DOI: http://dx.doi.org/10.18203/2394-6040.ijcmph20183382

Pathophysiology of cataracts

Mohammed Alamri, Alaa Alsammahi, Majid Alharbi, Hamad Alshammari, Mousa Alshehri, Ibrahim Saeedi, Maher Alhomoud, Ismaeel Albakri, Hadeel Alwagdani, Khaled Bin Yousef

Abstract


Cataracts result in significant vision reduction. It is estimated that cataract was responsible for the morbidity of 10.8 million people (of overall 32.4 million blind people around the world), and 35.1 million people (of overall 191 million vision impaired people around the world). It is also the most common cause of blindness in many countries, including Saudi Arabia. We tried to understand, in details, the pathogenesis of cataracts, with special focus on how ageing is a contributory factor in its development. We conducted this review using a comprehensive search of MEDLINE, PubMed and EMBASE from January 1970 to March 2017. The following search terms were used: cataracts, pathogenesis of cataracts, pathophysiology in cataracts, ageing lens, aging and vision loss, lens degeneration. Cataracts heavily impacts the vision, thereby, the lives of individuals suffering from it. Due to its large prevalence, the impact on economy is large too. Although surgery is very promising, newer approach is focusing on its pathophysiology to emphasize on preventive options. Several changes, including oxidative stress, reduction in reductive enzymes, lens elasticity, and specific age related degeneration play major roles in its pathophysiology.


Keywords


Cataracts, Ageing lens, Age related changes in vision, Cataract pathophysiology

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References


Zampighi GA, Hall JE, Ehring GR, Simon SA. The structural organization and protein composition of lens fiber junctions. J Cell Biol. 1989;108:2255-75.

Parrey MU, Alswelmi FK. Prevalence and causes of visual impairment among Saudi adults. Pak J Med Sci. 2017;33:167-71.

Kupfer C. Bowman lecture. The conquest of cataract:a global challenge. Trans Ophthalmol Soc U K. 1985;104(Pt 1):1-10.

Winkler BS, Riley MV. Relative contributions of epithelial cells and fibers to rabbit lens ATP content and glycolysis. Invest Ophthalmol Vis Sci. 1991;32:2593-8.

Mathias RT, White TW, Gong X. Lens gap junctions in growth, differentiation, and homeostasis. Physiol Rev. 2010;90:179-206.

Lou MF. Redox regulation in the lens. Prog Retin Eye Res. 2003;22:657-82.

Spector A. Oxidative stress-induced cataract: mechanism of action. FASEB J. 1995;9:1173-82.

Giblin FJ. Glutathione: a vital lens antioxidant. J Ocul Pharmacol Ther. 2000;16:121-35.

Kleiman NJ, Spector A. DNA single strand breaks in human lens epithelial cells from patients with cataract. Curr Eye Res. 1993;12:423-31.

Harding JJ. Viewing molecular mechanisms of ageing through a lens. Ageing Res Rev. 2002;1:465-79.

Qiao F, Xing K, Lou MF. Modulation of lens glycolytic pathway by thioltransferase. Exp Eye Res. 2000;70:745-53.

Xing KY, Lou MF. Effect of age on the thioltransferase (glutaredoxin) and thioredoxin systems in the human lens. Invest Ophthalmol Vis Sci. 2010;51:6598-604.

Benedek GB. Theory of transparency of the eye. Appl Opt. 1971;10:459-73.

Michael R, van Marle J, Vrensen GF, van den Berg TJ. Changes in the refractive index of lens fibre membranes during maturation--impact on lens transparency. Exp Eye Res. 2003;77:93-9.

Van Den Berg TJ, Van Rijn LJ, Michael R, Heine C, Coeckelbergh T, et al. Straylight effects with aging and lens extraction. Am J Ophthalmol. 2007;144:358-63.

Brown N. The change in shape and internal form of the lens of the eye on accommodation. Exp Eye Res. 1973;15:441-59.

Weeber HA, Eckert G, Pechhold W, van der Heijde RG. Stiffness gradient in the crystalline lens. Graefes Arch Clin Exp Ophthalmol. 2007;245:1357-66.

Glasser A. Restoration of accommodation. Curr Opin Ophthalmol. 2006;17:12-8.

Sharma KK, Santhoshkumar P. Lens aging: effects of crystallins. Biochim Biophys Acta. 2009;1790:1095-108.

Brownlee M. Biochemistry and molecular cell biology of diabetic complications. Nature. 2001;414:813-20.

Shang F, Taylor A. Function of the ubiquitin proteolytic pathway in the eye. Exp Eye Res. 2004;78:1-14.

Varma SD, Chand D, Sharma YR, Kuck JF, Jr. Richards RD. Oxidative stress on lens and cataract formation:role of light and oxygen. Curr Eye Res. 1984;3:35-57.

Truscott RJ. Presbyopia. Emerging from a blur towards an understanding of the molecular basis for this most common eye condition. Exp Eye Res. 2009;88:241-7.

Harding JJ. Free and protein-bound glutathione in normal and cataractous human lenses. Biochem J. 1970;117:957-60.

Sweeney MH, Truscott RJ. An impediment to glutathione diffusion in older normal human lenses: a possible precondition for nuclear cataract. Exp Eye Res. 1998;67:587-95.

Sasaki H, Jonasson F, Shui YB, Kojima M, Ono M, Katoh N, et al. High prevalence of nuclear cataract in the population of tropical and subtropical areas. Dev Ophthalmol. 2002;35:60-9.

Mitchell P, Cumming RG, Attebo K, Panchapakesan J. Prevalence of cataract in Australia: the Blue Mountains eye study. Ophthalmology. 1997;104:581-8.

Vrensen G, Willekens B. Classification and prevalence of early senile lens opacities in human donor eyes. Dev Ophthalmol. 1989;17:181-7.