[Multifocal electroretinogram and age-related macular degeneration]

To assess the value of multifocal electroretinogram (mfERG) in clinical evaluation of the response of patients with choroidal neovascularization (CNV), secondary to age-related macular degeneration, to photodynamic therapy (PDT).

We designed a prospective non-comparative case series and enrolled 23 eyes of 22 patients with predominantly classic CNV. The initial evaluation included clinical examination with measurement of visual acuity (Colenbrander), biomicroscopic evaluation (BMC), retinography, fluorescein angiography (FA), Humphrey 24-2 visual field examination and mfERG. All patients were treated with PDT. Clinical follow-up was performed two and six months after treatment with visual acuity evaluation, BMC, visual field assessment and mfERG. FA was repeated after an interval of between four and six months in all patients.

Visual acuity remained stable or improved in all patients included in the study. Visual field examination gave erratic and unreliable results because of patients' unstable fixation. N1 and P1 wave peak amplitudes in the central rings did not change significantly after treatment but they improved in rings 3 (p=0.000), 4 and 5 (p=0.008).

Multifocal ERG is a useful tool for the clinical follow-up of CNV. It offers interesting non-subjective data of retinal sensitivity of patients with macular diseases treated with PDT. In addition we obtained a central retinal sensitivity map where we were able to evaluate the extent and depth of retinal damage.