JCRS

Prism IOL for AMD

An innovative Fresnel prism intraocular lens (IOL) could benefit patients with stable end-stage age-related macular degeneration (AMD). Researchers implanted the first of its kind in-the-bag Fresnel prism IOL (P-Flex, Rayner) in three patients with AMD. All underwent cataract surgery and unilateral implantation of the prismatic IOL. All patients reported displacement of the scotoma, and no patient reported diplopia. One patient developed posterior capsule opacification. The Fresnel prism was selected in favour of a conventional prism to reduce bulk and to make implantation easier. The researchers believe that the image degradation that occurs with a Fresnel prism might be less important in these eyes because the best expected decimal CDVA would be on the order of 0.1, which is the resolving power of the extrafoveal retina. While the current pilot was performed using a prototype IOL with single power and single angle of deviation, there is much potential for individual patient optimisation, they note. FJ Potgieter et al., JCRS, “Safety and efficacy of an intraocular Fresnel prism intraocular lens in patients with advanced macular disease: Initial clinical experience”, Volume 40, No. 7,1085-1091.

How’s the weather?

What affect might meteorological conditions have on refractive surgery outcomes? To answer this question, German researchers compared the outcomes of two groups of consecutive patients who underwent refractive laser surgery over a two-year period, some in the winter months, some in the summer. The study included 1,052 eyes of 1,052 patients. At one month's follow-up, the efficacy index was 0.023 higher in eyes with refractive surgery during summer than in eyes treated during winter (P=.032), indicating less efficacy during winter. The differences in the safety index and postoperative SE between summer and winter were not statistically significant. No eye had a change of more than one line on the logMAR scale (corrected distance visual acuity). However, the overall difference in the outcomes of LASIK was not clinically relevant, the researchers note. I Neuhaus et al., JCRS, “Variation in the effectiveness of refractive surgery during the year: Results from the Hamburg Weather Study”, Volume 40, No. 7,1139-1146.

Adjustable outcomes

Adjustable IOLs now available and in the pipeline offer the capability of changing the IOL power to correct and improve the initial visual outcomes after implantation. US researchers present an overview of the adjustable IOL surgical procedures. These include the light-adjustable IOL, the multicomponent IOL, the mechanically adjustable IOL and the repeatedly adjustable IOL. They also discuss IOLs that can be adjusted non-invasively in the postoperative setting, such as the magnetically adjustable IOL, the liquid crystal IOLs with wireless control. Also in the pipeline are IOLs that can be adjusted using the femtosecond laser or 2-photon chemistry. J Ford et al. JCRS, “Adjustable intraocular lens power technology”, Volume 40, No. 7,1205-1223.