WHAT IS A CATARACT?
The lens in the eye can become cloudy and hard, a condition known as a cataract. Cataracts can develop from normal aging, from an eye injury, or if you have taken medications known as steroids. Cataracts may cause blurred vision, dulled vision, sensitivity to light and glare, and/or ghost images. If the cataract changes vision so much that it interferes with your daily life, the cataract may need to be removed. Surgery is the only way to remove a cataract. You can decide not to have the cataract removed. If you don’t have the surgery, your vision loss from the cataract will continue to get worse.
HOW WILL REMOVING THE CATARACT AFFECT MY VISION?
The goal of cataract surgery is to correct the decreased vision that was caused by the cataract. During the surgery, the ophthalmologist (eye surgeon) removes the cataract and puts in a new artificial lens called an intraocular lens or IOL. The IOL will be left in the eye permanently. Cataract surgery will not correct other causes of decreased vision, such as glaucoma, diabetes, or age-related macular degeneration. Most people still need to wear glasses or contact lens after cataract surgery for either near and/or distance vision and astigmatism.
EXAMINATIONS PRIOR TO SURGERY
If you agree to have the surgery, you will undergo a complete eye examination by your surgeon. This may include an examination to determine your eyeglass prescription (refraction), measurement of your vision with and without glasses (visual acuity), measurement of the pressures inside your eye (tonometry), measurement of the curvature of your cornea (keratometry), ultrasonic measurement of the length of your eye (axial length), intraocular lens calculation (biometry) to determine the best estimate of the proper power of the implanted IOL, microscopic examination of the front part of your eye (slit-lamp examination), and examination of the retina of your eye with your pupils dilated.
NEED TO STOP WEARING CONTACT LENSES PRIOR TO SURGERY
If you wear contact lenses, you must leave them out of your eyes for a period of time before your preoperative eye examination and before your surgery. This is done because the contact lens rests on the cornea and distorts its shape, which can affect the accuracy of the doctor’s measurements of the IOL power. When you stop wearing your contact lenses, the corneas can return to their natural shape. Stop wearing both soft and rigid (including gas permeable and standard hard) contacts for at least three weeks. If you wear rigid contacts, your vision will usually vary for a while as your corneas change shape. Although the cornea usually returns to its natural state within three weeks, this process may take longer, and you will need to remain contact lens free until your vision and cornea stabilize.
MORE INFORMATION ABOUT MEASURING YOUR IOL
While the method used to calculate the power of the IOL is very accurate in most patients, the final result may be different from what you and your surgeon planned. As the eye heals, the IOL can shift very slightly toward the front or the back of the eye. The amount of this shift is not the same in everyone, and it may cause different vision than predicted. If the eye’s visual power after surgery is considerably different than what was planned, surgical replacement of the IOL might be considered. It is usually possible to replace the IOL and improve the situation. Patients who are highly nearsighted or highly farsighted have the greatest risk of differences between planned and actual outcomes. Patients who have had LASIK or other refractive surgeries are especially difficult to measure precisely.
PRESBYOPIA AND ALTERNATIVES FOR NEAR VISION AFTER SURGERY
Patients who have cataracts have, or will eventually develop presbyopia, which is a condition caused by aging that develops when your eye loses its ability to shift from distance to near vision. Presbyopia is the reason that reading glasses become necessary, typically after age 40, even for people who have excellent distance and near vision without glasses. Presbyopic individuals require bifocals or separate (different prescription) reading glasses in order to see clearly at close range. There are several options available to you to achieve distance and near vision after cataract surgery. This is probably the most important decision you need to make about your cataract surgery, so please take the time to review your options and ask questions.
GLASSES: You can choose to have a monofocal (single focus) IOL implanted for distance vision and wear separate reading glasses, or have the IOL implanted for near vision and wear separate glasses for distance.
MONOVISION: The ophthalmologist could implant IOLs with two different powers, one for near vision in one eye, and one for distance vision in the other eye. This combination of a distance eye and a reading eye is called monovision. It can allow you to read without glasses. Many patients who wear contacts or who have had refractive surgery have monovision and are happy with it. Your surgeon will discuss and demonstrate this option to see if it might work for you.
MULTIFOCAL IOL: The ophthalmologist could implant a “multifocal” IOL. This is a newer, “deluxe” type of IOL that provides distance vision AND restores some or all of your eye’s ability to focus. It corrects for both distance vision and other ranges, such as near or intermediate. Choosing this option will usually lead to higher out-of-pocket expenses since most insurance companies only pay for a monofocal (single focus) lens.
MORE INFORMATION ABOUT MONOVISION
In order to have good depth perception, your eyes need to be corrected for any refractive problems such as nearsightedness or farsightedness, and "balanced" for distance. Eye care professionals refer to this as binocular vision. Monovision or “blended” vision can impair depth perception to some extent, because the eyes are not focused together at the same distance. It is important to choose which eye you will use for distance vision. Eye surgeons generally believe that one eye is the dominant one, preferred for viewing. This is similar to people being right- or left-handed. Several tests can be performed to determine which eye is dominant in a particular person. With monovision, the dominant eye is usually corrected for distance, and the non-dominant eye corrected for near. However, a very small percentage of persons may be co-dominant (this is similar to being ambidextrous). In rare circumstances, a person may actually prefer using the dominant eye for near viewing. Your doctor will discuss and try to demonstrate monovision with glasses or even contact lenses to simulate the type of vision you will have after cataract surgery. Because your vision is decreased by the cataract, it is not possible to show you exactly what your postoperative vision will be like. If you would prefer not to have to wear glasses for quick tasks like looking at your cell phone, a menu, a computer, or an invoice, then you might be interested in monovision. Most monovision patients will often be more comfortable wearing glasses to balance their vision for prolonged reading tasks or for driving (especially at night), or for sports like tennis or golf, so you will most likely still need to wear glasses even with monovision. If you have been wearing contacts lens for monovision, you will most likely be happy with this option after cataract surgery. Although many patients will adjust well to monovision, some may find it uncomfortable. For those patients, the monovision can usually be reversed by elective laser vision correction, but this surgery will not be covered by your medical insurance.
INFORMATION ABOUT TREATING ASTIGMATISM
Patients with nearsightedness and farsightedness often also have astigmatism. An astigmatism is caused by an irregularly shaped cornea; instead of being round like a basketball, the cornea is shaped like a football. This change in shape can make your vision blurry. There are several treatment options for astigmatism: 1) you can have an IOL for near or distance vision and continue to wear glasses or contact lens for the astigmatism; 2) you can have a toric IOL placed in your eye, 3) you can have refractive surgery called LASIK or PRK, or 4) your surgeon can perform a procedure before, during, or after cataract surgery called a limbal relaxing incision. A limbal relaxing incision (LRI) is a small cut or incision the ophthalmologist makes into your cornea to make its shape rounder. More than one incision may be required.
ANESTHESIA, PROCEDURE, AND POSTOPERATIVE CARE
The ophthalmologist or the anesthesiologist/nurse anesthetist will make your eye numb with either drops or an injection (local anesthesia). You may also undergo light sedation administered by an anesthesiologist or nurse anesthetist, or elect to have the surgery with only local anesthesia. There are risks associated with anesthesia and sedation. These include injury to the eye, heart and breathing problems, and in very rare cases, death.
An incision, or opening, is then made in the eye. This is at times self-sealing but it may require closure with very fine stitches (sutures) which will gradually dissolve over time. The natural lens in your eye will then be removed. There are several ways to remove the lens; the most common technique is called phacoemulsification, which uses a vibrating probe to break the lens up into small pieces. These pieces are gently suctioned out of your eye through a small, hollow tube inserted through a small incision into your eye. After your natural lens is removed, the IOL is placed inside your eye. In rare cases, it may not be possible to implant the IOL you have chosen, or any IOL at all.
Your eye will be examined the day after surgery by your surgeon or an eye doctor chosen by your surgeon, and then at intervals determined by your surgeon. During the immediate recovery period, you will place drops in your eyes for about 2 to 4 weeks, depending on your individual rate of healing. If you have chosen monovision or a multifocal IOL to reduce your dependency on glasses or contacts, they may still be required either for further improvement in your distance vision, reading vision, or both. You should be able to resume your normal activities within 2 or 3 days, and your eye will usually be stable within 3 to 6 weeks, at which time glasses or contact lenses could be prescribed.