Cataracts are cloudy areas that form in the lens, which is normally transparent. They are the main cause of vision loss in people aged over 40 years.
Cataracts cause more vision problems globally than any other eye condition or disease, and the number of cataracts is increasing with the aging population.
In the United States in 2010, there were 20.48 million cases, rising to 24.41 million in 2015. By 2050, nearly 50 million Americans are expected to have cataracts.
A cataract causes a part of the lens to becomes opaque, or cloudy. Light does not pass through easily, and vision becomes blurry, like looking through a fogged-up window. The cloudier the lens, the worse the vision will be.
Congenital cataracts may be present at birth or appear shortly after, or at some time during infancy or childhood.
Age-related cataracts appear later in life and are the most common type. This article will focus on age-related cataracts.
Cataract surgery is a routine operation nowadays and the most common kind of eye surgery.
A doctor will normally recommend surgery for cataracts.
For severe cataracts, the only effective treatment is surgery.
The specialist will recommend surgery if the patient:
Is having trouble looking after themselves or someone else
Cannot drive or finds driving difficult
Has problems leaving the house
Finds it hard to see or recognize people’s faces
Has problems doing their job
Cannot read or watch television properly
Patients who take alpha-blockers or are considering taking alpha-blockers should be aware that these drugs may increase the difficulty of cataract surgery.
What to expect in surgery
Pre-operative assessment: Before surgery, the specialist will assess the patient’s eyes and general health. The eye will be measured so that the replacement artificial lens can be prepared.
Before the operation: Eye drops will be given just before the procedure, to dilate, or widen, the pupils. Sometimes the eye drops will contain an anesthetic, or the doctor may inject local anesthesia into the tissue around the eye.
As the anesthetic starts working, the area will become numb, and the patient will feel nothing. During the operation they will be aware of a bright light, but they will not be able to see what is happening. Cataract surgery is normally keyhole, or minimally invasive, surgery, and the patient will return home on the same day.
Various types of replacement lens may be used:
A monofocal lens is a fixed-strength lens that is set for one level of vision, usually distance
A multifocal lens may have two or more different strengths, providing for near and distance vision
An accommodating lens is most similar to the natural human lens. It allows the eye to focus on near and distant objects
The operation involves removing the cloudy lens from the eye and putting an artificial, clear, plastic one in its place. This is an intraocular implant, or an intraocular lens.
This is known as phacoemulsification or phaco-extracapsular extraction.
The eye surgeon makes a tiny cut in the cornea at the front and inserts a minute probe through the cut. The probe uses ultrasound and breaks up the cloudy lens into very small pieces. These are sucked out.
The artificial lens is then inserted through the cut. The lens capsule acts as a pocket, to hold the lens in place. When it is first inserted the lens is folded, but it unfolds when in position.
The whole procedure takes around 30 minutes. Most patients will wear an eye pad for protection for a short while.
Other surgical procedures
In manual extracapsular extraction, the lens is removed in one piece, and no ultrasound is used to break it up. The surgeon will make a slightly larger cut in the eye.
In intracapsular extraction, both the lens capsule and the lens are removed. The artificial lens is sewn into the eye. This type of procedure is much less common.
If both eyes need operating, this will usually be done 4 weeks apart.
Cataract surgery may be done using traditional tools, or it may be laser-assisted.
Laser may later be used to solve a complication known as after-cataract surgery that may occur months or years later.
After the operation
For most patients, vision improves almost immediately. It may take a while for the eye to settle down completely. Sometimes, the cut in the eye needs a stitch, but this is normally small enough to heal by itself.
Patients should avoid vigorous activities for a while, but most people find they can go about their daily activities as soon as they get home.
The patient will need a vision test, because they will probably need different glasses after their operation. The new glasses can only be determined after their vision has settled down, but this can take several weeks.
Cataracts cause the lens to become cloudy.
Cataracts normally take years to develop, and they tend to appear in older age. The lens gradually becomes cloudy.
Cataracts can make it hard to read or drive a car, especially during the night. Seeing people’s facial expressions can become difficult.
They develop slowly, so most people do not know they have them at first, but as the clouding progresses, the vision gradually gets worse. Long-distance vision is more severely affected at the beginning.