Errors Associated with IOLMaster Biometry as a Function of Internal Ocular Dimensions
Purpose: To evaluate the error in the estimation of axial length (AL) with the IOLMaster partial coherence interferometry (PCI) biometer and obtain a correction factor that varies as a function of AL and crystalline lens thickness (LT). Methods: Optical simulations were produced for theoretical eyes...
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| Format: | Article |
| Language: | English |
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Elsevier
2014-04-01
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| Series: | Journal of Optometry |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1888429613000861 |
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| author | Miguel Faria-Ribeiro Daniela Lopes-Ferreira Norberto López-Gil Jorge Jorge José Manuel González-Méijome |
| author_facet | Miguel Faria-Ribeiro Daniela Lopes-Ferreira Norberto López-Gil Jorge Jorge José Manuel González-Méijome |
| author_sort | Miguel Faria-Ribeiro |
| collection | DOAJ |
| description | Purpose: To evaluate the error in the estimation of axial length (AL) with the IOLMaster partial coherence interferometry (PCI) biometer and obtain a correction factor that varies as a function of AL and crystalline lens thickness (LT).
Methods: Optical simulations were produced for theoretical eyes using Zemax-EE software. Thirty-three combinations including eleven different AL (from 20 mm to 30 mm in 1 mm steps) and three different LT (3.6 mm, 4.2 mm and 4.8 mm) were used. Errors were obtained comparing the AL measured for a constant equivalent refractive index of 1.3549 and for the actual combinations of indices and intra-ocular dimensions of LT and AL in each model eye.
Results: In the range from 20 mm to 30 mm AL and 3.6–4.8 mm LT, the instrument measurements yielded an error between −0.043 mm and +0.089 mm. Regression analyses for the three LT condition were combined in order to derive a correction factor as a function of the instrument measured AL for each combination of AL and LT in the theoretical eye.
Conclusions: The assumption of a single “average” refractive index in the estimation of AL by the IOLMaster PCI biometer only induces very small errors in a wide range of combinations of ocular dimensions. Even so, the accurate estimation of those errors may help to improve accuracy of intra-ocular lens calculations through exact ray tracing, particularly in longer eyes and eyes with thicker or thinner crystalline lenses. |
| first_indexed | 2024-12-10T21:10:52Z |
| format | Article |
| id | doaj.art-4f55df2990e049e0a1ef28e715e1360f |
| institution | Directory Open Access Journal |
| issn | 1888-4296 |
| language | English |
| last_indexed | 2024-12-10T21:10:52Z |
| publishDate | 2014-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Optometry |
| spelling | doaj.art-4f55df2990e049e0a1ef28e715e1360f2022-12-22T01:33:29ZengElsevierJournal of Optometry1888-42962014-04-0172757810.1016/j.optom.2013.12.005Errors Associated with IOLMaster Biometry as a Function of Internal Ocular DimensionsMiguel Faria-Ribeiro0Daniela Lopes-Ferreira1Norberto López-Gil2Jorge Jorge3José Manuel González-Méijome4Clinical & Experimental Optometry Research Lab, School of Sciences (Optometry), University of Minho, Braga, PortugalClinical & Experimental Optometry Research Lab, School of Sciences (Optometry), University of Minho, Braga, PortugalCiencias de la Visión, Facultad de Óptica y Optometría, Universidad de Murcia, Murcia, SpainClinical & Experimental Optometry Research Lab, School of Sciences (Optometry), University of Minho, Braga, PortugalClinical & Experimental Optometry Research Lab, School of Sciences (Optometry), University of Minho, Braga, PortugalPurpose: To evaluate the error in the estimation of axial length (AL) with the IOLMaster partial coherence interferometry (PCI) biometer and obtain a correction factor that varies as a function of AL and crystalline lens thickness (LT). Methods: Optical simulations were produced for theoretical eyes using Zemax-EE software. Thirty-three combinations including eleven different AL (from 20 mm to 30 mm in 1 mm steps) and three different LT (3.6 mm, 4.2 mm and 4.8 mm) were used. Errors were obtained comparing the AL measured for a constant equivalent refractive index of 1.3549 and for the actual combinations of indices and intra-ocular dimensions of LT and AL in each model eye. Results: In the range from 20 mm to 30 mm AL and 3.6–4.8 mm LT, the instrument measurements yielded an error between −0.043 mm and +0.089 mm. Regression analyses for the three LT condition were combined in order to derive a correction factor as a function of the instrument measured AL for each combination of AL and LT in the theoretical eye. Conclusions: The assumption of a single “average” refractive index in the estimation of AL by the IOLMaster PCI biometer only induces very small errors in a wide range of combinations of ocular dimensions. Even so, the accurate estimation of those errors may help to improve accuracy of intra-ocular lens calculations through exact ray tracing, particularly in longer eyes and eyes with thicker or thinner crystalline lenses.http://www.sciencedirect.com/science/article/pii/S1888429613000861Intra-ocular lens calculationIOL calculationAxial length measurement |
| spellingShingle | Miguel Faria-Ribeiro Daniela Lopes-Ferreira Norberto López-Gil Jorge Jorge José Manuel González-Méijome Errors Associated with IOLMaster Biometry as a Function of Internal Ocular Dimensions Journal of Optometry Intra-ocular lens calculation IOL calculation Axial length measurement |
| title | Errors Associated with IOLMaster Biometry as a Function of Internal Ocular Dimensions |
| title_full | Errors Associated with IOLMaster Biometry as a Function of Internal Ocular Dimensions |
| title_fullStr | Errors Associated with IOLMaster Biometry as a Function of Internal Ocular Dimensions |
| title_full_unstemmed | Errors Associated with IOLMaster Biometry as a Function of Internal Ocular Dimensions |
| title_short | Errors Associated with IOLMaster Biometry as a Function of Internal Ocular Dimensions |
| title_sort | errors associated with iolmaster biometry as a function of internal ocular dimensions |
| topic | Intra-ocular lens calculation IOL calculation Axial length measurement |
| url | http://www.sciencedirect.com/science/article/pii/S1888429613000861 |
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