Interobserver agreement in clinical grading of vitreous haze using alternative grading scales.
OBJECTIVE
To evaluate the reliability of clinical grading of vitreous haze using a new 9-step ordinal scale versus the existing 6-step ordinal scale.


METHODS
Evaluation of diagnostic test (interobserver agreement study).


METHODS
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.


METHODS
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.
The Ocular Inflammation Service, Scheie Eye Institute, Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania.
Dana M
DM
Hornbeak
The Ocular Inflammation Service, Scheie Eye Institute, Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania; Ocular Inflammation Service, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland; Massachusetts Eye Research and Surgery Institution, Cambridge, Massachusetts.
Abhishek
A
Payal
Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania; Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania.
Maxwell
M
Pistilli
Pathology Services, Sankara Nethralaya, and Medical and Vision Research Foundation, Chennai, Tamil Nadu, India.
Jyotirmay
J
Biswas
Uveitis Services, Sankara Nethralaya, Chennai, Tamil Nadu, India; Medical and Vision Research Foundation, Chennai, Tamil Nadu, India.
Sudha K
SK
Ganesh
Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
Vishali
V
Gupta
Uvea Service, Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Madurai, Tamil Nadu, India; Aravind Medical Research Foundation, Madurai, Tamil Nadu, India.
Sivakumar R
SR
Rathinam
Bascom-Palmer Eye Institute/Department of Ophthalmology, Miller School of Medicine, University of Miami, Miami, Florida.
Janet L
JL
Davis
The Ocular Inflammation Service, Scheie Eye Institute, Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania; Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address: john.kempen@uphs.upenn.edu.
John H
JH
Kempen
D003430:Cross-Sectional Studies; D003941:Diagnostic Techniques, Ophthalmological; D005128:Eye Diseases / Q000145:classification*; D006801:Humans; D015588:Observer Variation; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D014605:Uveitis / Q000145:classification*; D014822:Vitreous Body / Q000473:pathology*