Dataset Information

Long-Term Follow-Up of Intrastromal Corneal Ring Segments in Paracentral Keratoconus with Coincident Corneal Keratometric, Comatic, and Refractive Axes: Stability of the Procedure.

ABSTRACT: PURPOSE:To assess the long-term outcomes of implanting intrastromal corneal ring segments (ICRS) in paracentral keratoconic eyes. METHODS:58 eyes with paracentral keratoconus with coincident refractive, keratometric, and comatic axes were evaluated. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity and refractive errors were recorded before and at all follow-up visits. The postoperative follow-up was 5 years. Patients were divided into two groups: group I (30 years old or younger) and group II (more than 30 years old). RESULTS:The mean UDVA (logMAR) rose from a preoperative 0.83?±?0.31 to a five-year postoperative 0.42?±?0.33 (P < 0.0001). The mean CDVA varied from 0.16?±?0.17 to 0.11?±?0.18 (P = 0.0003). Both the UDVA and CDVA were stable over the postoperative period in both groups (P > 0.05). The spherical equivalent and the refractive cylinder declined steeply after ICRS implantation in both groups (P < 0.001), and were stable over the postoperative period (P > 0.05). The keratometric values were also stable over the postoperative follow-up. CONCLUSION:Ferrara-type ICRS implantation in keratoconus that meets the characteristics of the sample under study reduces the refractive error at the same time as it improves postoperative UDVA and CDVA six months after surgery and that these results remain stable over five years of follow-up.

SUBMITTER: Fernandez-Vega Cueto L

PROVIDER: S-EPMC5602624 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Long-Term Follow-Up of Intrastromal Corneal Ring Segments in Paracentral Keratoconus with Coincident Corneal Keratometric, Comatic, and Refractive Axes: Stability of the Procedure.

Fernández-Vega Cueto Luis L Lisa Carlos C Madrid-Costa David D Merayo-Lloves Jesús J Alfonso José F JF

Journal of ophthalmology 20170829

<h4>Purpose</h4>To assess the long-term outcomes of implanting intrastromal corneal ring segments (ICRS) in paracentral keratoconic eyes.<h4>Methods</h4>58 eyes with paracentral keratoconus with coincident refractive, keratometric, and comatic axes were evaluated. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity and refractive errors were recorded before and at all follow-up visits. The postoperative follow-up was 5 years. Patients were divided into two groups: group I (30 years ol ...[more]

PMID: 28948045

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Project description:Purpose:To evaluate a new tangential map-based nomogram versus the axial map-based nomogram for ICRS in keratoconus. Methods:A prospective case series study including 64 eyes of 64 patients who underwent ICRS implantation. Cone location was determined for each eye with two maps: the axial and the tangential. Appropriate ring selection was determined using two surgical nomograms: axial map-based and tangential map-based. Visual, refractive, and topographic outcomes were assessed before, as well as at 3, 6, and 12 months after ICRS implantation. Results:The cone location, and consequently the ring selection, was significantly different in the two nomograms with a "centralization tendency" in the tangential map. In the axial group, UDVA and CDVA improved from 0.12?±?0.04 and 0.24?±?0.08 to 0.28?±?0.08 and 0.4?±?0.1, respectively. Similarly, MRSE substantially decreased from -6.7?±?3.3 to -1.2?±?1.1D at 12 months after the procedure. In the tangential group, UDVA and CDVA improved from 0.09?±?0.06 and 0.2?±?0.1 to 0.5?±?0.2 and 0.7?±?0.2, respectively. MRSE substantially decreased from -4.9?±?1D at 12 months after the procedure. In the tangential group, UDVA and CDVA improved from 0.09?±?0.06 and 0.2?±?0.1 to 0.5?±?0.2 and 0.7?±?0.2, respectively. MRSE substantially decreased from -4.9?±?1D at 12 months after the procedure. In the tangential group, UDVA and CDVA improved from 0.09?±?0.06 and 0.2?±?0.1 to 0.5?±?0.2 and 0.7?±?0.2, respectively. MRSE substantially decreased from -4.9?±?1P=0.01 ? . Similarly, the gain in the CDVA was 0.4 and 0.15 in the tangential and axial groups, respectively, at 12 months, P=0.01 ? . Similarly, the gain in the CDVA was 0.4 and 0.15 in the tangential and axial groups, respectively, at 12 months. Conclusion:The tangential map-based nomogram attained better visual and refractive outcomes at 1 year. In addition, the cone location was significantly different between both maps with a centralization tendency in the tangential one.

Project description:Custom high-resolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT) was used to characterize three-dimensionally (3-D) corneal topography in keratoconus before and after implantation of intracorneal ring segments (ICRS). Previously described acquisition protocols were followed to minimize the impact of the motions of the eye. The collected set of images was corrected from distortions: fan (scanning) and optical (refraction). Custom algorithms were developed for automatic detection and classification of volumes in the anterior segment of the eye, in particular for the detection and classification of the implanted ICRS. Surfaces were automatically detected for quantitative analysis of the corneal elevation maps (fitted by biconicoids and Zernike polynomials) and pachymetry. Automatic tools were developed for the estimation of the 3-D positioning of the ICRS. The pupil center reference was estimated from the segmented iris volume. The developed algorithms are illustrated in a keratoconic eye (grade III) pre- and 30 days post-operatively after implantation of two triangular-section, 0.3-mm thick Ferrara ring segments. Quantitative corneal topographies reveal that the ICRS produced a flattening of the anterior surface, a steepening of the posterior surface, meridional differences in the changes in curvature and asphericity, and increased symmetry of the anterior topography. Optical distortion correction through the ICRS (of a different refractive index from the cornea) allowed accurate pachymetric estimates, which showed increased thickness in the ectatic area as well as in peripheral corneal areas. Automatic tools allowed estimation of the depth of the implanted ICRS ring, as well as its rotation with respect to the pupil plane. Anterior segment sOCT provided with fan and optical distortion correction and analysis tools is an excellent instrument for evaluating and monitoring keratoconic eyes and for the quantification of the changes produced by ICRS treatment.

Project description:Purpose:To evaluate the outcomes of femtosecond laser-assisted implantation of a 355-degree intracorneal ring (ICR) (Keraring) in patients with keratoconus in the three-year follow-up. Setting:Future Femtolaser Center, Sohag, Egypt. Design:Prospective interventional case series. Patients and Methods:A prospective case series of 38 eyes of 26 patients with keratoconus had implantation of the 355-degree ICR keraring after tunnel creation with a femtosecond laser. The uncorrected visual acuities (UCVA) and best-corrected visual acuities (BCVA), sphere, cylinder, and manifest refraction spherical equivalent (SE), and mean keratometry (K), K max, and K min were evaluated preoperatively and 3, 6, 12, 24, and 36 months postoperatively, and all complications were reported. Results:38 eyes of 26 patients with mean age 25.92?±?5.44 years were enrolled in the study, 11 were males (42.3%). The mean UCVA improved from 0.93?±?0.21 to 0.63?±?0.21 logMAR (P ? 0.001) and the mean BCVA from 0.67?±?0.22 to 0.43?±?0.26 logMAR (P < 0.001). The mean sphere, cylinder, and spherical equivalent have been changed dramatically from preoperative to 3 month postoperative, which is statistically significant (P ? 0.001), and the changes between 1 and 2 years and 2 and 3 years are also considerable and statistically significant; the K max and K min and K mean improved and the changes were statistically significant (P ? 0.001), and the changes between one, two, and three years were also statistically significant. The safety and efficacy indices were changed through the three-year follow-up. The complications were corneal neovascularization (36.84%), corneal melting (26.3%), and ring extrusion (31.5%) at the end of the study. Conclusions:Implantation of a 355-degree intracorneal keraring using femtosecond laser improved the visual, refractive, and topographic parameters in keratoconus patients, with a high rate of ICR extrusion and instability. The study has been registered for the Pan African Clinical Trial Registry (http://www.pactr.org) database within No: PACTR201810796878908 on 29 October 2018.

Project description:Background:To analyze the clinical results of an artificial neural network (ANN) that has been processed in order to improve the predictability of intracorneal ring segments (ICRS) implantation in keratoconus. Methods:This retrospective, comparative, nonrandomized, pilot, clinical study included a cohort of 20 keratoconic eyes implanted with intracorneal ring segments KeraRing (Mediphacos, Belo Horizonte, Brazil) using the ANN (ANN group) and 20 keratoconic eyes implanted with KeraRing using the manufacturer's nomograms (nomogram group). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA) (visual acuity is expressed in decimal value and in LogMAR value in brackets), manifest refraction, corneal topography, tomography, aberrometry, pachymetry and volume analysis (Sirius System. CSO, Firenze, Italy) were performed during the preoperative visit; and the two groups, ANN group and nomogram group, did not differ significantly preoperatively in all of the parameters evaluated. These preoperative values were compared with the results obtained at the third-month visit. Mann-Whitney test and Wilcoxon test were used for the statistical analyses. Results:The spherical equivalent and the keratometric values decreased significantly in both groups. The CDVA improved from 0.60?±?0.23 (0.22 LogMAR) pre-operatively to 0.73?±?0.21 (0.14 LogMAR) post-operatively in the ANN group (p?<?0.005), and from 0.54?±?0.19 (0.27 LogMAR) pre-operatively to 0.62?±?0.19 (0.21 LogMAR) post-operatively in the nomogram group (p?<?0.01), with statistically significant difference between the two groups (p?<?0.05), being better in the ANN group. Coma-like aberrations decreased significantly in the ANN group, while in the nomogram group they did not change significantly, but no statistically significant difference was found between the two groups. Conclusions:ANN to guide ICRS provides an increase in the visual acuity, reduction in the spherical equivalent and improvement in the optical quality of keratoconus patients. ANN gives better results when compared with the manufacturer's nomograms in terms of better corrected vision and reduction of the coma-like aberrations. The constant inclusion of new cases will make the predictability of ANN increasingly better as the software finetunes its learning.

Dataset Information

Long-Term Follow-Up of Intrastromal Corneal Ring Segments in Paracentral Keratoconus with Coincident Corneal Keratometric, Comatic, and Refractive Axes: Stability of the Procedure.

Publications

Long-Term Follow-Up of Intrastromal Corneal Ring Segments in Paracentral Keratoconus with Coincident Corneal Keratometric, Comatic, and Refractive Axes: Stability of the Procedure.

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