Subjective visual halos after sildenafil (Viagra) administration - Electroretinographic evaluation

Purpose: The ophthalmologic and electroretinographic (ERG) findings in one subject with subjective visual disturbances after sildenafil administration are described. Design: Interventional case report. Methods: A complete ophthalmologic examination was performed, including best-corrected visual acuity and ERG, repeated 1 and 2 hours after administration of 100 mg of sildenafil. Main Outcome Measures: Rod responses were obtained over a range of retinal illuminances from those producing a minimum detectable response to those producing rod saturation. Intensity amplitude function was determined. Results: At 2 hours after 100 mg of oral sildenafil, we observed significant variations from baseline in parameters of best-fit Naka-Rushton function; V-max was notably higher, and K was 0.14 log units lower than baseline. Conclusions: Sildenafil administration resulted in a higher rod response to light stimuli and in a higher rod sensitivity. These findings are consistent with the weak PDE-6 inhibition induced by sildenafil. Ophthalmology 2001;108:877-881 (C) 2001 by the American Academy of Ophthalmology.