By Altos Eye Physicians
The Light Adjustable Lens (LAL) is an intraocular lens (IOL) whose power can be adjusted several weeks after cataract surgery. The technology is designed to improve how well you see without eyeglasses compared to a basic single focus lens implant.
Dr Chang explains the LAL
What is the advantage of the light adjustable lens over other IOLs?
Every other IOL comes in a fixed range of powers, and preoperative calculations are performed to assist the surgeon in estimating the lens power to use for your eye. Preoperative eye measurements are plugged into several IOL formulas, which estimate the IOL that is most likely to hit the target that you select with your cataract surgeon. As you might expect, these prediction formulas are not perfectly accurate for every patient because of individual differences in eye anatomy and healing.
Certain factors may make IOL power selection much less accurate, such as a history of prior refractive surgery like LASIK, PRK, or RK (radial keratotomy). Others are born with an unusually flat or steep cornea. An adjustable IOL may be especially beneficial for these situations. Those who want some degree of monovision—using one eye for distance and the other for near—will enjoy the precision of the LAL because of its ability to fine tune each eye for its optimal target.
How does the light adjustable lens work?
The LAL contains molecules that are light-sensitive. Their distribution and position can be adjusted by an external UV light beam, which alters the shape of the IOL without requiring additional surgery. As the shape of the IOL changes, its power changes, which can adjust for astigmatism, nearsightedness, or farsightedness. We provide special UV blocking sunglasses for you to wear temporarily to protect the IOL from receiving too much UV light until the adjustment process is complete.
The postoperative adjustments are painless and take less than 2 minutes. They are performed in our office, where we use a light delivery device to send the beam that reshapes the IOL. The first customized treatment is typically performed several weeks after the cataract surgery when the vision has stabilized. Additional adjustments are performed at approximately weekly intervals as determined by the doctor. It is possible to make up to 3 adjustments, although some eyes require only one. When the result has been optimized, 2 final “lock-in” treatments are performed, after which the IOL can no longer change or be adjusted. After lock-in, no extra protection is needed for sunlight or UV light; there is no need for any other special precautions or follow-up . Because the LAL is adjustable postoperatively, many patients elect to have both eyes operated on at the same time (or a few days apart) with this option.
What is astigmatism?
Like nearsightedness or farsightedness, astigmatism describes a common type of natural blur in healthy eyes that is corrected by wearing eyeglasses. It results from an inherited, imperfect optical shape of the cornea, the clear front window of the eye. The more astigmatism one has, the more optically blurry the vision is without eyeglasses. There is no advantage to astigmatism because it adds blur to every focal distance. Corrective eyeglasses and contact lenses can compensate for this corneal shape to correct this blur and to focus eyes with astigmatism properly.
Astigmatism can be reduced or nearly eliminated at the same time that cataract surgery is done. Traditionally, this is done by building the astigmatism correction into the artificial lens, which is called a toric lens implant. The LAL has the advantage of being able to provide customized astigmatism correction after your eye has healed, giving more precision. For this reason, it can provide the most accurate final outcome. Although it can increase slightly in some eyes with age, astigmatism won’t go away on its own; therefore, the benefit of the LAL should be life-long.
Will I still need eyeglasses with the light adjustable lens?
Most patients will still need glasses in some situations with the LAL, usually for reading small print. However, the LAL can provide “depth of focus,” meaning that it gives more range of vision than the basic single focus lens. Unlike a multifocal lens, the LAL does not have rings, so it does not cause additional glare, starbursts, or halos at nighttime. If you choose to set both eyes for distance vision, you will need glasses for reading and other near activities. However, many patients will obtain good range of vision with the LAL by choosing to focus one of eye slightly closer than the other. If someone cannot adapt to this slight difference, it can be reversed with a second LAL adjustment.
Unlike all other IOLs currently available, the LAL allows patients to experience what their vision is like without corrective lenses and after cataract removal before deciding whether they want to change it. If the goal is to have one eye focused closer than the other, it allows the patient to choose the sweet spot where the eye has enhanced near function without making the distance vision too blurry. Patients who have done this with contact lenses know that they could switch contact lens powers to bring the focus of one eye closer to find that sweet spot.
Some patients, such as those with prior LASIK, PRK, or RK, have irregular corneas, meaning that the shape of the window in the front of their eye is asymmetric. If your cornea is irregular to the point that you need a rigid gas permeable (“hard”) contact lens, the LAL will not be able to correct for all your imperfections in cornea shape. Also, no IOL can compensate for having other issues with your eye health, such as glaucoma, macular degeneration, or diabetic retinopathy. Because the LAL does not have rings and does not split light, however, it still can be an appropriate choice for those with co-existing eye problems because it has outstanding optical quality.
What are the risks or disadvantages to the light adjustable lens?
Cataract surgery with the LAL poses no additional medical risk and is perfectly safe. The surgery is performed in the usual manner through a small incision. However, some patients are not eligible to receive this IOL, such as if their pupils do not dilate widely enough. Your surgeon will determine this at the time of your consultation.
Because of the expensive in-office technology needed to offer the LAL, its availability is more limited. In 2019, we became the first practice in Northern California—and one of the first in the United States—to offer the LAL, which has given us extensive experience with this unique technology.
Of all the special artificial lens implants, the LAL is the most expensive upgrade because it is basically a lens that becomes customized for your individual eye. Health insurance, including Medicare and PPOs, covers the costs of cataract surgery with a basic single focus lens implant. However, the additional charge for implanting and adjusting the LAL is not covered and must be paid out-of-pocket by the patient. Remember that the benefit of the LAL is to improve your natural eyesight without eyeglasses. The lenses are not “medically necessary” because they have nothing to do with improving your eye health.