Tomographic characteristics of thick corneas
0
Citation
23
Reference
10
Related Paper
Abstract:
To investigate the tomographic characteristics of corneas with excessive thickness and to explore their potential impact on the assessment of candidates for refractive surgery. One hundred and two eyes from 102 patients with the thinnest pachymetry (TP) < 500 μm, 100 eyes from 100 patients with TP ranging from 500 to 580 μm, and 102 eyes from 102 subjects with TP ≥ 580 μm were included. Pentacam ectasia indices were compared among these different groups. When compared to eyes with TP between 500 and 580 μm, significantly higher values in anterior radius of curvature (ARC), anterior corneal astigmatism (KAp), back elevation at the thinnest pachymetry (BE), deviation of normality of the back elevation (Db), and a more negative Q value for the back surface (Qback) were observed in eyes with TP ≥ 580 μm (Mann-Whitney U test: P < 0.001). No significant differences were observed in the indices for the anterior cornea (Mann-Whitney U test: index of height decentration, P = 0.348; inferior-superior value, P = 0.334; keratoconus percentage index, P = 0.077; deviation of normality of the front elevation, P = 0.891). The proportion of abnormalities was highest in eyes with TP ≥ 580 μm for BE (16.7%, Chi-square test: P < 0.001) and Db (20.6%, Chi-square test: P = 0.001). The tomography of thick corneas reveals greater BE and Db, as well as a more negative Qback while no significant disparities emerged in the anterior corneal indices.Keywords:
Astigmatism
Ectasia
Purpose To determine the reproducibility of keratometric parameters obtained by OCULUS® Pentacam® HR in the evaluation of keratoconus progression. Methods Thirty nine eyes of 25 patients from the Cornea Department of the Centro Hospitalar de Lisboa Central were included in the study. Fourteen eyes presented with clinical and topographic diagnosis of keratoconus (stage 1-3) and were defined as the “keratoconus without ring” group; 9 eyes had already an intrastromal ring implanted and were defined as the “keratoconus with ring”; the remaining 16 eyes, without clinical or topographic evidence of disease, were used as controls. Every eye was submitted to identical methodology: 5 consecutive keratometric measurements obtained with OCULUS® Pentacam® HR; central keratometry, SKmax, minimal pachymetry and anterior chamber depth were used to determine the existence of statistically significant reproducibility. Results Overall significant measurement variability was obtained in the “keratoconus without ring” group (Km 0.129 D vs 0.0375 D, SKmax 0.507 D vs 0.0625 D, Minpach 5.429 μm vs 2.5625 μm, ACD 0.024 mm vs 0.0194 mm), with highest variability in the subgroup of patients with more advanced disease. In the “keratoconus with ring” group statistically significant variability was found for all parameters except for anterior chamber depth (Km 0.289 D vs 0.0375 D, SKmax 0.444 D vs 0.0625 D, Minpach 4.333 μm vs 2.5625 μm, ACD 0.024 mm vs 0.0194 mm). Conclusion Keratometric measurements obtained with OCULUS® Pentacam® HR should be assessed cautiously in the evaluation of keratoconus progression, with or without intrastromal ring; the use of single measurements is unadvised.
Cite
Citations (0)
This work shows a retrospective evaluation of the patients with progressive keratoconus, stadium I, II, III, to which corneal collagen cross-linking was performed to stop the evolution. The patients were monitored by refraction, visual acuity, keratometry, pachimetry and topography. In all cases it was noticed an improvement or the maintenance of the followed parameters.
Corneal collagen cross-linking
Cite
Citations (3)
Astigmatism
Cite
Citations (2)
Intrastromal corneal ring segments (ICRSs) are small arc-like implants that are being used increasingly as a minimally invasive treatment for patients with keratoconus. This study assessed the effectiveness of KeraRing implants, a type of ICRS, to treat keratoconus.Retrospective case series descriptive study of 43 patients (55 eyes) with keratoconus who underwent KeraRing implantation from February 2008 to June 2009. Patients who had intraoperative or postoperative complications and/or did not complete at least 6 months of follow-up were excluded. All patients underwent complete ophthalmologic examinations that included measurement of the uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and keratometry before and 2 days, 2 weeks, 1 month, and 3 and 6 months after surgery. The ring segments were chosen based on a nomogram from the manufacturer.Six months postoperatively, the mean UCVA increased significantly (P < 0.05) from 0.10 ± 0.11 to 0.32 ± 0.25 and the mean BSCVA increased from 0.36 ± 0.23 to 0.57 ± 0.24 (P < 0.05). The mean spherical refractive error significantly (P < 0.05) improved from -4.85 ± 2.90 diopters (D) to -1.89 ± 2.68 D, and the mean cylindrical refractive error significantly (P < 0.05) improved from -3.65 ± 1.70 D to -2.60 ± 1.62 D. The mean spherical equivalent significantly (P < 0.05) decreased from -6.68 ± 2.93 D to -3.19 ± 2.75 D, and the mean keratometry value decreased from 51.83 ± 4.14 D to 47.27 ± 3.68 D. The improvement in the UCVA and BSCVA continued over the 6-month postoperative period, but significant changes occurred only during the first 3 months. These changes occurred in patients with all grades of keratoconus.KeraRing implantation provided significant improvement in visual acuity, spherical equivalent, and keratometry results. This ICRS is an effective treatment for managing keratoconus and might delay or even avoid the need for penetrating keratoplasty.
Nomogram
Cite
Citations (54)
ABSTRACT Intacs, intrastromal corneal rings are widely used to reduce myopia, astigmatism, keratometry readings and high order aberrations in patients suffering from keratoconus, almost 15 years have passed from the first procedure which was performed in the eye of a patient with unsatisfactory visual acuity and contact lenses intolerance. Many publications including book chapters, retrospective studies, case reports and literatures reviews have been published on this issue. In this review, we are reporting on the complications of Intacs implanted in keratoconic eyes, we are reporting on intraoperative and postoperative complications. The review although focusing on complications of the does not contradict the positive results of the procedure on the quality of life of the patients suffering from keratoconus and the its safety. How to cite this article Barbara A, Barbara R. Intacs Intracorneal Ring Segments Complications in Patients Suffering from Keratoconus. J Kerat Ect Cor Dis 2013;2(3):121-128.
Cite
Citations (5)
ABSTRACT Purpose To evaluate the influence of age and severity of keratoconus in the clinical outcomes of implantation of Ferrara intrastromal corneal ring segments (ICRS). Methods A total of 1,073 eyes of 810 patients, consecutively operated from January 2006 to July 2008, were evaluated. Two independent analysis were made according to the age of patients and keratoconus staging. Four groups were created according to the age of patients: < 20 years old, 20 to 30, 30 to 40 and >40 years old. The patients were also evaluated according to the keratoconus stage (I to IV). The outcome analysis included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry (K), asphericity (Q), corneal volume (CV) and pachymetry. All patients were evaluated using the Pentacam. Results The postoperative increase in UDVA and CDVA was statistically significant in all groups (p < 0.05). The magnitude of improvement of CDVA was larger for patients between 21 and 30-year-old (CDVA = 20/40) and patients with keratoconus grade I (CDVA = 20/35) (p < 0.05). There was a statistically significant increase in CV and pachymetry postoperatively in all groups. The keratometry (3.95D) and asphericity (–0.77) reduction were larger in patients younger than 20-year-old and in patients with keratoconus grade IV (p < 0.05). Conclusion The best clinical outcomes are seen in patients between 20 and 30-year-old and initial cases of keratoconus (grade I). The more advanced the keratoconus, the larger magnitude of K and Q reduction after ICRS implantation. How to cite this article Torquetti L, Ferrara G, Ferrara P. Predictors of Clinical Outcomes after Intrastromal Corneal Ring Segments Implantation. Int J Keratoco Ectatic Corneal Dis 2012;1(1):26-30.
Corneal pachymetry
Cite
Citations (12)
To evaluate the surgical outcomes of microthin intracorneal ring segment (INTACS) implantation in advanced keratoconus.INTACS implantation was performed in eyes with advanced keratoconus. The main outcome measures were uncorrected visual acuity, best spectacle-corrected visual acuity, change in mean refractive spherical equivalent (MRSE), and keratometry.Intacs were implanted in 14 eyes with advanced keratoconus. At 6 months, uncorrected visual acuity improved from 0.05 +/- 0.08 to 0.16 +/- 0.11 (P < 0.05), and best spectacle-corrected visual acuity improved from 0.50 +/- 0.23 to 0.67 +/- 0.00 (P = 0.01). The spherical refractive error improved from -6.68 D +/- 6.44 to -3.11 D +/- 3.08 (P = 0.03), whereas the cylindrical refractive error improved from -4.89 D +/- 1.91 to -3.64 D +/- 1.27 (P = 0.04). The MRSE reduced from -9.13 D +/- 5.62 to -4.93 D +/- 3.19 (P = 0.01), and the average keratometry decreased from 53.01 D +/- 3.70 to 49.42 D +/- 3.79 (P < 0.05). The results were stable from 6 months to 1 year. The procedure showed 100% safety, and more than 60% tolerated contact lenses. Younger age, male sex, and minimum central pachymetry of more than 400 microm seemed to be associated with better outcomes.In this series, Intacs provided good results with respect to visual acuity, corneal topography, and MRSE in eyes with advanced keratoconus without major complications or the need for segment explanation. INTACS is potentially a safe and efficacious treatment option in the management of advanced keratoconus.
Cite
Citations (133)
• A retrospective review of 398 eyes of 199 patients with keratoconus revealed 106 eyes of 53 patients with an association between contact lens wear and the development of keratoconus. The absence of keratoconus at the time of contact lens fitting was confirmed by slit-lamp examination, keratometry readings, and manifest refraction. Keratoconus was diagnosed after a mean of 12.2 years of contact lens wear. This group was compared with patients with sporadic keratoconus with either no history of contact lens wear or a history of contact lens wear after the diagnosis. They were older at the time of diagnosis, had central vs decentered cones, and had a tendency toward flatter corneal curvatures. We believe that these patients suggest that long-term contact lens wear is a factor that can lead to keratoconus.
Cite
Citations (118)
AIM:To evaluate the clinical outcomes after Ferrara intrastromal corneal ring segments(ICRS)reoperation in patients with keratoconus.METHODS:A total of 37 keratoconus eyes implanted with intrastromal corneal ring segments,which had an ICRS exchange,addition,reposition or removal were evaluated.Uncorrected visual acuity(UCVA),best corrected visual acuity(BCVA),keratometry(K),asphericity(Q)and pachymetry at the thinnest point(PTP)of the cornea were evaluated using a corneal tomography(Oculus Pentacam,USA)RESULTS:The mean follow-up time after the reoperation was 30.5±9.7 months.The mean UCVA improved from 20/300 to 20/80(P=0.005);the mean BCVA improved from 20/160 to 20/50(P=0.0002),the mean keratometry reduced from 49.33±4.19D to 46.16±3.90D(P=0.0001),the mean pachymetry at the thinnest point increased from 450±42.9μm to 469±40.8μm(P=0.0001).The asphericity increased from-0.84±0.74 to-0.35±0.81(P=0.15)and the spherical equivalent reduced from-4.64±4.87D to-3.04±3.45D(P=0.137).The changes in the asphericity and spherical equivalent were not statistically significant.CONCLUSION:Ferrara ICRS implantation showed to be a reversible and readjustable surgical procedure for keratoconus treatment.Good outcomes can be obtained even after removal,addition,reposition or exchange of ICRS.
Corneal pachymetry
Cite
Citations (0)
Objective: To evaluate the changes in corneal parameters (keratometry, corneal thickness, topography indices) after corneal collagen cross-linking in keratoconus. Methods: The medical records of 6 patients who underwent corneal collagen cross-linking treatment for keratoconus and have been followed-up for a minimum of 24 months were recruited. Best corrected visual acuity (BCVA), maximum keratometry (Kmax), central corneal thickness (CCT) values and corneal topography indices: index of surface variance (ISV), index of vertical asymmetry (IVA), keratoconus index (KI), central keratoconus index (CKI), minimum radius of curvature (Rmin), index of height asymmetry (IHA), and index of height decentralisation (IHD) were recorded. Results: The mean preoperative Kmax value was 46.67±4.15 (43.30-57.10) D and the mean Kmax value at the final postoperative visit was 45.41±2.95 (43.00-53.20) D. Mean preoperative CCT was 494.70±33.69 (438-537) µm and final postoperative mean CCT was 495.60±34.99 (433-539) µm. The deterioration in corneal topography indices stopped during the follow-up period of each case. Conclusion: Stopping the deterioration of corneal parameters in keratoconus is the desired outcome after cross-linking treatment. Our results found an improvement or at least stabilization in all topography indices in keratoconus patients.
Corneal collagen cross-linking
Cite
Citations (0)