The Repeatability of Axial Length Measurements Using a Scheimpflug-based System
Abstract Purpose: To assess the repeatability of Pentacam AXL as a Scheimpflug-based system or measuring axial length according to the age, sex, lens type, axial length value, and type of cataract. Methods: The present study was conducted using multistage cluster sampling in Tehran, Iran. Ocular bio...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Knowledge E
2023-11-01
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| Series: | Journal of Ophthalmic & Vision Research |
| Subjects: | |
| Online Access: | https://doi.org/10.18502/jovr.v18i4.14551 |
| _version_ | 1797361093110136832 |
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| author | Sara Sardari Mehdi Khabazkhoob Ebrahim Jafarzadehpur Akbar Fotouhi |
| author_facet | Sara Sardari Mehdi Khabazkhoob Ebrahim Jafarzadehpur Akbar Fotouhi |
| author_sort | Sara Sardari |
| collection | DOAJ |
| description | Abstract Purpose: To assess the repeatability of Pentacam AXL as a Scheimpflug-based system or measuring axial length according to the age, sex, lens type, axial length value, and type of cataract. Methods: The present study was conducted using multistage cluster sampling in Tehran, Iran. Ocular biometry was performed, using the Pentacam AXL, by an experienced optometrist on all the participants. The axial length (AL) measurements were taken thrice, with a gap of 10 minutes. To evaluate the repeatability, the intraclass correlation coefficient (ICC) and the repeatability coefficient (RC) were calculated. To determine the significant difference in the repeatability index among study variables, the tolerance index (TI) was calculated. Results: In this report, 897 eyes of 677 individuals aged between 20 and 91 years (mean ± SD: 64.90 ± 13.62 years) were reported. The ICC of the axial length measurements was 0.981 for all cases. Based on the within-subject standard deviation, the RC was 0.401. The ICC was 0.976 and 0.985 in men and women, respectively. The TI showed better RC of measurements among females. The ICC decreased from 0.999 in participants under 40 years to 0.973 in individuals over 60 years of age. The TI showed a decrease in RC with advancing age. The RC was worse in eyes with nuclear cataracts; the RC was also worse in the first quartile of the signal-to-noise ratio (SNR) compared to the other SNR quartiles. Conclusion: The Scheimpflug-based systemPentacam AXL had high repeatability in measuring axial length. Some variables such as male gender, older age, and nuclear cataract were associated with reduced repeatability of the measurements. A higher SNR was associated with better repeatability of the axial length measurements. |
| first_indexed | 2024-03-08T15:48:59Z |
| format | Article |
| id | doaj.art-a4c8dc189c6a42659ab66fe2ee404f81 |
| institution | Directory Open Access Journal |
| issn | 2008-2010 2008-322X |
| language | English |
| last_indexed | 2024-03-08T15:48:59Z |
| publishDate | 2023-11-01 |
| publisher | Knowledge E |
| record_format | Article |
| series | Journal of Ophthalmic & Vision Research |
| spelling | doaj.art-a4c8dc189c6a42659ab66fe2ee404f812024-01-09T07:54:41ZengKnowledge EJournal of Ophthalmic & Vision Research2008-20102008-322X2023-11-0118439640410.18502/jovr.v18i4.14551jovr.v18i4.14551The Repeatability of Axial Length Measurements Using a Scheimpflug-based SystemSara Sardari0Mehdi Khabazkhoob1Ebrahim Jafarzadehpur2Akbar Fotouhi3 Research and Technology Deputy, Tehran University of Medical Sciences, Tehran, Iran Department of Basic Sciences, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, IranAbstract Purpose: To assess the repeatability of Pentacam AXL as a Scheimpflug-based system or measuring axial length according to the age, sex, lens type, axial length value, and type of cataract. Methods: The present study was conducted using multistage cluster sampling in Tehran, Iran. Ocular biometry was performed, using the Pentacam AXL, by an experienced optometrist on all the participants. The axial length (AL) measurements were taken thrice, with a gap of 10 minutes. To evaluate the repeatability, the intraclass correlation coefficient (ICC) and the repeatability coefficient (RC) were calculated. To determine the significant difference in the repeatability index among study variables, the tolerance index (TI) was calculated. Results: In this report, 897 eyes of 677 individuals aged between 20 and 91 years (mean ± SD: 64.90 ± 13.62 years) were reported. The ICC of the axial length measurements was 0.981 for all cases. Based on the within-subject standard deviation, the RC was 0.401. The ICC was 0.976 and 0.985 in men and women, respectively. The TI showed better RC of measurements among females. The ICC decreased from 0.999 in participants under 40 years to 0.973 in individuals over 60 years of age. The TI showed a decrease in RC with advancing age. The RC was worse in eyes with nuclear cataracts; the RC was also worse in the first quartile of the signal-to-noise ratio (SNR) compared to the other SNR quartiles. Conclusion: The Scheimpflug-based systemPentacam AXL had high repeatability in measuring axial length. Some variables such as male gender, older age, and nuclear cataract were associated with reduced repeatability of the measurements. A higher SNR was associated with better repeatability of the axial length measurements.https://doi.org/10.18502/jovr.v18i4.14551axial lengthsignal-to-noise ratiorepeatabilityscheimpflug imagingpartial coherence interferometry |
| spellingShingle | Sara Sardari Mehdi Khabazkhoob Ebrahim Jafarzadehpur Akbar Fotouhi The Repeatability of Axial Length Measurements Using a Scheimpflug-based System Journal of Ophthalmic & Vision Research axial length signal-to-noise ratio repeatability scheimpflug imaging partial coherence interferometry |
| title | The Repeatability of Axial Length Measurements Using a Scheimpflug-based System |
| title_full | The Repeatability of Axial Length Measurements Using a Scheimpflug-based System |
| title_fullStr | The Repeatability of Axial Length Measurements Using a Scheimpflug-based System |
| title_full_unstemmed | The Repeatability of Axial Length Measurements Using a Scheimpflug-based System |
| title_short | The Repeatability of Axial Length Measurements Using a Scheimpflug-based System |
| title_sort | repeatability of axial length measurements using a scheimpflug based system |
| topic | axial length signal-to-noise ratio repeatability scheimpflug imaging partial coherence interferometry |
| url | https://doi.org/10.18502/jovr.v18i4.14551 |
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