BA. Holden, TR. Fricke, SM. Ho, “Global vision impairment due to uncorrected presbyopia,” Arch Ophthalmol, vol. 126, pp. 1731–1739, 2008.
 World Health Organization, “Vision 2020 global initiative for the elimination of avoidable blindness,” Fact sheet no 1231, Geneva: WHO, 2000.
 I. Patel and SK. West, “Presbyopia: prevalence, impact, and interventions,” Community Eye Health, vol. 20, pp. 40-1, 2007.
 A. Glasser and MC. Campbell, “Presbyopia and the optical changes in the human crystalline lens with age,” Vision Res, vol. 38, pp. 209-29, 1998.
 E. Santos-Neto , M. Ruiz, “New concepts in accommodation and presbyopia,” Rev Bras Oftalmol, vol. 70, pp. 306-11, 2011.
 AR. Ghaffariyeh, M. Shahinpoor, D. Soltanpour and N. Honarpisheh, “Novel theory for treatment of presbyopia: Rejuvenation of zonular fibers by capsular anterior annular peripheral shrinkage (CAPS),” Irn J Med Hypotheses Ideas, vol. 4, pp. 1-3, 2010.
 V. Helmholtz, “Physiological optics,” New York: Dover, p. 143-172, 375-415, 1962.
 BA. Holden, TR. Fricke, SM. Ho, R. Wong, G. Schlenther, S. Cronje, et al., “Global vision impairment due to uncorrected presbyopia,” Arch Ophthalmol, vol. 126, pp. 1731-9, 2008.
 BA. Holden, TR. Fricke, SM. Ho, R. Wong, G, Schlenther, S, Cronje, et al., “Global vision impairment due to uncorrected presbyopia, Archives of Ophthalmology, vol. 126, pp. 1731-1739, 2008.
 PK. Nirmalan, S. Krishnaiah, BR. Shamanna, GN. Rao and R. Thomas, “A population-based assessment of presbyopia in the state of Andhra Pradesh, south India: the Andhra Pradesh Eye Disease Study,” Invest Ophthalmol Vis Sci, vol. 47, pp. 2324-8, 2006.
 JN Uche, IR Ezegwui, E Uche, EN Onwasigwe, RE Umeh, CN Onwasigwe, “Prevalence of presbyopia in a rural African community, © JN Uche, IR Ezegwui, E Uche, EN Onwasigwe, RE Umeh, CN Onwasigwe, A licence to publish this material has been given to James Cook University, 2014.
 WHO, “Prevention of Blindness and Deafness. Elimination of avoidable visual disability due torefractive errors, Report of an informal planning meeting, Geneva: 3–5, 2001. Geneva: 8-9. (WHO/PBL/00.79).
 AG. Burke, I. Patel, B. Munoz, Ophthalmology, vol. 113, pp. 723–7, 2006.
 H. Laviers, “The prevalence of presbyopia and the feasibility of community distribution of near spectacles in adults in Zanzibar, East Africa,” Community Eye Health, vol. 20, pp. 73, 2007.
 SN. Nwosu, “Ocular problems of young adults in rural Nigeria,” International Ophthalmology, vol. 22, pp. 259-263, 1998.
 S. Marmamula, JE. Keffe, GN. Rao, “Uncorrected refractive errors, presbyopia and spectacle coverage Results from a rapid assessment of refractive error survey,” Ophthalmic Epidemiology, vol. 16, pp. 269-274, 2009.
 WR. Duarte, AJ. Barros, JS. Dias-da-Costa and JM. Cattan, “Prevalence of near vision deficiency and related factors: a population-based study,” Cad Saude Publica, vol. 19, pp. 551-9, 2003.
 AG. Burke, I. Patel, B. Munoz, A. Kayongoya, W. McHiwa, AW. Schwarzwalder, et al. “Population-based study of presbyopia in rural Tanzania,” Ophthalmology, vol. 113, pp. 723-7, 2006.
 P. Nirmalan, S Krishnaiah, BR. Rao, R. Thomas, “A population-based assessment of presbyopia in the state of Andhra Pradesh Eye Disease Study,” Investigative Ophthalmology and Visual Science. Vol. 47, pp. 2324-2328, 2006.