Visual outcome with +10 diopter sphere correction after intracapsular cataract extraction

BACKGROUND

The aim of curing cataract blindness is to restore the patient's vision after surgery. The aim of the study was to determine the proportion of surgeries done for cataract blind patients and the visual outcome with +10 diopter sphere (DS) aphakic correction in two consecutive years.

METHODS

Of the cataract operations done in the years 1995 and 1996, 8-15 cases were selected from each month by proportionate simple random sampling. Thirty-two (32) were excluded for incomplete or missing records. One hundred and eighteen (118) and one hundred (100) patient records were analyzed for 1995 and 1996 respectively.

RESULTS

The patients' ages ranged from 40 to 80 years and all had age related cataract. There were 161 males and 57 females. All had intracapsular cataract extraction (ICCE) without intraocular lens implantation. Eighty-nine patients (75%) and seventy-six patients (76%) had their sight restored in 1995 and 1996 respectively. The proportion of surgeries on blind patients' was 31% and 42% respectively. The proportion of those who remained blind after surgery was the same for both years (2%). Using chi-square test, there was a statistically significant difference in the patients' vision status after ICCE with +10 DS correction (1995, p = 0.021; 1996, p = 0.017) but no difference in the visual outcome due to gender. [1995, p = 2.09; 1996, p = 1.98 (Yates correction applied)] [corrected].

CONCLUSION

Intracapsular cataract extraction with +10 DS correction improves the patients vision status and priority must be given to those already blind.

Sutureless cataract surgery with nucleus extraction: outcome of a prospective study in Nepal

AIM

To report the short and medium term outcome of a prospective series of sutureless manual extracapsular cataract extractions (ECCE) at a high volume surgical centre in Nepal.

METHODS

Cataract surgery was carried out, on eyes with no co-existing diseases, in 500 consecutive patients who were likely to return for follow up. The technique involved sclerocorneal tunnel, capsulotomy, hydrodissection, nucleus extraction with a bent needle tip hook, and posterior chamber intraocular lens (PC-IOL) implantation according to biometry findings. Surgical complications, visual acuity at discharge, 6 weeks, and 1 year follow up, and surgically induced astigmatism are reported.

RESULTS

The uncorrected visual acuity at discharge was 6/18 or better in 76.8% of eyes, and declined to 70.5% at 6 weeks' follow up, and 64.9% at 1 year. The best corrected visual acuity was 6/18 or better in 96.2% of eyes at 6 weeks and in 95.9% at 1 year. Poor visual outcome (<6/60) occurred in less than 2%. Intraoperative complications included 47 (9.4%) eyes with hyphaema, and one eye (0.2%) with posterior capsule rupture and vitreous in the anterior chamber. Surgery led to an increase in against the rule astigmatism, which was the major cause of uncorrected visual acuity less than 6/18. Six weeks postoperatively, 85.5% of eyes had against the rule astigmatism, with a mean induced cylinder of 1.41 D (SD 0.8). There was a further small increase in against the rule astigmatism of 0.66 D (SD 0.41) between 6 weeks and 1 year. The mean duration of surgery was 4 minutes and the average cost of consumables, including the IOL, was less than $10.

CONCLUSION

Rapid recovery of good vision can be achieved with sutureless manual ECCE at low cost in areas where there is a need for high volume cataract surgery. Further work is required to reduce significant postoperative astigmatism, which was the major cause of uncorrected acuity less than 6/18.

1,4-dibenzylpiperazines possess anticocaine activity

N,N-dibenzylpiperazines have high affinity for sigma receptors, and we aimed to increase their anticocaine activity by introducing substituents known to enhance such activity in other sigma ligands. Ligands with high affinity for sigma-1 receptors resulted, but their activity in attenuating cocaine-induced convulsions did not correlate with sigma-1 binding affinity, and may be more closely related to their sigma-2 binding affinities.

Myopia in secondary school students in Mwanza City, Tanzania: the need for a national screening programme

BACKGROUND/AIMS

The prevalence of significant refractive errors and other eye diseases was measured in 2511 secondary school students aged 11-27 years in Mwanza City, Tanzania. Risk factors for myopia were explored.

METHODS

A questionnaire assessed the students' socioeconomic background and exposure to near work followed by visual acuity assessment and a full eye examination. Non-cycloplegic objective and subjective refraction was done on all participants with visual acuity of worse than 6/12 in either eye without an obvious cause.

RESULTS

154 (6.1%) students had significant refractive errors. Myopia was the leading refractive error (5.6%). Amblyopia (0.4%), strabismus (0.2%), and other treatable eye disorders were uncommon. Only 30.3% of students with significant refractive errors wore spectacles before the survey. Age, sex, ethnicity, father's educational status, and a family history of siblings with spectacles were significant independent risk factors for myopia.

CONCLUSION

The prevalence of uncorrected significant refractive errors is high enough to justify a regular school eye screening programme in secondary schools in Tanzania. Risk factors for myopia are similar to those reported in European, North-American, and Asian populations.

Eye healthcare services in eastern Europe: Part 2. Vitreoretinal surgical services

AIM

To describe vitreoretinal surgical services in 1998 in 12 eastern European countries and to identify ways for their further improvement.

METHODS

All inpatient eye departments in the 12 countries received a standardised questionnaire; the data obtained were processed at the international study coordinating centre in Prague.

RESULTS

All 458 eye departments in the region were involved. The number of retinal detachments treated by extraocular surgery, or pars plana vitrectomy, per one million inhabitants respectively, were as follows: Belarus (52; 6), Federation of Bosnia and Herzegovina (21; 2), Bulgaria (39; 19), the Czech Republic (78; 40), Estonia (60; 17), Hungary (81; 88), Latvia (82; 36), Lithuania (68; 6), Trans-Dniester Region of Moldova (6; -), Poland (70; data not available), Romania (24; 25), and Slovakia (67; 55). The number of people per one retinal laser was assessed (in millions): Belarus (1.26), Federation of Bosnia and Herzegovina (2.23), Bulgaria (0.59), the Czech Republic (0.22), Estonia (0.24), Hungary (0.23), Latvia (0.41), Lithuania (0.62), Poland (0.36), Romania (2.25), and Slovakia (0.14).

CONCLUSIONS

Conditions for posterior eye segment surgery in the central and eastern European region vary substantially. Underserved regions require (1) more eye doctors trained in surgical and laser retinal treatment; (2) improvement in screening for diabetic eye complications and retinopathy of prematurity; (3) technical equipment for places in need.

Eye healthcare services in eastern Europe: Part 1. Cataract surgery

AIM

To describe cataract surgical services in 1998 in 12 eastern European countries and to identify their needs to reduce cataract blindness.

METHODS

All inpatient eye departments in the 12 countries received a standardised questionnaire; the data obtained were further processed at the coordinating centre in Prague.

RESULTS

All 458 eye departments in the region were involved. The response rate was 100%, except for Bulgaria (93%) and Romania (93%). The total number of cataract surgeries per one million inhabitants in 1998 was calculated: Belarus (800), Federation of Bosnia and Herzegovina (1275), Bulgaria (1730), the Czech Republic (4210), Estonia (2530), Hungary (3530), Latvia (1860), Lithuania (1550), Trans-Dniester Moldova (1300), Poland (1475), Romania (1260), and Slovakia (2430). Cataracts were mostly operated on by the extracapsular technique. Intracapsular extractions were frequently performed in Federation of Bosnia and Herzegovina (47%), Belarus (46%), Bulgaria (18%), and Romania (14.3%). Phacoemulsification was uncommonly used in 1998, except for the Czech Republic (86%), Estonia (50%), Slovakia (38%), and Hungary (16%). An IOL was implanted in more than 90% of patients in the Czech Republic, Estonia, Hungary, Latvia, Lithuania, and Slovakia.

CONCLUSIONS

Conditions for cataract surgery in the eastern European region differ. The main barriers to cataract surgery were state budget limitations, insufficient supply of consumables, underutilisation of operating theatres, and poor detection of patients requiring surgery.

Does prospective monitoring improve cataract surgery outcomes in Africa?

AIMS

To determine if prospective monitoring influences cataract surgical outcomes in east Africa.

METHODS

A prospective observational study of all routine extracapsular cataract extractions with posterior chamber lens implants carried out at Kikuyu Eye Unit, Kenya, between 1 January 1999 and 31 December 1999.

RESULTS

Out of 1845 eligible eyes 1800 were included in the study. Two months' follow up was available in 67.2% of patients. The proportion achieving a good outcome increased steadily from 77.1% in the first quarter to 89.4% in the fourth quarter (chi(2) for trend, p<0.001). There was no change in the incidence of operative complications; however, the proportion of patients achieving a good visual outcome following vitreous loss increased from 47.2% in the first 6 months to 71.0% in the last 6 months (chi(2) p<0.05). Of the eyes with poor outcome (best corrected acuity <6/60 at 2 months) half were due to pre-existing eye diseases. The proportion of patients with known ocular comorbidity decreased from 10.2% in the first quarter to 5.9% in the fourth quarter (chi(2) for trend, p<0.05). Poor outcome was associated with age over 80 years, known diabetes, preoperative bilateral blindness, any ocular comorbidity, and intraoperative vitreous loss.

CONCLUSIONS

This study demonstrates improvement in visual outcome results after cataract surgery over a 1 year period. Monitoring of outcomes appears to be associated with a change in surgeons' attitudes, leading to greater emphasis on appropriate case selection, better management of surgical complications, and improved visual outcomes.

Longitudinal study of trachomatous trichiasis in the Gambia

AIM

Investigation of the natural history of trachomatous trichiasis in the Gambia and of the outcome of self epilation and surgery for the condition.

METHODS

A 1 year longitudinal study of 190 subjects with trichiasis was performed. Major trichiasis cases (five lashes or more) were referred for surgery and minor trichiasis cases were advised to epilate. Outcome measures included progression of trichiasis and corneal scarring; attendance for and results of surgery.

RESULTS

34 of 148 (23%, 95% CI 16 to 31) subjects with major trichiasis attended for surgery over the year. Progression from minor to major trichiasis occurred in 18 of 55 subjects (33%, 95% CI 21 to 47). Progression of corneal scarring occurred in 60 of 167 patients (36%, 95% CI 29 to 44). Clinically active trachoma and conjunctival bacterial isolation predicted progression of corneal opacity. Surgery was successful in 39 of 54 (72%) eyes.

CONCLUSIONS

Despite the overall decline in trachoma in the Gambia, patients with both minor and major trichiasis remain at risk of developing corneal opacity. Active trachomatous inflammation and additional infection with bacteria may accelerate this process. Antibiotic treatment for trichiasis patients (in addition to surgery) should be investigated. Surgery for minor trichiasis may be indicated. Regular audit of surgical results is necessary with retraining where needed.

Surgical interventions for age-related cataract

BACKGROUND

Cataract is the major cause of global blindness, accounting for 40 to 80% of all blindness in developing countries. The number of people blind from cataract is expected to rise due to the changing age distribution and increasing life expectancy. There is currently no proven intervention to prevent cataract and surgery is the only form of treatment.

OBJECTIVES

The objective of this review is to compare the effects of different surgical interventions for age-related cataract.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register - CENTRAL/CCTR, which contains the Cochrane Eyes and Vision Group specialised register (Cochrane Library Issue 3 2001), MEDLINE (1966 to August 2001), EMBASE (1980 to September 2001), the reference lists of identified trials, and we contacted investigators and experts in the field for details of published and unpublished trials.

SELECTION CRITERIA

We included randomised controlled trials evaluating surgical treatment for people with age-related cataract.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and discrepancies were resolved by discussion. Where appropriate, relative risks, odds ratios and weighted mean differences were summarised after assessing heterogeneity between the studies. We used a fixed effect model due to the low number of trials in each comparison.

MAIN RESULTS

We identified six trials that randomised a total of 7828 people. Phacoemulsification gave a better visual outcome than extracapsular surgery and gave a similar average cost per procedure in one trial conducted in the UK. Extracapsular surgery with posterior chamber lens implant and intracapsular surgery with or without an anterior chamber intraocular lens implant gave acceptable visual outcomes at 12 to 24 months after surgery. In three large trials in south Asia, best-corrected visual acuity of less than 6/60 ranged from 0.5 to 4%. Higher rates of poor outcome were observed in a multicentre study with 19 surgeons compared to a single-centre study with two surgeons.

REVIEWER'S CONCLUSIONS

This review provides evidence from one randomised controlled trial that phacoemulsification gives a better visual outcome than extracapsular extraction with sutures. However, this trial was conducted in a developed country specialised hospital setting and extrapolation to other settings must be made with caution. This review also found evidence that extracapsular cataract extraction with a posterior chamber lens implant provides better visual outcome than intracapsular extraction with aphakic glasses. This finding is also based on the results of a single trial. The long term effects of posterior capsular opacification need to be assessed in larger populations. The data in the review suggest that intracapsular extraction with an anterior chamber lens implant is an effective alternative to intracapsular extraction with aphakic glasses, with similar safety. Further data from developing regions are needed to compare all aspects of intraocular lens surgery with the three main surgical procedures - intracapsular extraction with an anterior chamber lens, extracapsular surgery with a posterior chamber lens with or without sutures.

The regulation of T cell homeostasis and autoimmunity by T cell-derived LIGHT

Costimulatory molecules on antigen-presenting cells (APCs) play an important role in T cell activation and expansion. However, little is known about the surface molecules involved in direct T-T cell interaction required for their activation and expansion. LIGHT, a newly discovered TNF superfamily member (TNFSF14), is expressed on activated T cells and immature dendritic cells. Here we demonstrate that blockade of LIGHT activity can reduce anti-CD3-mediated proliferation of purified T cells, suggesting that T cell-T cell interaction is essential for this proliferation. To test the in vivo activity of T cell-derived LIGHT in immune homeostasis and function, transgenic (Tg) mice expressing LIGHT in the T cell lineage were generated. LIGHT Tg mice have a significantly enlarged T cell compartment and a hyperactivated peripheral T cell population. LIGHT Tg mice spontaneously develop severe autoimmune disease manifested by splenomegaly, lymphadenopathy, glomerulonephritis, elevated autoantibodies, and severe infiltration of various peripheral tissues. Furthermore, the blockade of LIGHT activity ameliorates the severity of T cell-mediated diseases. Collectively, these findings establish a crucial role for this T cell-derived costimulatory ligand in T cell activation and expansion; moreover, the dysregulation of T cell-derived LIGHT leads to altered T cell homeostasis and autoimmune disease.

An overview of foot disease in patients with diabetes

Effective management of diabetic foot disease requires a multidisciplinary approach and good communication between all healthcare professionals involved. This article provides an overview of the main factors that need to be considered when assessing patients with diabetic foot disease.

Natural history of trachomatous scarring in The Gambia: results of a 12-year longitudinal follow-up

PURPOSE

The sight-threatening complications of trachoma are trichiasis and corneal opacity, and these remain the world's most common cause of preventable blindness. The aim of the study was to investigate the rate of progression of trachomatous conjunctival scarring to trichiasis and corneal opacity and to investigate risk factors for such progression.

DESIGN

A 12-year, longitudinal study of the incidence and risk factors for the development of trichiasis and corneal opacity in a cohort of patients initially identified with trachomatous scarring in The Gambia.

PARTICIPANTS

Six hundred thirty-nine subjects with some degree of trachomatous scarring were identified from the 1986 survey, and attempts were made to trace all these subjects.

METHODS

Successfully traced subjects were interviewed, examined, and graded for trachoma.

MAIN OUTCOME MEASURES

(1) Twelve-year rates of progression. (2) Risk factors for progression of disease.

RESULTS

Three hundred twenty-six of six hundred thirty-nine (51%) subjects were traced and examined, 108 (17%) had died, and 205 (32%) were lost to follow-up. After 12 years, 6.4% (95% confidence interval [CI], 4.0-9.97) of scarred subjects had trichiasis develop, 5.96% (95% CI, 3.67-9.42) had corneal opacity develop, 16.51% (95% CI, 12.71-21.13) had visual impairment/blindness develop, and 2.5% (95% CI, 1.2-5.0) had corneal visual impairment/blindness develop. Mandinka ethnicity was a risk factor for trichiasis (odds ratio [OR], 4.3; 95% CI, 1.3-14.4), and trichiasis at baseline was a risk factor for corneal opacity (OR, 8.4; 95% CI, 1.8-39.2). History of lid surgery for trichiasis was associated with corneal opacity at follow-up (OR, 4.4; 95%CI, 1.4-14.0). Older age was a significant risk factor for development of trichiasis, corneal opacity, and visual loss (OR, 1.07; 95% CI, 1.01-1.12). Bilateral cataract was present in 40% of traced subjects and was associated with the incidence of visual impairment/blindness (OR, 9.4; 95%CI, 4.5-19.6)

CONCLUSIONS

This is the first study to demonstrate the link between trichiasis and future corneal opacity, and it provides the rationale for performing lid rotation surgery on patients with trichiasis who do not yet have corneal opacity. The association between corneal opacity at follow-up and previous surgery among trichiasis patients suggests late presentation as a problem. The planning of surgical services will be aided by the incidence figures generated by this study.

Receiving help at home: the interplay of human and technological assistance

OBJECTIVES

This research investigated use of mobility equipment as a substitute for human assistance and also examined whether use of mobility equipment results in out-of-pocket cost savings associated with formal home care services.

METHODS

The authors analyzed data collected from 9,230 respondents to the Adult Followback Survey of the Disability Supplement to the 1994 and 1995 National Health Interview Survey (NHIS-D) who reported both mobility and limitations in daily living activities to test study hypotheses, using regression analyses to control for selection effects in mobility equipment use.

RESULTS

Use of canes and crutches (but not walkers and wheelchairs) reduced both formal and informal hours of care received per week by sample members; there was also evidence of substitution on the individual activities of daily living task level. Use of canes and crutches was also associated with lower out-of-pocket costs for formal helping services.

DISCUSSION

Findings suggest that canes and crutches are effective and efficient home care resources that have the potential to increase the autonomy of adults with disabilities and to facilitate chronic condition self-management.

The critical role of LIGHT, a TNF family member, in T cell development

Negative selection refers to the selective deletion of autoreactive thymocytes but its molecular events have not been well defined. In this study, we demonstrate that a cellular ligand for herpes virus entry mediator and lymphotoxin receptor (LIGHT), a newly identified member of the TNF superfamily, may play a critical role in negative selection. Using TCR transgenic mice, we find that the blockade of LIGHT signaling in vitro and in vivo prevents negative selection induced by peptide and intrathymically expressed Ags, resulting in the rescue of thymocytes from apoptosis. Furthermore, the thymi of LIGHT transgenic mice show severe atrophy with remarkably reduced CD4(+)CD8(+) double-positive cells caused by increased apoptosis, suggesting that LIGHT can delete immature T cells in vivo. Taken together, these results demonstrate a critical role of LIGHT in thymic negative selection of the T cell repertoire.

Clinical findings, consanguinity, and pedigrees in children with anophthalmos in southern India

This study aimed to describe clinical findings, pedigrees, and possible environmental risk factors in children with clinical anophthalmos and remnant microphthalmos in either eye in southern India. Twenty-four children (14 male, 10 female; mean age 10.3 years, age range 1.3 to 18 years,) were recruited from schools for the blind, hospitals, and community-based rehabilitation programmes in Andhra Pradesh, India, over 1 year. Family members were examined, and mothers interviewed. Fifteen children had anophthalmos and nine had remnant microphthalmos in one or both eyes. Twelve children had associated systemic findings, of which six were major and six were minor abnormalities. Information on consanguinity was available in 19 children, 12 of whom had consanguineous parents. Five children had a positive family history. Two mothers had a history of night blindness, and one had a history of pesticide exposure during pregnancy. High rates of consanguinity suggest a genetic recessive aetiology.

A prospective study of 413 cases of lens-induced glaucoma in Nepal

PURPOSE

To determine the frequency and types of lens-induced glaucoma (LIG), reasons for late presentation and outcome of current management.

METHODS

Prospective case series of 413 patients/eyes with LIG over a 12-month period in 1998; 311 of these patients underwent cataract surgery. Visual acuity and intraocular pressure (IOP) were pre- and postoperatively assessed.

RESULTS

Four hundred and thirteen (1.5%) of 27,073 senile cataracts seen in the outpatient department of Sagarmatha Choudhary Eye Hospital, Lahan, Nepal presented with LIG. There were 298 (72%) phacomorphic cases and 115 (28%) phacolytic glaucoma. Pain for more than 10 days was reported by 293 (71%) patients. The majority, 258 (62.4%), travelled a distance of more than 100 kms to the hospital. The major reasons for late presentation were "no escort" in 143 (34.6%) and "lack of money" in 128 (31.0%) cases. At presentation the IOP was more than 30 mm Hg in 327 (79%) eyes. Following cataract surgery, 251 (80.7%) had 21 mm Hg or less at discharge. The visual acuity was hand-movement or less before surgery in all eyes; at discharge 120 of 311 operated eyes (38.6%) achieved 6/60 or better, 97 (31.2%) less than 6/60, and 94 (30.2%) less than 3/60. The main causes for poor outcome in 94 cases were optic atrophy in 32 (34%) eyes, uveitis in 25 (26.6%)eyes and corneal oedema in 24 (25.5%) eyes.

CONCLUSION

The results highlight the importance of early diagnosis and treatment of visually disabling cataract. There is a need to educate both the patient and the cataract surgeon of the dangers of lens-induced glaucoma and of the poor outcome if treatment is delayed.

Postoperative astigmatism after intracapsular cataract surgery: results of a randomised controlled trial in Nepal

PURPOSE

Postoperative astigmatism following intracapsular cataract extraction with or without anterior chamber intraocular lens implantation is reported as an outcome from a randomised controlled trial.

METHODS

Five hundred and two of 1002 eyes randomised to intracapsular cataract extraction with anterior chamber intraocular lens (ICCE/AC IOL) and 417 of 998 eyes to intracapsular cataract extraction with aphakic spectacles (ICCE/AS) were seen for objective refraction one year after surgery. The prevalence and axis of astigmatism were evaluated using univariate analysis. Logistic regression was used to compare the postoperative astigmatism between the groups.

RESULTS

Acceptable astigmatism (-0.5 to 0.0 DCyl) in the AC IOL group was found in 60 (12.0%) patients (95% CI 9.1%-14.9%) and in the aphakic spectacles group (AS) in 69 (16.5%) patients (95% CI 12.9%-20.1%), moderate astigmatism (-1.0 to-1.5 DCyl) was found in 153 (30.4%) patients (95% CI 26.4-34.6%) in ACIOL group and in 288 (69.1%) patients (95% CI 64.6%-73.6%) in AS group; and large astigmatism (-2.0 to - 8.0 D Cyl) was found in 289 (57.6%) patients (95% CI 53.1%-61.6%) in ACIOL group and in 60 (14.4%) patients (95% CI 11.0% 17.8%) in AS group. Large astigmatism was approximately four times more common in the ICCE/AC IOL group compared to ICCE/AS group. In both groups, most patients had "against-the-rule" astigmatism, 446 (88.8%) (95%CI 86.0%-91.6%) in AC IOL group and 348 (83.5%) (95%CI 79.9%-87.1%) in AS group.

CONCLUSION

Astigmatism is common after intracapsular cataract extraction. Insertion of an anterior chamber IOL increases the risk of astigmatism.

Results of cataract surgery in young children in east Africa

BACKGROUND

Cataract is the leading cause of blindness in children in east Africa. The results of surgery are poor, partly because of inadequate correction of aphakia.

METHODS

A retrospective survey of 118 eyes in 71 children with bilateral cataract. All eyes had implantation of an IOL at the time of cataract surgery. The average age at surgery was 3.5 years. 28 patients(39%) were less than 2 years old at the time of surgery on their first eye.

RESULTS

Preoperatively, 75.4% of eyes and 76.1% of patients were blind. A follow up of at least 3 months was available in 91 (77.1%) eyes. In these eyes, 44% had a latest corrected vision of 6/18 or better and 91.2% had a latest corrected vision of 6/60 or better. Eyes with zonular cataract, and eyes operated after the age of 2 years were more likely to obtain a vision of 6/18 or better. 3.3% of eyes and 1.8% of patients had an acuity of less than 3/60. Nystagmus was present in 42.3% of patients before surgery. In those patients followed up for a minimum of 6 months, 10.2% still had nystagmus. The most frequent complication was severe fibrinous uveitis, which occurred in 36 (30.5%) eyes. 62 (52.5%) eyes had a posterior capsulotomy at the time of cataract extraction. Of the remaining 56 eyes, 20 (35.7%) had so far required a posterior capsulotomy. The leading cause of poor visual outcome was amblyopia. Two patients developed severe complications related to the intraocular lens.

CONCLUSIONS

Insertion of a lens implant at the time of cataract extraction appears to be well tolerated in the short term, and may offer significant advantages in an African setting.