External factors in the development of cataract

Abstract

Aims To provide an update on the risk factors for cataract development. Methods Review of the literature. Results Age and heredity are the most important risk factors associated with the different types of cataract. While the hereditary component is self-explanatory, increasing age serves as a surrogate for a number of potential external risk factors, the effect of which is cumulative. Identification of the risk factors that have a causal effect on cataract development may provide means for cataract prevention. There are only a few risk factors that satisfy the criteria for causal effect: smoking, which results in the increased risk of nuclear cataract, excessive UV-B exposure and diabetes that increase the risk of cortical cataract, and steroidal treatment, diabetes and ionising radiation that lead to the formation of posterior subcapsular opacity. The effect of medications on cataract development requires further study, since the effect of the diseases should be distinguished from that of treatment. 'Stop Smoking' and 'UV-B protection' campaigns are gaining momentum as preventative measures, while the attempts to actively prevent cataract with antioxidants have not been successful. Cataract research has been facilitated lately by improvements of precision and standardisation in measuring lens opacities. However, measurement precision on its own cannot give us a solution to this problem. Conclusion The major studies repeatedly measure the exposure to the traditional health hazards, while the missing parts in the equation are those risk factors that we do not know about and therefore do not measure. New approaches and new hypotheses are needed.

An Internal Disulfide Locks a Misfolded Aggregation-Prone Intermediate in Cataract-Linked Mutants of Human Gamma-D Crystallin

“…Its pathology has multiple contributing factors, including exposure to UV light, tobacco, and certain specific chemicals; however, the effect is generally the sameaggregation of the eye lens crystallins (5,13,16,17,60,61). In line with the multiple causality of the disease, several distinct biochemical perturbations in vitro have been shown to cause crystallin aggregation (54,(62)(63)(64).…”

Ultraviolet Radiation-Induced Corneal Degeneration in 129 Mice

“…Lifetime exposure to chronic UVR has been directly associated with the development of cortical cataracts in man, and the World Health Organization has reported that as much as 20% of cataract-associated blindness may be due to UVR exposure. Genetic factors, diabetes, steroid use, and smoking are also strongly associated with cataract formation in humans (Robman and Taylor, 2005).…”

Lens opacities among physicians occupationally exposed to ionizing radiation – a pilot study in Finland

“…Other risk factors for both cortical and PSC include diabetes and steroid use, while smoking increases the risks of nuclear and PSC (28). The risk of cortical cataract is also related to ultraviolet radiation (29). We collected information on these factors and all analyses were adjusted for age, with additional adjustment for gender and smoking where necessary (if there was indication of confounding).…”