Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data.
<h4>Purpose</h4>To analyse corneal power based on a large optical coherence tomography dataset using raytracing, and to evaluate corneal power with respect to the corneal front apex plane for different definitions of best focus.<h4>Methods</h4>A large OCT dataset (10,218 eyes...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2021-01-01
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| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0247048 |
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| author | Achim Langenbucher Nóra Szentmáry Johannes Weisensee Jascha Wendelstein Alan Cayless Rupert Menapace Peter Hoffmann |
| author_facet | Achim Langenbucher Nóra Szentmáry Johannes Weisensee Jascha Wendelstein Alan Cayless Rupert Menapace Peter Hoffmann |
| author_sort | Achim Langenbucher |
| collection | DOAJ |
| description | <h4>Purpose</h4>To analyse corneal power based on a large optical coherence tomography dataset using raytracing, and to evaluate corneal power with respect to the corneal front apex plane for different definitions of best focus.<h4>Methods</h4>A large OCT dataset (10,218 eyes of 8,430 patients) from the Casia 2 (Tomey, Japan) was post-processed in MATLAB (MathWorks, USA). Using radius of curvature, corneal front and back surface asphericity, central corneal thickness, and pupil size (aperture) a bundle of rays was traced through the cornea. Various best focus definitions were tested: a) minimum wavefront error, b) root mean squared ray scatter, c) mean absolute ray scatter, and d) total spot diameter. All 4 target optimisation criteria were tested with each best focus plane. With the best-fit keratometer index the difference of corneal power and keratometric power was evaluated using a multivariate linear model.<h4>Results</h4>The mean corneal powers for a/b/c/d were 43.02±1.61/42.92±1.58/42.91±1.58/42.94±1.59 dpt respectively. The root mean squared deviations of corneal power from keratometric power (nK = 1.3317/1.3309/1.3308/1.3311 for a/b/c/d) were 0.308/0.185/0.171/0.209 dpt. With the multivariate linear model the respective RMS error was reduced to 0.110/0.052/0.043/0.065 dpt (R² = 0.872/0.921/0.935/0.904).<h4>Conclusions</h4>Raytracing improves on linear Gaussian optics by considering the asphericity of both refracting surfaces and using Snell's law of refraction in preference to paraxial simplifications. However, there is no unique definition of best focus, and therefore the calculated corneal power varies depending on the definition of best focus. The multivariate linear model enabled more precise estimation of corneal power compared to the simple keratometer equation. |
| first_indexed | 2024-12-20T03:31:11Z |
| format | Article |
| id | doaj.art-29004d13db2f4b45ada0e2dec7df376d |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-20T03:31:11Z |
| publishDate | 2021-01-01 |
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| series | PLoS ONE |
| spelling | doaj.art-29004d13db2f4b45ada0e2dec7df376d2022-12-21T19:54:59ZengPublic Library of Science (PLoS)PLoS ONE1932-62032021-01-01162e024704810.1371/journal.pone.0247048Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data.Achim LangenbucherNóra SzentmáryJohannes WeisenseeJascha WendelsteinAlan CaylessRupert MenapacePeter Hoffmann<h4>Purpose</h4>To analyse corneal power based on a large optical coherence tomography dataset using raytracing, and to evaluate corneal power with respect to the corneal front apex plane for different definitions of best focus.<h4>Methods</h4>A large OCT dataset (10,218 eyes of 8,430 patients) from the Casia 2 (Tomey, Japan) was post-processed in MATLAB (MathWorks, USA). Using radius of curvature, corneal front and back surface asphericity, central corneal thickness, and pupil size (aperture) a bundle of rays was traced through the cornea. Various best focus definitions were tested: a) minimum wavefront error, b) root mean squared ray scatter, c) mean absolute ray scatter, and d) total spot diameter. All 4 target optimisation criteria were tested with each best focus plane. With the best-fit keratometer index the difference of corneal power and keratometric power was evaluated using a multivariate linear model.<h4>Results</h4>The mean corneal powers for a/b/c/d were 43.02±1.61/42.92±1.58/42.91±1.58/42.94±1.59 dpt respectively. The root mean squared deviations of corneal power from keratometric power (nK = 1.3317/1.3309/1.3308/1.3311 for a/b/c/d) were 0.308/0.185/0.171/0.209 dpt. With the multivariate linear model the respective RMS error was reduced to 0.110/0.052/0.043/0.065 dpt (R² = 0.872/0.921/0.935/0.904).<h4>Conclusions</h4>Raytracing improves on linear Gaussian optics by considering the asphericity of both refracting surfaces and using Snell's law of refraction in preference to paraxial simplifications. However, there is no unique definition of best focus, and therefore the calculated corneal power varies depending on the definition of best focus. The multivariate linear model enabled more precise estimation of corneal power compared to the simple keratometer equation.https://doi.org/10.1371/journal.pone.0247048 |
| spellingShingle | Achim Langenbucher Nóra Szentmáry Johannes Weisensee Jascha Wendelstein Alan Cayless Rupert Menapace Peter Hoffmann Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data. PLoS ONE |
| title | Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data. |
| title_full | Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data. |
| title_fullStr | Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data. |
| title_full_unstemmed | Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data. |
| title_short | Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data. |
| title_sort | prediction model for best focus power and spherical aberration of the cornea raytracing on a large dataset of oct data |
| url | https://doi.org/10.1371/journal.pone.0247048 |
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