Article Text

Download PDFPDF

Proposed classification for topographic patterns seen after penetrating keratoplasty
  1. Constantinos H Karabatsas,
  2. Stuart D Cook,
  3. John M Sparrow
  1. Department of Ophthalmology, Bristol Eye Hospital, Bristol
  1. Costas H Karabatsas, PO Box 16757, Athens 115 02, Greece.


AIMS To create a clinically useful classification for post-keratoplasty corneas based on corneal topography.

METHODS A total of 360 topographic maps obtained with the TMS-1, from 95 eyes that had undergone penetrating keratoplasty (PKP), were reviewed independently by two examiners in a masked fashion, and were categorised according to a proposed classification scheme.

RESULTS A high interobserver agreement (88% in the first categorisation) was achieved. At 12 months post-PKP, a regular astigmatic pattern was observed in 20/85 cases (24%). This was subclassified as oval in three cases (4%), oblate symmetric bow tie in six cases (7%), prolate asymmetric bow tie in six cases (7%), and oblate asymmetric bow tie in five cases (6%). An irregular astigmatic pattern was observed in 61/85 cases (72%), subclassified as prolate irregular in five cases (6%), oblate irregular in four cases (5%), mixed in seven cases (8%), steep/flat in 11 cases (13%), localised steepness in 16 cases (19%), and triple pattern in three cases (4%). Regular astigmatic patterns were associated with significantly higher astigmatism measurements. The surface asymmetry index was significantly lower in the regular astigmatic patterns.

CONCLUSIONS In post-PKP corneas, the prevalence of irregular astigmatism is about double that of regular astigmatism, with a trend for increase of the irregular patterns over time.

  • keratoplasty
  • corneal topography
  • astigmatism

Statistics from


    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.