Abstracts
The effects of multiple doses of ivermectin on ocular onchocerciasis: a six-year follow-up
Denise Mabey FRCOphth, James A Whitworth MRCP, Michael Eckstein FRCOphth, Clare Gilbert FRCS, Gillian Maude MSc, Michael Downham MSc
Background: Ivermectin has been shown to be a safe treatment for onchocerciasis and is now being distributed through mass treatment programs. Previous studies of up to 3 years of treatment have demonstrated that ivermectin improves anterior segment lesions and reduces the incidence of optic atrophy. The benefit of multiple doses of ivermectin on visual acuity and chorioretinitis has yet to be shown.
Methods: A community-based, double-blind, randomized, controlled trial of ivermectin was started in Bo, Sierra Leone, in 1987. Two cohorts are reported in this study: (1) 214 subjects had received four 6-month doses of ivermectin followed by up to six additional 6-month treatments. The second cohort, with 185 subjects, had received four 6-month doses of placebo followed by up to four annual doses of ivermectin. All subjects received a full ophthalmic examination in 1989 and again in 1994. For both cohorts, there was an 18-month gap between the fifth and sixth rounds of treatment.
Results: There was no significant difference in the prevalences of any ocular lesion nor of visual acuity categories between the cohorts at the second examination. Comparisons of the prevalences of anterior segment lesions for both cohorts combined between the first and second examinations show highly significant improvement (P < 0.001) for all lesions. Posterior segment lesions show a more variable pattern, with chorioretinitis showing highly significant deterioration (P < 0.001) and the emergence of new lesions in both groups.
Conclusion: The authors conclude that annual treatment with ivermectin is effective in controlling ocular onchocerciasis apart from chorioretinal lesions and that a 6-month treatment gives no additional benefit.
Published courtesy of: Ophthalmology 1996; 103: 1001-8
Correspondence to: Denise Mabey FRCOphth, Moorfields Eye Hospital, City Road, London EC1 2PD, UK.
Aetiology of childhood cataract in south India
Michael Eckstein, P Vijayalakshmi, Milind Killedar, Clare Gilbert, Allen Foster
Aim: To identify the causes of childhood cataract in south India with emphasis on factors that might be potentially preventable.
Methods: A total of 514 consecutive children with cataract attending an eye hospital outpatient clinic were examined and their parents interviewed by a trained interviewer using a standardised questionnaire in the local language. Serology was performed on children under one year of age to detect congenital rubella syndrome (CRS). Other investigations were performed as clinically indicated.
Results: Of the 366 children with non-traumatic cataract 25% were hereditary, 15% were due to congenital rubella syndrome, and 51% were undetermined. In children under one year of age 25% were due to rubella and cataract of nuclear morphology had a 75% positive predictive value for CRS. Mothers of children in the undetermined group were more likely to have taken abortifacients than a group of age matched controls (p=0.1) but use of other medications in pregnancy was similar in both groups. Of the 148 (29%) children with traumatic cataracts three quarters were over the age of six years. Stick injuries were responsible for 28%, thorn injuries for 21%, and firecrackers for 5%.
Conclusion: Nearly half of non-traumatic cataract in south India is due to potentially preventable causes (CRS and autosomal dominant disease). There is need for further work to identify the factors leading to childhood cataract in at least half of the cases for which no definite cause can as yet be determined.
Published courtesy of: Br J Ophthalmol 1996; 80: 628-32
Correspondence to: Dr A Foster, International Centre for Eye Health, Institute of Ophthalmology, Bath Street, London, EC1V 9EL, UK.
Glaucoma in Mongolia a population-based survey in Hövsgöl province, northern Mongolia
Paul J Foster FRCSEd, Jamyanjav Baasanhu MD DCEH, Poul Helge Alsbirk MD, Dorj Munkhbayar MD, Davaatseren Uranchimeg MD, Gordon J Johnson MD FRCSC
Objectives: To determine the prevalence of glaucoma and suspect glaucoma, and to classify the cases detected according to mechanism.
Design: A population-based prevalence study.
Setting: Rural and urban locations in Hövsgöl Province, Northern Mongolia.
Participants: Nine hundred and forty-two (94.2%) of 1000 individuals 40 years of age and older were examined.
Main Outcome Measure: Primary angle-closure glaucoma was diagnosed in subjects with previous acute or intermittent symptoms of angle closure and in individuals with an occludable angle and an intraocular pressure greater than 19 mm Hg or a glaucomatous visual field.
Results: The prevalence of manifest primary angle-closure glaucoma was 1.4% (14 subjects). The prevalence of gonioscopically occludable angles was 6.4% (64 subjects, including those with glaucoma). Primary open-angle glaucoma was diagnosed in 5 subjects (prevalence, 0.5%). As all these subjects were older than 60 years, the prevalence became 2.1% for this age group. Three cases (prevalence, 0.3%) of secondary open-angle glaucoma were detected. No cases of secondary angle-closure glaucoma were diagnosed. The prevalence of blindness was 1.2% (12 subjects), and primary glaucoma accounted for one third of these cases (4 subjects).
Conclusions: We confirmed glaucoma as a major public health problem in northern Mongolia. Primary angle-closure glaucoma is more prevalent than primary open-angle glaucoma, supporting clinic-based data from other east Asian countries. Among the subjects examined, 97 (9.7%) had either manifest, latent, or suspect glaucoma.
Neighbouring populations may be similarly affected owing to a shared genetic heritage.
Published courtesy of: Arch Ophthalmol 1996; 114: 1235-41
Copyright 1996, American Medical Association
Correspondence to: Professor G J Johnson, International Centre for Eye Health, Institute of Ophthalmology, Bath Street, London, EC1V 9EL, UK.
Long term follow-up of primary trabeculectomy for infantile glaucoma
T Fulcher, J Chan, B Lanigan, R Bowell, M O’Keefe
Background: The treatment for infantile glaucoma is surgical. Treatment options include goniotomy, trabeculotomy, combined trabeculotomy-trabeculectomy, and trabeculectomy.
Methods: Patients who had a follow up of 5 years or longer after primary trabeculectomy were examined to determine the long term stability in infantile glaucoma.
Results: In eyes with primary infantile glaucoma 92.3% achieved control of their glaucoma with a single trabeculectomy; 100% achieved control with two trabeculectomies; 85.7% of eyes with secondary infantile glaucoma achieved control with a single trabeculectomy. There were no serious complications experienced in either group.
Conclusion: Primary trabeculectomy is a safe and successful operation for infantile glaucoma.
Published courtesy of: Br J Ophthalmol 1996; 80: 499-502
Correspondence to: Mr Michael O’Keefe, The Children’s Hospital, Temple Street, Dublin, Ireland
Evaluation of high volume extracapsular cataract extraction with posterior chamber lens implantation in Sierra Leone, west Africa
Nicholas J Cook
Aims: Intraocular lens (IOL) implantation in sub-Saharan Africa is not the routine procedure of choice in the treatment of cataract. Previous series consist of small numbers of selected patients. The purpose of this study was to evaluate routine posterior chamber lens implantation in large numbers of consecutive patients.
Methods: 1059 cataract extractions with planned IOL (744 patients) were performed over a one-year period from August 1993 to July 1994.
Results: 94.6% (1002) of eyes showed an improvement in visual acuity. A postoperative uncorrected acuity of 6/18 or better was attained in; 41.7% of eyes, while 27.1% attained an uncorrected acuity of <6/18 to 6/60. The commonest operative complication was posterior capsule rupture (11.4%).
Conclusion: Extracapsular cataract extraction with posterior chamber lens implantation, performed in a well equipped clinic, can give satisfactory results in a developing country. Uncorrected visual acuity can be taken as an acceptable end-point in the majority of cases.
This study was carried out at: Kissy Eye Hospital, PO Box 115, Freetown, Sierra Leone
Published courtesy of: Br J Ophthalmol 1996; 80: 698-701
Correspondence to: Nicholas J Cook, 26 North Road, Liverpool, L19 OLR, United Kingdom.