A Study to Assess Whether PDE5 Inhibitors Increase the Chance of Triggering the Onset of Acute NAION

Sites will identify patients who meet the entry criteria during the conduct of their normal
practice. Patients meeting these criteria will be offered participation in the study after
reading and completing an informed consent document.

Inclusion Criteria:

- Male aged ≥45 years;

- Experienced abrupt visual change in only 1 eye

Exclusion Criteria:

- Pain determined by an ophthalmologist to be consistent with an inflammatory/arteritic
process or optic neuritis;

- History of NAION or optic neuritis.

- Participation in other studies within 60 days prior to entry in the study.