUSION

Significant gaps exist in that reliable population-based data from developing nations and indigenous populations in particular are lacking. Major differences in study characteristics and methodologies make comparisons very difficult. More research is required and study methodologies must be better standardized. This will provide important information for prevention and treatment strategies.