SAN FRANCISCO – Experts currently struggling to improve their estimation of intraocular lens power for clients undergoing cataract surgical treatment should look to the cornea, but in the future, postoperatively flexible lenses could be the method to go, professionals claimed at the American Academy of Ophthalmology 2019 Yearly Meeting.
Presently, only 70% to 80% of cataract surgeries are accurate within ± 0.5 D of predicted values. And success rates for complex eyes are even worse.
However “the one point we can do most around, in our technique is the cornea,” he stated.
In 2008, one researcher estimated that effective lens setting represented 35% of errors, axial size made up 27%, and also refraction accounted for 17%.
Yet that has actually changed, because optical biometers– such as optical or swept-source biometry – are more extra precise than those utilized in the past, such that axial size is no more a significant source of error.
Effective lens setting and refraction stay vital elements, but the anterior as well as posterior surfaces of the cornea additionally enter into the mix.
To begin to resolve issues of intraocular lens computation, formulas need to be classified by mechanism: geometric optics, which differ by the number of variables they make use of to compute effective lens setting; ray tracing; artificial intelligence; and also combination solutions.
“The usual objective of all these formulas, one way or the other, is to determine or to compensate the effective lens position,”.
In principle, ray tracing must work best since it integrates all the settings of either the cornea or the implanted lens, yet that has not been the case. Since each region of the eye has a distinct index of refraction, the segmentation of axial sizes can improve precision in both long as well as short eyes.
With a selection of brand-new lens types in advancement, postoperative adjustment will likely come to be mainstream, and, “These are interesting modern technologies to improve our outcomes.”
Laser-induced refractive index modification (LIRIC) study is under development and also “there are clinical tests underway,”. The two-photon strategy has actually functioned in rabbit tests.
Furthermore, “upgraded light-adjustable lens technology just began commercially in Europe with terrific success. I believe it offers wonderful choices to improve refractive outcomes,”.
The brand-new version of the light-adjustable lens (LAL 2.0) is a 13.0 mm, foldable, three-piece silicone lens with improved ultraviolet light absorption implanted with a proprietary injector though a cut less than 2.75 mm wide.
The LAL 2.0 can be adjusted to an extended depth of emphasis, or to correct as much as 2 D of myopia or hyperopia. It can be used to attain independently changed mini-monovision and to cause adverse asphericity.
In a potential trial, the doctors implanted the lens in 100 eyes of 50 individuals with 0.5 D to 3.0 D of preoperative keratometric astigmatism. They discovered that more patients had 20/20 uncorrected distance visual acuity after the lenses were changed than before (73% vs 33%).