Interobserver agreement in clinical grading of vitreous haze using alternative grading scales

Dana M. Hornbeak, Abhishek Payal, Maxwell Pistilli, Jyotirmay Biswas, Sudha K. Ganesh, Vishali Gupta, Sivakumar R. Rathinam, Janet L. Davis, John H. Kempen

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Purpose To evaluate the reliability of clinical grading of vitreous haze using a new 9-step ordinal scale versus the existing 6-step ordinal scale. Design Evaluation of diagnostic test (interobserver agreement study). Participants A total of 119 consecutive patients (204 uveitic eyes) presenting for uveitis subspecialty care on the study day at 1 of 3 large uveitis centers. Methods Five pairs of uveitis specialists clinically graded vitreous haze in the same eyes, one after the other using the same equipment, using the 6- and 9-step scales. Main Outcome Measures Agreement in vitreous haze grade between each pair of specialists was evaluated by the κ statistic (exact agreement and agreement within 1 or 2 grades). Results The scales correlated well (Spearman's ρ = 0.84). Exact agreement was modest using both the 6-step and 9-step scales: average κ = 0.46 (range, 0.28-0.81) and κ = 0.40 (range, 0.15-0.63), respectively. Within 1-grade agreement was slightly more favorable for the scale with fewer steps, but values were excellent for both scales: κ = 0.75 (range, 0.66-0.96) and κ = 0.62 (range, 0.38-0.87), respectively. Within 2-grade agreement for the 9-step scale also was excellent (κ = 0.85; range, 0.79-0.92). Two-fold more cases were potentially clinical trial eligible on the basis of the 9-step than the 6-step scale (P<0.001). Conclusions Both scales are sufficiently reproducible using clinical grading for clinical and research use with the appropriate threshold (≥2- and ≥3-step differences for the 6- and 9-step scales, respectively). The results suggest that more eyes are likely to meet eligibility criteria for trials using the 9-step scale. The 9-step scale appears to have higher reproducibility with Reading Center grading than clinical grading, suggesting that Reading Center grading may be preferable for clinical trials.

Original languageEnglish (US)
Pages (from-to)1643-1648
Number of pages6
Issue number8
StatePublished - Aug 2014


  • Abbreviation and Acronym
  • Standardization of Uveitis Nomenclature
  • SUN

ASJC Scopus subject areas

  • Ophthalmology
  • Medicine(all)


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