title: Subjective visual halos after sildenafil (Viagra) administration: Electroretinographic evaluation.
abstract: OBJECTIVE
  The ophthalmologic and electroretinographic (ERG) findings in one subject with subjective visual disturbances after sildenafil administration are described.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
authors.affiliation: Institute of Ophthalmology, University of Rome La Sapienza, Rome, Italy.
authors.forename: C B
authors.initials: CB
authors.lastname: Gabrieli
authors.forename: F
authors.initials: F
authors.lastname: Regine
authors.forename: E M
authors.initials: EM
authors.lastname: Vingolo
authors.forename: E
authors.initials: E
authors.lastname: Rispoli
authors.forename: A
authors.initials: A
authors.lastname: Fabbri
authors.forename: A
authors.initials: A
authors.lastname: Isidori
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors*; D000368:Aged; D004596:Electroretinography; D006801:Humans; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000009:adverse effects*; D010879:Piperazines / Q000009:adverse effects*; D011687:Purines; D017948:Retinal Rod Photoreceptor Cells / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D000068677:Sildenafil Citrate; D013450:Sulfones; D014786:Vision Disorders / Q000139:chemically induced* / Q000175:diagnosis / Q000503:physiopathology; D014792:Visual Acuity
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate; D015106:3',5'-Cyclic-GMP Phosphodiesterases