Evaluation of Cam Deformity on 3-Dimensional Computed Tomography With the Best-Fit Sphere Technique and the Alpha Angle Marking Method

Background: Three-dimensional computed tomography (3D-CT) is commonly used for the evaluation of cam deformity; however, it does not display the cam border directly. Purpose: To compare the efficacy of the best-fit sphere (BFS) method and the alpha angle marking (AAM) method in 3D-CT evaluation for the cam border. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: Twenty-six cases of cam deformity, confirmed during hip arthroscopy, were included in this study. All patients underwent a CT scan before surgery. Using multiplanar reconstruction, we obtained reformatted CT images of oblique axial, oblique coronal, and radial views. The alpha angle and femoral head-neck offset ratio (hnoR) were measured on the reformatted CT images. The cam area on 3D-CT was displayed in 4 different ways: by importing the markers from the reformatted CT images of the oblique axial view (cam-oa), the oblique coronal view (cam-oc), or the radial view (cam-r) using the AAM method, or by using the BFS method (cam-bfs). The sizes and locations of the displayed cams were compared. Results: All hips in this study had an alpha angle greater than 60° and an hnoR smaller than 0.17. The radial view measured a larger alpha angle and smaller hnoR than the oblique axial and coronal views ( P < .05). The areas of cam-oa, cam-oc, cam-r, and cam-bfs were 161.47 ± 27.96, 89.78 ± 19.23, 241.73 ± 34.55, and 329.75 ± 42.73 mm2, respectively, and their medial-to-lateral ranges along the acetabulum (clockface referents) were 12:30 to 03:00, 11:30 to 01:30, 11:30 to 03:00, and 11:00 to 03:30, respectively. Among the 4 displays, cam-bfs had the largest area and medial-to-lateral range ( P < .05), and cam-r had the second largest area and range ( P < .05). No significant difference in the mean distances from the acetabular rim to the superior border was detected among the 4 displays ( P > .05). Conclusion: The cam area displayed by the BFS method on 3D-CT was larger than those evaluated by the AAM method. In the reformatted CT, the sizes and locations of cam deformity differed among the oblique axial, oblique coronal, and radial views, with the radial view showing the greatest area.

Diagnostic Sensitivity of Different Reference Bodies When Using Scheimpflug Tomography in a Myopic Population with Keratoconus

Purpose. To establish which reference body offers the greatest sensitivity in keratoconus (KC) diagnosis, obtain normative data for the myopic population with toric ellipsoid reference bodies, and determine the cutoff points for a population with KC.Methods. A retrospective, observational study of the entire Scheimpflug tomographer database of the Fundación Jiménez Díaz in Madrid was conducted to identify a normal myopic and a KC myopic population. Three different reference bodies were tested on all patients: best fit sphere (BFS), best fit toric ellipsoid with fixed eccentricity (BFTEFE), and best fit toric ellipsoid (BFTE). Anterior and posterior elevation measurements at the apex and thinnest point were recorded, as well as the root mean square of posterior elevations (RMS-P). Normative data were extracted, and receiver operating characteristic (ROC) curves were generated to obtain cutoff points between the normal and KC population.Results. A total of 301 eyes were included, comprising 219 normal myopic and 82 myopic KC eyes. BFS and BFTEFE produced the best results when measuring posterior elevation at the thinnest point. BFTE had better sensitivity with the RMS-P. From all measurements, best sensitivity (100%) was achieved with a cutoff point of 8 μm of posterior elevation at the thinnest point using the BFTEFE. BFTE was found to hide the cone in certain patients.Conclusions. Posterior elevation measured at the thinnest point with a BFTEFE is the best-performing parameter and, therefore, is recommended to discriminate between normal and KC patients within a myopic population.

To evaluate the Role and Efficacy of Collagen Cross-linkage with Ultraviolet Therapy following Riboflavin Drops with Orbscan in Cases of Progressive Keratoconus

ABSTRACT Aim To evaluate the role and efficacy of collagen cross-linkage with riboflavin (C3R) in cases of progressive keratoconus. Study design Prospective, nonrandomized, single-center clinical study. Materials and methods The C3R was done in 32 eyes of 21 patients with at least 6 months of documented progression. Outcome of the procedure was measured by means of uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), corneal topography with Orbscan changes in posterior best fit sphere (PBFS), ratio of anterior and posterior best fit sphere (ABFS/PBFS), astigmatic changes in central 3- and 5-mm zone, central endothelial count postcorneal C3R. Results Thirty-two eyes with a follow-up of 6 months were analyzed. The mean age was 19.8 years. The preoperative values on the day of treatment were compared with postoperative values after the 6-month examination. The improvement in UCVA and BSCVA was statistically significant (p = 0.02 and 0.01 respectively). The change in power for PBFS was not statistically significant (p = —0.08). There was no significant difference in corneal endothelial counts pre- and post-C3R (p = 0.058). Mean value pre-C3R for ratio of ABFS/PBFS was 1.25 ± 3.7 and post-C3R was 1.22 ± 1.8 (p = 0.00). Mean value of astigmatism in 3-mm zone pre- and post-C3R was —4.3 ± 0.98 and —3.9 ± 0.66(p = 0.046) respectively. Mean value pre-C3R for astigmatism in 5-mm zone was —4.9 ± 1.91 and post-C3R was —4.0 ± 0.82 (p = 0.02). Conclusion The results show a stabilization and improvement in keratoconus after C3R in Indian eyes. How to cite this article Guleria P, Sharma V. To evaluate the Role and Efficacy of Collagen Cross-linkage with Ultraviolet Therapy following Riboflavin Drops with Orbscan in Cases of Progressive Keratoconus. Int J Kerat Ect Cor Dis 2017;6(2):67-72.

Corneal Elevation Values in Normal Eyes, forme fruste Keratoconus and Keratoconus at Different Stages Measured by Scheimpflug Imaging

ABSTRACT Purpose To compare corneal elevation values in normal eyes, forme fruste keratoconus (FFKC) and different stages of keratoconus using Scheimpflug imaging. Materials and methods This prospective, comparative study included 267 eyes (107 normal eyes, 21 FFKC and 139 keratoconus). Keratoconic eyes were divided into four groups according to keratometry values. Maximum posterior elevation (PE) above the (best fit sphere (BFS) at the central 5 mm were measured using the Pentacam (Oculus Optikgeräte GmbH). Receiver operating characteristic curves were used to determine the test's overall predictive accuracy and to identify optimal cutoff points to discriminate between the groups. Results PE had the smallest values in normal eyes and increased in FFKC and each progressive stage of keratoconus. Mean PE was 9.98 ± 5.33 µm in normal eyes, 18.09 ± 9.23 µm in FFKC and 24.97 µm ± 15.89, 37.82 ± 18.64, 46.82 ± 21.41 and 66.07 ± 39.09, in keratoconus stage I, II, III and IV respectively. Conclusion Posterior elevation values increased according to the severity of keratoconus disease. PE can be used as indicator of keratoconus progression. How to cite this article Henriquez MA, Izquierdo L Jr, Dañin D. Corneal Elevation Values in Normal Eyes, forme fruste Keratoconus and Keratoconus at Different Stages Measured by Scheimpflug Imaging. Int J Kerat Ect Cor Dis 2014;3(1):36-39.

Case Report: Pellucid-like keratoconus

Purpose: To study the tomographic features of pellucid-like keratoconus (PLK), and to report a new sign on the pachymetry map (PM) in pellucid marginal degeneration (PMD).Patients and methods: A retrospective descriptive case series was performed in Damascus University in 2011. Clinical and tomographic findings of 15 eyes (9 patients) that had the claw pattern of the anterior sagital map (ASM) were reviewed. Patients were distributed into two groups: (1) 4 eyes were considered PMD since they had inferior corneal thinning on both slitlamp biomicroscopy and PM; (2) 11 eyes were considered as PLK since they did not show inferior corneal thinning. Patients were studied using slitlamp biomicroscopy and Scheimpflug-based tomography (Pentacam HR). The ASM, anterior elevation map (AEM) and PM were analyzed and compared to study the “kissing birds” sign, the “bell” sign, and cone location.Results: Patients’ average age was 25.93±8.05 (16–44 years). In total, 60% of patients were male. In group 1, the AEM in the best fit sphere (BFS) mode revealed no kissing birds sign, and the cone was central in 1 eye (25%) and paracentral in 3 eyes (75%). PM showed the bell sign in 4 eyes (100%). In group 2, the AEM in the BFS mode revealed the kissing birds sign in 2 eyes (18.2%), and the cone was central in 1 eye (9.1%), paracentral in 8 eyes (72.7%) and peripheral in 2 eyes (18.2%). PM didn’t show the bell sign in any eye.Conclusion: The claw pattern on the ASM is not a hallmark of PMD; it can be seen in PLK. Cone location does not relate to diagnosis. The “bell” sign on the PM is a deferential diagnostic sign in PMD.