JCRS HIGHLIGHTS

Anterior segment optical coherence tomography (AS-OCT) can be useful for sizing a posterior chamber phakic intraocular lens (IOL), a Russian study suggests. In the first stage of the study, the researchers developed an algorithm using OCT to measure the distance from the iris pigment end to the iris pigment end. The sulcus-to-sulcus distance was measured using ultrasound biomicroscopy. In the second stage was a retrospective evaluation of 29 eyes of 16 patients. The mean sulcus-to-sulcus distance was similar to the mean distance from iris pigment end to iris pigment end. The posterior chamber phakic IOL sized using the new AS-OCT algorithm had a mean vault of 0.53 ± 0.18mm and did not produce adverse events during the 12-month follow-up. In 16 of 29 eyes, the posterior chamber phakic IOL vault was within an optimum interval. B Malyugin et al, JCRS, “Posterior chamber phakic intraocular lens sizing based on iris pigment layer measurements by anterior segment optical coherence tomography”, Volume 41, Issue 8, 1616-22.

TRIFOCAL VS BIFOCAL IOL

Researchers in the Netherlands compared visual outcomes in patients with cataract surgery and bilateral implantation of a trifocal (FineVision Micro F) or bifocal IOL (AcrySof IQ ReSTOR) in a prospective randomised clinical trial. Six months postoperatively, there were no significant differences in refractive outcomes, reading speed, or patient satisfaction. The trifocal group showed a more continuous defocus curve and better results at -1.0D of defocus (P < .01). The mean mesopic contrast sensitivity was higher in the bifocal group (P = .02). Complete spectacle independence was reported by 80 per cent of trifocal patients and 50 per cent of bifocal patients. 

S Jonker et al, JCRS, “Comparison of a trifocal intraocular lens with a +3.0 D bifocal IOL: Results of a prospective randomized clinical trial”, Volume 41, Issue 8, 1631-40.

EVALUATING THE CORRECTION OF MILD ASTIGMATISM

A group of US researchers conducted a study to re-evaluate the analysis of the correction of astigmatism. Referencing the previous work of Drs Alpins and Edelman, they used mathematical simulations to this end. They determined that correction index (correction ratio) is a useful vector-based metric for the evaluation of refractive procedures. They urged caution when judging the clinical significance of correction index analyses applied to treatments of low amounts of cylindrical refractive error. They emphasise that the decision to surgically correct small amounts of astigmatism should consider the visual demands of patients, the knowledge of the effects of small cylindrical errors on vision, and our ability to precisely measure astigmatism preoperatively and postoperatively.
M Bullimore et al, JCRS, “Correction of low levels of astigmatism”, Volume 41, Issue 8, 1641-49.