title: The art of nomograms
creator: Mosquera, Samuel
creator: Ortueta, Diego
creator: Verma, Shwetabh
subject: ddc-570
subject: 570 Life sciences
description: Background: To retrospectively analyse strategies for adjusting refractive surgery plans with reference to the preoperative manifest refraction.    Methods: We constructed seven nomograms based on the refractive outcomes (sphere, cylinder, axis [SCA]) of 150 consecutive eyes treated with laser in situ keratomileusis for myopic astigmatism. We limited the initial data to the SCA of the manifest refraction. All nomograms were based on the strategy: if for x diopters (D) of attempted metric, y D is achieved; we can reverse this sentence and state for achieving y D of change in the metric, x D will be planned. The effects of the use of plus or minus astigmatism notation, spherical equivalent, sphere, principal meridians notation, cardinal and oblique astigmatism, and astigmatic axis were incorporated.    Results: All nomograms detected subtle differences in the spherical component (p < 0.0001). Nomograms 5 and 7 (using power vectors) and 6 (considering axis shifts) detected significant astigmatic differences (nomogram 5, p < 0.001; nomogram 6, p < 0.05; nomogram 7, p < 0.005 for cardinal astigmatism, p = 0.1 for oblique astigmatism). We observed mild clinically relevant differences (~ 0.5 D) in sphere or astigmatism among the nomograms; differences of ~ 0.25 D in the proposals for sphere or cylinder were not uncommon. All nomograms suggested minor improvements versus actual observed outcomes, with no clinically relevant differences among them.    Conclusions: All nomograms anticipated minor improvements versus actual observed outcomes without clinically relevant differences among them. The minimal uncertainties in determining the manifest refraction (~ 0.6 D) are the major limitation to improving the accuracy of refractive surgery nomograms.
publisher: BioMed Central
date: 2018
type: Article
type: info:eu-repo/semantics/article
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/24349/1/40662_2018_Article_96.pdf
identifier: DOI:
identifier: urn:nbn:de:bsz:16-heidok-243494
identifier:   Mosquera, Samuel ; Ortueta, Diego ; Verma, Shwetabh  (2018) The art of nomograms.  Eye and Vision, 5 (2).  pp. 1-13.  ISSN 2326-0254     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/24349/
rights: info:eu-repo/semantics/openAccess
rights: Please see front page of the work (Sorry, Dublin Core plugin does not recognise license id)
language: eng