Abstract
Abstract: :
Purpose: to compare agreement in eyes progressing as defined by Heidelberg Retina Tomograph (HRT) rim area and by visual field sensitivity decay over time and respective times to detection of the two methods. Methods: 100 eyes from 80 ocular hypertensive and 20 normal subjects were followed prospectively with Humphrey Visual Fields (mean 16 tests, range 7–31) and HRT optic nerve imaging (mean 10 tests, range 5–15) for a minimum of 3 years (mean 5.7 years, range 3.1–7.2). HRT analysis using a 320µm reference plane and a manual alignment option was performed with progression defined as a significant slope of rim area over time (p<0.05). Field progression was established using PROGRESSOR when a test point achieved a significant negative slope (p<0.01) of at least –1dB/year and satisfied the ‘three–omitting’ criterion (Gardiner SK, Crabb DP – IOVS 2002). Time to identified progression was recorded and whether progression was maintained at the end of the study. Baseline HRT Moorfields Regression Analysis (MRA) was also recorded. Results: 12 eyes maintained both rim and field criteria at the end of the study with a mean time to progression (MTP) by rim of 3.8 years and 3.4 years by field. 20 eyes were found to be progressing by rim alone (MTP of 4.1 years) compared to 16 eyes by field alone (MTP of 3.3 years). 75% of subjects progressing by both rim and field had an abnormal baseline MRA compared to 50% progressing by rim or field alone and 42% of non–progressors. A significantly greater number of visual field tests were performed in the group progressing by field compared to the group by rim alone (unpaired t–test, p=0.03). There was no significant difference between the proportions identified as progressing by either method (McNemar’s test, p=0.41), although there was poor agreement between methods (Κ=0.14). Conclusions: agreement regarding progression was poor with a greater number progressing by rim. MTP was shorter by visual field than by rim although visual field testing was performed more frequently than HRT imaging. There is little difference in MTP between rim and field where both occur in the same eye, despite the greater number of field tests. More frequent HRT testing may result in earlier detection of progression.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual fields • imaging/image analysis: clinical