Correlation between Heidelberg Retinal Tomography (HRT II) Parameters and Visual Field Indices in Primary Open Angle Glaucoma Patients

Background: Glaucoma is a common cause of visual impairment and blindness. The Heidelberg Retinal Tomogram (HRT) evaluates the structural details of the optic disc and has been widely investigated as a research tool in imaging of the ONH. The correlation between the perimetry and HRT data in Caucasian eyes has been reported previously. Objective: To correlate the HRT parameters and visual field indices in Indian eyes including established glaucoma and glaucoma suspect patients. Methods: Eighty-three eyes of 50 patients having primary open angle glaucoma underwent automated Humphrey perimetry (30-2) and confocal scanning laser ophthalmoscopy (HRT II). The global visual field indices and the HRT II parameters were correlated. Results: The average MD of the study group was –3.70 3.99dB (range 1.11 to –19.54). The correlations between global parameters by HRT and global visual field indices were found to be significant for rim area, rim volume, height variation contour, mean RNFL thickness and found RNFL cross sectional area. The strongest correlation was between rim area and PSD (r = 0.32, p = 0.0029). Conclusion: There was a good correlation between global visual field indices and HRT II parameters with highest correlation coefficient of 0.32. Since we had several parameters correlating well, we can say that in early glaucomatous damage HRT II is as sensitive as perimetry and HRT II could be a useful tool in evaluation and diagnosis of glaucoma.