The detail that should be eliminated to improve the summary is "a school named for a visually impaired shipping merchant from Boston." This information, while interesting, does not directly contribute to the main plot or character development in Act I and can be considered extraneous for a concise summary.
Here is the revised summary without that detail:
"Act I introduces Annie Sullivan as she says good-bye to Anagnos, a kind man who has helped her for many years. Annie is leaving the Perkins School for the Blind. She and Anagnos discuss her new assignment, and Annie is curious about teaching a young girl with visual impairments. At the end of Act I, the other Perkins students enter to offer Annie presents and bid her farewell."