13 results on '"Corneal tomography"'
Search Results
2. Corneal characteristics in Down syndrome patients with normal and keratoconic cornea
- Author
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Hassan Hashemi and Soheila Asgari
- Subjects
Down syndrome ,corneal structure ,reference range ,keratoconic cornea ,corneal tomography ,Medicine (General) ,R5-920 - Abstract
PurposeTo determine the reference range of corneal indices in Down syndrome patients with normal corneas (DS-N) and to compare it with the corneal indices in Down syndrome patients with keratoconic corneas (DS-KC).MethodsA study was conducted using the data of 154 eyes of 154 DS-N and 25 eyes of 25 DS-KC patients. Eighteen indices related to thickness, anterior chamber, keratometry, elevation, and aberrations routinely used for KC diagnosis were extracted from the Pentacam.ResultsThe mean age of the participants in DS-N and DS-KC groups was 16.73 ± 4.70 and 16.56 ± 4.22 years (P = 0.852). In the DS-N group, 95% CI were 511.65–520.31 for minimum corneal thickness, 2.97–3.07 for anterior chamber depth (ACD), 46.83–47.37 for maximum keratometry (Kmax), 46.13–46.62 for zonal Kmax at 3 mm, 0.35–0.58 for inferior-superior asymmetry (I-S value), 1.56–1.88 for Belin/Ambrósio display-total deviation, 8.65–10.79 for best-fit-sphere posterior elevation at the thinnest point, and 0.18–0.22 for corneal vertical coma. The age-related change in I-S value and corneal spherical aberration (SA) was significant (both P < 0.05). There were significant inter-gender differences in 11 indices; the female DS patients had shallower, steeper, more elevated, and more aberrated corneas (all P < 0.05). There were significant differences in all indices except for ACD (P = 0.372) and corneal SA (P = 0.169) between DS-N and DS-KC groups.ConclusionIn DS patients aged 10–30 years, the reference ranges of corneal indices are different from the range reported for non-DS subjects and are close to values reported for mild KC non-DS cases. The normal values are different between DS male and female; hence, sex-specific ranges should be considered for diagnosis of corneal abnormality in DS patients.
- Published
- 2022
- Full Text
- View/download PDF
3. Determining the center of a keratoconus: Comparison of different tomographic parameters and impact of disease severity
- Author
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Gernot Steinwender, Alexander Kollenc, Mehdi Shajari, Michael Sommer, Andrea Borenich, Jutta Horwath-Winter, Ewald Lindner, Nora Woltsche, Wolfgang List, and Andreas Wedrich
- Subjects
keratoconus ,corneal tomography ,cornea ,customized cross-linking ,ectasia ,Medicine (General) ,R5-920 - Abstract
PurposeThere exists remarkable variation in definitions for the location of the center of a keratoconus. The objective of this study was to analyze deviations between locations obtained by different tomographic maps for that purpose. Furthermore, it was investigated whether these deviations are influenced by disease severity.MethodsIn 162 eyes with keratoconus, corneal tomographic maps derived by Scheimpflug technology were retrospectively analyzed to determine the cone location with 5 different methods: maximum axial curvature of the front surface (Kmax), maximum tangential curvature of the front surface (tKmax), minimum pachymetry (Pachymin), maximum elevation of the front surface (ELEF), and maximum elevation of the back surface (ELEB). Distances between the locations were calculated and tested for a correlation with keratoconus severity and distance between cone and corneal vertex.ResultsCone locations derived from the curvature maps (Kmax, tKmax) showed the lowest agreement with the locations determined by pachymetry or elevation maps. The largest distances were found between Kmax and Pachymin [Median and Interquartile range: 1.19 mm (0.87, 1.60)], Kmax and ELEB [1.12 mm (0.79, 1.41)], and Kmax and ELEF [0.97 mm (0.64, 1.27)]. Low distances (
- Published
- 2022
- Full Text
- View/download PDF
4. Performances of Corneal Topography and Tomography in the Diagnosis of Subclinical and Clinical Keratoconus
- Author
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Cristina Ariadna Nicula, Adriana Elena Bulboacă, Dorin Nicula, Ariadna Patricia Nicula, Karin Ursula Horvath, and Sorana D. Bolboacă
- Subjects
keratoconus ,subclinical keratoconus ,corneal topography ,corneal tomography ,clinical utility ,Medicine (General) ,R5-920 - Abstract
AimThe purpose of the study was to assess the efficacy of topographical and tomographical indices given by the Pentacam (pachymetric, tomopetric, and aberometric) in clinical and subclinical keratoconus (KCN) diagnosis.Material and MethodsIn this observational analytic retrospective study, patients with abnormal findings in topography and tomography maps but with no signs on clinical examination (subclinical KCN group, sKCN), patients with clinical keratoconus (KCN group), and healthy subjects (Control group) were evaluated.ResultsThe KCN group proved significantly different (p < 0.001) values of the investigated parameters than the Control group. Eleven out of 28 investigated parameters proved significantly different in the sKCN group compared to controls (p < 0.001). Two topographic measurements, namely I-S (cut-off = 1.435, a large value indicates the presence of KCN) and CCT (cut-off = 537, a small value indicates the presence of KCN), showed AUCs equal to 1 [0.999 to 1]. Six other Pentacam measurements, including Back maximum keratometry (Back Kmax) proved to be excellent parameters for case-finding and screening. In distinguishing sKCN from normal eyes, Pentacam index of vertical asymmetry (IVA), inferior-superior difference (I-S) value, thinnest point (TP), Belin Ambrosio Enhanced Ectasia Display (BAD_D) and root mean square total (RMS total) performed best.ConclusionsIn distinguishing sKCN from normal eyes, Back Kmax, IVA, I-S, and RMS total values demonstrated higher accuracy and utility. Six indices, namely ISV, IVA, KISA, PRC, RMS-HOA, and Back Kmax demonstrate excellent utility in case-finding and screening for clinical KCN.
- Published
- 2022
- Full Text
- View/download PDF
5. Influence of Ocular Residual Astigmatism and Target-Induced Astigmatism on the Efficacy of the Implantation of a Toric Implantable Collamer Lens With Central Hole for Myopic Astigmatism Correction
- Author
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Jing Zhao, Jiao Zhao, Wen Yang, Ling Sun, Yishan Qian, Xiaoying Wang, and Xingtao Zhou
- Subjects
ocular residual astigmatism ,target-induced astigmatism ,myopic astigmatism ,toric implantable collamer lens ,corneal tomography ,Medicine (General) ,R5-920 - Abstract
PurposeTo investigate the effects of ocular residual astigmatism (ORA) and target-induced astigmatism (TIA) on the efficacy of toric implantable collamer lens (TICL) with central hole for myopic astigmatism correction.MethodsRetrospective case series. One hundred and eighteen eyes implanted with a TICL (V4c) from 118 patients were included. Subjective refraction and corneal topography were examined preoperatively, at 1 and 12 months postoperatively. The eyes were divided into the low-ORA ( ≤ 0.5 D) and high-ORA (>0.5 D) groups based on vector analysis, and into the low-TIA (≥0.75D and 0.05). However, significantly lower IOS was found at 12 months compared with 1 month postoperatively for each group (P < 0.05).ConclusionsToric implantable collamer lens (TICL) implantation is effective in correcting myopic astigmatism and is more effective in eyes with high TIA, while ORA has a minor effect.
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- 2022
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6. Changes in Anterior and Posterior Corneal Elevation in Patients With Allergic Conjunctivitis
- Author
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Qian Wang, Fei Yu, Ziqing Feng, Weihua Li, Naiyang Li, Xinyue Du, Xuan Zhao, Saiqun Li, and Jin Yuan
- Subjects
allergic conjunctivitis ,corneal tomography ,corneal surface elevation ,corneal posterior surface ,corneal biomechanics ,Medicine (General) ,R5-920 - Abstract
Purpose: To evaluate corneal elevation changes in patients with allergic conjunctivitis (AC) and to analyze their correlations with ocular allergy signs and corneal biomechanical alterations.Methods: Thirty patients (30 eyes) with AC and twenty normal subjects (20 eyes) were included in this prospective study. All participants underwent a complete ocular examination, including corneal tomography by Pentacam and corneal biomechanics evaluation by Corvis ST. AC patients were evaluated for their eye rubbing frequency and ocular allergic signs.Results: The elevation at the thinnest location (TE) and the central location (CE), the elevation difference at the thinnest location (TED) and the central location (CED), and the mean value of elevation difference in the central 4 mm zoom (MED) of both the anterior and posterior corneal surface were significantly higher in the AC group than in the normal group (p < 0.05 for all). In AC patients, only anterior corneal elevation parameters were positively correlated with eye rubbing frequency and ocular allergy sign severity (p < 0.05 for all), while the tomography and biomechanical index (TBI) was positively correlated with the elevation parameters of both the anterior and posterior corneal surfaces (p < 0.05 for all).Conclusion: AC patients carry an increased risk of corneal ectasia. Posterior corneal elevation parameters are sensitive and reliable predictors of keratoconus (KC) risk in AC patients.Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT04299399, identifier [NCT04299399].
- Published
- 2021
- Full Text
- View/download PDF
7. Editorial: Progressive keratoconus: insights into etiopathogenesis, diagnosis, and treatment.
- Author
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Nicula CA and Bulboaca AE
- Abstract
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Published
- 2023
- Full Text
- View/download PDF
8. Changes in Anterior and Posterior Corneal Elevation in Patients With Allergic Conjunctivitis
- Author
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Naiyang Li, Saiqun Li, Weihua Li, Xuan Zhao, Qian Wang, Jin Yuan, Ziqing Feng, Xinyue Du, and Fei Yu
- Subjects
Medicine (General) ,Keratoconus ,medicine.medical_specialty ,genetic structures ,R5-920 ,Ophthalmology ,Medicine ,In patient ,corneal tomography ,Prospective cohort study ,Original Research ,business.industry ,corneal posterior surface ,General Medicine ,Corneal tomography ,medicine.disease ,eye diseases ,Allergic conjunctivitis ,Ocular allergy ,Normal group ,allergic conjunctivitis ,Increased risk ,corneal surface elevation ,sense organs ,corneal biomechanics ,business - Abstract
Purpose: To evaluate corneal elevation changes in patients with allergic conjunctivitis (AC) and to analyze their correlations with ocular allergy signs and corneal biomechanical alterations.Methods: Thirty patients (30 eyes) with AC and twenty normal subjects (20 eyes) were included in this prospective study. All participants underwent a complete ocular examination, including corneal tomography by Pentacam and corneal biomechanics evaluation by Corvis ST. AC patients were evaluated for their eye rubbing frequency and ocular allergic signs.Results: The elevation at the thinnest location (TE) and the central location (CE), the elevation difference at the thinnest location (TED) and the central location (CED), and the mean value of elevation difference in the central 4 mm zoom (MED) of both the anterior and posterior corneal surface were significantly higher in the AC group than in the normal group (p < 0.05 for all). In AC patients, only anterior corneal elevation parameters were positively correlated with eye rubbing frequency and ocular allergy sign severity (p < 0.05 for all), while the tomography and biomechanical index (TBI) was positively correlated with the elevation parameters of both the anterior and posterior corneal surfaces (p < 0.05 for all).Conclusion: AC patients carry an increased risk of corneal ectasia. Posterior corneal elevation parameters are sensitive and reliable predictors of keratoconus (KC) risk in AC patients.Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT04299399, identifier [NCT04299399].
- Published
- 2021
- Full Text
- View/download PDF
9. Determining the center of a keratoconus: Comparison of different tomographic parameters and impact of disease severity.
- Author
-
Steinwender G, Kollenc A, Shajari M, Sommer M, Borenich A, Horwath-Winter J, Lindner E, Woltsche N, List W, and Wedrich A
- Abstract
Purpose: There exists remarkable variation in definitions for the location of the center of a keratoconus. The objective of this study was to analyze deviations between locations obtained by different tomographic maps for that purpose. Furthermore, it was investigated whether these deviations are influenced by disease severity., Methods: In 162 eyes with keratoconus, corneal tomographic maps derived by Scheimpflug technology were retrospectively analyzed to determine the cone location with 5 different methods: maximum axial curvature of the front surface (Kmax), maximum tangential curvature of the front surface (tKmax), minimum pachymetry (Pachymin), maximum elevation of the front surface (ELEF), and maximum elevation of the back surface (ELEB). Distances between the locations were calculated and tested for a correlation with keratoconus severity and distance between cone and corneal vertex., Results: Cone locations derived from the curvature maps (Kmax, tKmax) showed the lowest agreement with the locations determined by pachymetry or elevation maps. The largest distances were found between Kmax and Pachymin [Median and Interquartile range: 1.19 mm (0.87, 1.60)], Kmax and ELEB [1.12 mm (0.79, 1.41)], and Kmax and ELEF [0.97 mm (0.64, 1.27)]. Low distances (<0.5 mm) were calculated between ELEB and ELEF, and ELEB and Pachymin. All of the calculated distances between the locations showed a significant negative correlation with keratoconus severity and most of them increased significantly with a more peripheral position of the cone ( p < 0.05)., Conclusions: There was low consistency between different methods for describing the location of a keratoconus. Curvature-based determinations of the cone center (Kmax, tKmax) showed the highest deviations and should not be used for that purpose. However, the discrepancies between different cone location methods diminished with increasing disease severity and more central position of the cone., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Steinwender, Kollenc, Shajari, Sommer, Borenich, Horwath-Winter, Lindner, Woltsche, List and Wedrich.)
- Published
- 2022
- Full Text
- View/download PDF
10. Corneal characteristics in Down syndrome patients with normal and keratoconic cornea.
- Author
-
Hashemi H and Asgari S
- Abstract
Purpose: To determine the reference range of corneal indices in Down syndrome patients with normal corneas (DS-N) and to compare it with the corneal indices in Down syndrome patients with keratoconic corneas (DS-KC)., Methods: A study was conducted using the data of 154 eyes of 154 DS-N and 25 eyes of 25 DS-KC patients. Eighteen indices related to thickness, anterior chamber, keratometry, elevation, and aberrations routinely used for KC diagnosis were extracted from the Pentacam., Results: The mean age of the participants in DS-N and DS-KC groups was 16.73 ± 4.70 and 16.56 ± 4.22 years ( P = 0.852). In the DS-N group, 95% CI were 511.65-520.31 for minimum corneal thickness, 2.97-3.07 for anterior chamber depth (ACD), 46.83-47.37 for maximum keratometry (Kmax), 46.13-46.62 for zonal Kmax at 3 mm, 0.35-0.58 for inferior-superior asymmetry (I-S value), 1.56-1.88 for Belin/Ambrósio display-total deviation, 8.65-10.79 for best-fit-sphere posterior elevation at the thinnest point, and 0.18-0.22 for corneal vertical coma. The age-related change in I-S value and corneal spherical aberration (SA) was significant (both P < 0.05). There were significant inter-gender differences in 11 indices; the female DS patients had shallower, steeper, more elevated, and more aberrated corneas (all P < 0.05). There were significant differences in all indices except for ACD ( P = 0.372) and corneal SA ( P = 0.169) between DS-N and DS-KC groups., Conclusion: In DS patients aged 10-30 years, the reference ranges of corneal indices are different from the range reported for non-DS subjects and are close to values reported for mild KC non-DS cases. The normal values are different between DS male and female; hence, sex-specific ranges should be considered for diagnosis of corneal abnormality in DS patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hashemi and Asgari.)
- Published
- 2022
- Full Text
- View/download PDF
11. Performances of Corneal Topography and Tomography in the Diagnosis of Subclinical and Clinical Keratoconus.
- Author
-
Nicula CA, Bulboacă AE, Nicula D, Nicula AP, Horvath KU, and Bolboacă SD
- Abstract
Aim: The purpose of the study was to assess the efficacy of topographical and tomographical indices given by the Pentacam (pachymetric, tomopetric, and aberometric) in clinical and subclinical keratoconus (KCN) diagnosis., Material and Methods: In this observational analytic retrospective study, patients with abnormal findings in topography and tomography maps but with no signs on clinical examination (subclinical KCN group, sKCN), patients with clinical keratoconus (KCN group), and healthy subjects (Control group) were evaluated., Results: The KCN group proved significantly different (p < 0.001) values of the investigated parameters than the Control group. Eleven out of 28 investigated parameters proved significantly different in the sKCN group compared to controls ( p < 0.001). Two topographic measurements, namely I-S (cut-off = 1.435, a large value indicates the presence of KCN) and CCT (cut-off = 537, a small value indicates the presence of KCN), showed AUCs equal to 1 [0.999 to 1]. Six other Pentacam measurements, including Back maximum keratometry (Back Kmax) proved to be excellent parameters for case-finding and screening. In distinguishing sKCN from normal eyes, Pentacam index of vertical asymmetry (IVA), inferior-superior difference (I-S) value, thinnest point (TP), Belin Ambrosio Enhanced Ectasia Display (BAD_D) and root mean square total (RMS total) performed best., Conclusions: In distinguishing sKCN from normal eyes, Back Kmax, IVA, I-S, and RMS total values demonstrated higher accuracy and utility. Six indices, namely ISV, IVA, KISA, PRC, RMS-HOA, and Back Kmax demonstrate excellent utility in case-finding and screening for clinical KCN., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Nicula, Bulboacă, Nicula, Nicula, Horvath and Bolboacă.)
- Published
- 2022
- Full Text
- View/download PDF
12. Influence of Ocular Residual Astigmatism and Target-Induced Astigmatism on the Efficacy of the Implantation of a Toric Implantable Collamer Lens With Central Hole for Myopic Astigmatism Correction.
- Author
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Zhao J, Zhao J, Yang W, Sun L, Qian Y, Wang X, and Zhou X
- Abstract
Purpose: To investigate the effects of ocular residual astigmatism (ORA) and target-induced astigmatism (TIA) on the efficacy of toric implantable collamer lens (TICL) with central hole for myopic astigmatism correction., Methods: Retrospective case series. One hundred and eighteen eyes implanted with a TICL (V4c) from 118 patients were included. Subjective refraction and corneal topography were examined preoperatively, at 1 and 12 months postoperatively. The eyes were divided into the low-ORA ( ≤ 0.5 D) and high-ORA (>0.5 D) groups based on vector analysis, and into the low-TIA (≥0.75D and <2 D) and the high-TIA (≥2 D and ≤ 4 D) groups according to preoperative refractive astigmatism. Correction index (CI) and index of success (IOS) were compared between different groups., Results: All surgeries were uneventful, and no complications occurred during follow-up. At 1 and 12 months postoperatively, no significant differences were found in CI or IOS values between the high and low ORA groups, while significantly higher CI and lower IOS were detected in the high-TIA group than in the low-TIA group ( P < 0.05). No significant difference was found in CI between 1 and 12 months postoperatively in either group ( P > 0.05). However, significantly lower IOS was found at 12 months compared with 1 month postoperatively for each group ( P < 0.05)., Conclusions: Toric implantable collamer lens (TICL) implantation is effective in correcting myopic astigmatism and is more effective in eyes with high TIA, while ORA has a minor effect., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhao, Zhao, Yang, Sun, Qian, Wang and Zhou.)
- Published
- 2022
- Full Text
- View/download PDF
13. Changes in Anterior and Posterior Corneal Elevation in Patients With Allergic Conjunctivitis.
- Author
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Wang Q, Yu F, Feng Z, Li W, Li N, Du X, Zhao X, Li S, and Yuan J
- Abstract
Purpose: To evaluate corneal elevation changes in patients with allergic conjunctivitis (AC) and to analyze their correlations with ocular allergy signs and corneal biomechanical alterations. Methods: Thirty patients (30 eyes) with AC and twenty normal subjects (20 eyes) were included in this prospective study. All participants underwent a complete ocular examination, including corneal tomography by Pentacam and corneal biomechanics evaluation by Corvis ST. AC patients were evaluated for their eye rubbing frequency and ocular allergic signs. Results: The elevation at the thinnest location (TE) and the central location (CE), the elevation difference at the thinnest location (TED) and the central location (CED), and the mean value of elevation difference in the central 4 mm zoom (MED) of both the anterior and posterior corneal surface were significantly higher in the AC group than in the normal group ( p < 0.05 for all). In AC patients, only anterior corneal elevation parameters were positively correlated with eye rubbing frequency and ocular allergy sign severity ( p < 0.05 for all), while the tomography and biomechanical index (TBI) was positively correlated with the elevation parameters of both the anterior and posterior corneal surfaces ( p < 0.05 for all). Conclusion: AC patients carry an increased risk of corneal ectasia. Posterior corneal elevation parameters are sensitive and reliable predictors of keratoconus (KC) risk in AC patients. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04299399, identifier [NCT04299399]., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wang, Yu, Feng, Li, Li, Du, Zhao, Li and Yuan.)
- Published
- 2021
- Full Text
- View/download PDF
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