Long-term stability of light adjustable intraocular lenses

J. Marín, E. Rubio Velazquez, E. Villegas, E. Alcon, P. Artal
Purpose: Light adjustable intraocular lenses (LALs) provide optimum optical and visual outcomes by refining the lens refraction after surgery by UV irradiation. Although the photosensitive material is locked, a possible issue could be the lens stability after years of patients’ exposure to ambient UV light. We measured optical and visual outcomes in a group of patients implanted with LALs during a continued period of four years after surgery.
Methods: Forty-three eyes were implanted with LALs (Calhoun Vision, Pasadena, USA). Two weeks after surgery, the implanted lenses were irradiated with appropriate spatial intensity profiles to correct the patients’ refractive errors. After the adjustment procedures, two photo-locking treatments were performed to ensure that the LAL was fixed. Wavefront-guided refraction was determined for every eye during the entire adjustment process and during the follow-up visits. Visual acuity (VA) was measured using a computer-assisted procedure. Series of measurements were performed 1, 3, 6, 12 months and 4 years after the surgery. Safety, efficacy, predictability and stability of the whole procedure were also evaluated.
Results: There were not significant differences in values of refraction (sphere and cylinder) and VA (corrected and uncorrected) between follow-ups (p-value > 0.05). Uncorrected VA was equal or higher than 20/25 in 75% of the tested eyes and the mean spherical equivalent was stable and around zero after four years of surgery and light treatments. The safety and efficacy indexes were 1.21±0.33 and 0.96±0.30 respectively. Three eyes (7%) developed posterior capsule opacification during the four years and none reported a significant endothelial cell loss.
Conclusions: Refractive and visual outcomes in patients implanted with LALs remained stable for a period of four years after surgery. This indicates that the lenses are optically stable and not affected by ambient light after proper photo-locking. Typical post-cataract surgery complications were similar than to other standard lenses. This demonstrates the excellent visual outcomes after surgery are maintained over time.