Morphologic classification of filtering blebs after glaucoma filtration surgery: The Indiana Bleb Appearance Grading Scale

Louis B. Cantor, Anand Mantravadi, Darrell WuDunn, Kala Swamynathan, Arnold Cortes

Research output: Contribution to journalArticle

188 Scopus citations


Purpose: To establish a new classification system for filtering blebs according to clinical morphologic parameters. The purpose of this classification system is to provide a uniform and objective assessment of bleb appearance and establish a framework system through which outcomes of filtration surgery may be better correlated to clinical morphology. Materials and Methods: The Indiana Bleb Appearance Grading Scale contains a set of photographic standards illustrating a range of filtering bleb morphology selected from the slide library of the Glaucoma Service at the Indiana University Department of Ophthalmology. These standards consist of slit lamp images for grading bleb height, extent, vascularity, and leakage with the Seidel test. For grading, the morphologic appearance of the filtration bleb is assessed relative to the standard images for the 4 parameters and scored accordingly. Fifty-one clinical bleb photographs were evaluated and scored by 3 glaucoma subspecialists in a masked fashion according to the scale. Results: For all of the grading scales, high interobserver agreement was found using the scale to classify the appearance of filtering blebs (height +0.76; extent +0.78; vascularity +0.90, interclass correlation coefficient for consistency using a 2-way mixed effect model). Conclusion: The Indiana Bleb Appearance Grading Scale is a simple, reproducible, yet comprehensive system for classifying the morphologic slit lamp appearance of filtration blebs.

Original languageEnglish (US)
Pages (from-to)266-271
Number of pages6
JournalJournal of Glaucoma
Issue number3
StatePublished - Jun 1 2003


  • Bleb
  • Classification
  • Glaucoma
  • Morphology

ASJC Scopus subject areas

  • Ophthalmology

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