Retinal Detachment in Developing Countries D Yorston and S Jalali 354

Eye (2002) 16, 353–358 2002 Nature Publishing Group All rights reserved 0950-222X/02 $25.00 www.nature.com/eye D Yorston1 and S Jalali2 Retinal detachment in CAMBRIDGE OPHTHALMOLOGICAL SYMPOSIUM developing countries Abstract retinal disease was the primary cause of 12.7% of blindness.2 Treatment of retinal detachment has been a Although most blind people live in the low priority in developing countries. It is Third World, ophthalmic personnel and thought to be less common in India and services are concentrated in industrialised Africa than in Europe and N America. The countries. For example, there are 50 aetiology and presentation of retinal ophthalmologists per million population in N detachment in the Third World are affected America. In Sub-Saharan Africa there is one by genetic and environmental factors. In ophthalmologist per million people.3 The level general, patients are more likely to present of training and equipment is also much lower late, and complex detachments are relatively in poor countries. The Guinness Eye Hospital more common. Despite these problems, the in eastern Nigeria is the only vitreo-retinal results of surgery are encouraging, with more unit for a population of three million people.4 than 80% final anatomical success, and over Between 1995 and 2000, Kikuyu Eye Unit was 60% of re-attached retinas obtaining vision the only centre in Kenya, Tanzania and of 6/60 or better. The management of retinal Uganda (total population 75 million) capable detachment in developing countries can be of performing posterior vitrectomy. Where improved by strengthening training facilities do exist, distribution is uneven. programmes and by developing and Andhra Pradesh state, in southern India, has a equipping centres to carry out retinal population of 75 million. There are surgery. approximately 15 clinics equipped to carry out Eye (2002) 16, 353–358. doi:10.1038/ laser photocoagulation, half of them in sj.eye.6700188 Hyderabad (population 8 million). The neighbouring state of Orissa (population 35 million) has no clinics equipped with a laser. Keywords: retinal detachment; Kenya; Africa; Against this background of limited India; blindness; outcomes; vitrectomy; risk resources, and the pressing problems of factors untreated cataract, trachoma and refractive error, treatment of rhegmatogenous retinal detachment (RD) in developing countries has Introduction a low priority. In this paper we will review 1Kikuyu Eye Unit The World Health Organisation estimated that what is known about retinal detachment, and Kenya there were 38 million blind (vision less than the outcome of surgery, in developing 3/60 in the better eye) people in 1995.1 This is countries. 2Vitreo-retinal Clinic increasing by about one million per year. Of Retinal detachment in the Third World LV Prasad Eye Institute differs from RD in the industrialised countries Hyderabad, these 38 million, 90% live in the developing Andhra Pradesh countries of Africa, Asia and Latin America. in a number of ways. The reasons for these India Sub-Saharan Africa contains less than 10% of differences can be summarised as either the world’s people, but 20% of the world’s genetic—eg ethnic differences, or Correspondence: blind. In contrast, countries with established environmental—eg geographic and socio- D Yorston FRCOphth economic factors, such as lack of facilities. Department of market economies account for 15% of the Epidemiology 1 global population, but only 6% of blindness. & International Eye Health About 70% of global blindness is caused by Institute of Ophthalmology Incidence and epidemiology cataract, trachoma, and glaucoma. Retinal Bath St disease is the major cause of visual loss in It is known that there are ethnic variations in London EC1V 9EL, UK Tel: 020 8368 9359 wealthy countries, but may be less important the incidence of RD. A study in Singapore Fax: 020 7250 3207 in the developing world. However a recent noted that patients of Chinese origin were E-mail: dhyorston@ population-based survey in India, found that three times more likely to have surgery for enterprise.net Retinal detachment in developing countries D Yorston and S Jalali 354 RD than patients of Indian origin.5 It has frequently Myopia is more common in Chinese and East Asians19 been reported that black Africans have a low incidence than in Africans.20 Indians and S Asians appear to of RD.6–11 However, these studies are based on hospital have a lower prevalence of myopia than the Chinese, or clinic attendances, which can be misleading. In a but greater than Africans.19 The prevalence of poor country, with limited facilities for the significant myopia associated with RD in several management of RD, patients may be less likely to different countries is shown in Table 1. attend an eye clinic than patients in a wealthy country, Cataract surgery ratios (number of cataract with better health care systems. Because some of these operations performed per million population per year) studies are surgical case series, inoperable RD may be are much lower in the developing world (except India) excluded. A study based on the use of B-scan than industrialised countries.3 Among N American ultrasonography detected 71 RD in a 6-month period at Caucasians, cataract surgery is associated with a 5.5 Menelik II Hospital in Addis Abeba.12 This seems high, times greater risk of RD.17 A study of Medicare but does include patients with inoperable detachment. patients who had cataract surgery demonstrated a A report from Luanda, in Angola, indicated that, significantly lower incidence (relative risk 0.75) of although uncommon, RD was the second most postoperative retinal detachment in African-Americans frequent cause of curable blindness, after cataract. 13 compared to Caucasians.21 It has been suggested that Foos14 examined the eyes of 2334 subjects (322 of approximately 1% of eyes will develop RD within 5 whom were African Americans) at post-mortem. He years of cataract surgery.17,21 The risk is greater when found no racial variation in the age-corrected surgery is complicated by vitreous loss.21 Although prevalence of lattice degeneration, retinal breaks, or cataract surgery ratios (CSR) in Africa are about one posterior vitreous detachment. tenth of the CSR in developed countries, aphakia and Although RD may be rarer in some developing pseudophakia are implicated in a significant proportion countries, the lack of facilities for treatment means that of RD. The proportion of RD that follow cataract the risk of blindness due to RD is relatively greater. In surgery in different settings is shown in Table 1. The SW England, 2% of blind registration is due to retinal incidence of RD following cataract extraction may be detachment.15 In Andhra Pradesh, 0.5% of blindness is higher in developing countries if complications are caused by RD.16 Given that the prevalence of blindness more frequent. For example, in Sierra Leone, 11.4% of (Ͻ6/60) is 1.84% in Andhra Pradesh, and extra-capsular surgeries were complicated by capsule approximately 0.4% in the UK, it is likely that the rupture,22 compared to 3.6% in a recent trial in the prevalence of blindness from RD is similar in India UK.23 and England. The World Health Organisation plans to increase the There are no population-based surveys of the annual number of cataract operations worldwide from incidence of retinal detachment in any developing the current level of 10 million to 32 million by 2020. country. A recent study in Minnesota showed an Almost all this increase will take place in developing incidence of nearly 18 per 100 000 per year.17 It seems likely that the incidence of RD in Africans Table 1 Preoperative characteristics of retinal detachment in is lower than in Caucasians, but how much lower is a different settings matter for speculation. Assuming a much lower annual Country No. Macula Myopia Aphakia/ Macular incidence of two per hundred thousand would yield an eyes off Ͼ6 D pseudophakia hole annual total of 600 in Kenya. We estimate that no more than 50 receive treatment at present. Zaire10 79 9 12 (11.4%) (15.2%) S Africa11 114 12 11 Aetiology (10.5%) (9.6%) Kenya 361 332 87 38 Trauma is an important cause of RD in Africa. Trauma (91.9%) (24.1%) (10.5%) was thought to contribute to the detachment in 30% of Iran26 233 190 64 eyes in S Africa,11 23% in Zaire,10 and 8% in Kenya. In (81.6%) (27.5%) India 434 377 80 155 16 Minnesota, trauma was responsible for 7% of (86.9%) (18.4%) (35.7%) (3.7%) 17 detachments, and in Japan, blunt trauma accounted China31 217 76 39 for only 1.6%.18 The high incidence of traumatic (35.0%) (18.0%) detachment in S Africa may be due partly to the civil UK36 153 90 32 41 conflict that occurred in KwaZulu-Natal at the time of (58.8%) (20.9%) (26.8%) UK27 348 237 41 3 the study. (68.1%) (11.8%) (0.9%) Myopia is associated with an increased risk of RD. Eye: Cambridge Ophthalmological Symposium Retinal detachment in developing countries D Yorston and S Jalali 355 countries. If this growth is achieved, it will lead to a 13% in Iran,26 compared to 4% in Cambridge,27 and 6% rise in the incidence of retinal detachment as well. in San Francisco.28 At St Thomas’s hospital, only 11 cases of full- thickness macular hole associated with RD were found Presenting features in 14 years,29 and in Helsinki30 only 1.7% of RD had a The mean age of detachment patients in India was 38 macular hole. Macular hole is much more common in years, in Zaire, 40,10 and in Kenya, 47.

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