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

• Published in: Ophthalmology (Rochester, Minn.) Vol. 108; no. 5; pp. 877 - 881
• Main Authors: Gabrieli, Corrado Balacco, Regine, Federico, Vingolo, Enzo M, Rispoli, Eduardo, Fabbri, Andrea, Isidori, Aldo
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.2001; Elsevier
• Subjects: 3',5'-Cyclic-GMP Phosphodiesterases - antagonists & inhibitors; Aged; Biological and medical sciences; Drug toxicity and drugs side effects treatment; Electroretinography; Humans; Male; Medical sciences; Pharmacology. Drug treatments; Phosphodiesterase Inhibitors - adverse effects; Piperazines - adverse effects; Purines; Retinal Rod Photoreceptor Cells - drug effects; Retinal Rod Photoreceptor Cells - pathology; Retinal Rod Photoreceptor Cells - physiopathology; Sildenafil Citrate; Sulfones; Toxicity: eye; Vision Disorders - chemically induced; Vision Disorders - diagnosis; Vision Disorders - physiopathology; Visual Acuity; Electroretinography; Human; Phosphodiesterase V; Erection disorders; Toxicity; Vision disorder; Enzyme inhibitor; Male; Case study; Electrodiagnosis; Eye disease; Chemotherapy; Treatment; Phosphodiesterase VI; Sildenafil; Male genital diseases; Halo
• ISSN: 0161-6420; 1549-4713
• DOI: 10.1016/S0161-6420(00)00648-5

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; Vmax 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.