Cataract is a condition of the eye that mainly affects the older population. It can also be caused by severe trauma and exposure to certain kinds of radiation. It is the main reason for blindness in people over 40. This disease is fairly common and most of us have heard of it as some elder family member has contracted it at some point or the other. As it’s an eye disease that affects the lens of the eye, let’s understand its location and other main aspects of the eye structure that are related to cataract. The eye is a spherical part of the body that helps us see and perceive the light that is reflected off everything around us and then process the resultant image through the brain.
When we look at the eye from the front angle, the first layer that is transparent is called the cornea. It is the primary structure of the eye and covers the iris which lies just behind it. The iris maintains and controls the amount and intensity of light entering the lens which is situated behind the iris. The lens is suspended behind the iris. When light enters our eye, light is first focused by the corneas.
Then light passes through the iris which reduces or intensifies the amount of light as per conditions and finally the lens focuses the light rays such that a clear image is formed on the retina. A cataract is the formation of dense and cloudy area on the lens which makes it very hard to see. This is due to the fact that the lens no longer receives enough light and hence it is unable to send the focused images to the cornea. Cataracts can develop in both eyes but rarely at the same time.
Symptoms of Cataract
The symptoms of cataract depend and vary with the type of cataract. They initially present with slight changes in vision like blurry or foggy vision. This is a common sign of sclerotic cataract. In posterior sub capsular cataract, people complain of a glare of the sunlight. The light from even a lamp seems too bright and oncoming headlights of cars seem brighter than usual. In both these types, the vision is compromised by either low visibility or reduction in the colors perceived. In a nuclear cataract, the vision of the patient improves at first. This is called second sight which is short lived. After some time, it goes away and the vision declines. Sub capsular cataract doesn’t show any symptoms until the late stages and the cataract is well developed.
Causes of Cataract
1. Age: Cataract is most common in old people. In due course of time, the suspended lens behind the iris degrades. This is also enhanced if the patient is also suffering from diabetes and high blood pressure.
2. Injury: When a person sustains an injury like a punch or by any other object in the vicinity of the eye, the eye lens swells and whitens. The selling does reduce with proper rest but the whitening of the lens might remain. This happens when the blunt force that strikes the eye perforates the chamber of the eye where the lens is located. This leads to fluid leakage from the surrounding parts which obstructs the view and clouds the lens.
3. Radiation: Radiation like ultra violet radiation, X-rays and radiation from microwaves may cause cataracts. The reason for this is somewhat unknown but various theories suggest that these radiations, damage the protective proteins in the eye.
4. Genetics: Cataract is also a genetic condition. Genes that are responsible for the protection and maintenance of the lens are responsible for this condition. Some examples of genetic conditions that cause cataracts are Alport’s syndrome, Conradi’s syndrome, myotonic dystrophy, and oculocerebrorenal syndrome
5. Skin problems: in the embryonic stage, the lens and the skin are pushed very close to each other. Therefore, a link establishes between them which makes them susceptible to similar conditions. Therefore, skin conditions like dermatitis may also cause cataracts to develop.
6. Smoking: Cigarette smoking can increase the chances of contracting cataracts.
Vitamin c deficiency: Low vitamin c consumption increase the risk of cataracts. So make sure to incorporate citrus fruits in your diet
Types of Cataract
There are three main types of cataracts namely, Nuclear sclerosis, Cortical cataracts and Posterior sub capsular cataract.
(a) Nuclear sclerosis cataract is the prominent cataract. This type affects the core part of the lens which is located at the center of the lens. This part can be called as nucleus and hence the name of this condition. Sclerosis means ‘hard’. The white layer that forms in this kind of cataract is soft in the beginning but hardens with time as the liquid surrounding the lens condenses on its surface. With time, nuclear sclerosis becomes more serious and develops into an advanced condition which is known as Brunescent disease. The common symptoms of nuclear sclerosis are nearsightedness and trouble in distant vision.
(b) Cortical cataract is that condition in which the outer layer of the lens is completely blocked and no light can pass through the iris to the lens. They are caused when fissuring occurs in the eye because of the imbalance in the liquid around the lens. It mainly present with problems like light scatter in the night or unusual sun glare.
(c) Posterior sub capsular cataracts are the cataracts in which the obstruction in vision due to the whitening is located on the rear side of the lens. The eye makes most of the adjustments in the later part of the lens and hence, the symptoms include disproportionate size of objects.
As the risk factors include Ultra violet rays and smoking, avoiding exposure to radiation and refraining from smoking can go a long way in prevention from this condition. While walking outside in the sun, sunglasses maybe used.
The most successful treatment for this eye disease is surgery. In this procedure, the doctor removes the damaged lens of the eye and replaces it with another one. The new lens is man-made. The surgery is very safe and the person is able to go home on the very same day. the most common surgical method of removing cataract is called Phacoemulsification which is a six step technique.