25 Feb Light Adjustable Lens IOL
History and FDA Approval of the Light Adjustable Lens IOL
The Light Adjustable Lens IOL gives the highest level of accuracy attainable after cataract surgery. This has been a God send for perfectionist doctors like me and for patients that would highly prize accuracy in their outcomes. Prior to the advent of the Light Adjustable Lens (LAL) we had longed for an intra-ocular Lens (IOL) that could be adjusted after the surgery to obtain great precision. Work began on the creation of an adjustable IOL in 1996 as a project between Robert Grubbs, Nobel laureate in Chemistry, and Daniel Schwartz.1 The first published paper showing practicality and safety of the concept was published in 2003.2 The FDA finally approved the LAL in 2017 after extensive testing over many years.3
How Does the Light Adjustable Lens IOL Work?
The light adjustable lens works through the principles of polymerization and diffusion. Molecules in the IOL called macromeres are designed to be photosensitive to UV light. When UV light is precisely shined on a specific area of the IOL, the photosensitive macromeres in that part of the lens connect into longer chains in a process called “polymerization.” Other non-treated macromeres in the areas of the IOL not treated then diffuse into that region causing the lens to become thicker in that area. This changes the power of the lens in a predictable manner. The treatment patters allow for treatment of up to 2.0 diopters of residual myopia, hyperopia, or astigmatism.
If the UV light is shined on the entire IOL, then all the macromeres polymerize at the same time. No diffusion occurs and the lens is then “locked” and not further changes can be made to the IOL power.
We provide special glasses that block UV light to LAL patients for wear from the time of surgery until their final lock in treatment to prevent UV light from the sun from prematurely causing power changes in the IOL.
Adjusting the LAL
About four weeks after your surgery, your prescription will be checked. Your eyes are then dilated and the glasses prescription is then programmed into the RxSight LAL treatment station which looks a lot like the slit lamp used to examine your eyes in a standard eye exam. You rest your chin on the chin rest. A lens is placed to improve focus and the doctor engages the treatment light for 30 to 120 seconds. This procedure is carried out for both eyes.
2. HC E, inventor Harry C Eggleston, assignee, Adjustable and removable intraocular lens implant, US patent 1997.
3. Schwartz DM, Light-adjustable lens, Trans Am Ophthalmol Soc, 2003;101:417–36.