Subjective visual halos after sildenafil (Viagra) administration: Electroretinographic evaluation.

Abstract

The ophthalmologic and electroretinographic (ERG) findings in one subject with subjective visual disturbances after sildenafil administration are described. Interventional case report. 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. 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. 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. 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.