Cataract develops when the lens of the eyes become opaque or cloudy and starts to affect vision. The lens of the eyes should always be transparent but once cataract is developed, the lens becomes similar to ‘frosted glasses'. Cataract could blur the patient's vision or it can lead to complete blindness of the infected eye.
This condition is very common for the elderly as it develops gradually changes he shape and structure of the lens through age. Cataracts can be treated by a day case surgery which involves the removal of the infected lens. Artificial lenses replace the infected lens. Cataract is causes blindness for a majority of cases especially in countries where the surgical innovations for this condition is still not available.
Mechanism of sight
When a person looks at an object, the light emanating from the object goes to the cornea and then to the lens. After that, light goes to the retina which is found at the back of the eye.
The lens focuses the majority of light from the eye to the macula which makes up a portion of the retina. The macula is full of ‘seeing cells' or the rods and the cones.
The nerve signals go through the rods and cones until it reaches the optic nerves that go straight to the brain. The brain then interprets the signal and allows us to see.
To effectively enable us to see, the lens should be transparent and clear.
Different types of cataract
- Senile cataract. This is also known as age-related cataract and affects the majority of elderly people. People who are sixty years old and above are at high risk of developing this condition. In UK, one out of three old people are afflicted with cataracts. Both sexes have equal chances of acquiring the condition. Majority of the cases would involve both eyes but only one eye would get the worse cataract build up. This type of cataract gradually develops as age progresses. Patients with early cataract may not realize that they have the condition because the cloudiness does not affect their vision severely. Some cases of cataract do not worsen over time but for some patients, it will go on and cause complete blindness.
- Causes of senile or age-related cataract. The exact mechanism of what causes this type if cataract is still not clear but some suggest that there must be a change in the structural proteins of the lens. The change can be a result of an impairment or disturbance in the pathway of the nutrients and fluids as they are being transported to the lens. Age can affect this pathway as well as proteins would clump in discreet places inside the lens. These clumps cause the cloudiness in the lens and these areas block the light from getting to the retina. The degree of severity depends largely on the amount or number of clumping areas which cause cloudiness in the lens. Aside from age, people with smoking habits, poor diet, overexposure to ultraviolet light, steroid medicines, and diabetes. People who have a family history of the condition are at high risk of developing cataract.
- Symptoms for senile cataract. The first symptoms would include blurring of the patient's vision. Next is the noticeable ‘spots', then seeing halos surrounding bright lights. The patient may not be able to see well in the sunlight or become easily dazzled with car headlights. After these first symptoms, the severity of the cataract would become worse and would lead to blindness.
- Diagnosis for senile cataract. An eye specialist for cataracts is called an optometrist and he will examine the eyes of the patient. Consultation can be done because the patient is wary about his blurred vision or can it can also be just a routine eye check-up.
- Treatment for senile cataract. If a person is diagnosed with early cataract, he may not notice any problems in their vision. The rate of deterioration is different per person and some patient would not require treatment because their vision is normal. But consulting an optometrist should be done either way as it could affect your life. Seeking treatment is subjective to the patient but should be an option for all. Cataract can affect the patient if the vision is also affected. You cannot do normal chores such as driving, watching TV, reading, studying or even taking care of yourself. The treatment interventions are usually very successful but some people would tend to develop minor complications. It is always a good idea to have regular eye check-ups to ensure that no eye complication is being developed in your system.
Infected lenses with cloudiness are replaced by artificial plastic lenses in an operation called the intraocular implant. In the UK, Phaco Extracapsular Extraction or Phacoemulsification is the most common operation done. This operation entails the removal of the infected lens as well. This operation takes about ten to thirty minutes and is often called a ‘day case'.
In Phaecoemulsification, a local anesthetic is given to the patient so he will remain awake throughout the entire operation. But fortunately, this operation is not painful because the anesthetic in the form of eye drops will numb your eyes. Other than eye drops, local anesthetic injections can also be used in the eye. Once the eyes are numb, the eye surgeon would create a small hole in the corneal region. After this, a small instrument is inserted inside the lens, just near the front portion of the lens capsule. The small instrument gives out ultrasound waves to break the lens contents inside the capsule. Once the components are broke, it is suctioned out by a needle. After removing the lens materials, the transparent plastic lens is inserted inside the capsule via the initial hole made in the front portion of the cornea. The posterior portion of the capsule remains attached so that the plastic lens is kept well in place. In some cases, plastic lenses are not used; instead glasses or contact lenses are used to imitate the role of the lens.
There are other surgical techniques that can treat cataract aside from phaecoemulsification. There is a technique called the manual extracapsular extraction wherein the surgeon makes a longer cut in the corneal side. The surgeon then takes out the center or focal point of the lens without breaking the contents using ultrasound waves. The posterior or back portion of the capsule if kept in place. The plastic lens is then put in place of the extracted lens. Aside from manual extracapsular extraction, there is another technique called the intracapsular extraction where the entire lens is extracted, along with the capsule. After the removal of the lens and capsule, plastic lens or glasses are placed in to imitate the role of the lens in the eye. This technique is rarely done in UK because it presents more risks and complications than the previously mentioned surgical techniques. But for less privileged countries, intracapsular extraction is still being done because the technology needed to perform modern treatment is still not available.
- Complications of surgery. Surgery for cataract is usually successful and it improves the vision immediately. But in some cases, complications like infection, inflammation and damage to the cornea and other eye parts, and bleeding can happen. These side effects are very rare and can be treated immediately. But for some, this can lead to permanent visual impairment.
Aside from these complications, posterior capsule opacification or simply called cloudiness can also arise after surgery. This complication happens after pahecoemulsification and manual extracapsular extraction. These procedures require keeping the posterior portion of the capsule intact after the operation. Often, this portion would thicken months after the operation. This results in the cloudiness of the lens which would affect the vision of the patient. This is treated using painless laser surgery. The laser burns a small hole in the central portion of the capsule to allow light to come in and restore vision.
- Congenital cataract. This is a rare case but very important to be diagnosed as early as possible. Vision is learned at an early stage during infancy and should a cataract be present at birth, it would block the eyes from learning and establishing the correct visual pathway. This can result to blindness which can persist even after the cataract is removed. Optometrist's examine the eyes of the babies to check for this condition and prevent blindness later in life.
- Other types. Cataract can also develop from an eye injury or from radiation damage due to overexposure. Cataract can also occur as secondary or comorbid problem if the patient has some serious eye complications or diabetes.