Cataract in the Kingdom of Morocco: indications for surgery and functional results.

AIM: To investigate the results of cataract surgery in different settings in the Kingdom of Morocco. METHOD: At four separate health facilities, 100 consecutive patients undergoing ECCE cataract extraction for age-related cataract were examined pre-operatively and 6-8 weeks post-operative for changes in visual acuity. RESULTS: Thirty-four percent of patients (better eye acuity) and 95.5% of operated eyes had a visual acuity of less than 3/60 pre-operatively. Six to eight weeks post-operatively 84.0% of patients (better eye acuity) and 74.7% of operated eyes achieved a visual acuity of 6/18 or better. Of 198 eyes having an intraocular lens (IOL) implanted, 87.9% achieved 6/18 and 3.0% were less than 6/60 post-operatively. Of 202 eyes having cataract surgery without an IOL, 61.7% achieved 6/18 and 4.5% were less than 3/60. The proportion of eyes receiving an IOL in the 4 centres ranged from 29% to 74%. CONCLUSION: Monitoring the pre and post-operative acuity of cataract patients can give useful information on the indications for surgery in different settings, the use of IOLs and the visual outcome. Implantation of an IOL should be encouraged in all people having cataract surgery unless contra-indicated.

2002 global update of available data on visual impairment: a compilation of population-based prevalence studies.

PURPOSE: For the past 25 years, the WHO Programme for the Prevention of Blindness and Deafness has maintained a Global Data Bank on visual impairment with the purpose of storing the available epidemiological data on blindness and low vision. The Data Bank has now been updated to include studies conducted since the last update in 1994. METHODS: An extensive literature search was conducted in international and national scientific and medical journals to identify epidemiological studies that fulfilled basic criteria for inclusion in the Data Bank, namely a clearly stated definition of blindness and low vision, and prevalence rates derived from population-based surveys. Sources such as National Prevention of Blindness Programmes, academic institutions or WHO country or regional reports were also investigated. RESULTS: Two-hundred-and-eight population-based studies on visual impairment for 68 countries are reported in detail, providing an up-to-date, comprehensive compilation of the available information on visual impairment and its causes globally.

[Trachoma in Senegal: results of a national survey]. / Le trachome au Sénégal: résultats d'une enquête nationale.

A national survey was conducted to determine the prevalence of trachoma in Senegal between February and July 2000. The methodology consisted of a cross-sectional survey based on random sampling with two levels of stratification in five areas or area groups. A total of 12,328 children under 10 years of age and 8753 women over the age of 14 years were examined from 150 clusters (30 clusters per stratum). Excluding the Dakar stratum, the estimated prevalence of active trachoma (TF/TI) and severe trachoma (TI) in children under 10 years of age was 10.8% (IC 95%: 9.2-11.4) and 1.2% (IC 95%: 0.5-2.3) respectively. The corresponding prevalence for the areas around Dakar were 3.3% et 0.3%. Prevalence rates were highest between the ages of 2 and 3 years (17.4%). However these rates concealed major differences between strata since prevalence ranged from 3.3% in Dakar to 14.2% in Thiès-Diourbel. Excluding Dakar, the estimated prevalence of entropion/trichiasis and corneal opacity among women over the age of 14 years was 2.6% (IC 95%: 1.9-3.4) and 1.4% (IC 95%: 0.9-1.8). The prevalence of trichiasis was over 1% in every area except Tambacouna and reached 4% in Thiès-Diourbel. Trichiasis was observed in 17.1% of women over the age of 70. Based on extrapolation of these data to the whole country, it can be deduced that 272,020 children have active trachoma requiring medical treatment and that 115,000 persons over 14 years of age present trichiasis requiring surgical treatment.

The prevalence and causes of blindness in the Sultanate of Oman: the Oman Eye Study (OES).

AIMS: To estimate the magnitude and the causes of blindness through a community based nationwide survey in Oman. This was conducted in 1996-7. METHODS: A stratified cluster random sampling procedure was used to select 12 400 people. The WHO/PBD standardised survey methodology was used, with suitable adaptation. The major causes of blindness were identified among those found blind. RESULTS: A total of 11 417 people were examined (response rate 91.8%) The prevalence of blindness in the Omani population was estimated to be 1.1% (95% CI 0.9 to 1.3), blindness being defined according to the WHO Tenth Revision of the International Classification of Diseases. Prevalence of blindness was clearly related to increasing age, with estimates of 0.08% for the 0-14 age group, 0.1% for the 15-39 age group, 2.3% for the 40-59 age group, and 16.8% for the group aged 60 +. There was a statistically significant difference between the prevalence in females (1.4%) and males (0.8%). The northern and central regions had a higher prevalence of blindness (1.3% to 3%). The major causes of blindness were unoperated cataract (30.5%), trachomatous corneal opacities (23.7%), and glaucoma (11.5%) CONCLUSIONS: Despite an active eye healthcare programme, blindness due to cataract and trachoma remains a public health problem of great concern in several regions of the sultanate. These results highlight the need, when planning effective intervention strategies, to target the eye healthcare programme to the ageing population, with special emphasis on women.

[The quality of trichiasis surgery in the kingdom of Morocco]. / Qualité de la chirurgie du trichiasis au royaume du Maroc.

In December 1998, a survey was carried out on the quality of trichiasis surgery, based on a random sample of 750 people chosen from the surgical records of 13 health centres of the provinces of Zagora and Errachidia (Kingdom of Morocco). Among those, 740 people were examined (participation ratio: 98.6%). The study population was mainly composed of women (63.8%) and people > 40 years (83.5%). The average age was 51.8 (48.5 for women and 57.4 for men). The most common surgical technique was the bilamellar tarsal rotation procedure. In 98.7% of cases, the operation concerned one of the upper eyelids, and in 58.5% of cases the right eye. At the time of the interviewers' visit, 11.1% of the people examined were blind (vision < 1/20 for the best eye) and 28.9% were visually impaired (vision > 1/20 but < 3/10). In addition, 17.6% of the eyes whose eyelids had been operated on rated as blind and 29% of them as visually impaired. The definition of recurrence was the presence of at least one or more eyelashes in contact with the eyeball. The recurrence rate is estimated to be 15.8%, divided into 2 categories: (1) Severe or total recurrence (2.4%) - At least one eyelash from the median part of the lid margin is in contact with the cornea - and, (2) Partial recurrence "One or more eyelashes affect the corners of the eyelids but never rub against the cornea" (13.4%). 14. 3% of the patients operated on were removing their eyelashes regularly which is a clear indicator of the failure of the operation. The following constitute risk factors for recurrence: being aged over 40, having been operated on in Errachidia province, having been operated on by a general practitioner or by an ophthalmologist. However, "time elapsed since the operation" does not appear to influence the recurrence rate in each of the three cohorts which were subsequently formed using the date of the operation (retrospectively). Most recurrences seem to develop during the first twelve months after the operation. The post-operational complications/sequelae detected were rarely sight-threatening, except in four cases, i.e., three ptoses and one case of tegumental necrosis with permanent exposure of the cornea. The most common complications were excessive rotation of the lid margin (over-correction) (2.3%) and cutaneous necroses with no exposure of the cornea (3.6%). In this series, 15.7% of the eyes examined presented central corneal opacity and 2.1% xerosis. In 1.6% of cases the eyeball was either destroyed (phthisis bulbi) or absent. A majority of patients (51.8%) was affected by persistent lacrimation or secretions.

Refractive Error Study in Children: sampling and measurement methods for a multi-country survey.

PURPOSE: The Refractive Error Study in Children was designed to assess the prevalence of refractive error and vision impairment in children of different ethnic origins and cultural settings. METHODS: Population-based cross-sectional samples of children 5 to 15 years of age were obtained through cluster sampling. Presenting, uncorrected, and best-corrected visual acuity, along with refractive error under cycloplegia, were the main outcome measures. Amblyopia and other causes of uncorrectable vision impairment were determined. RESULTS: Study design and sample size calculations, survey enumeration and ophthalmic examination methods, quality assurance monitoring, and da ta analyses and statistical methods are described. CONCLUSIONS: The study design, sample size, and measurement methods ensure that the prevalence of age-specific and sex-specific refractive error can be estimated with reasonable accuracy in the target populations. With commonality of methods, a comparison of findings between studies in different ethnic origins and cultural settings is possible.

Refractive Error Study in Children: results from Mechi Zone, Nepal.

PURPOSE: To assess the prevalence of refractive error and vision impairment in school age children in the terai area of the Mechi zone in Eastern Nepal. METHODS: Random selection of village-based clusters was used to identify a sample of children 5 to 15 years of age. Children in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and anterior segment, media, and fundus examinations were done from May 1998 through July 1998. Independent replicate examinations for quality assurance monitoring took place in all children with reduced vision and in a sample of those with normal vision in seven villages. RESULTS: A total of 5,526 children from 3,724 households were enumerated, and 5,067 children (91.7%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.5 (20/40) or worse in at least one eye was 2.9%, 2.8%, and 1.4%, respectively; 0.4% had best visual acuity 0.5 or worse in both eyes. Refractive error was the cause in 56% of the 200 eyes with reduced uncorrected vision, amblyopia in 9%, other causes in 19%, with unexplained causes in the remaining 16%. Myopia -0.5 diopter or less in either eye or hyperopia 2 diopters or greater was observed in less than 3% of children. Hyperopia risk was associated with female gender and myopia risk with older age. CONCLUSIONS: The prevalence of reduced vision is very low in school-age children in Nepal, most of it because of correctable refractive error. Further studies are needed to determine whether the prevalence of myopia will be higher for more recent birth cohorts.

Prevalence of blindness and cataract surgery in Nepal.

BACKGROUND: A national eye care programme was launched in Nepal in the early 1980s. The impact of this programme on blindness and cataract surgery prevalence was evaluated in two geographic zones. METHODS: People aged 45 years and older were sampled using a stratified cluster design. Within randomly selected clusters, door to door enumeration was followed by visual acuity measurement and eye examinations at conveniently located sites. The full survey was preceded by a pilot study where operational methods were refined and quality assurance measures carried out. RESULTS: Of the 5112 enumerated individuals 90% were examined. Blindness, defined as presenting visual acuity less than 6/60 in both eyes, was found in 5.3% (95% CI 3.6, 6.8) of individuals examined, with cataract being the principal cause in at least one eye in 78% of cases. Considering both cataract operated and unoperated cataract blind cases, surgical coverage was approximately 42%. CONCLUSION: The findings suggest that blindness prevalence may have decreased slightly from that estimated in a 1981 national survey, both overall and cataract related. Similarly, cataract surgical coverage may have increased somewhat. None of these changes, however, are at statistically significant levels. Accordingly, the blindness problem remains challengingly high.

The global impact of eye injuries.

Using data compiled from the ophthalmic literature and WHO's Blindness Data Bank, the available information on eye injuries from an epidemiological and public health perspective has been extensively reviewed. This collection of data has allowed an analysis of risk factors, incidence, prevalence, and impact of eye injuries in terms of visual outcome. However, most of the estimates are based on information from More Developed Countries (MDCs). The severity of eye injuries can be assessed through proxy indicators such as: (i) potentially blinding bilateral injuries; (ii) open-globe injuries; (iii) endophthalmitis; (iv) enucleation or (v) defined visual impairment. Major risk factors for ocular injuries include age, gender, socioeconomic status and lifestyle. The site where the injury occurs is also related to a risk situation. Available information indicates a very significant impact of eye injuries in terms of medical care, needs for vocational rehabilitation and great socioeconomic costs. The global pattern of eye injuries and their consequences emerging from the present review, undertaken for planning purposes in the WHO Programme for the Prevention of Blindness, suggests that: some 55 million eye injuries restricting activities more than one day occur each year; 750,000 cases will require hospitalization each year, including some 200,000 open-globe injuries; there are approximately 1.6 million blind from injuries, an additional 2.3 million people with bilateral low vision from this cause, and almost 19 million with unilateral blindness or low vision. Further epidemiological studies are needed to permit more accurate planning of prevention and management measures; a standardized international template for reporting on eye injuries might be useful to this effect, along the lines of the reporting occurring through the US Eye Injury Registry.

[Prevalence and causes of blindness in the Tunisian Republic. Results of a national survey conducted in 1993. Tunisian Team on the Evaluation of Blindness]. / Prévalence et causes de la cécité en République tunisienne. Résultats d'une enquête nationale conduite en 1993. L'équipe tunisienne d'évaluation de la cécité.

AIMS: to estimate the prevalence of visual impairment and blindness; to identify the major causes of visual impairment and blindness and to estimate their overall impact, particularly on cataracts. METHODS: We used a population-based method. A cluster sample was selected, with the number of households randomly selected from a community depending on the size of the population. Examinations and data collection were carried out using the procedures recommended by the WHO. RESULTS: We included 3,981 individuals, 3,547 of whom were given a medical examination (89% participation). The structure of the sample differed from that of the Tunisian population, with people over the age of 60 years over represented in the sample. The crude prevalence of blindness was 1.2% (adjusted prevalence 0.8%) and that for bilateral visual impairment was 3% (adjusted prevalence 2%). There were 225,000 individuals with severely impaired vision, of whom 64,500 were blind (including 2,100 children under the age of 15 years) and 160,000 were visually impaired (including 8,700 children). Individuals over the age of 60 were eight times more likely to become blind and 6.7 times more likely to suffer visual impairment than those below the age of 60. Cataracts, particularly associated with aging, were the main cause of blindness (66%) and bilateral visual impairment (54.6%). Uncorrected aphakia accounted for a significant fraction of the visual deficiencies identified in this survey (6.4% of cases of blindness and 11.8% of cases of bilateral visual impairment). 1.7% of the individuals examined (135,000 people) had ocular surgery and 80,000 had undergone surgery for cataracts. Only 41% of those individuals who had cataracts had undergone surgery. The provision of cataract surgery was therefore inadequate. CONCLUSION: About 80% of the cases of blindness registered were preventable or treatable. The development of appropriate strategies for dealing with cataract blindness should significantly reduce the incidence of blindness.

The Madurai Intraocular Lens Study. I: A randomized clinical trial comparing complications and vision outcomes of intracapsular cataract extraction and extracapsular cataract extraction with posterior chamber intraocular lens.

PURPOSE: The Madurai Intraocular Lens Study (MIOLS) was designed to compare safety, efficacy, and quality of life outcomes after either intracapsular cataract extraction with aphakic glasses (ICCE-AG) or extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/ PC-IOL). METHODS: The Madurai Intraocular Lens Study was a nonmasked randomized controlled clinical trial conducted at a single hospital. Thirty-four hundred patients with age-related cataracts and having a best-corrected visual acuity less than or equal to 20/120 in the better eye were randomly assigned to either of the two cataract operative procedures. The main clinical outcomes were safety (complication rates) and efficacy (best-corrected visual acuity at 1 year equal to or better than 20/40). In addition, a subset of 1,700 trial participants received questionnaires before surgery, at 6 months after surgery, and at 1 year after surgery to measure visual functioning and vision-related quality of life. RESULTS: Details of study design, study organization, clinical and quality of life outcome variables, sample size calculations, patient eligibility criteria and recruitment, randomization and masking, participant flow, adherence to follow-up, quality assurance, and statistical methods are presented. CONCLUSIONS: The Madurai Intraocular Lens Study has sufficient power to detect clinically significant differences between the treatment options. There were no statistically significant differences between the two treatment groups for any of the major study variables at baseline. A high level of quality assurance was maintained throughout the October 1993 to June 1996 study period. The results should be applicable to all settings where the requisite expertise and resources are present.

[World Health Organization alliance for the elimination of trachoma]. / L'alliance de l'Organisation Mondiale de la Santé pour l'élimination du trachome.

Although trachoma has either decreased or disappeared in many Third World countries through socio economic development during the past forty years, it remains a major problem among the poorest communities, which is often ignored by decision-makers when setting priorities. Fortunately, recent developments will allow to overcome many of the past obstacles and to offer new opportunities for trachoma control programmes. WHO aware of this new favourable context for trachoma control has taken the leadership in mobilizing and coordinating trachoma control efforts through the creation of a WHO Alliance for the Global Elimination of Trachoma. The aim of this Alliance is to assist Member States where trachoma is endemic achieve the goal of (global) elimination of trachoma by the year 2020. This is indeed possible through the combination of various interventions such as those proposed by the SAFE strategy (Surgery for trichiasis, Antibiotics, Face washing and Environmental changes) recommended by WHO. The prevention of trachoma and its treatment will rely largely on the efforts made by the endemic countries concerned with this problem. Therefore, new and or existing trachoma control programmes should be either implemented or strengthened at community-based level within the framework of the available primary health care systems based on the application of the SAFE strategy and on the assistance of the Alliance partners.

[Blinding cataract in Morocco]

A 1992 survey of the prevalence and causes of visual impairment in Morocco identified age-related cataract as the leading cause of blindness [45.5%] and low vision [43.1%]. The prevalence of cataract-related visual impairment was estimated to be 2.1%. Patients who had undergone cataract surgery represented 0.8% of the sample; the demand for surgical care is estimated at 25%. Only 60% of people with aphakia had the necessary corrective lenses. Stigmata/complications of posterior dislocation of the lens by the traditional method of cataract treatment were found in 0.1% of cases examined. Sound and sustained management of the public health problem posed by cataracts would reduce the current prevalence of blindness by about 40%, bringing it down to 0.5%, the long-term objective of the national blindness control programme

Blindness and low vision in southeast Turkey.

In preparation for the planning of a regional prevention of blindness programme, a population-based survey of blindness and eye disease was conducted in two provinces (Diyarbakir and Mardin) of southeast Turkey. A stratified cluster random sampling procedure was used to select 8,571 persons. The main objectives of the survey were to assess the population need for basic ophthalmic services, both in rural and in rapidly growing urban communities, and to secure baseline data for subsequent evaluation of the programme. The prevalence of visual impairment (best binocular vision poorer than 6/ 18) was estimated at 1.9% with 95% confidence limits of 1.6% and 2.1%, amounting to 29,400 +/- 4500 visually imparied persons in the regional population of 1.6 million. The prevalence of blindness (best vision poorer than 3/60) was 0.4%, and an estimated 1.5% had low vision (best vision poorer than 6/18, but not blind). Compared to the blindness prevalence of 0.2% in the European Economic Community (EEC), the age-standardised prevalence of blindness in southeast Turkey was 8 times as high. The main causes of blindness in the sample were cataract (50%), corneal opacity (15%), glaucoma (12%), phthisis (6%) and optic atrophy (6%). Cataract and refractive errors were responsible for 52% and 26% of the low vision, respectively. Acute inflammatory trachoma was prevalent in a number of rural and urban communities, affecting an estimated 25,900 people in the region. The need for basic ophthalmic services was estimated for the two provinces. Some 26,600 were in need of cataract surgery, 4,400 needed eyelid surgery for trachoma-induced entropion, and 28,600 required spectacles to improve their visual acuity to 6/18 or better. More than half of the current burden of severe visual loss in the two provinces of southeast Turkey is potentially remediable through the provision of cataract surgery and of spectacles to correct aphakia. The survey findings suggest that as the age structure of the regional population approaches that of the EEC through the "ageing trend', a four-fold increase in the burden of blindness might be expected, unless improvements are made in curative and preventive ophthalmic services in parallel with the general development that improves survival.