The hypothesis of this study is to determine if there is a benefit afforded by the use of
systemic Sildenafil to patients with choroidal and retinal degenerations and dystrophies,
such as vitelliform degeneration, dry and reticular age-related macular degeneration (AMD) as
well as patients with hereditary and acquired retinal dystrophies such as retinitis
pigmentosa and central serous retinopathy.