Thinning of the papillomacular bundle in the glaucomatous eye and its influence on the reference plane of the Heidelberg retinal tomography.

Purpose: To measure the thickness of the papillomacular bundle in glaucomatous eyes with good visual acuity and to evaluate the influence of an adjusted reference plane on the Heidelberg retinal tomography result. Methods: The thickness of the papillomacular bundle was measured with optical coherence tomography in both eyes of eight patients with asymmetric glaucoma. The eye with less glaucomatous damage with normal visual field served as the control. The difference in the thickness of the papillomacular bundle between the control eye and the glaucomatous eye was used to correct the reference plane of Heidelberg retinal tomography. Results: The thickness of the papillomacular bundle in glaucomatous eyes was reduced (P = 0.00037) and was 33.9 +/- 16.5 mum thinner than control eyes. A corrected reference plane in Heidelberg retinal tomography caused an increased classification value (-0.683 +/- 0.164), implying that more glaucoma damage was detected after the correction. In one case the value was shifted from normal to glaucomatous after an adjustment of the reference plane. Conclusion: The thickness of the papillomacular bundle is decreased in glaucomatous eyes, though these eyes have good visual acuity. Evaluation of glaucoma with Heidelberg retinal tomography using the standard reference plane may underestimate the glaucoma damage.