What are Cataracts?
A cataract can simply be referred to as a clouding or an opacity of the lens of the eyes. Normally, the lens of the eye is clear. The probability of developing cataracts gets higher with age.
How Cataracts Occur
The eye lens is transparent, elliptical in shape and sits just behind the pupil. Its function is to focus the light that gets in your eye through the pupil into images on the retina. Among young people, the lens can change shape easily since they are still flexible and elastic, hence allowing the eyes to clearly focus on both close and distant objects. However, as people age into their mid-forties, the lens harden and lose their elasticity due to some biochemical changes the lens cells undergo. The hardening of the lens leads to various eye problems such as presbyopia and long-sightedness, the reason you see most elderly people wearing glasses. For cataracts to form, the proteins in the eye lens of some people get clumped together forming opaque, cloudy areas in the lens known as cataracts. Depending on what causes the cataracts, they may either develop slowly over several years or rapidly over a short period of time. Cataracts vary in density and can be located anywhere in the lens. When they block the passage of light to the retina, vision becomes cloudy.
Types of Cataracts
Cataracts are named by their location in the lens, there are three major types:
Nuclear – these form in the inner core of the lens, also known as the nucleus. It is the most common type, mostly associated with old age.
Cortical – these form on the outer parts of the lens, that is, the cortex.
Posterior subcapsular – these are most commonly seen in people taking steroids, diabetics and overweight individuals. It forms on behind the eye lens like a capsule.
Causes of cataracts
Old age is widely accepted as the major risk factor for cataracts. Nevertheless, scientists are still uncertain about the exact biological mechanisms that make aging cause the cells in the lens clump together. The following are some of the leading factors that researchers have brought forward:
Oxidants and Lack of Glutathione
Oxidants, also known as Oxygen-free radicals are particles that are naturally produced in your body during chemical processes. Production of Oxygen-free radicals is accelerated by smoking, toxins, infections, UV radiation among other factors. When oxidants are in excess, they can have very adverse effects on body cells throughout the body. Cataracts is one such harmful effect that can be caused by overproduction of oxidants especially combined with the absence of a common anti-oxidant known as glutathione. Glutathione is usually found in large amounts in the eyes, and helps counter the effect of free radicals.
Sunlight and Ultraviolet (UV) Radiation
Normal sunlight consist of UV radiation which is capable of penetrating several layers of the skin and cause damage to the cells. The eye lens is protected from the harmful UV radiation by the body’s structural features such as the eyelids, the nose, overhanging brows, eyelashes etc. Over a long period of time, the UV exposure affects the lens causing changes to the pigments which contribute to the development of cataracts. A part of the UV radiation from sunlight called UVB is also known to cause muscular degeneration and disorders of the retina that are age-related. Some researchers are concerned that the growing global temperatures and damage to the ozone layer may increase the number of people with cataracts worldwide.
Some common radiation treatments for treating different types of cancers are known to cause cataracts as some of the side effects.
Researchers and scholars alike have raised questions about the effect of low radiation from computer screens. Up until now, there is no study linking the development of cataracts to screens, however, opticians suggest to sit at least a foot away from video display terminals.
Cataracts can be caused by a long-term use of oral steroids. Nasal-spray and inhaled steroids have shown conflicting results with regards to whether they can directly cause characters or not. Research about inhaled steroids is significant among medical practitioners since it is a common treatment for asthma and allergies.
Causes of cataracts in children
In very rare occasions, a child out of 10,000 births is born with cataracts. A condition known as congenital cataracts. Congenital cataracts are associated with genetic disorders. They are usually as a result of inborn abnormalities in the shape of the lens or the capsule. In addition to this, an infection during child delivery can also lead to cataracts especially if the mother abuses alcohol or other types of drugs.
Symptoms of Cataracts
Cataracts have little effect on vision during the early stages. As the cataracts develop, mostly with age, the following symptoms may occur:
- Double vision, cloudy vision, or both may occur as the initial signs.
- Yellowish tint on images reaching the retina due to the reduction of color vibrancy
- Increased sensitivity to bright lights making it hard to drive at night due to glare.
Symptoms may be different depending on where the cataracts occur. Additionally, highly developed cataracts, the pupil will look milky instead of its usual black and vision can be reduced to the discernment of just either dark or light.
Treatment of Cataracts
Currently, surgery is the only and most common treatment for cataracts. However, rarely does cataracts cause an emergency medical situation. Most cataracts only reduce the ability of a person to see clearly as they used to meaning surgery is often delayed for a long period of time. In addition, cataracts can be managed in its early stages in the following ways:
- Contact lenses or glasses with strong lenses
- Use of magnifying glasses while reading, or even regular reading glasses.
- Strong lighting
- Dilating the pupils using medication for people with capsular cataracts, however, this treatment does not stop the glare caused by cataracts.
Normally, patients and their families have a lot of time to go over the options available to treat or manage cataracts and discuss it with their opticians and ophthalmologists. Cataracts are not known to progress in any specific rate but progression varies from patient to patient.