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Prakash G, Mammen A, Jhanji V. Rate of fractional change in corneal tomography parameters in keratoconus using a combination of predictive parameters. EYE AND VISION (LONDON, ENGLAND) 2023; 10:40. [PMID: 37777798 PMCID: PMC10544119 DOI: 10.1186/s40662-023-00357-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 08/29/2023] [Indexed: 10/02/2023]
Abstract
BACKGROUND To compare the rate of fractional change for multiple corneal tomographic factors in progressive keratoconus (KC). METHODS In this retrospective case series, 40 eyes (40 patients) with progressive KC (increase in central keratometry of 1.00 D or maximum keratometry of 1.50 D on two visits at least six months apart) were included. Cases with previous history of ocular surgery, poor scans, corneal scars, severe dry eyes, post-excimer ectasia, pellucid marginal degeneration were excluded. Medical records, corneal tomography and anterior corneal wavefront (8 mm) (Scheimpflug tomography, Pentacam, Oculus, Germany) were analyzed. Rate of fractional change (Rx = (x1 - x0)/(|x0|tm)); where, x1 = value at follow-up, x0 = value at initial visit and tm = time in months, was measured. RESULTS The mean age of the patients was 30.0 ± 8.4 years. The mean follow-up duration was 8.9 ± 4.2 months. Coma (0.076 ± 1.4) had the largest rate of fractional change (P = 1.7 × 10-14, Kruskal-Wallis test). The rate of fractional change was higher for aberrometric parameters (anterior corneal higher-order aberrations root mean square and anterior coma) compared to pachymetric and keratometric parameters (P values ranging from 1.4 × 10-4 to 7.4 × 10-10, Mann-Whitney test, effect size ranging from 0.4-0.7). The rate of fractional change was comparable between pachymetric and keratometric factors (P > 0.05 for all comparisons, Mann-Whitney test). CONCLUSIONS Anterior corneal wavefront, especially anterior coma, were noted to have higher rate of fractional change compared to single point keratometric and pachymetric indices in progressive KC. This information can be used for decision-making when monitoring patients with KC.
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Affiliation(s)
- Gaurav Prakash
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Alex Mammen
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- University of Pittsburgh Medical Center, 203 Lothrop St, Suite 800, Pittsburgh, PA, 15213, USA.
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Tunç U, Çelebi AC, Ekren BY, Yıldırım Y, Kepez Yıldız B, Okullu SÖ, Sezerman OU. Corneal bacterial microbiome in patients with keratoconus using next-generation sequencing-based 16S rRNA gene analysis. Exp Eye Res 2023; 228:109402. [PMID: 36736649 DOI: 10.1016/j.exer.2023.109402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 01/21/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023]
Abstract
PURPOSE To investigate the corneal bacterial microbiome in patients with keratoconus using next-generation sequencing and develop a new perspective on the pathogenesis of the disease. METHODS This prospective observational study included 10 patients with keratoconus who underwent corneal crosslinking procedure and 10 healthy controls who underwent photorefractive keratectomy. Patients included in the study were aged 18 years or older. The demographic and clinical characteristics of participants were recorded. Corneal epithelial samples were collected between March 2021 and June 2021. Isolated bacterial DNA from corneal epithelial samples was analyzed using 16 S ribosomal RNA gene analysis. The relative abundance rates at the phylum and genus levels were calculated. Alpha diversity parameters were assessed. RESULTS Eleven phyla and 521 genera of bacteria were identified in all participants. At the phylum level, Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes were most abundant in both groups. There were no statistical differences between the two groups except Bacteriodetes (p < 0.05). At the genus level, the relative abundance rates of twenty bacteria were significantly different between keratoconus and healthy corneas (p < 0.05). Aquabacterium was the most abundant genus in patients with keratoconus, while Shigella was the most abundant genus in healthy controls. Alpha diversity parameters were lower in patients with keratoconus, although the difference did not reach statistical significance (p > 0.05). CONCLUSIONS Our preliminary study revealed that there are similarities and differences in the corneal microbiome between keratoconus and healthy individuals. Further research is required on the relationship between the abnormal corneal microbiome composition and the pathogenesis of keratoconus.
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Affiliation(s)
- Uğur Tunç
- Department of Ophthalmology, Eyupsultan State Hospital, Istanbul, Turkey; Beyoglu Eye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey.
| | - Ar Cenk Çelebi
- Department of Ophthalmology, Acibadem Mehmet Ali Aydinlar University, School of Medicine, Atasehir, Istanbul, Turkey
| | - Berkay Yekta Ekren
- Department of Bioinformatics and Medical Informatics, Acibadem Mehmet Ali Aydinlar University, School of Medicine, Atasehir, Istanbul, Turkey
| | - Yusuf Yıldırım
- Beyoglu Eye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Burçin Kepez Yıldız
- Beyoglu Eye Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Sinem Öktem Okullu
- Department of Medical Microbiology, Acibadem Mehmet Ali Aydinlar University, School of Medicine, Atasehir, Istanbul, Turkey
| | - Osman Uğur Sezerman
- Department of Bioinformatics and Medical Informatics, Acibadem Mehmet Ali Aydinlar University, School of Medicine, Atasehir, Istanbul, Turkey
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Yang L, Liu S, Zhou X, Zhao Y. Correlation between the ablation ratio and posterior corneal stability after small incision lenticule extraction for high myopia. Graefes Arch Clin Exp Ophthalmol 2023:10.1007/s00417-023-05979-5. [PMID: 36662234 DOI: 10.1007/s00417-023-05979-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/06/2022] [Accepted: 01/09/2023] [Indexed: 01/21/2023] Open
Abstract
PURPOSE The aim of this study is to investigate changes in posterior corneal elevation and their correlations with the ablation ratio 3 years after small incision lenticule extraction (SMILE) for high myopia. METHODS Eighty eyes underwent SMILE were enrolled in this study. Eyes were classified into two groups based on the ablation ratio (AR, lenticule thickness from SMILE machine/thinnest corneal thickness): group A (< 25%, 40 eyes) and group B (≥ 25%, 40 eyes). Pentacam was used to measure the posterior corneal elevation at the central point, thinnest point, and posterior maximum elevation (PME) and the mean posterior elevation in the central 2-mm area (MPE-2 mm), 4-mm area, and 6-mm area at the 3-year follow-up. RESULTS More than 85% of the eyes had an AR of less than 27%, and no cases of iatrogenic keratectasia developed. In both groups, for central region, posterior elevation decreased implying backward displacement; for peripheral region, it increased indicating forward trend. There was no significant difference in changes in all determined parameters between the two groups (P ≥ 0.07). Moreover, no significant correlation was noted between AR and posterior elevation changes. In group A, decreasing changes in PME (r = - 0.42, P = 0.01) and MPE-2 mm (r = 0.40, P = 0.01) demonstrated negative correlations with residual bed thickness. CONCLUSION Region-dependent changes were demonstrated in the eyes that underwent SMILE. The central area showed a subtly declining posterior elevation, and the peripheral area showed a slightly increasing elevation. The limited ablation ratio had no impact on the changes in posterior corneal elevation.
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Affiliation(s)
- Liyuan Yang
- Department of Ophthalmology, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Shengtao Liu
- Department of Ophthalmology and Optometry, Eye and ENT Hospital, Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xingtao Zhou
- Department of Ophthalmology and Optometry, Eye and ENT Hospital, Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China. .,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China. .,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
| | - Yu Zhao
- Department of Ophthalmology and Optometry, Eye and ENT Hospital, Fudan University, 83 Fenyang Road, Shanghai, 200031, People's Republic of China. .,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China. .,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
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Danesh Z, Sedaghat MR, Momeni-Moghaddam H, Yekta AA, Belin MW. Corneal Stability and Visual Acuity 1 Year After Corneal Cross-linking Assessed Using the ABCD Keratoconus Staging System. J Refract Surg 2021; 37:700-706. [PMID: 34661479 DOI: 10.3928/1081597x-20210712-09] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess corneal stability and corrected distance visual acuity (CDVA) 3, 6, and 12 months following corneal cross-linking (CXL) using the ABCD keratoconus staging system. METHODS This prospective longitudinal study included 31 eyes with keratoconus receiving CXL based on the standard Dresden protocol. CDVA, refraction, and Scheimpflug tomography with the Pentacam HR (Oculus Optikgeräte GmbH) were evaluated before and after surgery. Geometric and functional changes were assessed using the actual values and staging of each element of the ABCD keratoconus staging system. A, B, C, and D refer to the anterior and posterior radii of curvature in a 3-mm zone centered on the cor-neal thinnest point, minimum corneal thickness, and CDVA, respectively. RESULTS There were no significant changes in the actual values of anterior radius of curvature (P = .497) and CDVA (P = .082), whereas posterior radius of curvature (P = .007) and corneal thinnest point (P < .001) showed significant changes statistically. Pairwise comparison showed only a statistically significant steepening in posterior radius of curvature at 3 months after CXL compared to the preoperative radius (P = .002) and a significant decrease in corneal thinnest point at 3 (P < .001) and 6 (P = .028) months after CXL compared to baseline assessment. Staging of each element of the ABCD keratoconus staging system indicated no change between baseline and 3, 6, and 12 months after CXL. CONCLUSIONS The geometric and functional parameters included in the ABCD keratoconus staging system showed stability of corneal status and CDVA 1 year after CXL. [J Refract Surg. 2021;37(10):700-706.].
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Evaluating keratoconus progression prior to crosslinking: maximum keratometry vs the ABCD grading system. J Cataract Refract Surg 2021; 47:33-39. [PMID: 33181627 DOI: 10.1097/j.jcrs.0000000000000475] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/18/2020] [Indexed: 01/03/2023]
Abstract
PURPOSE To evaluate the correlation between changes in maximum keratometry (Kmax) and ABC values from the ABCD Progression Display (Pentacam) in progressive keratoconus (KC) and to evaluate whether the ABC changes were able to detect progression earlier than Kmax. SETTING Humanitas Clinical and Research Center, Rozzano, Milan, Italy. DESIGN Retrospective study. METHODS Kmax, ABC values, and thinnest point (ThCT) were recorded at the day of corneal crosslinking (CXL) (T0) and previous follow-up (T-1). In patients without earlier progression in Kmax, follow-up examination (T-2) was used to determine whether any of the ABC parameters reached statistical significance for progression. RESULTS Seventy-six eyes of 63 patients scheduled for CXL with documented progression (Kmax increase of >1.00 diopter) were included. There was a significant, albeit moderate, correlation between the change in Kmax between T0 and T-1 and the change in both A (ρ = 0.391) and B values (ρ = 0.339). There was no significant correlation between the change in Kmax between T0 and T-1 and the change in either C or ThCT. In patients with T-2 examinations, 16 (51.6%) of 31 patients showed a statistically significant change on the ABCD progression display that was not detected with Kmax. CONCLUSIONS This study showed a significant, but moderate, correlation between the change in Kmax and the change in A and B values in progressive KC. Moreover, more than half of the cases showed documented progression earlier with the ABCD progression display than that detected by standard Kmax changes. This study suggests possible changes in progression criteria to allow for earlier intervention.
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Repeatability of Zone Averages Compared to Single-Point Measurements of Maximal Curvature in Keratoconus. Am J Ophthalmol 2021; 221:226-234. [PMID: 32800828 DOI: 10.1016/j.ajo.2020.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/06/2020] [Accepted: 08/06/2020] [Indexed: 11/21/2022]
Abstract
PURPOSE To evaluate the repeatability of curvature zone averages centered on the point of maximum curvature (Kmax) compared to that of the single-point Kmax. DESIGN Comparative reliability analysis. METHODS Setting: American University of Beirut Medical Center, Beirut, Lebanon. STUDY POPULATION Sixty-five eyes of 65 adult keratoconus patients. Patients with other ocular disease, history of ocular surgery or trauma, and contact lens wear within 2 weeks of image acquisition were excluded. OBSERVATION PROCEDURES Eyes were evaluated with 3 consecutive scans using the Galilei dual Scheimpflug-Placido system. MAIN OUTCOME MEASURES Repeatability of axial and instantaneous Kmax single points, and zone averages with radii of 0.1-2.0 mm, centered on them. Repeatability was assessed by within-subject standard deviations, repeatability limits (r), and intraclass correlation coefficients. RESULTS Axial curvature zone averaging yielded clinically acceptable repeatability only in eyes with Kmax ≤50 diopters (D), for radii of 1.5 mm and 2.0 mm (r = 0.87 D and r = 0.76, respectively, vs r = 0.91 for the single-point axial Kmax). Compared to instantaneous Kmax, clinically acceptable repeatability was achieved with instantaneous zone averages of at least 1.5 mm radius in eyes with Kmax ≤50 D (r = 0.99 D and r = 0.70 D, respectively) and 2.0 mm radius in eyes with Kmax >50 D (r = 2.28 D and r = 0.87 D, respectively). For all eyes, the repeatability limit of the location of Kmax was 0.82 mm and 0.80 mm for axial and instantaneous curvature, respectively. CONCLUSIONS Instantaneous curvature zone averages centered on Kmax yielded a greater improvement in repeatability than axial zone averages and reached clinical adequacy with radii of at least 1.5 mm, for eyes with Kmax ≤50 D, and with a 2.0 mm radius for eyes with Kmax >50 D.
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Tunç U, Akbaş YB, Yıldırım Y, Kepez Yıldız B, Kırgız A, Demirok A. Repeatability and reliability of measurements obtained by the combined Scheimpflug and Placido-disk tomography in different stages of keratoconus. Eye (Lond) 2020; 35:2213-2220. [PMID: 33106613 DOI: 10.1038/s41433-020-01238-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 09/18/2020] [Accepted: 10/15/2020] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE The objective of this study is to evaluate the repeatability and reliability of corneal parameters in different stages of keratoconus patients using a combined Scheimpflug-Placido disc analysis system. MATERIALS AND METHODS In this prospective study, three consecutive measurements were performed by the same observer using Scheimpflug-Placido disc anterior segment analysis device in keratoconus patients. Flattest and steepest simulated keratometry and corneal volume, corneal aberrations, thinnest corneal thickness, symmetry index, keratoconus vertex and Baiocchi-Calossi-Versaci index were recorded. Keratoconic eyes were divided into four stages using the Amsler-Krumeich classification. Repeatability was evaluated using within the subject standard deviation, repeatability index (Ri) and coefficient of variation; reliability was evaluated by intraclass correlation coefficient (ICC). Pearson correlation coefficients were used to assess the correlation between the parameters evaluated. RESULTS Two hundred sixty-one eyes of 261 keratoconus patients were included in the study. The repeatability for all corneal curvature parameters decreased as the keratoconus severity increased, and there is a positive correlation between keratometry of the apex and corneal curvature parameters (p < 0.05) except mean simulated keratometry. The corneal aberrations were repeatable in all keratoconus subgroups (Ri < 0.34 μm). There are also positive correlations between keratometry of apex and corneal aberrations (p < 0.05) except total high-order root mean square and spherical aberration. The reliability was excellent (ICC > 0.90) for all indices except keratoconus vertex back. CONCLUSION The parameters used in the diagnosis and follow-up of keratoconus in the Sirius corneal tomography system may differ more than expected at stages 3 and 4 of the disease. Awareness of this situation may be helpful in planning follow-up and treatment.
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Affiliation(s)
- Uğur Tunç
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Yusuf Berk Akbaş
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Yusuf Yıldırım
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey.
| | - Burçin Kepez Yıldız
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Kırgız
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Demirok
- University of Health Sciences, Beyoğlu Eye Training and Research Hospital, Istanbul, Turkey
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Longitudinal Evaluation of the Progression of Keratoconus Using a Novel Progression Display. Eye Contact Lens 2019; 45:324-330. [PMID: 30724839 DOI: 10.1097/icl.0000000000000582] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Repeatability of Anterior Curvature Metrics in Healthy and Keratoconic Eyes with a Portable Handheld Topographer. Optom Vis Sci 2018; 95:1142-1148. [PMID: 30451801 DOI: 10.1097/opx.0000000000001307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
SIGNIFICANCE This is a prospective observational investigation that studies the repeatability of several outcomes obtained with the Keratron Scout in healthy and keratoconic corneas. In addition, we have been able to determine the "noise" values of the instrument, which can be very useful when evaluating possible progression in keratoconus (KCN). PURPOSE The purpose of this study was to evaluate the repeatability of several anterior curvature metrics provided by a portable and handheld Placido disk-based topographer in healthy and keratoconic eyes. METHODS One eye from 50 keratoconic patients and 50 eyes from healthy patients were included in this prospective observational study. Two consecutive sessions (with three scans per session) were performed, and the following parameters were analyzed with a Keratron Scout topographer: flat keratometry, steep keratometry, flat corneal axis, corneal astigmatism, and flat and steep asphericities. In addition, in the KCN cohort, indices derived from the Cone Location and Magnitude Index were also recorded. Intrasession (first session, all three measurements) and intersession (one measurement from each session, selected randomly) statistics were calculated. The following variables were calculated: within-subject standard deviation, coefficient of repeatability (R), coefficient of variation, and intraclass correlation coefficient (ICC). RESULTS In healthy eyes, the intrasession and intersession ICCs were high (0.947 to 0.999), and for both flat keratometry and steep keratometry, the within-subject standard deviation was 0.08 and R was 0.24 diopters. Repeatability was slightly lower in the KCN group, but the ICC was greater than 0.95, whereas the R for flat keratometry was 0.41 diopters. CONCLUSIONS The Keratron Scout provides repeatable measures for the studied metrics in healthy and keratoconic eyes.
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Kosekahya P, Koc M, Caglayan M, Kiziltoprak H, Tekin K, Atilgan CU. Longitudinal corneal tomographical changes in eyes of patients with unilateral and bilateral non-progressive keratoconus. Cont Lens Anterior Eye 2018; 42:434-438. [PMID: 30413377 DOI: 10.1016/j.clae.2018.10.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/27/2018] [Accepted: 10/31/2018] [Indexed: 11/19/2022]
Abstract
AIM To evaluate the tomographic indices changes in keratoconic eyes which were classified as unilateral and bilateral non-progressive keratoconus according to the definition of Global Consensus on keratoconus and ectatic disease. METHODS Fifty non-progressive fellow eyes of 50 keratoconus patients who underwent corneal cross-linking treatment for the other progressive eyes (group 1), 50 eyes of 50 keratoconus patients who were followed up as bilateral non-progressive keratoconus (group 2), and 50 eyes of 50 control subjects (group 3) were included in this retrospective study. Topographic, topometric, and Belin-Ambrósio Enhanced Ectasia Display-III indices were recorded at baseline and after six months. RESULTS Groups were similar in terms of age and gender. The changes in topographic parameters and topometric indices were similar among the three groups (p > 0.05 for all values). The maximum pachymetric progression index (PPImax), maximum Ambrósio relational thickness (ARTmax), and final D significantly increased at sixth-months in group 1 (p < 0.001, p = 0.004, and p = 0.02 respectively) but did not change in groups 2 and 3 (p > 0.05 for all values). ARTmax, PPImax, and final D value changes indicated a statistically significant difference among the groups using the one-way ANOVA test (p = 0.03, p = 0.007, and p = 0.03 respectively). The Bonferroni posttest revealed that these values increased at a higher rate in group 1 than in group 2 (p = 0.03, p = 0.01, and p = 0.04 respectively) and group 3 (p = 0.04, p = 0.03, and p = 0.04, respectively). CONCLUSIONS Fellow eyes of keratoconus patients who have underwent CXL for their progressive eyes may be more prone to progress than the patients who have no progression in both eyes. Screening unilateral non-progressive patients more closely than those with bilateral non-progressive patients and evaluating the changes in final D, ARTmax, and PPImax values may be helpful in the follow up of non-progressive keratoconus.
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Affiliation(s)
- Pinar Kosekahya
- Ulucanlar Eye Training and Research Hospital, Department of Ophthalmology, Ankara, Turkey.
| | - Mustafa Koc
- Ulucanlar Eye Training and Research Hospital, Department of Ophthalmology, Ankara, Turkey
| | - Mehtap Caglayan
- Gazi Yasargil Training and Research Hospital, Department of Ophthalmology, Diyarbakir, Turkey
| | - Hasan Kiziltoprak
- Ulucanlar Eye Training and Research Hospital, Department of Ophthalmology, Ankara, Turkey
| | - Kemal Tekin
- Ercis State Hospital, Department of Ophthalmology, Van, Turkey
| | - Cemile Ucgul Atilgan
- Ulucanlar Eye Training and Research Hospital, Department of Ophthalmology, Ankara, Turkey
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Shajari M, Steinwender G, Herrmann K, Kubiak KB, Pavlovic I, Plawetzki E, Schmack I, Kohnen T. Evaluation of keratoconus progression. Br J Ophthalmol 2018; 103:551-557. [PMID: 29858179 DOI: 10.1136/bjophthalmol-2017-311651] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/26/2018] [Accepted: 05/06/2018] [Indexed: 11/03/2022]
Abstract
AIM To define variables for the evaluation of keratoconus progression and to determine cut-off values. METHODS In this retrospective cohort study (2010-2016), 265 eyes of 165 patients diagnosed with keratoconus underwent two Scheimpflug measurements (Pentacam) that took place 1 year apart ±3 months. Variables used for keratoconus detection were evaluated for progression and a correlation analysis was performed. By logistic regression analysis, a keratoconus progression index (KPI) was defined. Receiver-operating characteristic curve (ROC) analysis was performed and Youden Index calculated to determine cut-off values. RESULTS Variables used for keratoconus detection showed a weak correlation with each other (eg, correlation r=0.245 between RPImin and Kmax, p<0.001). Therefore, we used parameters that took several variables into consideration (eg, D-index, index of surface variance, index for height asymmetry, KPI). KPI was defined by logistic regression and consisted of a Pachymin coefficient of -0.78 (p=0.001), a maximum elevation of back surface coefficient of 0.27 and coefficient of corneal curvature at the zone 3 mm away from the thinnest point on the posterior corneal surface of -12.44 (both p<0.001). The two variables with the highest Youden Index in the ROC analysis were D-index and KPI: D-index had a cut-off of 0.4175 (70.6% sensitivity) and Youden Index of 0.606. Cut-off for KPI was -0.78196 (84.7% sensitivity) and a Youden Index of 0.747; both 90% specificity. CONCLUSIONS Keratoconus progression should be defined by evaluating parameters that consider several corneal changes; we suggest D-index and KPI to detect progression.
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Affiliation(s)
- Mehdi Shajari
- Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | - Gernot Steinwender
- Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | - Kim Herrmann
- Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | | | - Ivana Pavlovic
- Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | | | - Ingo Schmack
- Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
| | - Thomas Kohnen
- Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany
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Repeated Same-Day Versus Single Tomography Measurements of Keratoconic Eyes for Analysis of Disease Progression. Cornea 2018; 37:474-479. [PMID: 29319597 PMCID: PMC5844585 DOI: 10.1097/ico.0000000000001513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Purpose: Corneal tomography is used to assess progression of keratoconus and to direct clinical decisions regarding corneal cross-linking. The purpose of this study was to analyze the variability of repeated Scheimpflug-tomography (Pentacam Classic; Oculus, Wetzlar, Germany) measurements of keratoconic eyes in a clinical setting and to assess the validity of such measurements as a clinical decision-making tool. Methods: Eighty keratoconic eyes of 45 patients (age range 16–32 years) were examined at baseline and after follow-up periods of 3 to 6 months using 3 consecutive tomography measurements at each visit. Minimum corneal thickness and anterior sagittal curvature map parameters were studied [simulated keratometry (K) astigmatism (SimKast); maximum simulated K-reading (SimKmax); average SimK (SimKave); maximum K-readings on the 3-mm (Kmax3) and 5-mm (Kmax5) rings; and maximum K-reading (Kmax)]. Results: When comparing the first measurements at the first and second visits, respectively, 9% to 20% of eyes were classified as progressive depending on which parameter was chosen. Using the average of 3 consecutive measurements at each visit, 5% to 19% of eyes were classified as progressive. An increase in the SD of 3 consecutive measurements of SimKast (SD_SimKast) at the first visit of 1 diopter makes true progression of keratoconus 3.6 times more likely (odds ratio = 3.6; 95% confidence interval: 0.846–16.027; area under the curve = 0.70). Conclusions: The approach used to analyze progression in keratoconus, that is, single versus repeated measurements, may confer a great impact on the decision to perform corneal cross-linking treatment or not.
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Combined wavefront-guided transepithelial photorefractive keratectomy and corneal crosslinking for visual rehabilitation in moderate keratoconus. J Cataract Refract Surg 2018; 44:571-580. [DOI: 10.1016/j.jcrs.2018.03.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 03/13/2018] [Accepted: 03/16/2018] [Indexed: 11/24/2022]
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Kosekahya P, Koc M, Caglayan M, Kiziltoprak H, Atilgan CU, Yilmazbas P. Repeatability and reliability of ectasia display and topometric indices with the Scheimpflug system in normal and keratoconic eyes. J Cataract Refract Surg 2018; 44:63-70. [DOI: 10.1016/j.jcrs.2017.10.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 11/16/2022]
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