Cataract
What, exactly, is a Cataract?
A cataract is a loss of transparency, or clouding, of the normally clear lens of the eye. As one ages, chemical changes occur in the lens that make it less transparent. The loss of transparency may be so mild vision is hardly affected or so severe that no shapes or movements are seen, only light and dark. When the lens gets cloudy enough to obstruct vision to any significant degree, it is called a cataract. Glasses or contact lenses cannot sharpen your vision if a cataract is present.
What causes cataracts?
The most common cause of cataract is aging. Other causes include trauma, medications such as steroids, systemic diseases such as diabetes and prolonged exposure to ultraviolet light. Occasionally, babies are born with a cataract.
Cataracts typically occur more frequently in the aging population, however there are many other factors such as family history, diabetes, long term UV exposure, or certain medications like steroids that can cause cataracts. Also, previous eye injuries can be an attributing factor.
How do you reduce your risk of developing a cataract?
Reducing the amount of ultraviolet light exposure by wearing a wide-brim hat and sunglasses may reduce your risk for developing a cataract but once developed there is no cure except to have the cataract surgically removed. Outpatient surgical procedures can remove the cataract through either a small incision (phacoemulsification) or a large incision (extracapsular extraction). The time to have the surgical procedure is when your vision is bad enough that it interferes with your lifestyle.
How can it be treated?
Cataract surgery is a very successful operation. One and a half million people have this procedure every year and 95% have a successful result. As with any surgical procedure, complications can occur during or after surgery and some are severe enough to limit vision. But in most cases, vision, as well as quality of life, improves.
Cataract Symptoms
Your eye works a lot like a camera. Light rays focus through your lens on the retina, a layer of light sensitive cells at the back of the eye. Similar to film, the retina allows the image to be "seen" by the brain. But over time the lens can become cloudy and prevent light rays from passing clearly through the lens. This cloudy lens is called a cataract.
The typical symptom of cataract formation is a slow, progressive, and painless decrease in vision. Other changes include: blurring of vision; glare, particularly at night; frequent eyeglass prescription change; a decrease in color intensity; a yellowing of images; and in rare cases, double vision.
Ironically as the lens gets harder, farsighted or hyperopic people experience improved distance vision and are less dependent on glasses. However, nearsighted or myopic people become more nearsighted or myopic, causing distance vision to be worse. Some types of cataracts affect distance vision more than reading vision. Others affect reading vision more than distance vision.
Other symptoms can include:
Blurry vision.
Lights seem too bright or have a “halo” effect.
Double vision in one eye.
Decreased night vision – sensitivity to glare from headlights.
Dull or fading colors.
If you feel you are experiencing any symptoms of cataract problems, we encourage you to contact us today to schedule a consultation!
Cataract Surgery
Cataract surgery is a very common procedure, and complications are rare and often treatable. The surgery itself is highly successful in improving the vision of patients about 95-99% of the time. Cataract surgery is an outpatient procedure usually taking less than 20 minutes to complete.
During the surgery, the doctor removes the cloudy natural lens from the eye while the patient is under monitored anesthesia care provided by an anesthesiologist.
Next, the doctor inserts an intraocular lens (IOL), which remains permanently in place of the removed natural lens. The IOL compensates for the magnification the old lens provided. Modern IOLs are designed for various functions and made out of different materials; your doctor will know which is most appropriate for your individual case. You can read more about the IOL below.
After the operation the doctor will apply a shield for the eye and discuss the post operative care.
Recovery from cataract surgery
The patient may return home the day of the procedure. With proper rest and avoidance of any strenuous activities such as heavy lifting, recovery is usually a matter of days, with only minor discomfort. Several follow up appointments will be required to ensure the eye is healing properly and initial results are sustained.
Intraocular Lenses (IOL’s)
An intraocular lens (IOL) is a tiny, lightweight, clear plastic disk placed in the eye during cataract surgery. An IOL replaces the focusing power of the eye's natural lens.
The lens of the eye plays an important role in focusing images on the retina. If the lens loses its clarity, as it does when a cataract develops, light rays do not focus clearly and the image one sees is blurry. Glasses or contact lenses cannot sharpen vision if a cataract is present.
The only treatment for a cataract is to remove the lens and implant an IOL. Intraocular lenses have many advantages. Unlike contact lenses, which must be removed, cleaned, and reinserted, the IOL remains in the eye after surgery.
An IOL is usually placed behind the iris in the natural shell or capsule that held the original natural lens. Modern IOLs are made from foldable acrylic material, allowing them to be inserted through small ~2mm incisions without any stitches.
Rapid evolution of IOL designs has led to a field termed “advanced technology” IOLs. These include the new Trifocal and toric IOLs. Toric lenses allow for the correction of astigmatism, which is caused by curvature of the clear covering of the eye. Trifocal lenses allow the patient to focus on distance, intermediate, and near objects. These advanced technology lenses are not covered by insurance companies so there is often a charge associated when these lenses are used.
The ORA System with VerifEye+ Technology
The ORA System was develop several years ago as a means to aid in IOL selection during cataract surgery. Traditionally, measurements for the new IOL are taken in the office in the weeks prior to the actual surgery. The cataract may introduce errors into these measurements and lead to a suboptimal result. With the ORA System, we became the first practice in Iowa to offer a different means for determining the IOL power during surgery. After the cloudy lens is removed, the ORA is used to determine the correct lens power. This is especially useful with advanced technology IOLs or in patients who have had prior LASIK or corneal surgery. In addition, we are constantly reviewing our surgical outcomes and using this data to adjust the mathematical formulas that are used to select the IOL. This leads to better patient outcomes.
Phacoemulsification (Phaco)
Phacoemulsification is a surgical method used to remove a cataract, which is a clouding of the eye's naturally clear lens. A cloudy lens interferes with light passing through to the retina, the light-sensing layer of cells at the back of the eye. Having a cataract can be compared to looking at the world through a foggy window.
In phacoemulsification, an ultrasonic oscillating probe is inserted into the eye. The probe breaks up the center of the lens. The fragments are suctioned from the eye at the same time. A small incision that often does not require sutures to close can be used since the cataract is removed in tiny pieces. Most of the lens capsule is left behind and a foldable intraocular lens implant, or IOL, is placed permanently inside to help focus light onto the retina. Vision returns quickly and one can resume normal activities within a short period of time.
Posterior Capsulotomy
During cataract surgery, your ophthalmologist removes your eye's natural, or crystalline lens. This cloudy lens is contained within a capsule, or sack, that holds the crystalline lens in place. The surgeon then replaces the cloudy lens with a new intraocular lens (IOL). This artificial lens implant is placed inside of the lens capsule from which the cataract was removed. Weeks, months or even years later, this capsule can become cloudy or wrinkled. When this occurs, a patient may return to our office exclaiming that their “cataract grew back”, reporting blurry vision or an increase in night glare while driving. This clouding of the capsule is called posterior capsular opacification (PCO).
PCO is a common post-operative complication following cataract surgery. Even with the best surgical technique, and the best IOL’s, patients can develop PCO. Fortunately, the treatment for this condition is relatively simple.
If you develop PCO, your surgeon may recommend an Nd:YAG laser capsulotomy, commonly referred to as a “Yag”. A Yag is when a laser is used to create a hole or window through the cloudy posterior capsule. This allows light to pass through the capsule clearly, with minimal diffraction or scattering of light. Yag refers to the type of laser used for this procedure, containing crystals of Neodymium, Yttrium Aluminum Garnet. A capsulotomy is performed in our office, and only takes about 5 minutes. Here is what will happen:
Your eye will be numbed and dilated using eye drops.
Your ophthalmologist will then use a laser to create a small window in the back of the lens capsule.
After the procedure, you can resume all of your normal daily activities.
It can take up to 24 hours for your vision to improve, as the dilation wears off.
As with any surgery, there are some risks and complications that may occur with Yag capsulotomy. Here are some of them:
Retinal detachment. While this is a serious complication, it is believed that less than 0.5% of patients will develop a retinal detachment (Review of Optometry, May 2018).
Elevated pressure within the eye, which may require pressure lowering eyedrops.
The IOL could potentially dislocate from posterior capsule opening.
Mild eye swelling or inflammation may require the use of steroid eyedrops temporarily
While these complications seldom occur, your surgeon will discuss these risks with you before electing to have a capsulotomy. If you feel that your vision is not as good as it was initially after cataract surgery, or that you are having more difficulty with glare at night, please call Eye Physicians and Surgeons to be evaluated for PCO.