Analyse d’un nouvel indice d’évaluation du champ visuel, le VFI, dans l’hypertonie oculaire et le glaucome

Abstract

The Visual Field Index -VFI- is a new perimetric index allowing evaluation of visual function level and progression. In this study, we analysed this new index, that provides a trend analysis of visual field loss progression in Ocular Hypertension and Glaucoma. We also compared results with event analysis. Retrospective study on 94 eyes of 54 patients: 35 OHT(ocular hypertension), 34 early POAG (primary open angle glaucoma) (0>MD>-6 dB), 13 moderate POAG (-6>MD>-12 dB) and 12 advanced POAG (MD<-12 dB), with a mean follow-up of 6.5 years (4 to 8 years). Each subject performed a mean number of 10 standard automated perimetry visual field tests (Humphrey SITA Standard 24-2), excluding tests without reliable indices. VFI progression rate was analysed. VFI progression during the first half period of follow up was compared with that during the second half period. VFI progression was confronted with script alert messages delivered by the last GPA (Guided Progression Analysis) event analysis program. VFI values were "stable or with low progression" in 100% of OHT patients, 88% of early POAG, 38.5% of moderate POAG, 33% of advanced POAG. Progression during the first half period (mean of 3 years) of follow-up could be extrapolated for the second half period in 97% of OHT patients, 76% of early POAG, 70% of moderate POAG, 75% of advanced POAG. Results from VFI trend analysis and GPA event analysis corresponded in 97% of OHT patients, 85% of early POAG, 85% of moderate POAG, and 87% of advanced POAG. VFI seems to be a useful indicator for glaucoma evaluation and progression follow-up. It completes the event analysis. Some very advanced POAG cannot be analysed by GPA event analysis. VFI should be able to be used for further follow-up. All these results require validation in larger population. The purpose would be to assess if VFI is able to detect different profiles of progression to help treatment decisions.