Deficits in the electroretinogram in neovascular age-related macular degeneration and changes during photodynamic therapy.
OBJECTIVE
To describe the deficits in four electroretinography (ERG) modalities in patients with neovascular age-related macular degeneration (AMD). To describe the changes in these parameters during a course of verteporfin photodynamic therapy (PDT).


METHODS
Pattern (PERG), multifocal (mfERG) (19 segment simplified test protocol), flash ERG and flicker ERG were performed in patients with active neovascular AMD before PDT and compared to fellow eye controls using paired t-tests. Changes in ERG parameters during the 12 month treatment course were visualised using 95% confidence intervals of the median difference. The statistical significance of any changes was quantified using Wilcoxon signed ranks tests.


RESULTS
Fifty patients were recruited and followed. At presentation all ERG amplitudes were reduced with greater reductions in focal as opposed to global test protocols (P < 0.05). Over the 12 month course of PDT, PERG P50 amplitude showed a general downward trend and latency remained unchanged. mfERG p1 amplitude density showed an upward trend at six months before returning to baseline by 12 months. mfERG ring 2 amplitude density was significantly increased at 12 months compared to baseline (P = 0.010). Flicker ERG latency was significantly increased at six months compared to baseline (P = 0.015).


CONCLUSIONS
The simplified mfERG protocol was tolerated by this patient group, however, they found the full test protocol demanding. Large deficits in the retinal ERG function occur in neovascular AMD and involve retinal locations adjacent to as well as overlying choroidal neovascularisation (CNV). After PDT there is an improvement in electro-retinal function in retinal locations overlying the CNV.
Department of Clinical Engineering, Royal Liverpool University Hospital, Prescot Street, Liverpool, UK.
Alison M
AM
Mackay
Malcolm C
MC
Brown
Richard P
RP
Hagan
Anthony C
AC
Fisher
Ian
I
Grierson
Simon P
SP
Harding
D000368:Aged; D000369:Aged, 80 and over; D020256:Choroidal Neovascularization / Q000209:etiology*; D004596:Electroretinography / Q000379:methods; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011166:Porphyrins / Q000627:therapeutic use*; D012160:Retina / Q000503:physiopathology; D000077362:Verteporfin
D017319:Photosensitizing Agents; D011166:Porphyrins; D000077362:Verteporfin