The main function of the lens is to focus light as it enters the eye allowing us to see clearly at both distance and at near.
Presbyopia
The initial change that occurs in the lens is the loss of elasticity of the fibers making up the lens. This elasticity normally allows the lens to change shape, called accommodation, which moves the focus of the eye from distance to near. Starting at about age 40, the loss of elasticity begins, known as presbyopia, and focusing on near objects becomes increasingly difficult. Once our arms can’t extend far enough out to bring things into focus, the use of reading glasses or bifocals become necessary to aid in near vision.
Cataract surgery today is much different than cataract surgery your parents or grandparents may have gone through. It is a quick 8-10 minute day surgery done in an outpatient surgery center using only mild anesthesia. Recovery is quick and getting back to your regular routine occurs within days.
Technological advancements have significantly increased the precision and safety of the surgery and have provided patients with many options for their post-operative vision.
Today’s cataract patient has many lens options to choose from depending on their lifestyle needs and how much independence they want from glasses. I would like to briefly review these lens options so that you may know your options fully in order to make the best personal decision for your vison and your lifestyle.
Cataract surgery involves removing the cloudy lens. Because the eye needs a lens to function properly, an artificial lens is implanted to replace the cataract lens that is removed. This lens is not like a contact lens as it is placed inside the eye behind your iris. You are not even aware it is in your eye other than the fact you can see clearly.
During your cataract evaluation, measurements will be taken of your eyes and sophisticated calculations performed using those measurements to estimate what power of lens needs to be implanted in each eye to give you the best vision. Because of new technology, patients have significantly more control over what their postoperative vision is like.
Basic cataract surgery starts with removing the cataract. Using a conventional lens, myopia (near-sightedness) or hyperopia (far-sightedness) can be corrected fairly well giving the patient a 75% chance of not needing distance glasses after surgery if there is no astigmatism or other issues affecting the focus of the eye. When using this lens, reading glasses and/or a bifocal will be necessary.
One option with this lens is monovision. If you are familiar with monovision and have tried it successfully with contact lenses, then monovision can be targeted with a conventional lens. With monovision, one eye is focused for distance and one eye focused for near, thus minimizing your need for glasses. Your eyes must be in perfect health to try this and there is still a chance post-operative glasses will be necessary for certain things.
Some patients have astigmatism which is a focusing problem causing blur due to an irregularly shaped cornea and/or lens. Glasses and contact lenses can correct this but the standard monofocal lens does not. A Toric lens can be used to help correct astigmatism at the time of cataract surgery while also correcting myopia (near-sightedness) or hyperopia (far-sightedness). For those with astigmatism, the Toric lens provides about a 75% chance of not requiring a glasses prescription for distance vision. 25% of patients will likely need some distance correction and all will still require reading glasses or a bifocal.
The AcrySof IQ Vivity IOL has been engineered to deliver an extended depth of focus to patients wanting to lessen their need for computer glasses without the possible side effect of glare or halos around lights that are common with the PanOptix lens and other multifocal lenses. With this lens, the distance focus is as good as the other monofocal lenses but with the benefit of better computer distance vision without glasses. These patients have about an 85% chance of not needing glasses at arm-length and a 50% chance of functional vision at near with good light.
The Alcon PanOptix lens is the first and only trifocal lens that is designed in a way to correct the patient’s vision at all 3 visual planes: near, far, and intermediate (computer) distance. This lens works very well allowing about 80% of patients choosing this lens to be glasses free for everything. About 20% of these patients still need glasses for one of the 3 distance planes, most commonly the far distance. Because of the design and technology of the lens, many people will notice halos around lights, particularly at night, but most are not bothered by them. In fact, 99% of patients say they are very happy with this lens choice, and they would choose this lens again.
With all of the above lenses, measurements are taken prior to surgery and lens calculations are performed using those measurements to predict what power of lens will function the best in the patient’s eye. Once the lens is implanted, no further changes can be made to the lens and any residual vision blur will need to be corrected with glasses or contact lenses.
The Light Adjustable Lens (LAL) offers customization to the patient and results that are unmatched by any other lens.
With the LAL, typical preoperative measurements and calculations are performed and routine cataract surgery is completed with the implantation of the LAL. After the eye has healed for 3-4 weeks, UV light treatments are performed to fine tune the focus of each eye. 1-3 treatments are performed on each eye after surgery to adjust the focus of the lens followed by 2 lock-in treatments that prevent any further change in the lens.
This gives the patient a chance to try out their vision while adjustments can still be made. Those patients who select the LAL are twice as likely to achieve 20/20 vision at 6 months without glasses as those who receive a standard monofocal lens.
Since we can alter the power of the lens AFTER surgery, many patients have great success using this monofocal lens to obtain a functional level of near vision in one eye without compromising the distance vision, thus freeing them from glasses use in most situations. By having the opportunity to try out your vision and adjust the focus, the LAL provides a level of customization that no other lens can provide.
Cataract surgery only needs to be performed one time on each eye. The artificial lens implanted does not “go bad” or cloud over. However, posterior capsule opacification may develop and create symptoms similar to cataract formation. About 25% of patients may develop clouding or opacification of the back surface of the capsule anywhere from a few months after cataract surgery to many years later.
The natural anatomy of the eye includes a lens that is inside a clear bag or sack that is suspended centrally behind the pupil with zonules. Zonules are like the springs on a round trampoline and they hold the lens tightly in place.
During cataract surgery, your surgeon creates a 5mm central round opening in the front part of the capsule in order to remove the cataract within. Once the cataract is gone, the artificial lens is implanted into that capsular bag to be held in place forever. The cataract cannot ever come back, but if you develop PCO, that can be just as problematic to your vision and may need to be treated.
Thankfully, the treatment for PCO is not surgical. It involves a quick, painless YAG laser procedure that takes about a minute. Using a specifically designed laser, a small opening is created in the back surface of the capsule where the opacification has developed. Light can then pass through that opening and vision is restored. This opening is large enough to clear the vision but not so large that the lens can escape from the bag.
The YAG laser procedure is incredibly safe and effective. Most patients do notice floaters immediately following the procedure, but these are temporary and will dissipate over the next 1-2 weeks. There is a minimal chance of more serious complications such as a retinal detachment and lens dislocation, but the benefits usually far outweigh the risks.
There are no medications or restrictions after this treatment and, like cataract surgery, only needs to be performed once per eye if posterior capsule opacification develops.
© 2024 McCarty Eye. Website By Nobox Creative
