Clinicians agreement in establishing glaucomatous progression using the Heidelberg retina tomograph

To assess the degree of concordance among clinicians reviewing 3 Heidelberg retina tomograph (HRT) printouts used to detect progression, the Moorfields regression analysis (MRA), the topographic change analysis (TCA), and trend analysis (TA), and to compare with progression identified by stereophotographs.

Observational cohort study.

We longitudinally followed 237 eyes of 168 patients (50 glaucomatous eyes, 187 glaucoma suspects) from the Diagnostic Innovation in Glaucoma Study (mean follow-up, 46.8+/-14.2 months), with a minimum of 4 HRT images (range, 4-8).

Three experienced observers judged the presence of progression using the HRT follow-up printouts available for each HRT method of analysis (MRA, TCA, TA). The overall assessment was based on majority rule, with >or=2 graders agreeing on the classification.

Observers agreement in assessing HRT progression and agreement for progression or no progression between the HRT methods of analysis and the reference standard represented by masked stereophotograph assessment. The kappa test was used to assess the interobserver agreement.

In general, agreement among clinicians for subjective assessment of progression based on HRT printouts was moderate to good; agreement (kappa) ranged from 0.52 to 0.71 for MRA, 0.61 to 0.63 for TCA, and 0.45 to 0.74 for TA. Of the 237 eyes, 16 (6.8%) were found to progress during follow-up based on masked stereophotograph assessment. Agreement for progression/no progression between the HRT methods and stereophotography was similar among MRA (84.8%, agreement on 5 progressing eyes and 196 nonprogressing eyes; kappa = 0.14), TCA, (82.3%, agreement on 8 progressing eyes and 187 nonprogressing eyes; kappa = 0.2), and TA (84%, agreement on 2 progressing eyes and 197 nonprogressing eyes; kappa = 0.01).

Clinicians' agreement in identifying suspected glaucomatous progression using different HRT methods of analysis was moderate to good and was similar among all methods, including MRA, which is not designed to detect progression. Agreement between progression identified by HRT and masked stereophotograph assessment was poor. These results suggest that assessment of the HRT and stereophotography may be identifying different aspects of structural change.

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