Clinical and Experimental Ophthalmology 2011; 39: 851–857 doi: 10.1111/j.1442-9071.2011.02576.x Original Article Outcomes of cataract surgery: a population-based developing world study in the Bhaktapur district, Nepal Suman S Thapa MD,1 Shankar Khanal PhD,2 Indira Paudyal MD,1 Shankha N Twyana MPH,1 Sanduk Ruit MD1 and Ger HMB van Rens MD PhD3 1Nepal Glaucoma Eye Clinic, Tilganga Institute of Ophthalmology, 2Central Department of Statistics, Tribhuvan University, Kathmandu, Nepal; and 3Vrije Universiteit Amsterdam, Amsterdam, The Netherlands ABSTRACT of visual impairment after best correction in all eyes. There was no significant association in visual Background: To evaluate the visual outcome after outcome based on age, sex, literacy and the duration cataract surgery in a population of Nepal. of surgery. Design: Population-based cross-sectional study. Conclusion: Correction of refractive errors, preopera- Participants: Forty years and above residing in Bhak- tive screening of coincidental diseases, reduction in tapur district. surgical complication rates and monitoring of post- operative follow-up care has to be addressed seri- Methods: Subjects were selected from 30 clusters ously in order to improve the outcome of cataract using cluster sampling procedure. All underwent a surgery to meet standards proposed by the World detailed examination at the base hospital, including Health Organization. In the future, longitudinal logarithm of minimal angle of resolution visual studies need to be undertaken to provide specific acuity, refraction, applanation tonometry, cataract information on the outcomes of cataract surgery in grading, retinal examination and perimetry when this community. indicated. Key words: cataract surgery, Nepal, population based Main Outcome Measures: Visual acuity after cataract study, visual outcome. surgery. Results: Out of 4003 subjects examined, 151 had NTRODUCTION undergone cataract surgery. Pseudophakia was I present in 142 (94.0%), aphakia in nine (6%). Pre- Cataract blindness is the leading cause of blindness senting and best-corrected visual acuity Ն6/18 was in developing countries. The Nepal Blindness achieved in 123 (54.4%) and 164 (72.4%) eyes, Survey (NBS) of 1981 estimated that 0.84% were 1 respectively. Among the pseudophakic eyes, at pre- blind from cataract. Based on data from this nation- wide survey, the Nepal Blindness Prevention and sentation 122 (57.5%), 72 (33.9%), 18 (8.5%) and Control Project worked to implement eye-care ser- after best correction 162 (76.2%), 33 (15.8%), 17 vices in Nepal. Several eye hospitals and community Ն < Ն (8.0%) had visual acuity of 6/18, 6/18– 6/60 eye centres were established throughout the and <6/60, respectively. Retinal disease (35.5%), country with the help of governmental and non- surgical complications (27.4%) and posterior capsu- governmental organizations. Eye camps were lar opacification (14.5%) were the principle causes designed to provide eye care to people residing in ᭿ Correspondence: Dr Suman S Thapa, Nepal Glaucoma Eye Clinic, Tilganga Institute of Ophthalmology, PO Box 561, Kathmandu, Nepal. Email: [email protected] Received 13 December 2010; accepted 28 March 2011. © 2011 The Authors Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists 852 Thapa et al. very remote areas. Population-based studies that published earlier.25 In brief, the survey involved the were conducted in different parts of the country after selection of 4800 subjects aged 40 years and above, the NBS of 1981 have estimated cataract blindness to using a WHO 30 cluster sampling procedure.26 In the range from 1% to 6% among people 40 years and first stage of sampling, a list of all the wards or above.2–5 In these studies severe bilateral blindness clusters (n = 161) from 16 VDCs and two municipali- was defined as visual acuity (VA) of less than 3/60 in ties was obtained from the 2001 Nepal national both eyes. The conclusion derived was that the census data. These clusters were arranged in order of prevalence of blindness had decreased slightly from population size and 30 of these clusters were that estimated in the 1981 national survey, both sampled with probability proportionate to the size. overall and cataract-related. Thereafter, field workers conducted a house to house The prevalence of blindness and cataract surgery census in the selected 30 clusters and a total of in Bhaktapur district has been reported in a compan- 11 232 eligible subjects were identified and an eligi- ion paper.6 The prevalence of blindness in Bhaktapur bility list prepared. For the second-stage sampling, was 0.73% at presentation and 0.43% after best cor- the names of all the eligible subjects (n = 11 232) rection that was lower than studies conducted in were recorded and a database prepared from which Nepal,2–5 neighbouring countries7–10 and the estimate 4800 subjects were selected using EPI-INFO soft- of 3.4% for the South-East Asian region.11 The preva- ware, version 3.5.1. The selected subjects were then lence of cataract blindness was lowest (1.5%) with revisited by the field workers and referred to the the highest cataract surgical coverage (90.36%) in base hospital in Kathmandu for a comprehensive eye comparison with all the other studies of Nepal. examination. Visual outcomes of cataract surgery have been The VA was measured using logarithm of reported by several population-based studies con- minimum angle of resolution tumbling E charts ducted in South Asia.12–18 In Nepal there are only two placed at 4 m. External eye examination and the studies that have reported the visual outcomes of pupillary reaction were assessed with a hand-held cataract surgery in a large population.19,20 In both flashlight and then the anterior segment was exam- studies the visual outcome did not meet the stan- ined with a slit-lamp biomicroscopy (Haag Streit BQ dards proposed by the World Health Organization 900, Bern, Switzerland). The peripheral anterior (WHO). A few studies in Nepal have also reported chamber depth was graded according to the van Her- the outcome of cataract surgery under different rick’s technique.27 The intraocular pressure was mea- settings.21–23 sured and gonioscopy performed on all subjects. Bhaktapur district does not have an eye hospital Intraocular pressure was measured using a Gold- and the delivery of eye-care service is through mann applanation tonometer, and gonioscopy was primary eye-care centres affiliated to tertiary level done with a Zeiss 4 mirror lens. Gonioscopy was eye hospitals in the capital city Kathmandu. The carried out in ambient light conditions with a short- main purpose of this paper is to report the visual ened slit beam that did not fall upon the pupil. All outcomes after cataract surgery and to investigate subjects had their pupils dilated unless contraindi- factors responsible for poor outcomes among sub- cated because of risk of angle closure. After dilata- jects residing in Bhaktapur district of Nepal. tion, the lens was examined and the cataract graded using the Lens Opacities Classification System II.28 Stereoscopic fundus examination was done at the METHODS slit-lamp using a 90-diopter lens. The clinical exami- Bhaktapur district is one of the three districts within nation was carried out by two glaucoma specialists. Kathmandu valley and is situated approximately This study was approved by the Institutional 15 km away from the capital city Kathmandu. It is Review Board and Ethics Committee and conducted located within the mid-mountainous region of in accordance with declaration of Helsinki. Informed Nepal. Bhaktapur is divided into two municipalities consent was obtained from all subjects after being and 16 village development committees (VDC). explained in detail about all the procedures to be Although the municipalities are urban areas, the undertaken. The informed consent was written in VDCs are rural regions. The municipalities and the the vernacular. The consent form was read out for VDCs are further divided into wards. A ward is those unable to read. Upon agreement by the subject, the smallest administrative unit and each generally they were asked to sign the consent form. For those contains approximately 200 households. According unable to sign, thumb impressions were taken. to the 2001 Census, the population of Bhaktapur was 225 461 with a population density of 1895 per Data and statistical analysis square kilometre.24 The present study is part of the Bhaktapur Glau- The visual outcomes were categorized as ‘good’ (6/18 coma Study, the methodology of which has been or better; logMAR, Յ 0.30), ‘borderline’ (worse than © 2011 The Authors Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists Outcomes of cataract surgery 853 Table 1. Demographics of cataract surgery group Age (years) Number Gender Literate Illiterate Pseudophakia Aphakia (male : female) (male : female) (male : female) (male : female) (male : female) 40–49 3 (2.0) 2:1 1:0 1:1 2:0 0:1 50–59 19 (12.6) 7:12 4:6 3:6 6:12 1:0 60–69 37 (24.5) 18:19 9:8 9:11 16:18 2:1 70–79 66 (43.7) 27:39 16:20 11:19 25:38 2:1 Ն80 26 (17.2) 9:17 1:10 8:7 9:16 0:1 Total 151 (100.0) 63:88 31:44 32:44 58:84 5:4 Table 2. Visual outcome of cataract operated subjects by presenting visual acuity† Presenting visual acuity Aphakic unilateral/ All bilateral Pseudophakia/aphakia Bilateral pseudophakia Unilateral pseudophakia No (%) No (%) No (%) No (%) 6/18 0 (0) 1 (50) 30 (43) 10 (14.2) 41 (27.2) <6/18 6 Ն 6/60 2 (22.2) 0 (0) 23 (32.9) 16 (22.9) 41 (27.2) <6/60 (worst eye) 3 (33.3) 0 (0) 15 (21) 29 (58.6) 47 (31.1) <6/60 Ն 3/60 (best eye) 1 (11.1) 0 (0) 0 (0) 1 (1.4) 2 (1.3) <3/60 3 (33.3) 1 (50) 2 (2.8) 2 (2.8) 8 (5.3) All 9 (5.3) 2 (1.3) 70 (46.4) 70 (46.4) 151 (100) †Data are given as number (%) of people Table 3.