The European registry of quality outcomes for cataract and refractive surgery(EUREQUO):a database study of trends in volumes,surgical techniques and outcomes of refractive surgery

Background:A European web-based registry for refractive surgery was established in 2008;The European Registry of Quality Outcomes for Cataract and Refractive Surgery(EUREQUO).The aim of the registry was to improve treatment and standards of care for refractive surgery.Further aims were to offer a tool for benchmarking by establishing a reference database and for surgeons to enter and analyze their own outcomes.The purpose of this study was to characterize the registry and analyze the data collected during its first decade.Methods:The characteristics of the web-based registry are described.Data collected from February 4^(th) 2004 until June 30th 2014 are included in the analysis.The database is analyzed in terms of surgical technique,indications for surgery,complications,and refractive and visual outcomes.Results:Data have been reported from 47 centers in 14 countries until mid-2014.About 4,000 procedures were reported annually.The most frequent procedure was laser-assisted in-situ keratomileusis(LASIK)with 11697 reported surgeries.Over time in the database,LASIK declined(p<0.001)while photorefractive keratectomy(PRK)and refractive lens exchange(RLE)increased(p<0.001 for both procedures).The indications for surgery,in terms of preoperative refraction and age,were stable over time,for all types of procedures.Surgical complications were reported infrequently and with a well-known relationship to the type of surgical procedure.The reported refractive outcomes were good.The visual outcomes indicate a significant increase of visual acuity after high myopia treatment by phakic intraocular lens in the anterior(phakic IOL AC)and the posterior(phakic IOL PC)chamber and a poorer visual outcome,after both myopia and hyperopia treatment,by epithelial LASIK(Epi-LASIK).Conclusions:We describe the establishment of a European registry for refractive surgery.The database increases at a rate of approximately 4000 refractive procedures per year.The most frequent procedure is LASIK,but both PRK and RLE are an increasing part of the reported procedures.The indications for surgery have been stable over time.Surgical complications and visual outcome vary,depending on the type of surgery.

A note on circle packing

The problem of packing circles into a domain of prescribed topology is considered. The circles need not have equal radii. The Collins-Stephenson algorithm computes such a circle packing. This algorithm is parMlelized in two different ways and its performance is reported for a triangular, planar domain test case. The implementation uses the highly parallel graphics processing unit （GPU） on commodity hardware. The speedups so achieved are discussed based on a number of experiments.