Presbyopia and the Sustainable Development Goals
Authors: Rohit C Khanna, Gullapalli N Rao
Journal: The Lancet Global Health (2018)

Current global estimates show that approximately 1·1 billion people are affected by presbyopia, nearly a third of whom are 50 years or older.1Bourne RRA Flaxman SR Braithwaite T et al.Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis.Lancet Glob Health. 2017; 5: e888-e897Summary Full Text Full Text PDF PubMed Scopus (1256) Google Scholar From crude data available, the prevalence of presbyopia is estimated to be 35·6% in people aged 35 years and older and increases to 40·3% for people aged 50 years and older.1Bourne RRA Flaxman SR Braithwaite T et al.Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis.Lancet Glob Health. 2017; 5: e888-e897Summary Full Text Full Text PDF PubMed Scopus (1256) Google Scholar More than 90% of these individuals are in developing countries.1Bourne RRA Flaxman SR Braithwaite T et al.Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis.Lancet Glob Health. 2017; 5: e888-e897Summary Full Text Full Text PDF PubMed Scopus (1256) Google Scholar, 2Holden BA Fricke TR Ho SM et al.Global vision impairment due to uncorrected presbyopia.Arch Ophthalmol. 2008; 126: 1731-1739Crossref PubMed Scopus (284) Google Scholar Uncorrected presbyopia is associated with difficulty in daily living activities, especially for those in professions demanding a keen eyesight for activities such as reading, writing, weaving, and so on. It also adversely affects quality of life, both in the developed and developing world,3Goertz AD Stewart WC Burns WR Stewart JA Nelson LA Review of the impact of presbyopia on quality of life in the developing and developed world.Acta Ophthalmol. 2014; 92: 497-500Crossref PubMed Scopus (55) Google Scholar and has a huge impact on productivity.4Frick KD Joy SM Wilson DA Naidoo KS Holden BA The global burden of potential productivity loss from uncorrected presbyopia.Ophthalmology. 2015; 122: 1706-1710Summary Full Text Full Text PDF PubMed Scopus (105) Google Scholar In 2015, the UN announced 17 Sustainable Development Goals (SDGs), most of which are related to improving health and productivity. However, there is conflicting evidence from different studies showing that investment in health improves productivity.5Fink G Masiye F Health and agricultural productivity: Evidence from Zambia.J Health Econ. 2015; 42: 151-164Crossref PubMed Scopus (33) Google Scholar, 6Edgerton VR Gardner GW Ohira Y Gunawardena KA Senewiratne B Iron-deficiency anaemia and its effect on worker productivity and activity patterns.BMJ. 1979; 2: 1546-1549Crossref PubMed Scopus (140) Google Scholar, 7Gilgen DD Mascie-Taylor CG Rosetta LL Intestinal helminth infections, anaemia and labour productivity of female tea pluckers in Bangladesh.Trop Med Int Health. 2001; 6: 449-457Crossref PubMed Scopus (73) Google Scholar, 8Pereira MJ Coombes BK Comans TA Johnston V The impact of onsite workplace health-enhancing physical activity interventions on worker productivity: a systematic review.Occup Environ Med. 2015; 72: 401-412Crossref PubMed Scopus (61) Google Scholar It is also known that the global labour productivity has slowed down negatively, affecting the global economy. Hence, the randomised trial by Priya Adhisesha Reddy and colleagues in The Lancet Global Health is a useful addition to what is already known about the impact of health interventions on productivity.9Reddy PA Congdon N MacKenzie G et al.Effect of providing near glasses on productivity among rural Indian tea workers with presbyopia (PROSPER): a randomised trial.Lancet Glob Health. 2018; (published online July 23)http://dx.doi.org/10.1016/S2214-109X(18)30329-2Summary Full Text Full Text PDF PubMed Scopus (44) Google Scholar The study shows that a simple pair of presbyopic glasses in tea workers (mainly women) in India improved their productivity by more than 20%. Moreover, with increasing age, productivity increased in the intervention group, but it decreased in the control group, indicating the adverse effects of uncorrected presbyopia on productivity with increasing age. Productivity in the intervention group also increased with increased compliance to glasses and consequent improvement in quality of life. Nearly 95% of trial participants were willing to pay for the glasses if lost or broken. The authors acknowledge the limited generalisability of their findings. Hence, they suggest additional trials in different cohorts in different countries. Although they provided the mean productivity before and after the intervention, no information is available about the median values and the range. The authors are urged to provide this information as it is possible that some participants in the intervention group did not show a significant change in productivity and vice versa. It would be good to understand these additional factors that can influence productivity. Also since the baseline period was in June, 2017, and assessment was done in the peak period (July–October, 2017), there could have been an increased difference in productivity in both groups due to seasonal variation. It would be interesting to see whether this high difference in productivity persists at all ages and in other seasons of the year. As participants were from three estates, it is likely that they were from nearby villages and so a clustering effect cannot be ruled out. The study does not describe the effects of clustering on the results. Finally, as acknowledged by the authors, a placebo effect could not be studied because the control group was not given glasses. Prospectively, additional trials in different cohorts in different countries are needed to understand the impact of presbyopic correction on productivity. Functional presbyopia (ie, vision less than N8 restored to N8 with correction) has to be differentiated from objective presbyopia, which includes individuals who need correction both for distance and near vision, to plan for targeted interventions. Research is needed to understand the cost-effectiveness of glasses compared with other interventions such as cataract surgery; and operational research is also needed to develop strategies for broad-scale implementation to improve productivity and contribute to the SDGs. We declare no competing interests. Effect of providing near glasses on productivity among rural Indian tea workers with presbyopia (PROSPER): a randomised trialA substantial productivity increase was achieved in this rural cohort by providing glasses to correct presbyopia, with little cost and high intervention uptake. Full-Text PDF Open AccessPresbyopia and the Sustainable Development GoalsWe appreciate the Comment from Rohit Khanna and Gullapalli Rao1 on our Article,2 and would like to address some of the important points they raise. The authors mention that “no information is available about the median values and range” of the main outcome. The distributions of outcomes were of sufficient size, and were sufficiently normal, to justify the exclusive use of means and SDs. To this end, we provided error bars (indicating 95% CIs) in figure 2, and provided means and confidence intervals for the baseline and evaluation periods for both study groups in table 2 and the main text. Full-Text PDF Open Access