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Langenbucher A, Hoffmann P, Cayless A, Wendelstein J, Szentmáry N. Evaluation of corneal power from an AS-OCT thick lens model and ray tracing: reliability of the keratometer index. J Cataract Refract Surg 2024; 50:360-368. [PMID: 37962174 DOI: 10.1097/j.jcrs.0000000000001363] [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: 07/27/2023] [Accepted: 11/07/2023] [Indexed: 11/15/2023]
Abstract
PURPOSE To investigate and compare different strategies of corneal power calculations using keratometry, paraxial thick lens calculations and ray tracing. SETTING Tertiary care center. DESIGN Retrospective single-center consecutive case series. METHODS Using a dataset with 9780 eyes of 9780 patients from a cataractous population the corneal front (Ra/Qa) and back (Rp/Qp) surface radius/asphericity, central corneal thickness (CCT), and entrance pupil size (PUP) were recorded using the Casia 2 tomographer. Beside keratometry with the Zeiss (PK Z ) and Javal (PK J ) keratometer index, a thick lens paraxial formula (PG) and ray tracing (PR) was implemented to extract corneal power for pupil sizes from 2 mm to 5 mm in steps of 1 mm and PUP. RESULTS With PUP PK Z /PK J overestimates the paraxial corneal power PG in around 97%/99% of cases and PR in around 80% to 85%/99%. PR is around 1/6 or 5/6 diopters (D) lower compared with PK Z or PK J . For a 2 mm pupil PR is around 0.20/0.91 D lower compared with PK Z /PK J and for a 5 mm pupil PR is comparable with PK Z (around 0.03 D lower) but around 0.70 to 0.75 D lower than PK J . CONCLUSIONS "True" values of corneal power are mostly required in lens power calculations before cataract surgery, and overestimation of corneal power could induce trend errors in refractive outcome with axial length and lens power if compensated with the effective lens position.
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Affiliation(s)
- Achim Langenbucher
- From the Department of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany (Langenbucher, Wendelstein); Augen- und Laserklinik Castrop-Rauxel, Castrop-Rauxel, Germany (Hoffmann); School of Physical Sciences, The Open University, Milton Keynes, United Kingdom (Cayless); Department of Ophthalmology, Johannes Kepler University Linz, Linz, Austria (Wendelstein); Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg/Saar, Germany (Szentmáry); Department of Ophthalmology, Semmelweis-University, Budapest, Hungary (Szentmáry)
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Moshirfar M, Harvey DH, Wang Q, Payne CJ, West DG, Hoopes PC. Comparison of Corneal Power Difference Maps with Achieved Myopic Correction Using Scheimpflug Tomography After LASIK, PRK, and SMILE. Clin Ophthalmol 2023; 17:1717-1727. [PMID: 37361690 PMCID: PMC10290189 DOI: 10.2147/opth.s419327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/08/2023] [Indexed: 06/28/2023] Open
Abstract
Purpose To compare corneal power difference maps (∆maps) obtained from the Pentacam in patients with 1 year follow-up after LASIK, PRK, and SMILE with further stratification to low, moderate, and high myopia. Patients and methods This retrospective study was comprised of patients who had preoperative and 1-year postoperative power maps that were obtained-front sagittal (SagF), refractive power (RP), true net power (TNP), and total corneal refractive power (TCRP)-for evaluation. Measurements were recorded and compared at the 4mm, 5mm and 6mm pupil and apex zones. Comparisons were made between each specific power ∆map and the surgically induced refractive change (SIRC). Further analysis of the ∆maps was performed based on degree of myopia (high, moderate, and low). Correlation and agreement were also assessed with regression and limits of agreement (LoA). Results There were 172 eyes in the LASIK group, 187 eyes in the PRK group, and 46 eyes in the SMILE group. In the LASIK group, TNP ∆map at 5mm pupil zone had the least absolute mean difference with SIRC (0.007 ± 0.42D). In the PRK group, TNP ∆map at 5mm apex zone was most accurate compared to SIRC (0.066 ± 0.45D). In the SMILE group, TCRP ∆map at 4mm apex zone had the closest absolute value when compared to SIRC (0.011 ± 0.50D). There was good correlation and agreement for all three surgery groups, LASIK: r = 0.975, LoA -0.83D to +0.83D, PRK: r = 0.96, LoA -0.83D and +0.95D, and SMILE: r = 0.922, LoA -0.97 D to +0.99D. Conclusion TNP ∆maps most accurately measured corneal power in the LASIK and PRK groups while TCRP ∆maps were most accurate in the SMILE group. The degree of myopia may change which ∆map is most accurate.
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Affiliation(s)
- Majid Moshirfar
- Hoopes Vision Research Center, Hoopes Vision, Draper, UT, USA
- John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA
- Utah Lions Eye Bank, Murray, UT, USA
| | | | | | - Carter J Payne
- Hoopes Vision Research Center, Hoopes Vision, Draper, UT, USA
- Department of Ophthalmology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - David G West
- University of Utah School of Medicine, Salt Lake City, UT, USA
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Güçlü H, Akaray İ, Kaya S, Sattarpanah S, Çınar AC, Sakallıoğlu K, Korkmaz S, Gürlü V. Agreement of Anterior Segment Parameters Between Schiempflug Topography and Swept-Source Optic Coherence Based Optic Biometry in Keratoconus and Healthy Subjects. Eye Contact Lens 2021; 47:539-545. [PMID: 33813587 DOI: 10.1097/icl.0000000000000787] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of this study is to compare anterior segment parameters, including corneal thickness (CCT), keratometry and anterior chamber depth (ACD), and white to white corneal diameter (WTW), obtained by Pentacam Schiempflug imaging and intraocular lens (IOL) Master 700 swept-source optic coherence tomography biometry in keratoconus patients and healthy subjects. METHODS This prospective cross-sectional instrument agreement analysis includes 88 eyes of 50 keratoconus patients and 87 eyes of 50 healthy subjects. Biometry was performed using IOL Master 700, and topography was performed using Pentacam. The keratometry values (Kf, Ks, Km, and Kmax), ACD, WTW, CCT, axial length (AL), anterior chamber angle (ACA), and lens thickness (LT) were evaluated. Levels of agreement between devices were evaluated by Bland-Altman plots with 95% limits of agreement. RESULTS Intraocular lens Master 700 showed higher WTW, ACD, pupil diameter, and CCT values than Pentacam in both the keratoconus and control groups. However, there were no statistically significant differences in flat keratometry (Kf) and steep keratometry (Ks) values between the groups. CONCLUSION Pentacam and IOL Master 700 may be used interchangeably in normal eyes and keratoconus eyes for the measurement of keratometry values and axis; however, these two devices should not be considered interchangeable for WTW, ACD, pupil diameter, and CCT measurements in both keratoconus patients and healthy subjects.
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Affiliation(s)
- Hande Güçlü
- Department of Ophthalmology (H.G., İ.A., S. Kaya, S.S., A.C.Ç., K.S., V.G.), Trakya University of Medicine, Edirne, Turkey; and Department of Biostatistics and Medical Informatics (S. Korkmaz), Trakya University of Medicine, Edirne, Turkey
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Wang Q, Chen M, Ning R, Savini G, Wang Y, Zhang T, Lin X, Chen X, Huang J. The Precision of a New Anterior Segment Optical Coherence Tomographer and Its Comparison With a Swept-Source OCT-Based Optical Biometer in Patients With Cataract. J Refract Surg 2021; 37:616-622. [PMID: 34506238 DOI: 10.3928/1081597x-20210610-02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE To assess the precision of a new spectral-domain optical coherence tomographer (SD-OCT)/Placido topographer (MS-39; CSO) and its comparison with a swept-source OCT (SS-OCT) biometer (Argos; Movu, Inc) in patients with cataract. METHODS Fifty-three right eyes from 53 patients were examined by two experienced operators three times using both devices randomly. Employing the within-subject standard deviation (Sw), test-retest variability, coefficient of variation, and intraclass correlation coefficient to evaluate intraoperator repeatability and interoperator reproducibility; the double-angle plots to analyze astigmatism; and Bland-Altman plots and 95% limits of agreement to verify the agreement between devices. RESULTS The SD-OCT/Placido tomographer showed high precision, with coefficient of variation of 0.44% or less, intraclass correlation coefficient of 0.945 or greater for all parameters, test-retest variability of 4.21 µm or less for central corneal thickness (CCT), 0.03 mm or less for anterior chamber depth (ACD) and aqueous depth (AQD), and 0.25 diopters (D) or less for mean keratometry (Km), J0, and J45. The inter-device differences in Km, J0, and J45 were statistically insignificant, whereas the remaining were statistically but not clinically significant. The 95% limits of agreement of CCT, ACD, AQD, Km, J0, and J45 were -3.70 to 15.25 µm, -0.06 to 0.04 mm, -0.06 to 0.04 mm, -0.28 to 0.35 D, -0.27 to 0.26 D, and -0.27 to 0.21 D, respectively. The double-angle plot confirmed the high agreement in astigmatism. CONCLUSIONS For CCT, ACD, AQD, Km, and astigmatism measurements in patients with cataract, the new SD-OCT/Placido tomographer has excellent precision and high agreement with the Argos SS-OCT biometer, and can be used interchangeably. [J Refract Surg. 2021;37(9):616-622.].
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Agreement and repeatability of corneal tomography in healthy eyes using a novel Swept-Source optical coherence tomographer, a rotating Scheimpflug camera and a dual Scheimpflug-Placido system. J Cataract Refract Surg 2021; 48:190-198. [PMID: 34224476 DOI: 10.1097/j.jcrs.0000000000000734] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 06/22/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate the accordance and repeatability of tomographic parameters measured by a novel Swept-Source optical coherence tomographer (SS-OCT, ANTERION), a rotating Scheimpflug camera (RSC, Pentacam) and a dual Scheimpflug-Placido system (DSP, Galilei G6). SETTING Department of Ophthalmology of Univ. Hospital Carl Gustav Carus, Dresden, Germany. DESIGN Prospective reliability analysis. METHODS Thirty randomly selected eyes of 30 healthy participants were enrolled in this study. Normal tomography were ensured by bilaterally evaluating appropriated parameters using RSC. All subjects received three consecutive measurements on each device by the same operator and in the uniform order RSC, SS-OCT and DSP. Anterior (ACP) and posterior (PCP) corneal parameters such as flat and steep keratometry and corneal thickness were analyzed. Repeatability was assessed by using a coefficient of repeatability (CR) and a coefficient of variation (CV). Agreement between RSC and SS-OCT as well as RSC and DSP were shown by Bland-Altman plots (BA). RESULTS CR of ACP did not exceed 0.5 D. There were no statistical differences in repeatability of ACP obtained from the three devices (P>0.05). For PCP and corneal thickness there was statistically significant higher repeatability mostly found for SS-OCT as opposed to RSC and DSP (P<0.05). For a wide range of analyzed parameters there were large limits of agreement (95%-LoA) found between the devices. CONCLUSION The SS-OCT showed highly repeatable measurements in healthy subjects regarding anterior, posterior and corneal thickness parameters. Repeatability of ACP did not differ between the devices. A mostly wide range of 95%-LoA prevents interchangeability between the devices.
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Corneal Topography for Intraocular Lens Selection in Refractive Cataract Surgery. Ophthalmology 2020; 128:e142-e152. [PMID: 33221325 DOI: 10.1016/j.ophtha.2020.11.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 10/26/2020] [Accepted: 11/13/2020] [Indexed: 11/22/2022] Open
Abstract
The purpose of this review is to evaluate the usefulness of corneal topography to select premium intraocular lenses (IOLs), including aspherical IOLs, toric IOLs, and multifocal IOLs, in refractive cataract surgery. Corneal topography can detect corneal regular astigmatism, corneal irregular astigmatism (higher-order aberrations [HOAs]) including spherical aberration, and corneal shape abnormalities after corneal refractive surgery. Surgeons can explain to the patients with significant corneal HOAs about its effect on postoperative visual function before surgery. Multifocal IOLs should not be selected for such eyes. For eyes with abnormal corneal shape, appropriate IOL power calculation formulae can be applied. In the case of toric IOLs, regular astigmatism and corneal HOAs should be checked. Before implanting an aspheric IOL, it is ideal to confirm spherical aberration of the cornea is not below the normal range. Because corneal HOAs, abnormal corneal shape after corneal refractive surgery, corneal regular astigmatism, and corneal spherical aberration increase postoperative refractive errors and poor vision quality with premium IOLs, corneal topography before cataract surgery is helpful in screening patients who are not appropriate candidates for premium IOLs.
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de Luis Eguileor B, Acera A, Santamaría Carro A, Feijoo Lera R, Escudero Argaluza J, Etxebarria Ecenarro J. Changes in the corneal thickness and limbus after 1 year of scleral contact lens use. Eye (Lond) 2020; 34:1654-1661. [PMID: 31822857 PMCID: PMC7608222 DOI: 10.1038/s41433-019-0729-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 10/16/2019] [Accepted: 11/21/2019] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To assess the physiological changes in the cornea over time in patients with irregular cornea fitted with Rose K2 XL gas-permeable scleral contact lenses. METHODS Prospective study of 16 eyes of patients who did not tolerate gas-permeable corneal contact lenses and were fitted with Rose K2 XL scleral lenses. We assessed the central vault and the corneal thickness centrally and at peripheral regions (2 to 5 mm annulus). All these measures were obtained by anterior segment optical coherence tomography. The measurements were taken immediately after fitting the lenses and 1, 6 and 12 months later. Prior to the study and at 1 year, we performed an objective test for diagnosing limbal stem cell deficiency (Limbokit). RESULTS The mean vault was 201.7 ± 82.3 µm 20 min after fitting the contact lens; 189.4 ± 94.0 µm at 1 month; 165.1 ± 75.9 µm at 6 months and 142.1 ± 76.8 µm at 1 year, the values at 6 and 12 months being significantly different to baseline. After 1 year, the central corneal thickness had increased by 2.3% (IQR = 5.6), but the changes were only significant for the superior thickness. There is no limbal stem cell deficiency after 1 year of scleral contact lens use. CONCLUSIONS After use of Rose K2 XL scleral contact lenses, the corneal physiology of patients with an irregular cornea remains unchanged, as assessed by corneal thickness measurements and the Limbokit test. In all cases, however, the vault decreased over time.
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Affiliation(s)
| | - Arantxa Acera
- Bioftalmik, Parque Tecnológico de Vizcaya, Derio, Spain
| | | | | | - Julene Escudero Argaluza
- Unidad de Epidemiología Clínica, Hospital Universitario Cruces/Biocruces Health Research Institute, Barakaldo, Spain
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Zhao Y, Chen D, Savini G, Wang Q, Zhang H, Jin Y, Song B, Ning R, Huang J, Mei C. The precision and agreement of corneal thickness and keratometry measurements with SS-OCT versus Scheimpflug imaging. EYE AND VISION 2020; 7:32. [PMID: 32528997 PMCID: PMC7285531 DOI: 10.1186/s40662-020-00197-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 05/19/2020] [Indexed: 11/23/2022]
Abstract
Purpose To assess the repeatability and reproducibility of swept-source optical coherence tomography (SS-OCT) and Scheimpflug system and evaluate the agreement between the two systems in measuring multiple corneal regions in children. Methods Pachymetric and keratometric maps for both systems were evaluated. Central, midperipheral and peripheral corneal thickness (CT), keratometry and astigmatism power vectors were recorded. The three outcomes yielded by the same observer were used to assess intraobserver repeatability. The differences in the mean values provided by each observer were used to evaluate interobserver reproducibility. Within-subject standard deviation, test-retest repeatability (TRT) and coefficient of variation (CoV) were used to analyze the intraobserver repeatability and interobserver reproducibility. Paired T-test and Bland-Altman were used to appraise interdevice agreement. Results Seventy-eight eyes of 78 children were included. The CoV was ≤2.12 and 1.10%, respectively, for repeatability and reproducibility. TRT and CoV were lower for central and paracentral CT measurements than for peripheral measurements. The SS-OCT device generated higher precision when acquiring CT data, whereas Scheimpflug system showed higher reliability when measuring corneal keratometry. Although the CT readings measured using SS-OCT were significantly thinner than Scheimpflug device (P < 0.001), the central and thinnest CT values were still of high agreement. The interdevice agreement of keratometry measurement was high for the central corneal region and moderate for the paracentral and peripheral areas. Conclusions The precision of CT measurements by SS-OCT was higher, while the reliability of keratometry measurements by the Scheimpflug system was higher in children. Apart from the measured values in the central corneal region, the thickness and keratometry readings should not be considered interchangeable between the two systems.
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Affiliation(s)
- Yune Zhao
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China.,Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang China
| | - Ding Chen
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China
| | | | - Qing Wang
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Hongfang Zhang
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China.,Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang China
| | - Yili Jin
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Benhao Song
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Rui Ning
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Jinhai Huang
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China.,Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang China.,Eye Hospital of Wenzhou Medical University, 270 West Xueyuan Road, Wenzhou, 325027 Zhejiang China
| | - Chenyang Mei
- School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang China.,Key Laboratory of Vision Science, Ministry of Health P.R. China, Wenzhou, Zhejiang China.,Eye Hospital of Wenzhou Medical University, 270 West Xueyuan Road, Wenzhou, 325027 Zhejiang China
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Longitudinal evaluation of posterior corneal power by anterior segment optical coherence tomography 18 months following photorefractive keratectomy. J Cataract Refract Surg 2020; 46:1159-1164. [PMID: 32355080 DOI: 10.1097/j.jcrs.0000000000000224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the change in anterior, posterior, and net corneal power more than 18 months after photorefractive keratectomy (PRK) by RTVue anterior segment optical coherence tomography (OCT). SETTING Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN Prospective observational study. METHODS PRK was performed using Technolas TENEO 317 laser platform. Anterior, posterior, and net corneal power was measured by the RTVue-XR anterior segment OCT system with the Pachymetry + Cpwr scan pattern at baseline and months 1, 3, 6, 12, 18, and more than 18 (up to 27) after PRK. RESULTS Three hundred twenty-six eyes of 163 patients (61 men [37.4%], 102 women [62.6%]; mean age 29.71 years; range 18.5 to 46.5 years) were enrolled in this study. Mean preoperative spherical equivalent was -3.15 ± 1.50 diopter (D) (range -8.37 to -0.62 D). The mean change in net corneal power was 3.052 D, 3.281 D, 3.324 D, 3.114 D, 3.446 D, and 3.972 D at months 1, 3, 6, 12, 18, and more than 18 postoperatively compared with baseline, respectively (P < .001 for all comparisons). The mean change in posterior corneal power at postoperative visits compared with baseline was not statistically significant (P > .1) except for 1 month postoperatively, which increased by 0.13 D (P < .001). Changes in posterior corneal power were not correlated with any of the preoperative clinical and Scheimpflug variables. CONCLUSIONS Posterior corneal power did not change for more than 18 months after PRK, except for an early small increase at 1 month postoperatively.
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Piñero DP, Camps VJ, de Fez D, García C, Caballero MT. Validation of posterior corneal curvature measurements with color light-emitting diode topography. Eur J Ophthalmol 2019; 30:1261-1267. [PMID: 31432704 DOI: 10.1177/1120672119870738] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To evaluate the intrasession repeatability and validity of posterior corneal curvature and astigmatism measurements provided by a color light-emitting diode reflection topography system in healthy eyes. METHODS A total of 40 healthy eyes of 40 patients (age, 16-66 years) were enrolled. A complete eye examination was performed in all cases including posterior topographic analysis with two systems: the Scheimpflug-based system (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany) and the Cassini system (i-Optics; Ophthec, The Hague, The Netherlands). With this last system, three consecutive measurements were taken to assess the level of intrasession repeatability (within-subject standard deviation, Sw; intraclass correlation coefficient). The Bland & Altman analysis was used to evaluate the interchangeability of both devices. RESULTS The Sw was ⩽0.06 mm for all posterior corneal radius measurements, with intraclass correlation coefficient of ⩾0.960. The Sw for the magnitude of astigmatism, J0, and J45 were 0.15, 0.04, and 0.04 D, respectively, with intraclass correlation coefficient values of 0.876, 0.897, and 0.840, respectively. Statistically significant differences between devices were found in all parameters evaluated (p ⩽ 0.025). The interchangeability analysis revealed the presence of clinically relevant limits of agreement for the flattest (0.03 to 0.50 mm) and steepest posterior corneal radii (-0.01 to 0.39 mm). In contrast, limits of agreements were not clinically relevant for the magnitude of posterior astigmatism (-0.17 to 0.27 D) and their power vector components (-0.11 to 0.15 D). CONCLUSION The Cassini system provides consistent measures of posterior corneal curvature and astigmatism in healthy eyes, but only measures of posterior astigmatism can be considered as interchangeable with those provided by the Pentacam.
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Affiliation(s)
- David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain.,Department of Ophthalmology, Vithas Medimar International Hospital, Alicante, Spain
| | - Vicent J Camps
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Dolores de Fez
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Celia García
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
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Analysis of Intrasession Repeatability of Ocular Aberrometric Measurements and Validation of Keratometry Provided by a New Integrated System in Mild to Moderate Keratoconus. Cornea 2019; 38:1097-1104. [DOI: 10.1097/ico.0000000000002034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Das M, Menda SA, Panigrahi AK, Venkatesh Prajna N, Yen M, Tsang B, Kumar A, Rose-Nussbaumer J, Acharya NR, McCulloch CE, Lietman TM, McLeod SD, Keenan JD. Repeatability and Reproducibility of Slit Lamp, Optical Coherence Tomography, and Scheimpflug Measurements of Corneal Scars. Ophthalmic Epidemiol 2019; 26:251-256. [PMID: 31018742 DOI: 10.1080/09286586.2019.1600199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Purpose: To determine the repeatability and reproducibility of anterior segment optical coherence tomography (AS-OCT) and Scheimpflug photography for several measurements of corneal scars, including scar size, scar depth, and corneal thickness. Methods: A series of patients treated for fungal keratitis at a tertiary eye care center in South India were recalled two years after successful treatment. Eyes with corneal scars had a slit lamp examination performed by two ophthalmologists masked to the other's examination. For AS-OCT and Scheimpflug photography, each eye had two scans taken by one technician and a third scan taken by a separate technician. Scar measurements were subsequently assessed from AS-OCT images by three graders masked to each other's results. Repeatability and reproducibility were assessed by calculating the intra-class correlation coefficient (ICC) from mixed effects linear regression models. Results: Fifty eyes had all measurements taken. The corneal scar size, measured as the geometric mean of the two longest perpendicular meridians, ranged from 0.8 to 5.4 (mean 2.8 mm, 95%CI 2.6 to 3.1). Scar size measurements taken by two separate individuals were most reproducible when the border of the scar was traced from the OCT (ICC 0.90, 95%CI 0.86 to 0.94), and least repeatable when assessed from slit lamp examination (ICC 0.80, 95%CI 0.70 to 0.90). Conclusions: AS-OCT and Scheimpflug imaging of corneal scars produced measurements with acceptable reproducibility that could be useful as cornea-specific outcomes for clinical trials.
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Affiliation(s)
- Manoranjan Das
- a Department of Cornea and External Disease , Aravind Eye Care System , Madurai , India
| | - Shivali A Menda
- b Department of Ophthalmology , University of California , San Francisco , USA
| | - Arun K Panigrahi
- a Department of Cornea and External Disease , Aravind Eye Care System , Madurai , India
| | - N Venkatesh Prajna
- a Department of Cornea and External Disease , Aravind Eye Care System , Madurai , India
| | - Michael Yen
- c Francis I. Proctor Foundation, University of California , San Francisco , USA
| | - Betty Tsang
- c Francis I. Proctor Foundation, University of California , San Francisco , USA
| | - Alisha Kumar
- c Francis I. Proctor Foundation, University of California , San Francisco , USA
| | - Jennifer Rose-Nussbaumer
- b Department of Ophthalmology , University of California , San Francisco , USA.,c Francis I. Proctor Foundation, University of California , San Francisco , USA
| | - Nisha R Acharya
- b Department of Ophthalmology , University of California , San Francisco , USA.,c Francis I. Proctor Foundation, University of California , San Francisco , USA
| | - Charles E McCulloch
- d Department of Epidemiology & Biostatistics, University of California , San Francisco , USA
| | - Thomas M Lietman
- b Department of Ophthalmology , University of California , San Francisco , USA.,c Francis I. Proctor Foundation, University of California , San Francisco , USA.,d Department of Epidemiology & Biostatistics, University of California , San Francisco , USA.,e Institute for Global Health , University of California , San Francisco , USA
| | - Stephen D McLeod
- b Department of Ophthalmology , University of California , San Francisco , USA.,c Francis I. Proctor Foundation, University of California , San Francisco , USA
| | - Jeremy D Keenan
- b Department of Ophthalmology , University of California , San Francisco , USA.,c Francis I. Proctor Foundation, University of California , San Francisco , USA
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Piñero DP, Soto-Negro R, Ruiz-Fortes P, Pérez-Cambrodí RJ, Fukumitsu H. Interchangeability of corneal curvature and asphericity measurements provided by three different devices. Int J Ophthalmol 2019; 12:412-416. [PMID: 30918809 DOI: 10.18240/ijo.2019.03.10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/17/2018] [Indexed: 12/22/2022] Open
Abstract
AIM To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles. METHODS A total of 40 eyes of 40 patients with a mean age of 34.1y were included. In all cases, a corneal curvature analysis was performed with IOL-Master (IOLM), iDesign 2 (ID2), and Sirius systems (SIR). Differences between instruments for flattest (K1) and steepest (K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity (Q) between SIR and ID2 were also evaluated. RESULTS Mean differences between devices for K1 were 0.20±0.21 (P<0.001), -0.12±0.36 (P=0.046) and -0.32±0.36 D (P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33 (P<0.001), -0.08±0.43 (P=0.265) and -0.39±0.38 D (P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance (0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis (26.68°, 33.83° and 18.37°, P≥0.121) and for Q between SIR and ID2 (0.16, P<0.001). CONCLUSION The keratometric corneal power, astigmatic axis and asphericity measurements provide by the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.
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Affiliation(s)
- David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, San Vicente del Raspeig 03690, Alicante, Spain.,Department of Ophthalmology (OFTALMAR), Vithas Medimar International Hospital, Alicante 03014, Spain
| | - Roberto Soto-Negro
- Department of Ophthalmology (OFTALMAR), Vithas Medimar International Hospital, Alicante 03014, Spain
| | - Pedro Ruiz-Fortes
- Department of Ophthalmology (OFTALMAR), Vithas Medimar International Hospital, Alicante 03014, Spain
| | - Rafael J Pérez-Cambrodí
- Department of Ophthalmology (OFTALMAR), Vithas Medimar International Hospital, Alicante 03014, Spain
| | - Hideki Fukumitsu
- Department of Ophthalmology (OFTALMAR), Vithas Medimar International Hospital, Alicante 03014, Spain.,Department of Ophthalmology, Marina Baixa Hospital, Villajoyosa 03570, Alicante, Spain
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Evaluation of the Reliability and Repeatability of Scheimpflug System Measurement in Keratoconus. Cornea 2018; 37:177-181. [PMID: 28957978 DOI: 10.1097/ico.0000000000001373] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess the reliability and repeatability of the parameters obtained using a Scheimpflug system (Pentacam HR-high resolution) for monitoring progression in eyes with keratoconus. METHODS A prospective study was conducted based on measurements taken with the Pentacam HR in 82 eyes with keratoconus. We calculated the intraclass correlation coefficient (ICC) and the repeatability limit for topographic and aberrometric parameters. RESULTS All the parameters analyzed had excellent ICCs, above 0.95 in all cases, except for the measurement of the anterior best-fit sphere, for which the ICC was 0.873. The key repeatability limits for the parameters analyzed were as follows: 1.54 diopters (D) for the maximum keratometry in the central cornea, 1.08 D for maximum keratometry, 32.6 degrees for the axis of corneal astigmatism, 11.9 degrees for the coma axis, and 14.2 μm for thinnest corneal thickness. CONCLUSIONS The level of repeatability of the measurements obtained with a Pentacam HR confirms the usefulness of this system for the diagnosis of keratoconus. Nevertheless, it has certain limitations for monitoring individual progression of keratoconus and planning intrastromal corneal ring segment insertion.
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Precision of a new ocular biometer in eyes with cataract using swept source optical coherence tomography combined with Placido-disk corneal topography. Sci Rep 2017; 7:13736. [PMID: 29061989 PMCID: PMC5653855 DOI: 10.1038/s41598-017-13800-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 10/02/2017] [Indexed: 11/08/2022] Open
Abstract
The present study was to assess the precision (repeatability and reproducibility) of a new optical biometer (OA-2000, Tomey, Japan) based on swept-source optical coherence tomography (SS-OCT) and Placido disk topography in eyes with cataracts. Seventy-eight eyes from seventy-eight patients with cataracts were evaluated. Axial length (AL), anterior chamber depth (ACD), keratometry (K) over a 2.5 mm and 3.0 mm diameter, lens thickness (LT), central corneal thickness (CCT) and white-to-white (WTW) distance were measured by 2 skilled operators. OA-2000 measurements were highly repeatable and reproducible for all parameters (intraclass correlation, 0.925 to 1.000). OA-2000 derived K-values with a diameter of 3.0mm showed narrower 95% limits of agreement (LoA) (SRK/T: −0.18 to 0.16D; Holladay 1: −0.20 to 0.19D; Hoffer Q: −0.22 to 0.20D) than those with a diameter of 2.5 mm for IOL power calculations (SRK/T: −0.20 to 0.20D; Holladay 1: −0.23 to 0.23D; Hoffer Q: −0.25 to 0.25D). The precision (repeatability and reproducibility) of the OA-2000 was excellent for all parameters. The 3.0mm diameter K-readings appear to be the most reliable choice for calculation of IOL power with the OA-2000. In addition, the average values determined from each operator’s 3 consecutive readings were more reproducible.
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Applications of Anterior Segment Optical Coherence Tomography in Cornea and Ocular Surface Diseases. J Ophthalmol 2016; 2016:4971572. [PMID: 27721988 PMCID: PMC5046038 DOI: 10.1155/2016/4971572] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 07/31/2016] [Indexed: 11/29/2022] Open
Abstract
Optical coherence tomography (OCT) is a noncontact technology that produces high-resolution cross-sectional images of ocular tissues. Anterior segment OCT (AS-OCT) enables the precise visualization of anterior segment structure; thus, it can be used in various corneal and ocular surface disorders. In this review, the authors will discuss the application of AS-OCT for diagnosis and management of various corneal and ocular surface disorders. Use of AS-OCT for anterior segment surgery and postoperative management will also be discussed. In addition, application of the device for research using human data and animal models will be introduced.
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Findl O, Hirnschall N. Principles of corneal measurement for intraocular lens power calculation. EXPERT REVIEW OF OPHTHALMOLOGY 2016. [DOI: 10.1586/17469899.2016.1164596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mir TA, Woreta FA, Bower KS. The role of the posterior corneal surface in surgical planning. EXPERT REVIEW OF OPHTHALMOLOGY 2015. [DOI: 10.1586/17469899.2015.1116386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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