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RISK FACTORS TO SENILE CATARACT 6

Risk Factors to Senile Cataract

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The natural eye lens is a crystalline substance that helps in the production of a clear passage for light. Cataract refers to the opacity within this clear lens of the eye. A cataract is a major social and medical issue that majorly contributes to the higher percentages of individuals diagnosed with blindness. Senile cataract is considered to an age-associated, vision-impairing illness that is characterized by a steady progressive clouding and the thickening of the eye lens. Senile cataract is considered to the global leading cause of the treatable blindness. The key symptoms of the senile cataract are myopic shifts. The monocular diplopia, glare, and reduced visual acuity. It is only treatable through the surgical process and the insufficient surgical process leads to more complications. The insufficient surgical facilities to help in the performance of the surgical procedure has resulted in more research work to help in finding out about the modes of treatment (Gupta et al., 2014).

Senile cataract is grouped into three categories i.e. nuclear cataract, cortical cataract, and the posterior subcapsular cataract. Senile cataract is caused by the multifactorial pathogenesis process that is involving a complicated interaction between a different physiologic process that is modulated by the environment, genetic, nutritional, and systematic factors. Therefore, various factors are considered to be contributing to multiple mechanisms leading to the loss of transparency of the lens. These factors make the lens epithelium to undergo age-related changes for example reduction in the lens epithelium and the aberrant differentiation of the lens fibers. Individuals are exposed to the senile cataract as a result of the risk factors such as smoking, ultraviolet radiation, inherited defects, nutritional inadequacy, and age (Garg et al., 2020).

Smoking

The cigarette smoke is extremely toxic and it is composed of more than 4,000 active compounds such as tar, polycyclic, and aromatic hydrocarbons among others. Smoking has been directly connected to the two leading causes of vision loss, cataracts, and macular degeneration. Research has shown that smokers are at a double risk of developing cataracts as compared to non-smokers. The senile cataract occurs when the clear lens naturally grows cloudy with time. This leads to the blurry vision, faded colors, and the increased sensitivity to the glare. Smoking leads to the alteration of the cells of the lens through the oxidation process. It also leads to an increase in the accumulation of heavy metals such as cadmium in the eye lens. Therefore, smoking exposes individuals to the senile cataract (Bragin et al., 2017).

Age

Age is considered to be the biggest risk factor for the cataract and as individual ages, the risk of the disease increases. The age-related senile cataract is caused by the changes in the later stages of the lifespan. As the individual ages, there are molecular changes in the crystalline lens. This leads to a gradual decrease in transparency. The aging processes of the crystalline lens reaches a point whereby the vision becomes impaired. For the individuals of ages more than 50 years, there are mechanical, chemical, and radiation trauma that exposes individuals to the senile cataract. The condition is becoming more severe and common in elderly individuals. There are a breakdown and the aggregating proteins, oxidative damages, and increased levels of calcium thus exposing elderly individuals to the senile cataract. The mechanical processes leading to the abnormal lens epithelium cell movement, the oxidative damages, and the increased level of calcium is caused by dehydration crisis, hypertension, and smoking among others. Therefore, the aging process is associated with several changes in the eye lens that exposes individuals to senile cataract (Gupta et al., 2014).

The radiation and the electromagnetic waves

The radiation includes ultra-violet rays, infrared, and electromagnetic waves. Research has shown that there are regions with higher UV radiation in Australia and have recorded high cases of cataracts thus linking the UV radiation as a risk factor to the disease. The report also shows that the incidence of cataracts in regions with an average of 12 hours of daily sunlight exposure is 3.8 times higher as compared to the regions receiving 7 hours of exposure in Nepal. The electromagnetic radiation that has longer waves for example UVR-A is contributing to adverse biological impacts. The exposure to the solar UVR leads to the lens epithelial damages and the swelling of the lens fibers. The UVR-B of size 300nm passes cornea then gets absorbed by the lens epithelium thus causing the damage (Gupta et al., 2014).

The prolonged exposure to the infrared rays leads to the discoid posterior subcapsular opacities and the oxfoliation of the anterior capsule. Exposure to microwave radiation leads to cataract. The insufficiently protected technicians, patients being treated for the malignant tumors, and the employees working in the atomic energy plants are prone to cataract disease. Therefore, radiation and electromagnetic waves are among the risk factors exposing individuals to the senile cataract (Gupta et al., 2014).

Nutritional inadequacy

Nutritional factors play an important role in the cataract illness and healthy eating index (HEI) is being utilized as a unique strategy to the study of the connection between the diet and the illness. The risk of cataracts increases with the high consumption of meat and dairy products as compared to the consumption of the vegetables and consumption of less meat. Nutrition is also linked to cataract disease formation due to diarrhea and poverty. The deficiencies of the micronutrient are interfering with the antioxidant systems in the eye lens. The application of the nutritional supplements and the balancing of the antioxidants in the older age and during diarrhea is helping in the prevention of the senile cataract. Individuals with low diet in antioxidants such as vitamin E, C, thiamine, lutein, flavonoids, and the carotenoids are exposed to the cataract disease (Ghanavati, et al., 2015).

Inherited defects

The cataract disease that occurs as a result of the genetic factors is usually caused by the anomaly in the chromosomal patterns of the individuals. It is estimated that approximately one-third of the congenital cataracts are caused by hereditary. The genetic factors are accounting for 50 percent of the risk for age-related cataracts. The family-based linkage research works have determined the number of genetic exposure loci for the age-associated cataract. Some genes are involved in the antioxidant metabolism, galactose metabolism, heat shock stress response, and the ephrin signaling pathways. The characterization of the underlying genetic causes of the cataracts is linked to the non-surgical treatments for age-related cataracts. The genetic cause of senile cataract is linked to the cases such as the retinal degenerations; multisystem genetic illness like the chromosome abnormalities, the Lowe syndrome and the neurofibromatosis; and the developmental anomalies. There is also a PITX3 gene that leads to the inherited cataracts within the interior segments of the mesenchymal dysgenesis (Gupta et al., 2014).

References

Bragin, E., Azizova, T. V., & Bannikova, M. V. (2017). Risk of senile cataract among nuclear industry workers. Vestnik Oftalmologii, 133(2), 57-63. Garg, P., Mullick, R., Nigam, B., & Raj, P. (2020). Risk factors associated with the development of senile cataract. Ophthalmology Journal, 5, 17-24. Ghanavati, M., Behrooz, M., Rashidkhani, B., Ashtray-Larky, D., Zamenni, D. S., & Alipour, M. (2015). Healthy Eating Index in Patients With Cataract: A Case-Control Study. Iranian Red Crescent Medical Journal, 17(10), e22490. Gupta, V. B., Rakagopala, M., & Ravishankar, B. (2014). Etiopathogenesis of cataract: An appraisal. Indian Journal of Ophthalmology, 62(2), 103-110.