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Francis M, Matalia H, John AA, Matalia J, Chinnappaiah N, Bhandary P, Shetty R, Nuijts RMMA, Sinha Roy A. Minimum Corneal Diameter and Anterior Steep Axis Curvature Share the Same Meridian: A Novel Finding. Am J Ophthalmol 2023; 256:175-185. [PMID: 37669730 DOI: 10.1016/j.ajo.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/25/2023] [Accepted: 08/25/2023] [Indexed: 09/07/2023]
Abstract
PURPOSE To define the external scleral sulcus (ESS) on a Scheimpflug image and use it for a morphometric analysis of corneal diameter (CD). DESIGN Retrospective, cross-sectional study of pediatric Asian-Indian eyes. METHODS One random eye of 353 subjects between 5 and 18 years underwent 25-scan Pentacam HR imaging. For all scans, densitometry values along the anterior corneal edge were recorded and differentiated. The peaks on the differentiated curve were chosen as the ESS points, and this distance between them was called CD. Vertical (vCD), maximum (maxCD), minimum (minCD) CD and their meridians were defined. Multiple regression models (MRMs) with CD and other Pentacam parameters were built to predict astigmatism and its axis, mean keratometry (Kmean), and Belin/Ambrósio enhanced ectasia display deviation (BAD-D). MRMs were validated using intraclass correlation coefficient (ICC). Estimated horizontal CD (hCD) was validated against digital caliper measurement using ICC. RESULTS The ICC (95% CI) between caliper and hCD was 0.96 (0.93, 0.97). MRM predictions (P < .001) used CD parameters, anterior chamber depth, corneal volume and distance from the corneal thinnest location to apex. These predictions achieved an ICC of 0.34 (0.18, 0.46), 0.82 (0.78, 0.86), 0.87 (0.84, 0.89), and 0.81 (0.76, 0.84), respectively. The astigmatism axis prediction depended on the minCD and maxCD meridians. Its within-subject SD (4.97°) was less than 2 consecutive Pentacam scan angles (7.2°). CONCLUSIONS The CD metric strongly correlated with the astigmatism axis, keratometry, and BAD-D. Its spatial description may be significant in corneal treatment planning and disease diagnoses.
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Affiliation(s)
- Mathew Francis
- From the Imaging, Biomechanics and Mathematical Modelling Solutions, Narayana Nethralaya Foundation (M.F., A.S.R.), Bangalore, India; Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Himanshu Matalia
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Ansu Ann John
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Jyoti Matalia
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Nandini Chinnappaiah
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Prarthana Bhandary
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Rohit Shetty
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India; University Eye Clinic Maastricht, Maastricht University Medical Center (MUMC+) (M.F., R.S., R.M.M.A.N.), Maastricht, Netherlands
| | - Rudy M M A Nuijts
- University Eye Clinic Maastricht, Maastricht University Medical Center (MUMC+) (M.F., R.S., R.M.M.A.N.), Maastricht, Netherlands
| | - Abhijit Sinha Roy
- From the Imaging, Biomechanics and Mathematical Modelling Solutions, Narayana Nethralaya Foundation (M.F., A.S.R.), Bangalore, India.
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Mejia-Salgado G, Cifuentes-González C, Rojas-Carabali W, Zarate-Pinzón L, Peña-Pulgar LF, Polania D, Cruz-Reyes DL, de-la-Torre A. Colombian Ocular Diseases Epidemiology Study (CODES): incidence and sociodemographic characterisation of keratoconus between 2015 and 2020. BMJ Open Ophthalmol 2023; 8:bmjophth-2023-001238. [PMID: 37278430 DOI: 10.1136/bmjophth-2023-001238] [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: 01/07/2023] [Accepted: 04/08/2023] [Indexed: 06/07/2023] Open
Abstract
OBJECTIVE To estimate the incidence and describe the demographic characteristics of keratoconus (KC) in Colombia using national health registry data between January 1st 2015 and December 31th 2020. METHODS AND ANALYSIS We conducted a nationwide, population-based study using the Integrated Social Protection Information System from the Colombian Ministry of Health, the unique official database in the country. We used the International Classification of Diseases code for KC (H186) to identify the number of new cases of KC and estimate the incidence rates both overall and according to age and sex. We made a standard morbidity ratio map to graph Colombia's morbidity risk of KC onset. RESULTS Of 50 372 424 subjects, 21 710 had KC between 2015 and 2020. However, due to the COVID-19 pandemic, all the incidence rates of this study were based on the 18 419 reported until 2019. The incidence rate in the general population was 10.36 (95% CI 10.08 to 10.64) per 100 000 inhabitants. The incidence peak among males was in their early 20s and females in their late 20s. The overall male to female incidence rate ratio was 1.60. Regarding the distribution of the disease, most cases were reported in Bogotá (48.64%), Antioquia (14.04%) and Cundinamarca (10.38%). CONCLUSION We performed the first nationwide, population-based study of KC in Latin America, finding distribution patterns similar to those reported in the literature. This study provides valuable information on the epidemiology of KC in Colombia, which is helpful in the development of policies for the diagnosis, prevention and treatment of the disease.
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Affiliation(s)
- Germán Mejia-Salgado
- Neuroscience Research Group (NEUROS), NeuroVitae Center. Institute of Translational Medicine (IMT). Escuela de Medicina y Ciencias de la Salud. Universidad del Rosario, Bogotá, Colombia
- Ophthalmology Interest Group, Neuroscience (NEUROS) Research Group, Neurovitae Research Center, Institute of Translational Medicine (IMT), Universidad Del Rosario Escuela de Medicina y Ciencias de la Salud, Bogotá, Colombia
| | - Carlos Cifuentes-González
- Neuroscience Research Group (NEUROS), NeuroVitae Center. Institute of Translational Medicine (IMT). Escuela de Medicina y Ciencias de la Salud. Universidad del Rosario, Bogotá, Colombia
| | - William Rojas-Carabali
- Neuroscience Research Group (NEUROS), NeuroVitae Center. Institute of Translational Medicine (IMT). Escuela de Medicina y Ciencias de la Salud. Universidad del Rosario, Bogotá, Colombia
| | - Laura Zarate-Pinzón
- Neuroscience Research Group (NEUROS), NeuroVitae Center. Institute of Translational Medicine (IMT). Escuela de Medicina y Ciencias de la Salud. Universidad del Rosario, Bogotá, Colombia
- Ophthalmology Interest Group, Neuroscience (NEUROS) Research Group, Neurovitae Research Center, Institute of Translational Medicine (IMT), Universidad Del Rosario Escuela de Medicina y Ciencias de la Salud, Bogotá, Colombia
| | - Luisa Fernanda Peña-Pulgar
- Neuroscience Research Group (NEUROS), NeuroVitae Center. Institute of Translational Medicine (IMT). Escuela de Medicina y Ciencias de la Salud. Universidad del Rosario, Bogotá, Colombia
- Ophthalmology Interest Group, Neuroscience (NEUROS) Research Group, Neurovitae Research Center, Institute of Translational Medicine (IMT), Universidad Del Rosario Escuela de Medicina y Ciencias de la Salud, Bogotá, Colombia
| | - Diego Polania
- Neuroscience Research Group (NEUROS), NeuroVitae Center. Institute of Translational Medicine (IMT). Escuela de Medicina y Ciencias de la Salud. Universidad del Rosario, Bogotá, Colombia
- Ophthalmology Interest Group, Neuroscience (NEUROS) Research Group, Neurovitae Research Center, Institute of Translational Medicine (IMT), Universidad Del Rosario Escuela de Medicina y Ciencias de la Salud, Bogotá, Colombia
| | - Danna Lesley Cruz-Reyes
- Grupo de Investigación Clínica, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Alejandra de-la-Torre
- Neuroscience Research Group (NEUROS), NeuroVitae Center. Institute of Translational Medicine (IMT). Escuela de Medicina y Ciencias de la Salud. Universidad del Rosario, Bogotá, Colombia
- Ophthalmology Interest Group, Neuroscience (NEUROS) Research Group, Neurovitae Research Center, Institute of Translational Medicine (IMT), Universidad Del Rosario Escuela de Medicina y Ciencias de la Salud, Bogotá, Colombia
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Baraya M, Moore J, Lopes BT, Wu R, Bao F, Zheng X, Consejo A, Abass A. Limitations of Reconstructing Pentacam Rabbit Corneal Tomography by Zernike Polynomials. BIOENGINEERING (BASEL, SWITZERLAND) 2022; 10:bioengineering10010039. [PMID: 36671611 PMCID: PMC9854916 DOI: 10.3390/bioengineering10010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 12/30/2022]
Abstract
The study aims to investigate the likelihood of Zernike polynomial being used for reconstructing rabbit corneal surfaces as scanned by the Pentacam segment tomographer, and hence evaluate the accuracy of corneal power maps calculated from such Zernike fitted surfaces. The study utilised a data set of both eyes of 21 rabbits using a reverse engineering approach for deductive reasoning. Pentacam raw elevation data were fitted to Zernike polynomials of orders 2 to 20. The surface fitting process to Zernike polynomials was carried out using randomly selected 80% of the corneal surface data points, and the root means squared fitting error (RMS) was determined for the other 20% of the surface data following the Pareto principle. The process was carried out for both the anterior and posterior surfaces of the corneal surfaces that were measured via Pentacam scans. Raw elevation data and the fitted corneal surfaces were then used to determine corneal axial and tangential curvature maps. For reconstructed surfaces calculated using the Zernike fitted surfaces, the mean and standard deviation of the error incurred by the fitting were calculated. For power maps computed using the raw elevation data, different levels of discrete cosine transform (DCT) smoothing were employed to infer the smoothing level utilised by the Pentacam device. The RMS error was not significantly improved for Zernike polynomial orders above 12 and 10 when fitting the anterior and posterior surfaces of the cornea, respectively. This was noted by the statistically non-significant increase in accuracy when the order was increased beyond these values. The corneal curvature calculations suggest that a smoothing process is employed in the corneal curvature maps outputted by the Pentacam device; however, the exact smoothing method is unknown. Additionally, the results suggest that fitting corneal surfaces to high-order Zernike polynomials will incur a clinical error in the calculation of axial and tangential corneal curvature of at least 0.16 ± 01 D and 0.36 ± 0.02 D, respectively. Rabbit corneal anterior and posterior surfaces scanned via the Pentacam were optimally fitted to orders 12 and 10 Zernike polynomials. This is essential to get stable values of high-order aberrations that are not affected by Zernike polynomial fittings, such as comas for Intracorneal Ring Segments (ICRS) adjustments or spherical aberration for pre-cataract operations. Smoothing was necessary to replicate the corneal curvature maps outputted by the Pentacam tomographer, and fitting corneal surfaces to Zernike polynomials introduces errors in the calculation of both the axial and tangential corneal curvatures.
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Affiliation(s)
- Mohamed Baraya
- Department of Production Engineering and Mechanical Design, Faculty of Engineering, Port Said University, Port Said 42526, Egypt
| | - Jessica Moore
- Department of Civil Engineering and Industrial Design, School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
| | - Bernardo T. Lopes
- Department of Civil Engineering and Industrial Design, School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
- Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo 04017-030, Brazil
| | - Richard Wu
- Brighten Optix Corporation, Shilin District, Taipei 11167, Taiwan
| | - FangJun Bao
- Eye Hospital, Wenzhou Medical University, Wenzhou 325035, China
| | - XiaoBo Zheng
- Eye Hospital, Wenzhou Medical University, Wenzhou 325035, China
| | - Alejandra Consejo
- Department Applied Physics, University of Zaragoza, 50009 Zaragoza, Spain
| | - Ahmed Abass
- Department of Production Engineering and Mechanical Design, Faculty of Engineering, Port Said University, Port Said 42526, Egypt
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
- Correspondence:
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The Efficiency of Using Mirror Imaged Topography in Fellow Eyes Analyses of Pentacam HR Data. Symmetry (Basel) 2021. [DOI: 10.3390/sym13112132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Purpose: To investigate the effectiveness of flipping left corneas topography and analysethem quantitively along with fellow right corneas based on the assumption that they are mirror images of each other. Methods: The study involved scanning both eyes of 177 healthy participants (aged 35.3 ± 15.8) and 75 keratoconic participants (aged 33.9 ± 17.8). Clinical tomography data were collected for both eyes using the Pentacam HR and processed by a fully automated custom-built MATLAB code. For every case, the right eye was used as a datum fixed surface while the left cornea was flipped around in the superior–inferior direction. In this position, the root-mean-squared difference (RMS) between the flipped left cornea and the right cornea was initially determined for both the anterior and posterior corneal surfaces. Next, the iterative closest point transformation algorithm was applied on the three-dimensional flipped cornea to allow the flipped left corneal anterior surface to translate and rotate, minimising the difference between it and the right corneal anterior surface. Then, the RMS differences were recalculated and compared. Results: A comparison of the dioptric powers showed a significant difference between the RMS of both the flipped left eyes and the right eyes in the healthy and the KC groups (p < 0.001). The RMS of the surfaces of the flipped left corneas and the right corneas was 0.6 ± 0.4 D among the healthy group and 4.1 ± 2.3 among the KC group. After transforming the flipped left corneas, the RMS was recorded as 0.5 ± 0.3 D and 2.4 ± 2 D among the healthy and KC groups, respectively. Conclusions: Although fellow eyes are highly related in their clinical parameters, they should be treated with care when one eye topography is flipped and processed with the other eye topography in an optic-related research analysis where translation might be needed. In KC, an asymmetric disease, it was observed that a portion of the asymmetry was due to a corneal apex shift interfering with the image acquisition. Therefore, transforming the flipped left eyes by rotation and translation results in a fairer comparison between the fellow KC corneas.
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Bagheri NM, Kadkhodaei M, Pirhadi S, Mosaddegh P. Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis. Sci Rep 2021; 11:14433. [PMID: 34257343 PMCID: PMC8277910 DOI: 10.1038/s41598-021-93821-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 06/30/2021] [Indexed: 11/08/2022] Open
Abstract
The implementation of intracorneal ring segments (ICRS) is one of the successfully applied refractive operations for the treatment of keratoconus (kc) progression. The different selection of ICRS types along with the surgical implementation techniques can significantly affect surgical outcomes. Thus, this study aimed to investigate the influence of ICRS implementation techniques and design on the postoperative biomechanical state and keratometry results. The clinical data of three patients with different stages and patterns of keratoconus were assessed to develop a three-dimensional (3D) patient-specific finite-element model (FEM) of the keratoconic cornea. For each patient, the exact surgery procedure definitions were interpreted in the step-by-step FEM. Then, seven surgical scenarios, including different ICRS designs (complete and incomplete segment), with two surgical implementation methods (tunnel incision and lamellar pocket cut), were simulated. The pre- and postoperative predicted results of FEM were validated with the corresponding clinical data. For the pre- and postoperative results, the average error of 0.4% and 3.7% for the mean keratometry value ([Formula: see text]) were predicted. Furthermore, the difference in induced flattening effects was negligible for three ICRS types (KeraRing segment with arc-length of 355, 320, and two separate 160) of equal thickness. In contrast, the single and double progressive thickness of KeraRing 160 caused a significantly lower flattening effect compared to the same type with constant thickness. The observations indicated that the greater the segment thickness and arc-length, the lower the induced mean keratometry values. While the application of the tunnel incision method resulted in a lower [Formula: see text] value for moderate and advanced KC, the induced maximum Von Mises stress on the postoperative cornea exceeded the induced maximum stress on the cornea more than two to five times compared to the pocket incision and the preoperative state of the cornea. In particular, an asymmetric regional Von Mises stress on the corneal surface was generated with a progressive ICRS thickness. These findings could be an early biomechanical sign for a later corneal instability and ICRS migration. The developed methodology provided a platform to personalize ICRS refractive surgery with regard to the patient's keratoconus stage in order to facilitate the efficiency and biomechanical stability of the surgery.
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Affiliation(s)
- Niksa Mohammadi Bagheri
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Mahmoud Kadkhodaei
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Shiva Pirhadi
- Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, 14778-93855, Iran
| | - Peiman Mosaddegh
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
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Zhou D, Abass A, Lopes B, Eliasy A, Hayes S, Boote C, Meek KM, Movchan A, Movchan N, Elsheikh A. Fibril density reduction in keratoconic corneas. J R Soc Interface 2021; 18:20200900. [PMID: 33622146 DOI: 10.1098/rsif.2020.0900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
This study aims to estimate the reduction in collagen fibril density within the central 6 mm radius of keratoconic corneas through the processing of microstructure and videokeratography data. Collagen fibril distribution maps and topography maps were obtained for seven keratoconic and six healthy corneas, and topographic features were assessed to detect and calculate the area of the cone in each keratoconic eye. The reduction in collagen fibril density within the cone area was estimated with reference to the same region in the characteristic collagen fibril maps of healthy corneas. Together with minimum thickness and mean central corneal refractive power, the cone area was correlated with the reduction in the cone collagen fibrils. For the corneas considered, the mean area of keratoconic cones was 3.30 ± 1.90 mm2. Compared with healthy corneas, fibril density in the cones of keratoconic corneas was lower by as much as 35%, and the mean reduction was 17 ± 10%. A linear approximation was developed to relate the magnitude of reduction to the refractive power, minimum corneal thickness and cone area (R2 = 0.95, p < 0.001). Outside the cone area, there was no significant difference between fibril arrangement in healthy and keratoconic corneas. The presented method can predict the mean fibril density in the keratoconic eye's cone area. The technique can be applied in microstructure-based finite-element models of the eye to regulate its stiffness level and the stiffness distribution within the areas affected by keratoconus.
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Affiliation(s)
- Dong Zhou
- Department of Mathematical Sciences, School of Physical Sciences, University of Liverpool, Liverpool, UK
| | - Ahmed Abass
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, UK.,Department of Production Engineering and Mechanical Design, Faculty of Engineering, Port Said University, Egypt
| | - Bernardo Lopes
- Department of Civil Engineering and Industrial Design, School of Engineering, University of Liverpool, Liverpool, UK.,Department of Ophthalmology, Federal University of Sao Paulo, Brazil
| | - Ashkan Eliasy
- Department of Civil Engineering and Industrial Design, School of Engineering, University of Liverpool, Liverpool, UK
| | - Sally Hayes
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Craig Boote
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Keith M Meek
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Alexander Movchan
- Department of Mathematical Sciences, School of Physical Sciences, University of Liverpool, Liverpool, UK
| | - Natalia Movchan
- Department of Mathematical Sciences, School of Physical Sciences, University of Liverpool, Liverpool, UK
| | - Ahmed Elsheikh
- Department of Civil Engineering and Industrial Design, School of Engineering, University of Liverpool, Liverpool, UK.,Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing 100083, People's Republic of China.,NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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Eliasy A, Abass A, Lopes BT, Vinciguerra R, Zhang H, Vinciguerra P, Ambrósio R, Roberts CJ, Elsheikh A. Characterization of cone size and centre in keratoconic corneas. J R Soc Interface 2020; 17:20200271. [PMID: 32752996 DOI: 10.1098/rsif.2020.0271] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A novel method to locate the centre of keratoconus (KC) and the transition zone between the pathological area and the rest of the corneal tissue is proposed in this study. A spherical coordinate system was used to generate a spherical height map measured relative to the centre of the optimal sphere fit, and normal to the surface. The cone centre was defined as the point with the maximum height. Second derivatives of spherical height were then used to estimate the area of pathology in an iterative process. There was mirror symmetry between cone centre locations in both eyes. The mean distance between cone centre and corneal apex was 1.45 ± 0.25 mm (0.07-2.00), the mean cone height normal to the surface was 37 ± 23 µm (2-129) and 75 ± 45 µm (5-243) in the anterior and posterior surfaces, respectively. There was a significant negative correlation between the cone height and the radius of the sphere of optimal fit (p < 0.05 for both anterior and posterior surfaces). On average, posterior cone height was larger than the corresponding anterior cone height by 37 ± 24 µm (0-158). The novel method proposed can be used to estimate the cone centre and area, and explore the changes in anterior and posterior corneal surfaces that take place with KC progression. It can help improve understanding of keratoconic corneal morphology and assist in developing customized treatments.
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Affiliation(s)
- Ashkan Eliasy
- School of Engineering, University of Liverpool, Liverpool, UK
| | - Ahmed Abass
- School of Engineering, University of Liverpool, Liverpool, UK
| | - Bernardo T Lopes
- School of Engineering, University of Liverpool, Liverpool, UK.,Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.,Department of Ophthalmology, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
| | | | - Haixia Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, People's Republic of China
| | - Paolo Vinciguerra
- Department of Biomedical Science, Humanitas University, Via Manzoni 56, Rozzano, Milan, Italy.,Eye Center, Humanitas Clinical and Research Center, Via Manzoni 56, Rozzano, Milan, Italy
| | - Renato Ambrósio
- Department of Ophthalmology, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil.,Department of Ophthalmology, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
| | - Cynthia J Roberts
- Department of Ophthalmology and Visual Science and Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, UK.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, People's Republic of China.,NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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Schröder S, Eppig T, Liu W, Schrecker J, Langenbucher A. Keratoconic eyes with stable corneal tomography could benefit more from custom intraocular lens design than normal eyes. Sci Rep 2019; 9:3479. [PMID: 30837552 PMCID: PMC6401116 DOI: 10.1038/s41598-019-39904-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 01/31/2019] [Indexed: 12/18/2022] Open
Abstract
We investigated whether eyes with keratoconic corneal tomography pattern could benefit more from aberration correction with custom intraocular lenses (IOLs) than normal cataractous eyes despite the effect of misalignment on the correction of aberrations. Custom IOLs (cIOLs) were calculated for twelve normal and twelve keratoconic eyes using personalized numerical ray tracing models. The Stiles-Crawford weighted root-mean-square spot-size (wRMS) at the virtual fovea was evaluated for cIOLs and aberration-neutral IOLs (nIOLs) in a simulated clinical study with 500 virtual IOL implantations per eye and per IOL. IOL misalignment (decentration, tilt, rotation) and pupillary ectopia (4.5 mm iris aperture) were varied upon each virtual implantation. The nIOLs achieved average wRMS of 16.4 ± 4.3 μm for normal, and 92.7 ± 34.4 μm for keratoconic eyes (mean ± standard deviation). The cIOLs reduced the average wRMS to 10.3 ± 5.8 μm for normal, and 28.5 ± 18.6 μm for keratoconic eyes. The cIOLs produced smaller wRMS than nIOLs in most virtual implantations (86.7% for normal and 99.4% for keratoconic eyes). IOL misalignment resulted in larger wRMS variations in the keratoconus group than in the normal group. Custom freeform IOL-optics-design may become a promising option for the correction of advanced aberrations in eyes with non-progressive keratoconic corneal tomography pattern.
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Affiliation(s)
- Simon Schröder
- Saarland University, Institute of Experimental Ophthalmology, Kirrberger Str. 100, Bldg. 22, D-66424, Homburg/Saar, Germany.
| | - Timo Eppig
- Saarland University, Institute of Experimental Ophthalmology, Kirrberger Str. 100, Bldg. 22, D-66424, Homburg/Saar, Germany
| | - Weidi Liu
- Saarland University, Institute of Experimental Ophthalmology, Kirrberger Str. 100, Bldg. 22, D-66424, Homburg/Saar, Germany
- University of Rochester, Institute of Optics, 275 Hutchison Road, Rochester, NY, 1427-0186, USA
- Rice University, 301 Space Science, 6100 Main, St Houston, TX, 77005, USA
| | - Jens Schrecker
- Rudolf-Virchow-Klinikum Glauchau, Department of Ophthalmology, Virchowstr. 18, D-08371, Glauchau, Germany
| | - Achim Langenbucher
- Saarland University, Institute of Experimental Ophthalmology, Kirrberger Str. 100, Bldg. 22, D-66424, Homburg/Saar, Germany
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Abass A, Lopes BT, Jones S, White L, Clamp J, Elsheikh A. Non-Orthogonal Refractive Lenses for Non-Orthogonal Astigmatic Eyes. Curr Eye Res 2019; 44:781-789. [PMID: 30829079 DOI: 10.1080/02713683.2019.1589523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Purpose: To present a novel design method for non-orthogonal lenses to reduce the problem of residual astigmatism in non-orthogonal, astigmatic eyes Methods: A method to create spectacle trial lenses with non-orthogonal power axes was developed based on a novel optimised light ray-tracing algorithm rather than conventional lens design methods which could not fully eliminate spherical aberration. Using this method, three sets of refraction trial lenses were made with the angles between power axes of each set controlled at 80°, 70° and 60°, respectively. Within each set, the cylindrical power varied from -1.00 D to -6.00 D in 1.00 D steps in addition to a -0.50 D lens. Computer-based numerical simulation of the lenses optical performance was carried out to apply orthogonal and non-orthogonal lenses on simulated astigmatic eyes. Subsequently, three clinical trial cases were investigated. Results: Computer-simulated optical performance of non-orthogonal lenses showed the ability to achieve high performance in correcting non-orthogonal astigmatism. Subsequently, three patients with irregular astigmatism were refracted with the non-orthogonal lens sets, and clinically observed improvement at least two lines in the LogMAR chart was achieved in all three cases, compared with correction with orthogonal lenses, along with subjective improvement in image quality. Conclusions: Non-orthogonal astigmatism, which is commonly ignored by current eye prescription systems, is taken into account in this study in the design of spectacle and soft contact lenses. The new approach considers the possible non-orthogonal positions of the eye's two optical power meridians and appears to be better able to correct the vision of irregular astigmatic eyes and significantly reduce residual astigmatism.
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Affiliation(s)
- Ahmed Abass
- a School of Engineering , University of Liverpool , Liverpool , UK
| | - Bernardo T Lopes
- a School of Engineering , University of Liverpool , Liverpool , UK.,b Department of Ophthalmology , The Federal University of São Paulo , São Paulo , Brazil
| | - Steve Jones
- a School of Engineering , University of Liverpool , Liverpool , UK
| | - Lynn White
- c Department of Research and Development , UltraVision CLPL , Leighton Buzzard , UK
| | - John Clamp
- c Department of Research and Development , UltraVision CLPL , Leighton Buzzard , UK
| | - Ahmed Elsheikh
- a School of Engineering , University of Liverpool , Liverpool , UK.,d National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology , London , UK.,e School of Biological Science and Biomedical Engineering , Beihang University , Beijing , China
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