Acute effects of sildenafil on the electroretinogram and multifocal electroretinogram

PURPOSE: To evaluate the acute effects of sildenafil (Viagra; Pfizer, Inc, New York, New York) on the electroretinogram and multifocal electroretinogr am. METHODS: Eighteen healthy individuals (ages 21-49 years) were studied; 14 w ere given 200 mg sildenafil orally and four were given only water. All subj ects were tested before sildenafil and 1 hour after sildenafil (or water) w ith a desaturated Panel D-15 color test, a full-field standard electroretin ogram, and a multifocal electroretinogram using the VERIS system; five subj ects were also tested 5 hours after sildenafil. RESULTS: Responses from the subjects who received sildenafil were compared with those from the control subjects. At I hour after sildenafil, photopic single-flash waveforms were attenuated by 9% and scotopic maximal response amplitudes were increased slightly. Photopic and 30-Hz flicker electroretin ogram responses were delayed; multifocal electroretinogram waveforms were d elayed (5%-9%) and attenuated (14%-22%) across the posterior pole. These ch anges did not resolve by 5 hours. Nine of the subjects who had received sil denafil (64%) reported visual or systemic symptoms, including one who repor ted bluish vision. Ten of those subjects (71%) showed a slight increase in color test errors I hour after sildenafil. CONCLUSIONS: For at least 5 hours after taking 200 mg of sildenafil, cone f unction was slightly depressed in the macula and periphery, as measured by full-field electroretinogram and multifocal electroretinogram recordings. H owever, the affected electroretinogram and multifocal electroretinogram par ameters still remained within normal limits. (Am J Ophthalmol 2001;132: 388 -394. (C) 2001 by Elsevier Science Inc. All rights reserved.).