Rapid Assessment of Avoidable Blindness in Iran

A systematic literature review for evaluation of knowledge, attitude, and self-care practice regarding common eye diseases in the healthy general population

Background and purpose

Increasing people's knowledge and then changing their attitude and practice with the aim of taking care of their eye health are very important. Considering the importance of the mentioned topic, the main goal of this study was to evaluate the knowledge, attitude, and practice about eye diseases in the general population of the world in the form of a systematic literature review.

Materials and Methods

This study was a systematic literature review study, and to do it, a systematic search was conducted in internationally available databases including Web of Science, ScienceDirect, Scopus, PubMed, and Google Scholar in the time range of 1998 to 2023. Finally, considering the inclusion and exclusion criteria of the study, the results of 18 articles were extracted.

Results

The findings showed that in general, people's level of knowledge about glaucoma was lower compared to other eye diseases, and the level of knowledge of men and women about eye diseases was different. In addition, the results showed that there was significant relationship between age and knowledge of various eye diseases. The results of all evaluated studies showed that people with higher education have more knowledge about eye diseases.

Conclusion

Based on this, it can be concluded that as glaucoma is one of the most important causes of blindness worldwide, it is necessary to plan to increase the level of public knowledge to recognize the symptoms and complications of this disease. In addition to that, it is necessary to increase people's advertisement by ophthalmology centers and eye specialists about the use of glasses and also to encourage people to visit the eye physician regularly.

Prevalence of cataract and its contributing factors in Iranian elderly population: the Gilan eye study

PURPOSE

To report the prevalence and the associated factors leading to cataract among the Iranian population living in Gilan Province, Iran.

METHODS

This population-based cross-sectional study was performed from June to November 2014 on 2,975 residents aged ≥ 50 years old living in urban and rural regions of the Gilan Province in Iran. A representative sample of residents in the province was recruited into the study through door-to-door visiting, and baseline data were collected by questionnaire. All participants were referred to the medical center for comprehensive ophthalmic examination, laboratory tests, and blood pressure measurement.

RESULTS

Among the population, 2,588 (86.99%) subjects were eligible to be included in this study, categorized either into the cataract or the non-cataract group. The mean age of participants was 62.59 ± 8.92 years, and 57.5% were female. Higher prevalence of cataract was found in individuals of older ages (odds ratio (OR) = 1.13; 95% confidence interval (CI) = 1.10 to 1.16; P < 0.001) and a history of previous ocular surgery (OR = 5.78; 95% CI = 2.28 to 14.63; P < 0.001). At the same time, a lower prevalence of cataract was seen in patients exposed to sunlight for more than 4 h per day (OR = 0.49; 95% CI = 0.32 to 0.73; P = 0.001).

CONCLUSION

Cataract affects 50.50% of the study population, especially those over 80. The mildest form of cataract, grade zero, is the most common. Surgery for cataract has good outcomes. The risk of cataract is higher for those older or who have had eye surgeries. People not affected by cataract tend to be exposed to more sunlight.

Prevalence of age-related macular degeneration in Iran and its projections through 2050: a systematic review and meta-analysis

BACKGROUND

Age-related Macular Degeneration (AMD) is one of the most common causes of vision loss. A substantial increase in the burden of AMD is expected in the aging populations, including the Iranians. We investigated the age and gender-specific prevalence of AMD and its determinants in Iran.

METHODS

We systematically searched international (PubMed, Scopus, Embase, etc.) and local (IranDoc, Magiran, etc.) online databases. We included cross-sectional or cohort studies, either clinic- or population-based, published on the prevalence of AMD among Iranians, with no limitation on age. Joanna Briggs Institute (JBI) tools for critical appraisal were used. Prevalence estimates are pooled by applying random-effects modeling. Subgroup analysis and meta-regression were performed.

RESULTS

Seventeen studies with 16,120 participants were included. Based on studies in general population, the pooled prevalence of AMD was 10.8% (95% CI: 6.5-16.2%) in males, and 9.8% (95% CI: 4.7-16.4%) in females. 8.5% of moderate vision impaired, 13.6% of severe vision impaired, and 15.7% of blind participants were affected by AMD. The prevalence of AMD was 2% in 40-49, and 32.3% in the ≥ 80 population. The prevalence of AMD was 11.9% among the visually impaired vs. 8.7% in the general population. The study's sampling method, location, and mean age were correlated with the heterogeneities of the prevalence. We observed an increasing trend in the number of AMD cases (average annual percent change = 3.66%; 95% CI: 3.65-3.67%) from 1990 to 2050. The expected number of AMD cases in Iran will be near 5.5 million by 2050.

CONCLUSION

The prevalence of AMD in Iran was somewhere between the prevalence of Asians and Europeans. Given the aging trend of the Iranian community and an average annual percent change of 3.66%, it is indispensable to adopt preventive and screening policies to diminish the burden of the disease in the future decades.

The role of mobile health in prevention, diagnosis, treatment and self-care of COVID-19 from the healthcare professionals' perspectives

Background

To facilitate disease management, understanding the attitude of healthcare professionals regarding the use of this tool can help mobile health (mHealth) program developers develop appropriate interventions.

Aims

To assess the perspective of healthcare professionals regarding the contribution of mobile-based interventions in the prevention, diagnosis, self-care, and treatment (PDST) of COVID-19.

Methods

This is a survey study conducted in 2020 in Iran with 81 questions. In this study mHealth functionalities were categorized into four dimensions including innovative, monitoring and screening, remote services, and education and decision-making. The data were analyzed using descriptive statistics, ANOVA, and the Kruskal-Wallis test to compare the attitudes of the different job groups.

Results

In total, 123 providers participated, and 87.4% of them reported that mHealth technology is moderate to most helpful for the management of COVID-19. Healthcare professionals believed that mHealth technology could be most helpful in self-care and least helpful in the diagnosis of COVID-19. Regarding the functionalities of the mobile application, the results showed that the use of patient decision aids can be most helpful in self-care and the use of computer games can be least helpful in treatment. The participants believed that mHealth is more effective in monitoring and screening dimensions and less effective in providing remote services.

Conclusions

This study showed that healthcare professionals believed that mHealth technology could have a better contribution to self-care for patients with COVID-19. Therefore, it is better to plan and invest more in the field of self-care to help patients to combat COVID-19. The results of this study revealed which mhealth functionalities work better in four domains of prevention, treatment, self-care, and diagnosis of COVID-19. This can help healthcare authorities to implement appropriate IT-based interventions to combat COVID-19.

The Prevalence and Causes of Low Vision and Visual Impairment in School-Aged Children: The Shiraz Pediatric Eye Study

Purpose

To determine the prevalence and causes of visual impairment (VI) in Shiraz schoolchildren aged between 6 and 12 years.

Methods

In the present population-based study, stratified random sampling was used to select 2400 schoolchildren aged 6-12 years from all four educational districts of Shiraz, Iran. Using the definitions of the World Health Organization, VI was defined as best-corrected visual acuity (BCVA) ≤0.5 logMAR (20/60) in the better eye, and blindness as BCVA worse than 1.3 logMAR (20/400) in the better eye. The low vision was defined as BCVA equal to or worse than 0.5 logMAR (20/60) in either eye. Data were recorded from a detailed interview and ocular examination of each eligible student.

Results

The mean age of the students was 9.1 ± 1.6 years. The prevalence of VI was 3/2001 (0.14%). The cause of VI in all these three patients (100%) was amblyopia due to high refractive errors (high ametropia and astigmatism). Regarding the main refractive errors leading to VI among these three patients, one patient had bilateral high hyperopia (compound hyperopic astigmatism), one of them had bilateral high astigmatism, and the other one had compound myopic astigmatism. According to a visual acuity of less than or equal to 20/60 in at least one eye, 9/2001 (0.4%) of children had low vision.

Conclusions

This study revealed a low prevalence of VI in a sample of 6- to 12-year-old school-aged children. Amblyopia in the setting of high ametropia and astigmatism were the most common causes of VI.

Population-based cross-sectional prevalence survey of diabetes and diabetic retinopathy in Sohag-Egypt, 2019

OBJECTIVES

To determine the prevalence of diabetes mellitus (DM), prevalence of diabetic retinopathy (DR) and sight-threatening conditions among persons with DM aged 50 years and older in Sohag governorate in Upper Egypt.

DESIGN

Population-based, cross-sectional survey using the standardised Rapid Assessment of Avoidable Blindness with the addition of the Diabetic Retinopathy module methodology.

SETTINGS

Sohag governorate in Egypt where 68 clusters were selected using probability proportional to population size. Households were selected using the compact segment technique.

PARTICIPANTS

4078 people aged 50 years and older in 68 clusters were enrolled, of which 4033 participants had their random blood sugar checked and 843 examined for features of DR.

PRIMARY AND SECONDARY OUTCOMES

The prevalence of DM and DR; secondary outcome was the coverage with diabetic eye care.

RESULTS

The prevalence of DM was 20.9% (95% CI 19.3% to 22.5%). The prevalence in females (23.8%; 95% CI 21.4% to 26.3%) was significantly higher than in males (18.9%; 95% CI 17.1% to 20.7%) (p=0.0001). Only 38.8% of persons diagnosed with diabetes had good control of DM. The prevalence of DR in the sample was 17.9% (95% CI 14.7% to 21.1%). The prevalence in females was higher (18.9%; 95% CI 14.0% to 23.8%) than in males (17.1%; 95% CI 13.0% to 21.2%). Up to 85.3% of study participants have never had eye examination. Sight-threatening DR (R4 and/or M2) was detected in 5.2% (95% CI 3.4% to 7.0%) with only 2.3% having had laser treatment.

CONCLUSION

The prevalence of uncontrolled DM in Sohag governorate in Egypt is higher than the national prevalence. There is a high prevalence of sight-threatening retinopathy and/or maculopathy with few people having access to diabetic eye care. A public health approach is needed for health promotion, early detection and management of DR.

Fast QLB algorithm and hypothesis tests in logistic model for ophthalmologic bilateral correlated data

In ophthalmologic or otolaryngologic studies, bilateral correlated data often arise when observations involving paired organs (e.g., eyes, ears) are measured from each subject. Based on Donner's model , in this paper, we focus on investigating the relationship between the disease probability and covariates (such as ages, weights, gender, and so on) via the logistic regression for the analysis of bilateral correlated data. We first propose a new minorization-maximization (MM) algorithm and a fast quadratic lower bound (QLB) algorithm to calculate the maximum likelihood estimates of the vector of regression coefficients, and then develop three large-sample tests (i.e., the likelihood ratio test, Wald test, and score test) to test if covariates have a significant impact on the disease probability. Simulation studies are conducted to evaluate the performance of the proposed fast QLB algorithm and three testing methods. A real ophthalmologic data set in Iran is used to illustrate the proposed methods.

Eye Care Utilization in A Community-oriented Mobile Screening Programme for Improving Eye Health in Iran: A Cluster Randomized Trial

PURPOSE

To evaluate the effect of a mobile-based screening programme on eye care utilization in Iran.

METHOD

In this cluster randomized community trial, a representative sample of residents aged≥50 years from urban and rural areas in four districts in Tehran province were enrolled. The clusters were randomly assigned to one of the three parallel arms; the mHealth arm with digital data collection, vision screening test and retina evaluation using an integrated mobile application, the conventional arm with manual data collection and screening tests using Snellen chart and Fundus photography at the local primary healthcare facility, and the control arm with manual data collection without screening tests. The main outcome measure was eye care utilization which was defined as at least one visit to an optometrist or ophthalmologist.

RESULTS

Of 3312 eligible individuals, 2520 (76.1%) participated. In the first 3 months after the screening programme, eye care utilization was higher among those who were referred by the mHealth method (35.6% 95%CI: 31.1-40.4%) compared to those referred by the conventional method (32.7%, 95%CI: 27.5-38.2%) and to those observed in the control arm (4.5%, 95%CI: 3.2-6.0). Eye care utilization improved (OR = 1.5, 95%CI: 1.2-1.9) among the referred people after the screening programme compared to the utilization before this programme; however, this improvement was significantly higher in the mHealth method (OR: 1.7, 95%CI: 1.2-2.4) compared to the conventional method (OR: 1.2, 95%CI: 0.8-1.8).

CONCLUSION AND RELEVANCE

The mobile-based screening programme can significantly improve eye care utilization at the community level.

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.

Rapid Assessment of Avoidable Blindness in Kurdistan, Iran

Purpose:

To determine the magnitude and causes of blindness and visual impairment (VI) in Kurdistan, using the Rapid Assessment of Avoidable Blindness methodology.

Methods:

In this population-based cross sectional study, 99 clusters were selected through probability proportional to size sampling. Visual acuity (VA) was measured using a standard tumbling “E” chart. Ophthalmologists examined participants with VA < 6/18 in both eyes. The cause of VI in the better eye or the most treatable cause was considered as the primary cause of VI.

Results:

A total of 3203 (response rate: 92.4%) individuals aged 50 years and older participated, of whom 1657 (51.7%) were female. The standardized prevalence of blindness, severe visual impairment (SVI), and moderate visual impairment (MVI) based on available correction (presenting VA) were 2.1% (1.5-2.6), 1.7% (1.2-2.2), and 9.6%(8.4-10.8), respectively. The proportion of avoidable causes of blindness, SVI, and MVI were 58.1%, 78.4%, and 83.4%, respectively. The most common cause of blindness and SVI was cataract (27.4% and 60.8% respectively), followed by age-related macular degeneration (25.8% and 13.7%, respectively). The leading causes of MVI were uncorrected refractive errors (RE) (37.2%) and cataract (33.6%).

Conclusion:

The prevalence of blindness in the study population seems comparable to the region. According to our results, blindness, SVI, and MVI were mostly due to avoidable causes. Cataract and refractive errors are the principal causes of blindness and VI in Kurdistan.

Factors Associated with Knowledge, Attitude and Practices of Common Eye Diseases in General Population: A Multicenter Cross-Sectional Study from Pakistan

High prevalence of blindness coupled with low public awareness of eye diseases is a severe problem in Pakistan. The objective of this study was to evaluate the awareness, attitude and practices related to common ocular problems and eye care use among general population of Punjab, Pakistan. Data were collected cross-sectionally, using random selection of participants from five districts of Punjab, Pakistan. A pre-tested questionnaire was used to collect the data from January to March 2017. The ordinal data were converted to interval--based data by Rasch analysis, which is termed as "knowledge score" and ranges from -3 to +3. Descriptive statistics, linear regression, binary logistic regression and chi square analysis were performed to evaluate the data. Of the 2073 people contacted, 96.4% (2019) responded the interviewer. The mean (SD) age was 39.9 (11.4) years, majority were males (64.8%) and only 3.1% were illiterate. The majority (68.1%) of respondents were aware that blindness can be prevented and are least aware of age-related macular degradation (31.4%). Multivariate analysis to knowledge scores demonstrated that male gender (β = 0.53 95%CI = 0.39, 0.66, p < 0.001), higher education (β = 0.31 95%CI = 0.25, 0.37, p < 0.001) were significantly associated with knowledge score. Eighty-two percent of our respondents had a positive attitude towards health-seeking behavior and those who had adequate income on most of occasions were 1.82 (AOR = 1.82 95%CI = 1.26, 2.62 p = 0.001) times more prone towards health-seeking behavior than those who had insufficient income. Out of all respondents, 21.5% had an eye examination at least once a year and this frequency was significantly higher in lower age, females, high education and high Socio Economic Status level (p < 0.05). Among the general population of Pakistan, awareness about prevention of blindness and refractive error was optimum, while awareness of blindness causing eye conditions, like age-related macular degradation was low. Intensive improvements in the health literacy and public interventions-specifically in old age people, males and respondents with lower education-are urgently needed.

Designing a Screening Program for Prevention of Avoidable Blindness in Iran through a Participatory Action Approach

Purpose

To design a screening program for prevention of blindness at the community level in Iran.

Methods

In this qualitative study, the components and properties of the screening program were identified using a participatory action research method with focus group meetings (FGMs) with relevant health care providers and authorities. A content analysis approach was used for data analysis.

Results

In total, 18 stakeholders including six ophthalmologists with different sub-specialties participated in the five FGMs. The screening program aims to discover vision-threatening eye conditions in people aged 50 years and over. Primary health care workers deliver the program including vision tests and fundus imaging with the support of an ophthalmic technician. Retina specialists perform decision-making. Referral plans are interacted through an automated digital program. The screening environment, feedback, ethics and medical legal issues are other main components of the program.

Conclusion

This study presents the initial concepts and components of a screening program for prevention of blindness in the adult population in Iran. The program has the potential to improve eye health at the community level and may potentially be replicated as a model for similar settings elsewhere.

How to improve Iranians' vision health: on the national policy of preventing Iranians' blindness

AIM

To review vision health situation of Iranian community, analyze its determinants, and discuss the adopted improvement strategies by the Iran Ministry of Health and Medical Education (MOHME).

METHODS

This was a rapid situation analysis with a qualitative approach in three parts of recognition, orientation and implementation. The data were gathered via review of upstream documents, national and international experiences, and experts and stakeholders' opinions.

RESULTS

Eradicating trachoma, increasing human resources, increasing educational and research centers and promotion of ophthalmic technologies were important achievements in the field of vision health in Iran. Through these achievements, it seemed that the pattern of causes of blindness and low vision was similar to that of the developed countries. However, the review of Iranians' vision health indicators showed that a considerable percent of the blindness and low vision was avoidable through a national program demanding 3 types of interventions in social determinants of health (SDH), community education, and increasing the access to health care services by integrating the necessary services in primary health care system.

CONCLUSION

Managing the issue requires attentions from a national committee for preventing blindness with participation of all stakeholders, implementing a national survey on vision health, preparation of the primary level health centers including employment and education of community health workers (Behvarzes), optometrists and general practitioners, fair distribution of specialized human resources and establishing at least one specialized center in each province for referring patients from the primary levels.

Changes in corneal thickness and corneal endothelial cell density after phacoemulsification cataract surgery: a double-blind randomized trial

Background

Age-related cataract is a leading cause of visual impairment, considered a global health burden, it is responsible for over 47% of blindness worldwide. Surgical intervention is usually the treatment of choice and phacoemulsification cataract surgery with implantation of an intraocular lens is the most common procedure, which may have several complications.

Objectives

To determine the effects of phacoemulsification surgery on corneal endothelial cell density and corneal thickness in patients undergoing cataract surgery.

Methods

The present study was conducted on patients diagnosed with immature senile cataract requiring surgical intervention from November 2013 to 2014 in Khatam al Anbia Hospital (a tertiary ophthalmology center). Physical examination included best-corrected visual acuity using the Snellen chart, refraction, slit-lamp bio-microscopy for anterior chamber evaluation, keratometry, Goldman tonometry, gonioscopy, and dilated indirect ophthalmoscopy, pachymetry, specular microscopy and biometry. Surgery was performed by similar method and technique in all patients. The change in the corneal endothelial cell count or density and central corneal thickness (CCT) number were compared preoperatively and one day, one week, one month, and three months post–operatively.

Results

A total of 92 eyes of 85 patients (43 females and 42 males with mean age of 62.1±12.2 years) were studied. Patients’ visual acuity improved (log MAR: 1±0.5 preoperatively to 0.45±0.34 post-operatively) (p=0.001). There was 11.4% endothelial cell loss (ECL) and significant decrease in ECC (from 2,791.15±99.86 to 2,472.87±472.14) (p=0.04). The central corneal thickness increased significantly (from 530.47±2.60 to 540.91±36.07). Diabetic patients (12.9%) had a statistically significant higher ECL rate after phacoemulsification (14.6% versus 8.7% respectively, p=0.002).

Conclusion

Phacoemulsification resulted in significant corneal endothelial damage, which is particularly important in patients with a borderline reservoir of endothelial cell, such as diabetic patients, which highlights the necessity of refining the current surgical methods and instruments to minimize the endothelial damage.

Trial registration

The trial was registered in the Thai clinical trial registry (http://www.clinicaltrials.in.th) with the ID: TCTR20171122001.

Funding

The study was supported by a research grant of Mashhad University of Medical Sciences.

Prevalence of Blindness and Low Vision in Iran: A Systematic Review and Meta-Analysis

PURPOSE

Visual impairment is responsible for medical, mental, and socio-economic problems. Several studies have investigated the prevalence of blindness and low vision in different parts of Iran. This study aims to estimate the pooled results of these studies to estimate the total prevalence of this problem in Iran.

METHODS

National and international databases were searched using specific keywords. The selected primary studies were quality assessed using STROBE checklist. According to the results of the heterogeneity tests (Cochrane and I-squared indices), fixed- or random-effect models were applied to estimate the pooled results. The factors responsible for the heterogeneity were investigated using meta-regression models. The point and pooled estimates were presented by forest plots, and the presence of publication bias was assessed based on Egger test.

RESULTS

Considering the results of 10 eligible studies showed that the prevalence (95% confidence intervals) of blindness among men, women, urban, and rural population as well as total population was 0.96% (0.60-1.31), 1.00% (0.70-1.31), 0.81% (0.19-1.44), 0.89% (0.45-1.32), and 1.02% (0.71-1.34), respectively. Prevalence (95% confidence intervals) of low vision among men, women, urban, and rural populations and also total populations was estimated at 2.19% (1.60-2.79), 2.60% (2.08-3.12), 2.81% (1.26-4.36), 3.67% (2.17-5.17), and 2.85% (2.12-3.58), respectively.

CONCLUSION

Our meta-analyses showed that more than 3% of Iranian people are suffering from visual problems. In addition, we found that prevalence of blindness and low vision among Iranian women was more common than that of Iranian men and also was higher in rural areas than urban areas.

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.

Prevalence and Major Causes of Visual Impairment in Iranian Adults: A Systematic Review

PURPOSE:

The purpose of this study is to provide a pooled estimate of moderate-to-severe visual impairment (MSVI) and blindness in Iran for people 50 years and over and to identify the major causes through systematic review.

MATERIALS AND METHODS:

International (PubMed, ISI Web of Science, and Scopus) and national databases (Scientific Information Database, Barakat Knowledge Network System, Iran Databank of Ophthalmology Research, and Magiran) databases were searched. Following relevance assessment and critical appraisal, eight studies were included. A funnel plot was drawn to explore the stability for estimation. Single-variable meta-regression analysis was applied for heterogeneity assessment, and a random effect model was used (but no significant source for the observed heterogeneity was found).

RESULTS:

Age-standardized pooled estimate of MSVI was 4.24% (95% confidence interval [CI]: 2.92–5.56); 3.98% (95% CI: 2.37–5.59) for men, and 4.08% (95% CI: 2.95–5.21) for women. Blindness (visual acuity <3/60) prevalence was 1.31% (95% CI: 1.23–1.39); 0.96% (95% CI: 0.89–1.03) for men, and 1.13% (95% CI: 1.06–1.20) for women. Causes of visual impairment (VI) were cataract (40.23%), amblyopia (12.03%), corneal opacity (9.63%), age-related macular degeneration (9.31%), diabetic retinopathy (4.94%), and glaucoma (3.67%).

CONCLUSION:

VI prevalence in the 50 years and older population in Iran seems significantly better than the corresponding global estimates. A rough 60% rate of treatable VI was estimated, mostly attributable to unoperated cataract.

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.

Visual impairment and blindness in a population-based study of Mashhad, Iran

Purpose

To determine the prevalence of visual impairment and blindness and related factors in the 1- to 90-year-old urban population of Mashhad.

Methods

In this cross-sectional study of 1- to 90-year-old residents of Mashhad, in northeastern Iran, sampling was done through random stratified cluster sampling (120 clusters). After selecting the samples and their participation in the study, all subjects had vision testing including measurement of visual acuity and refraction, as well as examinations with the slit-lamp and ophthalmoscopy. Visual impairment (primary outcomes) was defined as a visual acuity worse than of 0.5 logMAR (20/60) in the better eye.

Results

Of the 4453 selected persons, 3132 (70.4%) participated in the study. The prevalence of visual impairment based on presenting vision and best-corrected vision was 3.95% (95% confidence interval [CI]: 3.13–4.77) and 2.23 (95% CI: 1.54–2.91), respectively. The prevalence of presenting visual impairment increased from 1.59% in children under 5 years of age to 43.59% in people older than 65 years of age; these figures were respectively 1.59% and 42.31% based on corrected visual acuity. In the logistic regression model, older age (OR = 1.06, 95% CI: 1.04–1.07, P < 0.001), higher education (OR = 0.16, 95% CI: 0.06–0.38, P < 0.001), and low income (OR = 1.36, 95% CI: 1.21–1.72, P < 0.001) correlated with impaired sight. Based on presenting vision and best-corrected vision, the prevalence of blindness was 0.86% (95% CI: 0.51–1.22) and 0.32% (95% CI: 0.1–0.55). The most common causes of visual impairment were uncorrected refractive error (41.8%) and cataract (20%).

Conclusions

According to our findings, the prevalence of visual impairment was intermediate in comparison with other studies. The prevalence of visual impairment in our study was similar to the global average; however, it was markedly high at older ages. Nonetheless, refractive errors and cataracts remain as the main causes of impaired vision and blindness in this population, while these two conditions are easily treatable with correction or surgery.

Diabetic Retinopathy Clinical Practice Guidelines: Customized for Iranian Population

PURPOSE

To customize clinical practice guidelines (CPGs) for management of diabetic retinopathy (DR) in the Iranian population.

METHODS

Three DR CPGs (The Royal College of Ophthalmologists 2013, American Academy of Ophthalmology [Preferred Practice Pattern 2012], and Australian Diabetes Society 2008) were selected from the literature using the AGREE tool. Clinical questions were designed and summarized into four tables by the customization team. The components of the clinical questions along with pertinent recommendations extracted from the above-mentioned CPGs; details of the supporting articles and their levels of evidence; clinical recommendations considering clinical benefits, cost and side effects; and revised recommendations based on customization capability (applicability, acceptability, external validity) were recorded in 4 tables, respectively. Customized recommendations were sent to the faculty members of all universities across the country to score the recommendations from 1 to 9.

RESULTS

Agreed recommendations were accepted as the final recommendations while the non-agreed ones were approved after revision. Eventually, 29 customized recommendations under three major categories consisting of screening, diagnosis and treatment of DR were developed along with their sources and levels of evidence.

CONCLUSION

This customized CPGs for management of DR can be used to standardize the referral pathway, diagnosis and treatment of patients with diabetic retinopathy.

National Burden of Eye Diseases in Iran, 1990-2010; Findings from the Global Burden of Diseases Study 2010

Purpose:

The disability-adjusted life-years (DALYs) lost due to eye diseases and trends in DALYs in Iran has not been previously reported. The object of this study is to report the burden of eye diseases in Iran and to compare changes from 1990 to 2010 based on age and gender.

Methods:

Data from the Global Burden of Disease Study 2010 (GBD 2010) are used to report DALYs for cataract, refraction/accommodation (functional) disorders, macular degeneration, and glaucoma.

Results:

Cataract, refraction/accommodation (functional) disorders, macular degeneration, and glaucoma were the 84^th, 87^th, 138^th, and 151^st causes of DALY in 1990 and the 89^th, 72^nd, 99^th, and 137^th in 2010, respectively. Cataract accounted for 0.085% of national DALY in 1990 and 0.09% in 2010, refraction/accommodation (functional) disorders accounted for 0.42% in 1990 and 0.47% in 2010, macular degeneration accounted for 0.017% in 1990 and 0.071% in 2010 and glaucoma accounted for 0.0099% in 1990 and 0.025% in 2010. There was a steady increase in DALY with age for each eye disease for both genders and dichotomized for males and females from 1990 to 2010.

Conclusions:

Epidemiologic transition is reflected in major ophthalmic and blinding diseases in the GBD data for Iran. The burden of macular degeneration is rising, followed by glaucoma. The burden of presbyopia affected individuals past their middle age. The burden of cataract manifested as a slower increase that could be attributable to better access to treatment.

Customized Clinical Practice Guidelines for Management of Adult Cataract in Iran

Purpose:

To customize clinical practice guidelines (CPGs) for cataract management in the Iranian population.

Methods:

First, four CPGs (American Academy of Ophthalmology 2006 and 2011, Royal College of Ophthalmologists 2010, and Canadian Ophthalmological Society 2008) were selected from a number of available CPGs in the literature for cataract management. All recommendations of these guidelines, together with their references, were studied. Each recommendation was summarized in 4 tables. The first table showed the recommendation itself in clinical question components format along with its level of evidence. The second table contained structured abstracts of supporting articles related to the clinical question with their levels of evidence. The third table included the customized recommendation of the internal group respecting its clinical advantage, cost, and complications. In the fourth table, the internal group their recommendations from 1 to 9 based on the customizing capability of the recommendation (applicability, acceptability, external validity). Finally, customized recommendations were sent one month prior to a consensus session to faculty members of all universities across the country asking for their comments on recommendations.

Results:

The agreed recommendations were accepted as conclusive while those with no agreement were discussed at the consensus session. Finally, all customized recommendations were codified as 80 recommendations along with their sources and levels of evidence for the Iranian population.

Conclusion:

Customization of CPGs for management of adult cataract for the Iranian population seems to be useful for standardization of referral, diagnosis and treatment of patients.

Prevalence and Causes of Visual Impairment and Blindness in Central Iran; The Yazd Eye Study

PURPOSE

To determine the prevalence and causes of blindness and visual impairment (VI) in Yazd, central Iran.

METHODS

This population-based, cross-sectional study was performed on adults aged 40-80 years, residing in Yazd district, in 2010-2011. Eligible subjects were selected using cluster random sampling. Each participant underwent an interview and complete ophthalmologic examination. Blindness and VI were defined as best-corrected visual acuity (VA) <3/60 and < 6/18 in the better eye, respectively.

RESULTS

Out of 2,320 eligible individuals, 2,098 participated in the study (90.4% response rate), of whom, 2,023 subjects completed all evaluations. The standardized prevalence of blindness and VI were 0.7% (95% confidence interval [CI], 0.3-1.0%) and 4.4% (95% CI, 3.3-5.4%), respectively which was significantly associated with older age (odd ratio [OR] = 3.2, 95% CI: 1.9-5.2 and OR = 3.1, 95% CI: 2.3-4.2, respectively) and female sex (OR = 3.6, 95% CI: 1.1-12.3 and OR = 1.7, 95% CI: 1.2-2.5, respectively). The proportion of avoidable causes of blindness and VI were 92.9% (95% CI: 80.0-100.0%) and 76.6% (95% CI: 69.2-85.0%), respectively. Major causes of blindness were diabetic retinopathy (50.0%), glaucoma (21.4%) and cataracts (14.3%) whereas main causes of VI were cataracts (41.5%), diabetic retinopathy (17.0%) and age-related macular degeneration (13.8%).

CONCLUSIONS

Diabetic retinopathy, glaucoma, cataract and age-related macular degeneration were the leading causes of blindness and VI in Yazd, most of which are avoidable. Planning for prevention of blindness is highly recommended to decrease the proportion of avoidable blindness.

Healthy Eating Index in Patients With Cataract: A Case-Control Study

Background:

Nutritional factors play an important role in cataract disease and the healthy eating index (HEI) is a unique approach to study the relationships between diet and diseases.

Objectives:

The current study aimed to evaluate and compare healthy eating index among the patients with cataract and healthy individuals.

Patients and Methods:

This case-control study was conducted on 97 patients with cataract and 198 healthy people (as a control group) in Iran. Individuals were selected by the convenience sampling method and the food frequency questionnaire (FFQ) was completed for them. At first, HEI was calculated and then the HEI scores were compared in cataract patients and healthy individuals.

Results:

The analysis of FFQ showed that the scores of vegetables (7.81 v. 10), nutritional variation (5.5 v. 7) and sodium (2 v. 6) groups (P < 0.001) were significantly lower among the patients with cataract than the healthy individuals. Also this significant difference was observed in the scores of total HEI and fruits (respectively 73.26 v.79.30 and 7.1 v. 9.8) (P < 0.01). On the other hand, the scores of saturated fatty acids (10 v. 9; P = 0.02), total fat (8 v. 7; P = 0.004) and cereals (10 v. 10; P < 0.001) were higher among the patients with cataract than the healthy individuals. The comparison of dietary intake among all types of cataract shows that the scores of the meat group were significantly higher in the patients with nuclear cataract and mixed cataract than the ones with posterior cataract (respectively 9.4 v. 6.5 and 9 v. 6.5) (P = 0.02). In addition, after adjusting the confounding factors the results showed that the HEI high score was associated with reducing the risk of coming down with cataract (OR = 0.18, CI: 95%, P < 0.001, 0.08 - 0.41).

Conclusions:

The results of the current study suggest that increasing the quality of the diet calculated according to HEI can reduce the risk of coming down with cataract.

Prevalence, causes of blindness, visual impairment and cataract surgical services in Sindhudurg district on the western coastal strip of India

Background:

Konkan coast of India is geographically distinct and its pattern of blindness has never been mapped.

Aim:

To study the prevalence and causes of blindness and cataract surgical services in Sindhudurg district of West Coast.

Subjects:

Individual aged > 50 years.

Materials and Methods:

Rapid assessment of avoidable blindness used to map blindness pattern in the district. Statistical analysis: SPSS version 19.

Results:

Amongst those examined 1415 (51.7%) had visual acuity (VA) >20/60, 924 (33.8%, confidence interval (C.I) 30.5%-36.8%) had VA 20/200-<20/60(visual impairment), 266 (9.7%, C.I. 6.1%-13.3%) had VA < 20/200-20/400 (severe visual impairment) and 132 (4.8%, C. I. 1.1%-8.5%) had VA < 20/400 (blindness by WHO standards). There was no significant gender difference in prevalence of blindness, but blindness and visual impairment was more in older and rural residing individuals. Amongst those with presenting vision < 20/200 in better eye, 309 (82.4%) had cataract, 36 (9.7%) had corneal scars, 13 (3.5%) had diabetic retinopathyand 3 (0.8%) had glaucoma. Cataract surgical coverage for the district was only 30.5%; 32% for males and 28.4% for females. Unable to afford, lack of knowledge and lack of access to services were the commonest barriers responsible for cataract patients not seeking care. Amongst those who had undergone cataract surgery, only 50% had visual acuity ≥ 20/60.46.9% of the population had spectacles for near, but only 53.3% of the population had presenting near vision < N10.

Conclusion:

Cataract, refractive errors and diabetes were significant causes of visual impairment and blindness.

Homogeneity test for correlated binary data

In ophthalmologic studies, measurements obtained from both eyes of an individual are often highly correlated. Ignoring the correlation could lead to incorrect inferences. An asymptotic method was proposed by Tang and others (2008) for testing equality of proportions between two groups under Rosner's model. In this article, we investigate three testing procedures for general g ≥ 2 groups. Our simulation results show the score testing procedure usually produces satisfactory type I error control and has reasonable power. The three test procedures get closer when sample size becomes larger. Examples from ophthalmologic studies are used to illustrate our proposed methods.

"Planning eye health services in Varamin district, Iran: a cross-sectional study"

BACKGROUND

A recent survey of avoidable blindness in Varamin District, Iran, identified moderately high levels of visual impairment (10%) and blindness (1.5%) in people >50 years. This study aimed to define current provision, identify gaps and suggest practical solutions for improving eye health services in this area.

METHODS

The World Health Organization (WHO) framework for analyzing health systems has several key components: service delivery, health workforce, information system, medical products and technologies, financing, and governance. We used this structure to investigate the strengths and weaknesses of the eye health system in Varamin. All public and private eye care facilities and a random selection of primary health care (PHC) units were assessed using semi-structured researcher-administered questionnaires.

RESULTS

Varamin has 16 ophthalmic clinics, including two secondary hospitals that provide cataract surgery. There were ten ophthalmologists (1:68,000 population), two ophthalmic nurses and five optometrists working in Varamin district. There were no eye care social or community workers, ophthalmic counsellors, low vision rehabilitation staff. Although the Vision 2020 target for ophthalmologists has been met, numbers of other eye care staff were insufficient. The majority of patients travel to Tehran for surgery. The recent survey identified cataract as the leading cause of blindness, despite the availability of surgical services in the district and high health insurance coverage. Poor awareness is a major barrier. No units had a written blindness prevention plan, formal referral pathways or sufficient eye health promotion activities. Only one of the PHC units referred people with diabetes for retinal examination. There is partial integration between eye care services and the general health system particularly for prevention of childhood blindness: chemo-prophylaxis for ophthalmia neonatorum, school vision tests, measles immunization and Vitamin A supplementation.

CONCLUSIONS

This analysis demonstrated the need for better integration between eye care services and the general health system, local planning for prevention of blindness, an information system, a better staff mix and health education to increase community awareness and service uptake. There is the capacity to deliver far more surgery locally. All aspects of a health system need to be developed to deliver comprehensive and efficient eye care.

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.

Prevalence and causes of vision loss in North Africa and the Middle East: 1990-2010

BACKGROUND

To describe the prevalence and causes of visual impairment and blindness in North Africa and the Middle East (NAME) in 1990 and 2010.

METHODS

Based on a systematic review of medical literature, we examined prevalence and causes of moderate and severe vision impairment (MSVI; presenting visual acuity <6/18, ≥3/60) and blindness (presenting visual acuity <3/60).

RESULTS

In NAME, the age-standardised prevalence of blindness decreased from 2.1% to 1.1% and MSVI from 7.1% to 4.5%. In 2010, 3.119 million people were blind, and 13.700 million had MSVI. Women were generally more often affected than men. Main causes of blindness were cataract, uncorrected refractive error, macular degeneration and glaucoma. Main causes of MSVI were cataract and uncorrected refractive errors. Proportions of blindness and MSVI from trachoma significantly decreased.

CONCLUSIONS

Although the absolute numbers of people with blindness and MSVI increased from 1990 to 2010, the overall age-standardised prevalence of blindness and MSVI among all ages and among those aged 50 years and older decreased significantly (p<0.05). Cataract and uncorrected refractive error were the major causes of blindness and MSVI.

Prevalence of second-eye cataract surgery and time interval after first-eye surgery in Iran: a clinic-based study

Purpose:

To determine the prevalence of second-eye senile cataract surgery (SECS) as a proportion of all senile cataract surgeries and the trend in the interval between first and second cataract operations in a main referral and academic eye hospital.

Materials and Methods:

In this cross-sectional study, a list of patients who underwent senile cataract surgery over four consecutive years (2006-2009) was retrieved from hospital computer-based records as the sampling frame. With a systematic random method, 15% of records were selected (1,585 out of 10,517 records).

Results:

First- and second-eye operations were performed in 1,139 (71.9%; 95% confidence interval [CI], 69.5-74.1) and 446 eyes (28.1%; 95% CI, 25.9-30.35), respectively. The proportion of SECS procedures increased from 24.3% in 2006 to 33.4% in 2009 (P = 0.017). The median (interquartile range) interval between the two operations was 9 (4-24) months, which remained stable during the study period. The SECS rate was 10.4% higher (P = 0.01) and the time interval was 13 months shorter (P = 0.007) in patients who underwent phacoemulsification than extracapsular cataract extraction.

Conclusion:

The number of cataract operations in this tertiary eye care setting increased 1.5 fold over the study period. The proportion of second-eye operations also rose from 1/4 to 1/3 during the same time.

Profile of cataract surgery in Varamin Iran: a population-based study

BACKGROUND

Cataract is the most popular cause of blindness. This study addresses some aspects of cataract surgery in an Iranian population.

DESIGN

A cross-sectional study.

PARTICIPANTS

3000 adults over 50 in Varamin district.

METHODS

Cataract surgical coverage was defined as the proportion of (pseudo) aphakic eyes of all operable and operated eyes with cataract. If there was obvious lens opacity in either or both eyes in combination with best corrected visual acuity less than 6/18, the person was asked why the operation for cataract was not done to find out about barriers of cataract surgery. Outcomes of cataract surgery were categorized as good, intermediate and poor using presenting visual acuity which were defined as visual acuity ≥ 6/18, 6/60 ≤ visual acuity < 6/18 and visual acuity < 6/60, respectively.

MAIN OUTCOME MEASURES

Cataract surgical coverage, barriers and outcomes of cataract surgery.

RESULTS

Out of 5638 examined eyes, 526 eyes (9.3%) had history of cataract surgery. 156 subjects (45.7%) had a unilateral and 185 subjects (54.2%) had bilateral operated eyes. Cataract surgical coverage was 66.4% in visually impaired eyes (visual acuity < 6/18), 90.4% in blind eyes (visual acuity < 3/60), 80.5% in visually impaired persons and 97.6% in blind persons. Cataract surgery in the majority of eyes (71.9%) had a good visual outcome. The main barrier of cataract surgery was unawareness of treatment.

CONCLUSION

Overall, the cataract services in the studied population were acceptable, although it should be improved, to achieve vision 2020 objectives.

Elimination of avoidable blindness due to cataract: where do we prioritize and how should we monitor this decade?

Background:

In the final push toward the elimination of avoidable blindness, cataract occupies a position of eminence for the success of the Right to Sight initiative.

Aims:

Review existing situation and assess what monitoring indicators may be useful to chart progress towards attaining the goals of Vision 2020.

Settings and Design:

Review of published papers from low and middle income countries since 2000.

Materials and Methods:

Published population-based data on prevalence of cataract blindness/visual impairment were accessed and prevalence of cataract blindness/visual impairment computed, where not reported. Data on prevalence of cataract blindness, cataract surgical coverage at different visual acuity cut offs, surgical outcomes, and prevalence of cataract surgery were analyzed. Scatter plots were used to look at relationships of some variables, with Human Development Index (HDI) rank. Available data on Cataract Surgical Rate (CSR) was plotted against prevalence of cataract surgery reported from surveys.

Results:

Worse HDI Ranks were associated with higher prevalence of cataract blindness. Most studies showed that a significant proportion of the blind were covered by surgery, while a fifth showed that a significant proportion, were operated before they went blind. A good visual outcome after surgery was positively correlated with higher surgical coverage. CSR was positively correlated with cataract surgical coverage.

Conclusions:

Cataract surgical coverage is increasing in most countries at vision <3/60 and visual outcomes after cataract surgery are improving. Establishing population-based surveillance of cataract surgical need and performance is a strong monitoring tool and will help program planners immensely.