Validation of a Photographic Vitreous Haze Grading Technique for Clinical Trials in Uveitis

To validate a photographic vitreous haze grading technique using a 9-step logarithmic scale in patients enrolled in a randomized, controlled clinical trial in uveitis. Retrospective study of clinical trials methodology. Setting: University-based department of ophthalmology. Study population: Baseline fundus photographs of patients with intermediate uveitis, posterior uveitis, or panuveitis enrolled in the Multicenter Uveitis Steroid Treatment (MUST) trial. Observational procedure: Grading of vitreous haze using a previously described photographic scale. Regrading of a subset of photographs to assess intraobserver agreement. Main outcome measures: Interobserver and intraobserver intraclass correlation for photographic haze grading, and correlation between photographic and clinical vitreous haze scores, assessment of the clinical findings that significantly affect the photographic haze score. Vitreous haze was graded in 271 eyes (142 patients) by 3 postgraduate ophthalmologists. The interobserver and intraobserver intraclass correlations were excellent, with correlation coefficients between 0.84 and 0.93. There was moderately strong correlation between the photographic and clinical vitreous haze scores ( r = 0.51; P < .001), with significant differences among the mean and median photographic haze scores for the 3 lowest clinical grades of haze, 0, 1+, and 2+. Other parameters that correlated with photographic vitreous haze score included visual acuity of 20/50 or worse ( P = .003), degrees of posterior synechiae ( P < .001), lens abnormality ( P = .023) or posterior capsule obscuration ( P = .001), and amount of anterior vitreous cell ( P = .002). Photographic grading of vitreous haze with a 9-step logarithmic scale is a highly reproducible methodology that may be adaptable to use in future clinical trials

Validation of a Photographic Vitreous Haze Grading Technique for Clinical Trials in Uveitis

PURPOSE: To validate a photographic vitreous haze grading technique using a 9-step logarithmic scale in patients enrolled in a randomized, controlled clinical trial in uveitis. DESIGN: Retrospective study of clinical trials methodology. METHODS: SETTING: University-based department of ophthalmology. STUDY POPULATION: Baseline fundus photographs of patients with intermediate uveitis, posterior uveitis, or panuveitis enrolled in the Multicenter Uveitis Steroid Treatment (MUST) trial. OBSERVATIONAL PROCEDURE: Grading of vitreous haze using a previously described photographic scale. Regrading of a subset of photographs to assess intraobserver agreement. MAIN OUTCOME MEASURES: Interobserver and intraobserver intraclass correlation for photographic haze grading, and correlation between photographic and clinical vitreous haze scores, assessment of the clinical findings that significantly affect the photographic haze score. RESULTS: Vitreous haze was graded in 271 eyes (142 patients) by 3 postgraduate ophthalmologists. The interobserver and intraobserver intraclass correlations were excellent, with correlation coefficients between 0.84 and 0.93. There was moderately strong correlation between the photographic and clinical vitreous haze scores (r = 0.51; P < .001), with significant differences among the mean and median photographic haze scores for the 3 lowest clinical grades of haze, 0, 1+, and 2+. Other parameters that correlated with photographic vitreous haze score included visual acuity of 20/50 or worse (P = .003), degrees of posterior synechiae (P < .001), lens abnormality (P = .023) or posterior capsule obscuration (P = .001), and amount of anterior vitreous cell (P = .002). CONCLUSIONS: Photographic grading of vitreous haze with a 9-step logarithmic scale is a highly reproducible methodology that may be adaptable to use in future clinical trials

Scale for Photographic Grading of Vitreous Haze in Uveitis

PURPOSE: To validate a scale for grading vitreous haze in uveitis using digitized photographs and standardized scoring. DESIGN: Evaluation of clinical research methodology. METHODS: Calibrated Bangerter diffusion filters inducing incremental decrements of spatial contrast were placed in front of the camera lens while photographing a normal eye to simulate vitreous haze. The photographs were digitized and an ordinal scale was created from 0 (none) to 8 (highest level of opacification at which fundus details could be seen). The scale steps correspond approximately to decimal Snellen visual acuities of 1.0, 0.8, 0.4, 0.2, 0.1, 0.04, 0.02, 0.01, and 0.002, with approximately 0.3 log step between each step. For validation, digitized fundus photographs of uveitis patients were displayed on a computer monitor for comparison with the standard photos. Three observers graded the test set twice under standard conditions. Interobserver and intraobserver variability and κ values for agreement greater than chance were calculated. RESULTS: Variance component analysis determined that 87.7% of the variance in grades was attributable to the test item rather than to grader or session. The intraclass correlation between graders and grading sessions varied from 0.84 to 0.91. Simple agreement within 1 grade between graders and sessions occurred in 90 ± 5.5% of gradings. κ values averaged 0.91, which is considered near perfect. CONCLUSIONS: A 9-step photographic scale was designed to standardize the grading of vitreous haze in uveitis patients using fundus photographs. The scale is potentially adaptable to clinical trials in uveitis