OOMC News

The Latest Advancement in Cataract Surgery: Light Adjustable Lenses

April 18, 2022

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Contributing Authored: Ayan Chatterjee, M.D.

Cataracts are one of the leading causes of blindness worldwide, and they occur when the body’s natural lenses become clouded over time. The condition is caused by the protein build-up in the lens, preventing it from sending clear images to the retina. The most common cause of cataracts is a change in the tissue that makes up the eye lens due to aging or injury. According to the National Eye Institute (NEI), more than half of all Americans over 80 have cataracts or have had cataract surgery.

Cataracts are traditionally treated by removing the affected lens and replacing it with an artificial intraocular lens (IOL). Standard intraocular lenses help reverse the effects of cataracts and improve the quality of vision. However, most patients who receive standard intraocular lenses during cataract surgery still need glasses or contact lenses to read or treat astigmatism. Thus, more advanced IOLs have entered the market to correct refractive errors and reduce dependence on corrective eyewear. One such premium IOL is the Light Adjustable Lens (LAL). 

 

Light Adjustable Lens 

Approved by the U.S. Food and Drug Administration (FDA) in 2017, the Light Adjustable Lens is the first and only adjustable intraocular lens that can be customized to refine your vision after cataract surgery. It is adjusted through ultraviolet (UV) light treatments and is designed to improve how well you can see without eyeglasses compared to a basic single focus lens implant. The LAL was designed and developed by Daniel Schwartz, MD, an ophthalmologist at the University of California, San Francisco, and Robert Grubbs, Ph.D., a chemistry professor at the California Institute of Technology. 

Although cataract surgery has advanced over the years, predicting the refractive outcome of the surgery remains difficult. As a result, only about six out of 10 cataract patients achieve their targeted vision. But with Light Adjustable Lens, the prescription can be adjusted after it is implanted, helping patients achieve the clearest far, near, and intermediate vision possible. Patients with LAL are more likely to achieve an uncorrected distance visual acuity of 20/20 at six months than those with a standard IOL. 

 

How Does the Light Adjustable Lens Work?

The LAL contains light-sensitive molecules whose positions can be changed by an external ultraviolet light beam delivered by a slit lamp-based digital light delivery device (LDD). As the shape of the IOL changes, so does its power and can be adjusted for nearsightedness, farsightedness, or astigmatism correction. Your doctor will temporarily provide you with special UV glasses (protective glasses) to wear outdoors to protect the IOL from too much UV light exposure until the procedure is complete.

Most patients may require four adjustments, although some may require fewer or more. The adjustments are performed in an outpatient setting and generally take about 90 seconds per eye. The first customized light treatment is performed two to three weeks after traditional cataract surgery. And additional adjustments are performed at weekly intervals.

Once your optimal vision is achieved, the final lock-in treatments are performed, after which the IOL can no longer be adjusted or changed. After the lock-in, protective glasses will also not be needed. Since the LAL is adjustable post-operation, most patients opt to have both eyes operated on simultaneously with this option. 

 

Recovery From LAL Implantation 

Following the cataract surgery to place the LAL, you must wear protective glasses during all waking hours to protect your eyes from UV light. You may remove them when showering, sleeping, or applying eye drops. 

As Light Adjustable Lenses are designed to react to UV light during the adjustment process, exposure can cause unintended vision changes that make it difficult to properly adjust the LAL with light treatments. Your eyes will also be sensitive to light during the healing period. Thus, glasses are worn indoors and outdoors until your eyes heal and the doctor permanently locks the lens power during the final refractive adjustment. 

 

Pros of LAL  

The most apparent benefit of LAL is its precise and accurate surgical vision correction. Most surgeons consider LAL to be especially suitable for complex refractive issues in eyes after LASIK. In patients who have had previous refractive surgery, the calculations for appropriate intraocular lens power become very difficult and error-prone, as the cornea has been changed forever and no longer fits our standard power prediction models.  But with LAL, we can compensate for these uncertainties in the post-operative period without having to do additional refractive surgery on the cornea. The LAL procedure is also painless and non-invasive, and the results tend to last a lifetime for most patients. 

Some of the other advantages of LALs include:

  • Simplifies pre-operative decision-making regarding the type of lens required, as eye power is optimized according to the visual outcome after surgery. 
  • Eliminates the need for pre-operative axis marking for astigmatism, multiple advanced formulae for accurate biometry, intraoperative aberrometry, and wavefront aberrometry. 
  • Allow patients to use trial and error to preview various lens powers in front of the eye, just like prescription eyeglasses.
  • Minimizes the error from inaccurate biometry, power calculation, and post-implantation IOL movement. In toric IOL, about 8-18% of cases showed a post-op rotation of more than five degrees even after carefully calculating posterior corneal astigmatism, surgically-induced astigmatism, pre-operative and inoperative digital alignment. Using LAL to correct astigmatism three weeks after surgery when the eye is completely healed helps avoid most of these problems. 
  • Requires only a short interval between the primary surgery and the final adjustments to the eye’s refractive power. Unlike other procedures such as PRK and LASIK, light-assisted optic adjustments are initiated at three weeks post-operation. 

 

Cons of LAL 

One of the main disadvantages of LALs is the time commitment required. Although the treatments are relatively quick and are done in a minute or two, you will have many post-operative visits and specialized light treatments after surgery. And since you will also need to be refracted and dilated, each visit may also take a while. 

Some of the other drawbacks of this advanced intraocular lens implant include:

  • Since LALs are premium IOLs, they tend to be more expensive than other artificial lens implants. They are also not covered by health insurance, including Medicare and PPOs, and must be paid out-of-pocket by the patient. 
  • The procedure can be challenging during poor pupil dilation. Since light adjustments require a full view of the lens optic, the pupil is dilated to a minimum of 6.5 to 7 mm. If not, a portion of the lens periphery may remain behind the iris containing untreated macromers. 
  • Corneal astigmatism can change over time, affecting the permanence of the vision provided by the LAL. A proposal has been made to combine adaptive optics with LAL to overcome this barrier and achieve patient satisfaction, which will allow the device to identify and compensate for optical distortions. 
  • If the cornea is irregular to the point that it requires a rigid gas-permeable contact lens, the LAL will not be able to correct all aberrations in the cornea shape. Furthermore, no IOL can compensate for having other eye health issues, such as glaucoma, macular degeneration, or diabetic retinopathy. However, since the LAL has a good optical quality and does not have rings, it can still be an appropriate option for those with co-existing eye problems. 

 

Will I Still Need Eyeglasses With LAL?

Most patients with LAL will still need corrective eyewear, especially when reading small prints. And if both eyes are set for distance vision, they will need eyeglasses for other close-up activities. Nevertheless, the LAL improves the depth of focus, implying that it provides more range of vision than the standard single focus lens. 

Most patients can obtain a good range of visual acuity with the LAL if they opt to have one of their eyes slightly nearsighted. However, if a patient finds it difficult to adjust to this difference, they can have it reversed with a second UV light treatment. Although the LAL does not provide as much near range as a multifocal lens, it does not cause additional glare, starbursts, or night-time halos as it does not have rings. 

 

Who Can Have Light Adjustable Lenses?

Cataract surgery with LAL is perfectly safe and poses no significant medical risks. And up to 4.5 diopters of cylindrical or spherical adjustment can be achieved with the LAL. However, not everyone is suitable for this premium IOL. 

Eligible patients for vision correction with LAL include those who:

  • Have pre-existing astigmatism 
  • Do not have a history of herpes eye infections or uncontrollable eye movements (nystagmus)
  • Do not use medications that are known to cause retinal damage 
  • Do not use medications that can increase sensitivity to UV light 

The best way to determine if LAL is right for you is to discuss your unique goals and concerns with an experienced eye doctor. 

The Light Adjustable Lens is a recent development in cataract surgical technique, which has proven to be a safe, accurate, and reliable approach to post-operative, non-surgical correction of residual refractive error. However, how much it affects the delivery of refractive surgery in the U.S. is yet to be seen.

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