Causes and prevalence of blindness in the Northern Province of Sierra Leone

Neglected tropical disease control in post-war Sierra Leone using the Onchocerciasis Control Programme as a platform

Strategic investments in the control of neglected tropical diseases (NTD) spearheaded by the US Government, the British Government and other bilateral donors such as foundations and key pharmaceutical partners have enabled the treatment of millions of people for the five targeted debilitating diseases (lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiasis and trachoma), paving the way for the potential elimination as public health problems of some of these diseases. Like many other countries, Sierra Leone has a high burden of these major NTDs. Despite the fragile infrastructure of a health system emerging from a devastating 10-year civil war, the country has successfully implemented the National NTD Control Programme, reaching national coverage in 2010. The NTD Control Programme uses the existing Onchocerciasis Control Programme as a platform and involves primary health workers. The programme has provided extensive training opportunities to health workers at national, district and community levels. The country currently has 31 161 trained community volunteers treating a population of five million people. It is shown that the investments in NTD control are not only to control NTDs but also to strengthen health systems, particularly at the primary level, through extensive capacity building of frontline health workers and community-directed distributors.

Evaluation of risk factors for advanced glaucoma in Ghanaian patients

PURPOSE

This study was to determine factors associated with individuals presenting late with advanced glaucomatous optic nerve damage.

METHODS

A case-control study recruiting 123 patients with early features of primary open angle glaucoma (control) and 93 patients with advanced glaucoma (cases) was carried out for risk-factor analysis. Exposures of interest included those already established as major risk factors for glaucoma. These were initial intraocular pressure (IOP), age, and family history. In addition, occupation, ethnic origin, history of diagnosis of diabetes mellitus, hypertension, sickle cell disease, and previous eye examination were of interest.

RESULTS

Univariate analysis showed that initial IOP>31 mmHg, age of > 60 years, absence of family history of glaucoma, occupational grouping, ethnicity, and male sex were associated with advanced glaucoma at presentation. Adjusted odds ratio or by multiple logistic regression model showed that initial IOP>31 mmHg in a patient was more likely to present with advanced glaucoma (OR 2.66, 95% confidence interval (CI) 1.45, 4.91; P-value 0.0017) than lower pressures. Patients aged 60-69 years (OR 2.53, 95% CI 1.01, 6.31; P-value 0.0473) and 70-90 years (OR 5.16, 95% CI 1.97, 13.51; P-value 0.0008) were more likely to present with advanced glaucoma than younger ones

CONCLUSIONS

Subjects with initial IOP>31 mmHg were nearly three times more likely to present with advanced glaucoma than those with IOP<32 mmHg. Subjects over the age of 60 years were more than two times likely to present with advanced glaucoma than younger subjects.

Measles blindness

Measles remains a major problem in developing countries, where it affects an estimated 30 million children a year and causes up to one million deaths annually. Measles blindness is the single leading cause of blindness among children in low income countries, accounting for an estimated 15,000 to 60,000 cases of blindness per year. There is a close synergism between measles and vitamin A deficiency that can result in xerophthalmia, with corneal ulceration, keratomalacia, and subsequent corneal scarring or phthisis bulbi. High-dose oral vitamin A supplementation is recommended for all children with measles in developing countries. Higher measles immunization coverage to interrupt measles transmission and interventions aimed at improving vitamin A nutriture of children are the main strategies to prevent measles blindness.

Prevalence of myocilin mutations in adults with primary open-angle glaucoma in Ghana, West Africa

PURPOSE

Investigators have noted that primary open-angle glaucoma (POAG) in West Africa has an earlier age of onset and appears to be more clinically severe than in the United States and Europe. Primary open-angle glaucoma patients with mutations in myocilin have a similar phenotype. Therefore, we investigated the role of mutations in myocilin in patients with POAG in a West African population.

MATERIALS AND METHODS

Patients seen at the Emmanuel Eye Clinic in Accra, Ghana, were recruited for this study. Informed consent was obtained from all study patients. Glaucoma specialists from the sponsoring institution (PC, LWH, or RRA) ascertained all POAG and control patients. Age-matched unaffected controls were obtained in patients with an IOP < 22 mm Hg and normal-appearing optic nerves. PCR amplification of each of the three myocilin exons was performed. Denaturing high-performance liquid chromatography (Transgenomics Corp.) was used to detect allelic differences and samples demonstrating a mobility shift were sequenced in both directions.

RESULTS

Ninety unrelated affecteds with POAG and 76 control patients were recruited. Four individuals with severe POAG were found to have novel missense mutations in exon 3. Two exhibit an Asp380Asn mutation and two an Arg342Lys mutation. These changes were not detected in 152 ethnically matched control chromosomes. Fourteen affected individuals and eight controls exhibit a translationally silent polymorphism in codon 325 (Thr325Thr).

CONCLUSIONS

A total of 4.4% of patients with POAG have novel disease-associated mutations in myocilin. Mutations in myocilin appear to play a limited role in the pathogenesis of POAG in this region of West Africa.

Survey of glaucoma in an eye clinic in Ghana, West Africa

PURPOSE

To report the various types of glaucoma among West African patients presenting to an eye clinic in Ghana.

METHODS

A complete evaluation was performed in 198 consecutive Ghanaian glaucoma patients. Main outcome measures included intraocular pressure, visual acuity, gonioscopy findings, visual field, and total number of glaucoma medications.

RESULTS

The most common form of glaucoma was primary open-angle glaucoma (44.2%). Open-angle glaucoma suspects also comprised a large percentage of the group (30.5%). Chronic angle-closure glaucoma was diagnosed in 6.6% of the patients.

CONCLUSIONS

Primary open-angle glaucoma is the most common form of glaucoma being treated in this outpatient eye clinic in Ghana. Chronic angle-closure glaucoma was the second most common form of glaucoma in this series and was usually undiagnosed due to a lack of gonioscopic evaluation. Gonioscopy is an important diagnostic tool that should be promoted to guide more effective glaucoma treatment in this region. Pseudoexfoliation and pseudoexfoliation-associated glaucoma were not seen in this population.

Visual loss in urban and rural chronic glaucoma patients in Ghana

The visual acuity of newly diagnosed glaucoma patients in a rural and an urban area were compared in a hospital-based cross-sectional study in Ghana. Age at presentation was strikingly higher in the rural group due to local factors which result in a difference-in-age structure of the rural and urban population. The crude relative frequency of bilateral blindness was significantly higher for rural than urban. However, with age adjusted relative frequencies for bilateral blindness there was no significant difference between rural and urban patients. There was significant difference between them for those aged 51-71 when blindness in one or both eyes were considered together. There was more consistent blindness in the rural community: the difference was attributed to local factors such as better access to eye care in the urban group.

Caffeine and intraocular pressure in a Nigerian population

PURPOSE

Caffeine is widely consumed as kola nuts and in other products in sub-Saharan Africa. We examined the acute effect of caffeine on the intraocular pressures of healthy Nigerian volunteers between the ages of 20 and 27 years.

METHODS

Intraocular pressure and blood pressure were measured 0, 30, 60, and 90 minutes after the ingestion of coffee by two groups of participants, namely the experimental (caffeinated coffee) and control (decaffeinated coffee) groups.

RESULTS

The result showed that ingested caffeine increases intraocular pressure and that the elevation, though variable across patients, is sustained for several minutes. The mean increase across patients rises monotonically with the postingestion time and by almost 4 mm Hg. There was also a corresponding increase in systolic and diastolic blood pressure of the caffeinated group. There was relatively no change in intraocular pressure or blood pressure with time in the control group. The difference between both groups was statistically significant (P < 0.05).

CONCLUSIONS

The results suggest the need for more glaucoma screenings and proper patient education, particularly in Nigerian populations in which the consumption of caffeine, contained in kola nuts and in other raw and processed products, is endemic and long-term.

Uveitis in children

PURPOSE

To summarize the prevalence and patterns of uveitis in children.

METHODS

Pertinent articles were reviewed.

RESULTS

Children constitute 5-10% of the patients with uveitis seen at tertiary referral centers, and girls appear to develop uveitis slightly more frequently than boys. Among all children with intraocular inflammation, anterior uveitis accounts for 30-40%, posterior uveitis accounts for 40-50%, intermediate uveitis accounts for 10-20%, and diffuse uveitis accounts for 5-10%. The most common cause of anterior uveitis is juvenile idiopathic arthritis (JIA), whereas the most frequent type of posterior uveitis is toxoplasmic retinochoroiditis. Most cases of intermediate and diffuse uveitis are bilateral, chronic, and idiopathic. The most common causes of vision loss in children with uveitis are cataract, band keratopathy, glaucoma, and cystoid macular edema. Up to one-third of the children with uveitis are left with severely impaired vision as a result of these complications.

CONCLUSIONS

Uveitis is an important cause of ocular morbidity in children. Prompt diagnosis and treatment is essential to minimize the risk of long-term vision loss.

Blindness from uveitis in a hospital population in Sierra Leone

A retrospective study was conducted to assess the causes of blindness and visual impairment in patients who visited an eye hospital in Sierra Leone, West Africa, in 1989 and 1992. These data were compared with figures from 1981. Throughout the years, senile cataract was the major cause of blindness, followed by uveitis (including onchocerciasis). Uveitis remained the second most important cause of blindness in this population, despite the significant decrease in blindness from onchocerciasis (from 30% in 1981 to 15% in 1992). An increasing number of patients with uveitis from non-onchocercal origin was observed: almost 10% of the blindness found in 1992 was due to uveitis of non-onchocercal origin. A reduction in visual handicap in patients with non-onchocercal uveitis could be achieved if local hospitals could obtain more accurate diagnoses in these patients.

Prevalence of blindness and low vision of people over 30 years in the Wenchi district, Ghana, in relation to eye care programmes

A population based survey on the prevalence of major blinding disorders was conducted in the Wenchi district in central Ghana between March and May 1991. In 10 villages, 1425 people of 30 years and older were screened, using the WHO eye examination record. The prevalence of bilateral blindness above 30 years proved to be 1.7% (best acuity < 3/60): the prevalence of low vision above 30 years was 2.0% (best visual acuity 6/18 to 3/60). The causes of blindness were determined as cataract (62.5%), onchocerciasis (12.5%), corneal opacity (non-trachomatous) (8.2%), refraction anomalies (4.2%), phthisis bulbi (4.2%), optic atrophy (4.2%), and vascular retinopathy (4.2%). In the Wenchi district, 1.0% of the population over the age of 30 years was found to need a cataract extraction because of blindness of both eyes. Another potential 1.0% needs a cataract extraction because of low vision. A minor second study (n = 149) was undertaken in the same district, but in a village in an area near the Black Volta river in which onchocerciasis is endemic. The prevalence of blindness (8.1%) and low vision (3.4%) caused by onchocerciasis and cataract both proved to be higher. The survey provided the basis for a preventive and curative eye care programme.

A prospective trial of intraoperative fluorouracil during trabeculectomy in a black population

In a study population of black Africans with advanced glaucoma in Ghana we conducted a prospective study of intraoperative 5-fluorouracil alone. Eyes undergoing trabeculectomy were randomly selected either to receive or not receive a single intraoperative application of 5-fluorouracil (50 mg/ml for five minutes). Fifty-five eyes had a mean follow-up of 282 days (minimum, 92 days). Twenty of 24 eyes (83%) in the 5-fluorouracil group vs 12 of 31 eyes (39%) in the control group had postoperative intraocular pressure of 20 mm Hg or less with or without medical therapy (P = .01). Eleven of 24 eyes (46%) in the 5-fluorouracil group and five of 31 eyes (16%) in the control group had intraocular pressure of 15 mm Hg or less (P = .02). Without medical therapy, 17 of 24 eyes (71%) in the 5-fluorouracil group and ten of 31 eyes (32%) in the control group had intraocular pressure of 20 mm Hg or less (P = .02). The overall complications were similar in the two groups. In this population, intraoperative 5-fluorouracil markedly improved the ability of trabeculectomy to lower intraocular pressure. We recommend that intraoperative 5-fluorouracil be considered in glaucoma surgery with poor prognosis as an alternative to postoperative subconjunctival injections when multiple injections are not feasible.

Visual loss in an onchocerciasis endemic community in Sierra Leone

The visual acuities of 1625 individuals recruited to a community-based clinical trial of ivermectin in southern Sierra Leone were measured, and the prevalence of visual loss in this rural population where onchocerciasis is hyperendemic was determined. Ocular examination was performed before treatment to establish the cause of visual loss. Using WHO definitions, 1.3% were blind (less than 3/60 in both eyes), 4.3% were visually impaired (between 6/24 and 3/60 in the better eye), and a further 3.4% were uniocularly blind (less than 3/60 in one eye and better than 6/24 in the other). Cataract and onchocerciasis were the major causes of visual loss in this population. More than half of the ocular morbidity was preventable or treatable by public health measures or basic curative medicine. These findings are discussed in the light of the available health and eye care services.

Points of action in the campaign against blindness in developing countries

This article provides a survey of the problems of prevention of blindness in developing countries. The World Health Organization estimates that 31 million people are blind and 15 million people partially-sighted. The main cause of blindness is cataract. Other causes are trachoma, glaucoma, xerophthalmia, river blindness, corneal scars and leprosy. Prevention or treatment of these causes is possible in more than 80% of cases. The number of blind persons, however, is still increasing due to the increase in population and the immense shortage of all kinds of ophthalmological equipment and personnel. An effective strategy for the prevention of blindness in developing countries should focus on: more cheap cataract operations, increasing teaching facilities for ophthalmic personnel, integration of ophthalmic care into the general health system and the promotion of blindness prevention in political organizations.

Clinical and pathological features of chronic glaucoma in north-east Ghana

Of 34 consecutive patients with chronic glaucoma seen in north-east Ghana, 22 (65%) were male and seven (21%) were aged under 40 years. Only 17% of eyes had a visual acuity better than 6/18 at presentation. Sixteen of 23 patients who underwent gonioscopy had PAS of which 13 had positive skin snips for onchocerciasis, compared with two out of seven patients with positive skin snips who had open angle glaucoma (p = 0.003). Of 22 trabecular meshworks examined by light microscopy ten (45%) showed marked melanin pigmentation which was more common in younger patients but did not correlate with onchocerciasis infection.

Primary eye care in rural sub-Saharan Africa

Primary eye care in rural sub-Saharan Africa is reviewed. In the context of eye care delivered by village health workers (VHW's) living in and supported by the community, such a system of health care does not exist in Africa today. There are no VHW's, and primary health care is currently a matter of experimentation and conjecture only. However, most basic eye care is rendered by non-ophthalmologists; such care consists of screening, treatment of infections and inflammations, and in some cases, cataract surgery. Lower levels of non-ophthalmic general health workers are being tasked to promote measures to prevent trachoma and xerophthalmia/nutritional blindness by intervention at the village level. Preliminary results of such programs are encouraging, and warrant further evaluation and expansion.

Eye screening in 2234 Sierra Leonean school students and detection of onchocerciasis

Screening of 2234 primary and secondary school students in a rain-forest area with endemic onchocerciasis showed that the percentage of students with positive skin snips increased with school age: from 0.7% in class 1 to 23% in form 5. Visual acuity of 6/12 or more in both eyes was found in 98% of the students. Students with an intraocular pressure higher than 21 mm showed a higher percentage of positive skinsnips than those with an intraocular pressure of 21 mm or less. The results of health education and treatment with diethylcarbamazine were better than those obtained in outpatients of the eye hospital in the same town. The possibilities of mass school screening in the Northern Province of Sierra Leone are discussed.