A normal human eye has clear lens. Clouding of this lens causes a condition known as cataract. Individuals with cataracts can't see clearly, as their vision becomes cloudy or foggy. They feel as if they are looking through a fogged-up window. People with cataracts have difficulty in performing normal tasks such as driving a car (particularly at night), reading, writing etc. Majority of the cataracts develop gradually and the eyesight is not impaired right away in the early stages of cataract; however, as the time goes on and the cataract increases, it starts to impede a person's vision.
In the initial stages, patients can get by using stronger lighting and eyeglasses, but as the vision impairment increases and interferes with daily activities, then cataract surgery is required. Cataract surgery is a safe and effective procedure.
Types of Cataracts
These are the cataracts that develop in the center of the lens. A person having nuclear cataract may initially become more nearsighted and may even experience a temporary improvement in his/her reading vision. However, as the time goes on, there is gradual dense yellowing of the lens which clouds the vision further. Nuclear cataracts may sometimes result in a patient seeing double or multiple images. As the cataract advances, there may be brown coloration to the lens. This advanced stage of yellowing or browning of the lens causes the patient difficulty in differentiating between shades of color.
This type of cataracts affects the edges or the rim of the lens. A cortical cataract starts as a wedge-shaped, whitish opacities or flecks on the outer rim of the cortex of the lens. As the condition advances, these flecks or opacities start to spread towards the center of the lens resulting in difficulty of light passing through the lens' center. Patients with this type of cataracts commonly experience trouble with glare.
Posterior Subcapsular Cataracts
These cataracts, as the name itself suggests, affect the posterior part of the lens. In the initial stages, the posterior subcapsular cataract start as a small, opaque region which often develops near the posterior part of the lens, exactly in the way of light as it passes to the retina. Individuals with a subcapsular cataract have difficulty in reading vision, experience decreased vision and also experience glare or halos around the lights during nighttime.
These are the cataracts which are present from birth, i.e. some individuals are born with cataracts. Some cataracts may develop during childhood itself. The cause of congenital cataracts is if the mother contracts an infection during pregnancy or they could be a result of some inherited syndromes. Congenital cataracts do not necessarily affect the vision; however if they do, then they can be removed surgically.
Causes and Risk Factors of Cataracts
Causes of Cataracts
- As the people age, their tendency to develop cataracts increases.
- Another cause is any injury or damage to the tissue of the eye's lens which results in a cataract.
- Some inherited genetic disorders, which cause other health problems in a person, increase the risk of developing cataracts.
Risk Factors for Cataracts
- Excessive intake of alcohol.
- Exposure to cancer radiation therapy and ionizing radiation.
- Excessive sunlight exposure.
- Hereditary, i.e. having a family history of cataracts.
- Hypertension (high blood pressure)
- Overweight / obesity
- Recent eye inflammation or injury.
- Recent eye surgery.
- Using corticosteroid medications for a long time.
Pathophysiology of Cataracts
Cataract develops in the lens which is located behind the iris (colored part of the eye). The function of the lens is focusing on the light which passes into your eye, where it produces clear and sharp images on the retina. Presence of a cataract disperses the light when it passes through the lens, thus preventing the formation of a clear or sharply defined images reaching to the retina. This results in blurry vision. As a person ages, the lenses in the eyes loses its flexibility, transparency and becomes thicker. Other age related changes of the lens causes breakdown and clumping of the tissues together resulting in clouding of small regions of the lens. As the cataract progresses, so does the clouding by becoming denser and affecting a larger region of the lens. A cataract can affect either one or both of the eyes.
Signs and Symptoms of Cataracts
- Patient experiences blurred, cloudy or dim vision.
- Patient experiences great difficulty with vision during night.
- Patient experiences sensitivity to light and glare.
- Patient visualizes "halos" around lights at night.
- Patients have to frequently change their eyeglasses or prescription for contact lens.
- Patient experiences fading or yellowing of colors.
- Patient experiences double vision in a single eye.
- Serious symptoms include sudden changes in the vision, double vision or blurriness.
Tests for Cataracts
- Visual Acuity Test where the patient is asked to read an eye chart to assess the degree of impairment in his/her vision.
- Slit-Lamp Examination: In this test, a light and magnification are used to examine the eye structures. It helps in detecting even the smallest abnormalities.
- Retinal Examination: This test comprises of dilating your eyes using dilating drops. This makes your pupils widen and makes it examining the posterior region of the eye, i.e., the retina, easier to detect any signs of cataract.
Treatment for Cataracts
Surgery is common line of treatment for cataracts, as it is the most effective method in cataract removal. When the cataracts start to affect the patient's quality of life then surgery is recommended. Patients should discuss with their doctors about the right time to have a cataract surgery. For majority of individuals, there is no hurry to remove cataracts, as they are not generally harmful to the eye. If you want to postpone the surgery, then discuss with your doctor the pros and cons of delaying the surgery and of having the surgery. If you want to have the surgery at a later date, then your ophthalmologist may recommend periodic follow-up exams to assess the progression of the cataracts.
- During the cataract surgery, the clouded lens is removed and replaced with a plastic lens implant which becomes a part of your natural eye.
- Sometimes, patients may have other eye problems due to which they cannot use replacement lens. In such cases, after the cataract removal, patient should use eyeglasses or contact lenses in order to have a correct vision.
- Surgery is commonly done on one eye at a time. A time period of few weeks is given between the surgeries. Cataract surgery is usually done on an outpatient basis and requires no overnight stay at hospital.
- Local anesthesia is used to numb the area around the eye and the patient remains awake during the surgery.
- Cataract surgery is generally safe; however, it does carry some risk of infection and bleeding and also increases the risk of retinal detachment.
Watch 3D Video Phacoemulsification Cataract Surgery:
Lifestyle and Home Remedies for Cataracts
- Always use correct prescription eyeglasses or contact lenses.
- When reading, try using a magnifying glass.
- The lighting at home should be improved with brighter lamps and bulbs.
- Always wear sunglasses or a broad-brimmed hat when you are outside in order to decrease the glare.
- Avoid driving at night.
Prevention of Cataracts
- Always have regular eye exams, as they help in detecting cataracts and other eye problems in their initial stages.
- If you are a smoker, then quitting smoking is highly recommended.
- Wear sunglasses when outside to block the ultraviolet B (UVB) rays.
- If you have other health problems such as diabetes etc. which increase your risk of cataracts, then take care of these problems.
- Lose your excess weight and always maintain a healthy weight by exercising and following a balanced diet comprising of colorful fruits and vegetables which have lots of anti-oxidants, as they can help in preventing damage to the lens and are beneficial to the health of the eyes.