JCRS Highlights

MULTIFOCALS AND ASTIGMATISM Unhappy multifocal intraocular lens (IOL) patients report such problems as glare, halos and reduced contrast. Patients also complain of substandard near or intermediate vision, where uncorrected astigmatism could play a role. A new rotationally asymmetric multifocal IOL appears to provide good visual acuity, even in the presence of varying amounts of residual refractive astigmatism or corneal astigmatism. McNeely and colleagues report a retrospective comparative case series in which 117 patients had been implanted with the Lentis Mplus LS-312 MF30 IOL. They evaluated the postoperative degree of tolerance towards different magnitudes of residual refractive astigmatism and corneal astigmatism, and the angles of corneal astigmatism in these patients. While there was a significant difference in uncorrected distance visual acuity (UDVA), refractive sphere, and defocus equivalent between the residual refractive astigmatism groups, there was no difference in quality of vision. Similarly, no difference was found for corneal astigmatism with UDVA and quality of vision. Overall, the angle of the residual corneal astigmatism in relation to the position of the multifocal IOL did not affect objective outcomes or the overall patient satisfaction rates. RN McNeely et al, JCRS, “Threshold limit of postoperative astigmatism for patient satisfaction after refractive lens exchange and multifocal intraocular lens implantation”, Volume 42, Issue 8, 1126-1134. NINE IOL FORMULAS COMPARED A new comparison study of nine IOL power calculation formulas confirms significant differences in their predictive ability. The formulas gave different results depending on which machine measurements were used. The Olsen formula was the most accurate, with optical low-coherence reflectometry (OLCR) measurements significantly better than the best formula with partial coherence interferometry (PCI) measurements. The Olsen was better, regardless of axial length. If only PCI measurements (without lens thickness) were available, the Barrett Universal II performed the best and the Olsen formula performed the worst. The pre-installed version of Olsen was not as good as the standalone version. DL Cooke et al, JCRS, “Comparison of 9 intraocular lens power calculation forumulas”, Volume 42, Issue 8, 1157-1164. More than 16 million LASIK procedures have been performed globally. A massive literature review of LASIK outcomes supports the safety and efficacy of the procedure and suggests improvement in patient satisfaction over time. The review included the as yet unpublished PROWL study conducted by the US FDA. The researchers note that patient selection has improved greatly over the past two decades. Candidacy criteria include sufficient corneal bed thickness following flap formation and corneal ablation, and a healthy tear film. HP Sandoval, JCRS, “Modern laser in situ keratomileusis outcomes”, Volume 42, Issue 8, 1224-1234.