The purpose of this study is to investigate whether taking 4-methylpyrazole (4-MP, fomepizole, Antizol™) inhibits dark adaptation of the eye. In other words, we are testing if 4-MP slows the processing of vitamin A derivatives in the eye. By slowing down these processes, individuals with Stargardt disease may have better chances of saving their remaining vision. 4-MP has been shown to slow dark adaptation in animals, and is FDA approved for human use to treat individuals with methanol or ethylene glycol (antifreeze) poisoning by shutting down the body's ability to process alcohols. This medication has an excellent safety profile and has been reported to have no short-term or long-term side effects, as long as patients refrain from any alcohol while the medication is in the body. A single dose of 4-MP remains in the body for about 12 hours, and therefore, it may inhibit dark adaptation of your eyes for up to 12 hours. Studying the effects of 4-MP may lead to effective medical treatment to save Stargardt patients' vision, and may also have similar effects in other macular degenerative diseases.

Inclusion Criteria:

• All nonpregnant, nonlactating adults with normal vision in both eyes

Exclusion Criteria:

• Previous ocular pathologies