What is a Cataract ?
A cataract is a clouding that develops in the eye's crystalline lens or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light. The lens works much like a camera lens, focusing light onto the retina to see things clearly both up close and far away.
It is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.
But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract, and over time, it may grow larger and cloud more of the lens, making it harder to see.
Cataracts are classified as one of three types:
- A subcapsular cataract begins at the back of the lens. People with diabetes, high farsightedness or retinitis pigmentosa, or those taking high doses of steroids, may develop a subcapsular cataract.
- A nuclear cataract is most commonly seen as it forms. This cataract forms in the nucleus, the center of the lens, and is due to natural aging changes.
- A cortical cataract which forms in the lens cortex, gradually extends its spokes from the outside of the lens to the centre. Many diabetics develop cortical cataracts.
Signs and Symptoms of Cataract
A cataract has at first little effect on your vision. You may notice that your vision is a bit blurred, like looking through a cloudy piece of glass.
A cataract may make light from the sun or a lamp seem too bright or glaring. Or you may notice when you drive at night that the oncoming headlights cause more glare than before. Colours may not appear as bright as they did before.
The type of cataract you have will affect exactly which symptoms you experience and how soon they occur. When a nuclear cataract first develops it can bring a temporary improvement in your near vision, called "second sight". Unfortunately, the improved vision is short-lived and will disappear as the cataract develops. On the other hand, a subcapsular cataract may not produce any symptoms until it's well-developed. If you think you have a cataract, see an eye doctor for an exam to make sure. Hazy or blurred vision may mean you have a cataract.
What Causes a Cataract ?
Many studies verify that exposure to ultraviolet light is associated with cataract development, so eye care practitioners recommend wearing sunglasses and a wide-brimmed hat to reduce your exposure.
Other types of radiation may also be causes. A 2005 study conducted in Iceland suggests that airline pilots have a higher risk of developing a nuclear cataract than non-pilots and that the cause may be exposure to cosmic radiation. A similar theory suggests that astronauts are also at risk from cosmic radiation.
Other studies prove people with diabetes are at risk of developing a cataract.
The same goes for users of steroids, diuretics and major tranquilizers, as well as smoking, air pollution and heavy alcohol consumption.
A small study found lead exposure to be a risk factor, but larger studies are needed to confirm whether lead can definitely put you at risk and, if so, whether the risk is from a one-time dose at a particular time in life or from chronic exposure over years.
Researchers say additional studies also are needed to confirm whether hormone replacement therapy (HRT) significantly increases chances that cataracts will form and progress to the point that surgical removal is required.
When symptoms begin to appear you may be able to improve your vision for a while using new glasses, strong bifocals, magnification, appropriate lighting or other visual aids.
An intraocular lens (IOL) is implanted in the eye in place of the clouded natural lens. It filters out blue light, which may be harmful to eyes.
Think about surgery when your cataracts have progressed enough to impair your vision seriously and affect your daily life. Many people consider poor vision an inevitable fact of aging, but cataract surgery is a simple, relatively painless procedure to regain vision.
Cataract surgery is very successful in restoring vision. In fact, it is the most frequently performed surgery in the United States, with more than 3 million Americans undergoing cataract surgery each year. Nine out of 10 people who have cataract surgery regain very good vision, somewhere between 50% and 100%. During surgery the surgeon will remove your clouded lens and, in most cases, replace it with a clear, plastic intraocular lens (IOL).
Success and post-operative complications
Cataract Surgery complications and problems after Cataract removal are generally pretty rare and are usually less than 5% in an otherwise healthy group of patients. In patients with additional eye diseases such as Glaucoma or Diabetic Retinopathy the complication rate may increase. Nonetheless the overall success rate for Cataract Surgery is generally regarded as being between 85-92% with overall patient satisfaction being in the 95% range. As with any surgery, patients should be familiar with possible complications so that they can bring any unusual symptoms or signs to the attention of their Cataract Surgeon in order to avoid potential complications of Cataract Surgery, Cataract Surgery problems or unusual side-effects after Cataract removal.
Short term Cataract Surgery problems and complications are those that we will define as occurring during, or very soon after, the actual surgical procedure-perhaps within the first 24 hours after surgery.
- Bleeding is a very unusual complication of Cataract Surgery. Bleeding inside the back of the eye is quite rare. While bleeding can occur inside the front of the eye where the actually surgery is being performed, this too is rare-especially since the tiny incision is made in the clear portion of the Cornea where there are no blood vessels. If bleeding does occur it is usually limited to the surface of the eye where your surgeon can easily cauterize it and stop it immediately.
- Bruise or "Black Eye" -If it was necessary to use an injection around your eye in addition to, or in place of, anaesthetic eye drops due to some factor regarding your overall health you may experience some temporary bruising around your eye. Although unusual, it does happen from time to time.
- Wound or Incision Leak -For the vast majority of patients the tiny incision placed during Cataract Surgery is self-sealing. Sometimes the Corneal incision does not seal properly and may actually leak-a situation that may expose you to infection. If this occurs your Cataract Surgeon may apply a contact lens or a pressure bandage or, in certain cases, place a stitch in order to help the incision seal.
- Endophthalmitis or "Inner Eye Infection"-Infection after Cataract Surgery is extremely rare occurring in one out of several thousand Cataract Surgery procedures. Nonetheless it is a serious complication of Cataract Surgery. To prevent infection, Cataract Surgeons place antibiotic eye drops in your eye before, during and after your surgery. In the rare event that you experience Endophthalmitis, your surgeon may recommend a procedure to take a culture of your infection and to administer antibiotics directly to the eye. Sometimes another operation is necessary to aspirate some of the infection. If swelling inside the eye without infection does occur it may be possible to treat the inflammation and swelling with a prescription of anti-inflammatory eye drops.
- Rupture of the Posterior Capsule -During your Cataract Surgery the cloudy or opacified lens material is "chopped up" and suctioned to remove it from your eye. However, the membrane that surrounds the lens is left in place to support the Intraocular Lens Implant. Occasionally it is possible that the posterior lens capsule will tear or rupture during your surgery. If this happens the surgeon will perform a Vitrectomy as part of your surgery in order to remove and repair the Vitreous Body that may have extended into the remaining capsule so that the Intraocular Lens Implant (IOL) can be set into position properly.
- Retinal Detachment -Retinal Detachment after Cataract Surgery is unusual. However, if you are extremely nearsighted you may be at greater risk for Retinal Detachment in general and especially when you have any type of eye surgery including Cataract Surgery. The symptoms of Retinal Detachment include floaters, flashing lights, a shadow in your vision, a bubble or curve in your vision, a sensation that a curtain or a veil is being pulled in front of your vision and a possible loss of your vision. If you experience ANY of these symptoms after Cataract Surgery you should call your Cataract Surgeon immediately as Retinal Detachment is a medical emergency. The shorter the time to treatment, the better the overall prognosis.
- Glaucoma -In general Secondary Glaucoma after Cataract Surgery is very unusual. However, if there is other bleeding or inflammation it can predispose you to developing Secondary Glaucoma after Cataract Surgery. In most instances Secondary Glaucoma after Cataract Surgery is temporary and can be treated with eye drops, laser treatment or a combination of both.
- Significant Astigmatism -In the event that it was necessary to use sutures or stitches because the Corneal incision did not seal properly, it is possible to distort the shape of the Cornea and induce astigmatism. Sometimes swelling of the Cornea alone can cause astigmatism to be induced. If swelling alone caused the induced astigmatism then it will gradually go away as the swelling diminishes. If the astigmatism was caused by the use of stitches, then once they are removed it is likely that the Cornea will return to its original shape.
Long term Cataract Surgery problems and complications are those that we will define as occurring from one week to as long as six months after Cataract Surgery.
- Decentred or Dislocated Intraocular Lens Implant (IOL) -While it is very rare, the artificial Lens Implant (IOL) used to correct your vision after Cataract Surgery can move slightly becoming decentred, or move a greater amount and become dislocated. A decentred or dislocated Lens Implant (IOL) may cause you to experience blurry vision, haloes, glare, double vision, fading vision, fluctuating and varying vision or shimmering vision. If this should occur your Cataract Surgeon will most likely reposition the Lens Implant (IOL) or replace it with a different Lens Implant.
- Cystoid Macular Edema -During the first three months or so after Cataract Surgery it is possible for the Macula, the visual center of the Retina, to be susceptible to microscopic swelling. Swelling of the Macula is likely to cause you to experience a decrease or blurring of your central or straight-ahead vision. This can be mild or it can be significant. In most cases, Cystoid Macular Edema is treated with a non-steroidal anti-inflammatory medication given as an oral and/or eye drop prescription.
- Secondary or After Cataract -The most common complication of Cataract Surgery is opacification of the posterior lens capsule resulting in the formation of a Secondary or After Cataract, which occurs after as many as 30% of Cataract Surgery procedures. When this occurs you will experience a gradual blurring of your vision. Fortunately your surgeon is able to use a YAG Laser to perform a quick painless procedure called a YAG Laser Capsulotomy in which a small opening is created in the cloudy membrane allowing your vision to be restored.
Problems and complications of Cataract Surgery are unusual if not rare. The overall success rate and patient satisfaction with Cataract Surgery make it a very safe and effective treatment for Cataracts. Nonetheless, those undergoing Cataract removal with Cataract Surgery and Lens Implants should become familiar with the possible, albeit unusual complications.
The information that has been provided here is intended to give patients an overview of the possible complications of Cataract Surgery. It is possible that your individual experience might be different. None of the information provided here is meant to be a substitute or replace your physician's consultation, nor does it replace the need for you to consult with your surgeon about specific details of Cataract Surgery complications.