Who is the best candidate for light adjustable lenses?

Jack Chapman, MD, managing partner at North Georgia Eye Associates, an EyeSouth Partners affiliate practice, gives additional overview on identifying the best candidates for the light adjustable lens, optometrists' role in lens fitting, and how lock-in periods work for the lenses in an Optometry Times interview.

Video transcript

Editor's note: This transcript has been lightly edited for clarity.

Jack Chapman, MD:

Starting out, in order for someone to be a candidate for the light adjustable lens, they have to have at least equal to or greater than .75 diopters of astigmatism. Coming in and having the optometrist nail that refraction, get it right on the first time that the patient wants, and getting it done so that when you bring the patient into the [Light Delivery Device, or] LDD machine, then you put the lens on. You dial in that prescription, and you're going to have that low level ultraviolet light that's going to shape that lens. Somewhere around 350 nanometers is the wavelength that it responds at, allows to be able to shape that lens, both for the stigmatism in the sphere that you need to be able to make that first adjustment [and] be right where you need to be on that.

As we all know from our optics days, that if you have astigmatism, you got to be able to control that or else the astigmatic patient can take you down and put you into an area of spherical equivalent, or into the circle of coronoid, which gives you that spherical equivalent and doesn't get the full astigmatism. That's where that's got to be nailed down. The first one to be able to have the others be more successful [makes it] easier to accomplish the goal that you want to.

Our optometrists come in, and we have 1 that's been trained and understands and does a fantastic job of not only communicating well with the patients but being able to nail that first refraction and get that done out of the out of the gate. Interestingly enough, the adjustment that tends to be the most critical you would think would be distance, but we're able to nail the distance pretty much with the first adjustment. It's the near that people come in with. We figure where their near is and when they go and try it out, test drive it at home, they come back and say, "Oh, well, I'd like to have a little bit more up close, or I'd like to have a little bit more pushed out." And so it tends to be the near eye most of the time that we end up doing the second and third adjustment.

On the back end, there's 2 lock-in periods that have to be done to be able to freeze that lens where you are. During all of this, the patient is wearing glasses. We give them clear ones and we also give them sunglass ones that filter out that ultraviolet light so they don't get a stray ultraviolet light, causing that material to be sharpened in a misshapen way, if you will, to give us a correction. That's not what we want.

There is a reported case out there. I haven't seen it, but I heard about it, of a person who was in that period who went to a tanning bed and went through a tanning bed. Of course, the lens went haywire and ended up having to have the lens taken out and another 1 put in, so that's an extreme case. We warn all of our patients not to go to a tanning bed. Other items that we look for are patients that are on any medications that may make them sensitive to light. Because anything that may make them sensitive to light, then they can have a negative response in the retina from the treatment of the ultraviolet light. We always look for that as well.