Structure Function Relationship in Glaucoma: Heidelberg Retinal Tomograph versus Standard Automated Perimetry, Frequency Doubling, Flicker Defined Form and Motion Detection

Abstract

Introduction: :

Purpose: : To evaluate the structure-function relationship between sectoral measures of rim area and corresponding sector measures of visual function.

Methods: : 57 patients with "glaucoma" from a planned 160 participants have been recruited and tested in a 4 centre study of perimetry instruments (mean age = 59 years, range 18 to 82 years). Selection criteria for patients were (i) Heidelberg Retina Tomograph (HRT) Moorfields Regression Analysis (MRA) ‘Outside Normal Limits’ (ONL); rim area >0.5mm² and (ii) IOP >21 mmHg at referral. Thus, the reference standard for "glaucoma" was independent of perimetry. One eye of each subject was tested on at least one occasion with Standard Automated Perimetry (SAP, 24-2 SITA standard), Frequency Doubling Technology Perimeter (FDT, 24-2 ZEST), Heidelberg Edge Perimeter (HEP) and the Moorfields Motion Displacement Test (MDT). Test order was randomized. Perimetry test locations were divided into 6 groups based on the disc sector classification of the HRT; only the 4 inferior and superior sectors were analyzed. Ordinal Scores of 0, 2, and 5 were assigned to the probability points p>5, p<5 and p<2, respectively; the mean of each sector was calculated. Pearson correlation coefficients (CC) were calculated for rim area versus mean probability score for each visual field test.

Results: : Moderate CCs were observed between rim area and corresponding visual field sectors for FDT, HEP and MDT, r=-0.60, 0.55, 0.39, respectively (p<0.05). SAP gave a weak CC of r=0.09.

Conclusions: : Patients with glaucoma showed a moderate correlation between FDT, HEP and MDT when compared with HRT rim area.

Keywords: visual fields