Document Detail

Accuracy of cornea and lens biometry using anterior segment optical coherence tomography.
MedLine Citation:
PMID:  18163839     Owner:  NLM     Status:  MEDLINE    
We assess the accuracy of the Visante anterior segment optical coherence tomographer (AS-OCT) and present improved formulas for measurement of surface curvature and axial separation. Measurements are made in physical model eyes. Accuracy is compared for measurements of corneal thickness (d(1)) and anterior chamber depth (d(2)) using-built-in AS-OCT software versus the improved scheme. The improved scheme enables measurements of lens thickness (d(3)) and surface curvature, in the form of conic sections specified by vertex radii and conic constants. These parameters are converted to surface coordinates for error analysis. The built-in AS-OCT software typically overestimates [mean+/-standard deviation(SD)]d(1) by +62+/-4 mum and d(2) by + 4 +/- 88 microm. The improved scheme reduces d(1) (-0.4 +/- 4 microm) and d(2) (0 +/- 49 microm) errors while also reducing d(3) errors from +218 +/- 90 (uncorrected) to +14 +/- 123 microm (corrected). Surface x coordinate errors gradually increase toward the periphery. Considering the central 6-mm zone of each surface, the x coordinate errors for anterior and posterior corneal surfaces reached +3 +/- 10 and 0 +/- 23 microm, respectively, with the improved scheme. Those of the anterior and posterior lens surfaces reached +2 +/- 22 and +11 +/- 71 microm, respectively. Our improved scheme reduced AS-OCT errors and could, therefore, enhance pre- and postoperative assessments of keratorefractive or cataract surgery, including measurement of accommodating intraocular lenses.
Mark C M Dunne; Leon N Davies; James S Wolffsohn
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of biomedical optics     Volume:  12     ISSN:  1083-3668     ISO Abbreviation:  J Biomed Opt     Publication Date:    2007 Nov-Dec
Date Detail:
Created Date:  2007-12-31     Completed Date:  2008-03-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9605853     Medline TA:  J Biomed Opt     Country:  United States    
Other Details:
Languages:  eng     Pagination:  064023     Citation Subset:  IM    
Aston University, Ophthalmic Research Group, Birmingham, United Kingdom.
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MeSH Terms
Anterior Eye Segment / anatomy & histology*
Cornea / anatomy & histology*
Lens, Crystalline / anatomy & histology*
Models, Anatomic
Tomography, Optical Coherence / methods*,  statistics & numerical data

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