ABSTRACT
PURPOSE: The purpose of this study was to describe a modified technique for sutureless intrascleral intraocular lens fixation in in patients without capsular support: the reverse 4-flanged technique. METHODS: A 2.2 mm corneal incision was made for aphakic patients. The 6-0 polypropylene sutures were threaded through a 30-gauge needle outside the eye. An MDJ® injector was employed to insert the IOL in the eye. A suture-needle snare with 7-0 polypropylene was used to exteriorize the superior end of the sutures through the sclerotomy. The 6-0 polypropylene was heated with a cautery to create the flanges. RESULTS: Nine eyes of nine patients underwent the reverse 4-flanged technique. The median follow-up time was 182 days (range 174 - 195). Best corrected distance visual acuity (BCVA) improved from 20/400 [hand movement - 20/33] to 20/120 [20/400-20/21]. No vitreous haemorrhage, retinal detachment, endophthalmitis, IOL luxation or flange exposure was recorded during the follow-up. CONCLUSION: The reverse 4-flanged technique maintains the advantages of the original 4-flanged technique in terms of IOL stability while reducing the incision size and surgical manoeuvres performed inside the eye. This modification promises to be a reliable, safe and relatively simple technique to correct aphakia in the absence of capsular support.
ABSTRACT
PURPOSE: To evaluate the prediction accuracy of 9 IOL power calculation formulas using a heteroscedastic statistical analysis and a novel method for IOL constant optimization. DESIGN: Retrospective case series. METHODS: The LenStar LS900 (Haag-Streit, Koeniz, Switzerland) was used for the preoperative biometry. The predicted SE refraction of the implanted IOL were calculated for: Barrett Universal II, EVO-2.0, Hill RBF-3.0, Hill-RBF 2.0, Kane, PEARL-DGS, SRK-T, Hoffer-Q and Holladay-1. IOL constants were optimized prior to the analysis. A heteroscedastic statistical method was used to compare the standard deviation (SD) of prediction errors (PE). RESULTS: Two hundred seventy-eight eyes of 278 patients were included. The SD of the Kane was 0.4214D and was the lowest in this database. The SD of the PE of the Kane and EVO 2.0 were significantly lower than the SRK-T, Holladay 1, and Hoffer-Q. The SD of the PE of the PEARL formula was significantly lower than the SRK-T and Hoffer-Q. The SD of the PE of the Hill-RBF 3.0 was not significantly different to the Hill-RBF 2.0, Kane, EVO 2.0, Barrett Universal II and PEARL. No significant difference was found between the SD of the PE of the new generation formulas analysed. CONCLUSIONS: the lowest SD of the prediction error was provided by Kane, followed by EVO 2.0 and PERL-DGS formulas. However, no statistically significant differences were found between the SD of the PE of new generation formulas. Further studies are necessary to evaluate the accuracy of these formulas in extreme eyes.
ABSTRACT
PURPOSE: The purpose of this study was to evaluate the intraobserver repeatability of several corneal parameters in healthy eyes using a new swept-source optical coherence topographer. METHODS: Fifty right eyes of 50 subjects were enrolled in this study. A single examiner performed 3 consecutive measurements using the Anterion swept-source optical coherence tomography. The following corneal parameters were evaluated: average keratometry (K), steep K, flat K, astigmatism, best fit sphere, and maximum keratometry on the anterior and posterior surfaces at 3 mm, average K, steep K, flat K, and astigmatism in the total corneal power map at 3 mm, central corneal thickness and thinnest point thickness in the pachymetric map, and corneal diameter. To assess the repeatability of the measurements, we calculated the following indexes: intrasubject SD (Sw), coefficient of variation, coefficient of repeatability, and intraclass correlation coefficient (ICC). RESULTS: High repeatability was reported for all the evaluated corneal parameters, with Sw values lower than 0.027, coefficient of variation values lower than 0.066%, and coefficient of repeatability values lower than 0.187. ICC values showed a high correlation between measurements in all cases, being the lowest value for the astigmatism of the anterior surface (ICC = 0.92); for the rest, ICC values were larger than 0.98. Finally, we have not found statistically significant differences between repeated measurements (P > 0.05). CONCLUSIONS: The anterior segment measurements provided by the Anterion swept-source optical coherence tomography device show high intraobserver repeatability in healthy eyes.
