Sensitivity of confocal laser tomography versus optical coherence tomography in detecting advanced glaucoma

Purpose: To determine the sensitivity of manufacturer supported normative algorithms in Heidelberg retinal tomography (HRT) and Stratus optical coherence tomography (OCT) in detecting advanced primary open angle glaucoma.

Methods: A total of 157 subjects with advanced primary open angle glaucoma were recruited. The eye with the more severe glaucoma, as judged by mean deviation on Humphrey visual field, was imaged. The total number of optic disc sectors classified as being outside normal limits on Moorfields Regression Analysis (MRA) from the HRT II and HRT 3 software or from the sector and quadrant averages analysis of the Retinal Nerve Fiber Layer OCT scans was compared using the Wilcoxon signed ranks test.

Results: At least one segment in each eye was identified as being outside normal limits by the OCT sector Retinal Nerve Fiber Layer analysis (100% sensitivity). Five eyes were classified as being within normal limits on the OCT quadrant average analysis (96.8% sensitivity). Four eyes were found to be either completely within normal limits or borderline on the HRT II MRA (97.5% sensitivity), of which one was subsequently identified as being outside normal limits by the HRT 3 MRA. The total number of segments classified as being outside normal limits was greater on HRT 3 MRA than HRT II MRA (P < 0.001).

Conclusion: Automated optic nerve imaging devices rarely produce a totally normal result in the presence of advanced primary open angle glaucoma. The Stratus OCT Retinal Nerve Fiber Layer clock hour normative database performs better than other modalities studied. These findings are important in considering the utility of these algorithms for community screening.