Cataracts
CATARACTS
The human eye is an intricate device with multiple components working together to result in the miracle of sight. One of these components is the lens in the eye, which provides one-third of the focusing power - about 20 dioptres. This is equivalent to about 10x the power of the average pair of reading glasses.
WHAT ARE CATARACTS?
With age, the lens gradually becomes less flexible and more cloudy. Becoming less flexible is the cause of presbyopia (needing reading glasses), and becoming cloudy is also known as age-related cataracts.
Cataracts are present in about 90% of individuals over 70yrs old(2).
SYMPTOMS
– Blurred/foggy vision
– Halos around lights
– Trouble distinguishing low contrast objects
Cataracts are the most common cause of visual impairment in the developed world. Every individual will develop cataracts if they live long enough as it is a normal age-related change that occurs in the lens. The age at which cataracts start to appear can depend on genetics and lifestyle.
For those interested in science, for most of your life, the cells in the lens are arranged in a formation that mimics the wavelength of visible lights so the rays pass right through without any reflections - hence the lens is completely transparent. However, as these cells age and oxidative stress (cell damage) occurs, this formation gradually changes and the lens gradually becomes less transparent. This is an irreversible process.
Note: there are other less common forms of cataract (such as diabetic, metabolic, congenital, toxic, traumatic, and secondary), however, age-related is the most common.
THE CAUSES
– Genetics
– Environmental Sun Exposure
– Smoking
Genetics play a major role in when cataracts develop, however, to try and slow down development and the need for surgery it is important to wear sunglasses whenever there is sun exposure. UV light rays increase the speed of oxidative damage in cells, and so will accelerate the development of cataracts in our eyes.
TREATMENT
The only treatment for cataracts is surgery. Cataract surgery is the most common surgery in the developed world(1), so it is very well practised and safe. The surgery usually involves putting the patient under a mild sedative, then removing the lens from inside the eye before replacing it with a new artificial one - usually with some form of prescription so your reliance on glasses is less than before the surgery. Over 95% of patients have visual improvement after the procedure(1).
The best way to assess whether you have cataracts is to book an Eye Examination with your Optometrist. They will be able to check your vision and the health of your lens and discuss whether you have cataracts and whether surgery is an option for you.
REFERENCES
McGhee, Charles NJ, 2017, Cataract surgery in New Zealand /Aotearoa approaching 2020, University of Auckland, presented on 02/10/2018.
Vashist P, Tandon R, Murthy GVS, Barua CK, Deka D, Singh S, et al. (2020) Association of cataract and sun exposure in geographically diverse populations of India: The CASE study. First Report of the ICMR-EYE SEE Study Group. PLoS ONE 15(1): e0227868. Reference here