Cataract Q & A
What is a Cataract?
Many people think that a cataract is something that grows inside the eye. That is incorrect. Humans are born with a crystalline lens inside of the eye. Normally, the lens focuses light onto the retina. A cataract is when the crystalline lens becomes opacified or cloudy over time. Think of it as a “window” in the eye, one that has become dirty and can not be cleaned. The clouding may be uniform and thus dim vision (like sunglasses), or it may be patchy and scatter light. Cataracts that scatter light tend to cause more visual difficulty. In general, the denser the opacification, the blurrier vision becomes. While the cause of age-related cataracts is not fully understood, they are related to increased exposure to sunlight and aging – two things that are difficult to avoid. They can progress more rapidly or occur earlier in life if you are diabetic, have myopia, or have a history of cigarette smoking.
When Should a Cataract Be Removed?
There are two reasons to remove a cataract. First, the cataract is interfering with quality of life, e.g., driving is compromised, reading is difficult, daily tasks such as walking are difficult. A recent study showed that seniors with un-operated cataracts were twice as likely to be involved in accident that results in a fatality than patients who have had their cataracts removed.1 Thus, if you drive and your cataract either causes a visual loss of 20/40 or worse; and/or significant glare we suggest that the cataract be removed.
The other reason to remove a cataract is that the doctor can not get a good view of the back of the eye. This is important in diseases such as glaucoma, diabetes, and/or macular degeneration. Medically it doesn’t make much difference when you take out the dirty “window” and replace it with a new “window”. However, it should also be kept in mind that it is surgically easier to remove a softer, less dense cataract than one than has become overly ripe or hard. Thus, the complication rate is less with an earlier cataract.
How is a Cataract Removed?
Cataracts are removed using a surgical technique called cataract extraction. Cataract extraction consists of removing the dirty “window” and replacing it with a clean new one.
First, the eye and surrounding areas are numbed using eye drops or a numbing injection. The steps to cataract surgery are as follows:
- Entry incisions: One or two small incisions a few mm wide are made into the cornea to allow access to the cataract.
- Capsulorhexis: The anterior capsule (the outer lining of the cataract) must be opened carefully so that the cataract inside can be accessed and fragmented.
- Lens fragmentation and removal: The lens is traditionally broken into small pieces using either manual forceps or a technique called phacoemulsification. Phacoemulsification uses ultrasound energy to fragment the lens. Newer techniques using a laser to break up the lens can reduce the amount of inflammation and swelling in the eye after surgery. Once the lens is fragmented, it is removed using suction.
- Lens implantation: Once the cataract has been removed, an intraocular lens (IOL) implant is inserted into the capsule inside the eye. The power of the IOL has been carefully chosen by the surgeon through measuring the front curvature of the eye (topography) and the length of the eye (axial length) to provide optimal vision.
After the surgery: The incisions are self-sealing and rarely require sutures or stitches. The eye is patched and the patient is able to return home that night. Patients are seen the next day in office for the patch to be removed. Patients are then on antibiotic and anti-inflammatory drops for around four weeks to allow for full healing of the eye.
Surgery has improved tremendously in the last 15 years. In the old days the whole lens was removed, which dragged on the jelly of the eye (vitreous), which in turn pulled on the retina. The result was a significant number of retinal detachments and thick glasses. This has all changed with modern cataract surgery.
Will My Cataract Grow Back?
No, a cataract will not grow back. However, the lens capsule may opacify and begin to cause similar symptoms to a cataract. This is called a posterior capsule opacification. It is easily treated using an in-office laser.
Will I Need Glasses After Cataract Surgery?
Traditionally, cataract surgery corrected patients for one focal point. For example, patients would achieve good distance vision, however they still required reading glasses or vice-versa. While this option provides patients with good vision, they are still highly dependent on glasses or contact lenses to see.
In the past decade, the FDA has approved of a new design of IOLs called “multifocal” IOLs that provide increased range of vision. Patients are able to perform activities at different ranges of distance without the need for glasses. These IOLs lenses have a series of rings of varying powers which correct for close, distant, and intermediate vision. One is call ReStor which provides for good distance and excellent reading vision, with limited intermediate vision; another is called ReZoom which provides excellent distance with good intermediate and fair near vision; a third is called Crystalens which actually restores some accommodation or focusing to the patient (the down side is that it takes awhile to work, and is limited in its restoration abilities; its advantage is that the optics are excellent). Sometimes, we use a combination of ReStor, ReZoom, or Crystalens.
Another alternative is mono-vision, where one eye is corrected for near and the other for distance. With monovision, most patients find good range of vision for the majority of their visual tasks and only occasionally need to put on a mild prescription for enhanced reading or distance vision.
During your cataract consultation with the team at Cooper Eye Care, your eye care professional will help determine the best option for you.
Are All Surgeons the Same?
Absolutely not. Though the majority of patients obtain a good result with most surgeons. The best surgeons perform “quieter surgery” with less disturbance to the eye. The result is quicker healing with less long-term complications. The best surgeons are also experienced with the newest technologies such as multifocal IOL implants and femto-second laser-assisted cataract surgery.
- Owsley C, McGwin, Jr G, Sloane M, Wells J, Stalvey BT, Gauthreaux S. Impact of Cataract Surgery on Motor Vehicle Crash Involvement by Older Adults. JAMA. 2002;288(7):841–849. doi:10.1001/jama.288.7.841
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