Light Adjustable Lens performs well in post-RK eyes
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The Light Adjustable Lens performs well in post-RK eyes, with good results that remain relatively stable over time, according to one presenter.
“In post-RK eyes, IOL power is even tougher to predict than after LASIK or PRK, even with the best of our tools,” James D. Lehmann, MD, said at the virtual American Academy of Ophthalmology annual meeting.
The small optical zones, the presence of irregular astigmatism and the altered anterior-to-posterior corneal ratio affect IOL calculation, so that refractive accuracy is achieved in these eyes in no more than 50% to 69% of the cases reported in the literature, he said.
The LAL (RxSight) is a silicone lens with a special macromere matrix that is photopolymerized upon exposure to UV light. The lens power is adjusted in the month after cataract surgery until the desired refraction is achieved and eventually locked in by re-irradiation. The lens has been shown to work well in normal corneas and was approved in 2018 after the phase 3 FDA trial in which 92% of patients achieved 20/20 and were within 0.5 D of refractive target.
“In our study, we investigated how the LAL works in post-RK eyes, both in the short and long term. Since June 2019, when this lens became commercially available, we have treated over 150 eyes. In a retrospective review, we selected those that had previous RK, a total of 23 eyes of 14 patients,” Lehmann said.
The mean absolute error after surgery but before adjustment was 0.94 D, and 48% of eyes were within 0.5 D.
“This is how they would be with a normal lens. After adjustment, 5 weeks after surgery, all eyes but one (95.7%) were within 0.5 D, and mean refractive error was 0.27 D,” he said.
A slight decrease was observed in the longer term, at a mean of 40 weeks, when mean refractive error was 0.43 D, and 78% of eyes were within 0.5 D. In the 17 eyes with a mean follow-up of 1 year, there was an average spherical equivalent shift of only –0.13 D and an absolute value shift of 0.27 D.
“We all know about the refractive instability of RK eyes. These results were still good and definitely better than the published data,” Lehmann said.
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Lehmann JD. Refractive outcomes of a light-adjustable IOL in cataract patients with a history of RK. Presented at: American Academy of Ophthalmology annual meeting; Nov. 13-15, 2020 (virtual meeting).
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