Correlation Between Frequency Doubling Technology and Heidelberg Retina Tomograph

Abstract

To evaluate the association between Heidelberg Retina Tomograph (HRT) parameters and the Frequency Doubling Technology (FDT) indices in ocular hypertension or primary open angle glaucoma patients. One eye was randomly chosen from 85 patients with primary open angle glaucoma (abnormal visual field and/or abnormal optic nerve and untreated IOP > 21 mm Hg) and ocular hypertension (normal visual field and normal optic nerve and untreated IOP > 21 mm Hg). All the patients were examined with Humphrey Perimeter program 30-2 full threshold, FDT program C 20-5, and HRT. Findings were analyzed using Pearson's correlation coefficient and linear regression. Within the entire sample of studied subjects we found a statistically significant correlation (Pearson's r) (P < 0.05) between FDT mean deviation and RA, CA, RV, CSM, RNFLt, and RNFLc of HRT, and between FDT pattern standard deviation and RA, CA, VOLC, CV, RV, CSM, RNFLt, and RNFLc of HRT. Linear regression analysis showed that cup shape measure was the most predictive parameter for FDT MD. No correlation was found between HRT parameters and FDT PSD indices in the glaucoma subgroup; in the ocular hypertensive subgroup some correlation was found between FDT PSD and some of the HRT parameters. In the entire group, cup shape measure showed to be the most significant factor correlating functional and morphologic changes. The presence of significant correlations between some HRT parameters and visual field indices in the ocular hypertensive and glaucoma subgroup suggested that HRT parameters and FDT indices could detect glaucoma damage differently.