@davidrevoy @ToonLink red-eye often sweeps through cat colonies. When I rescued Belisarivs she had a terrible case, but she was FIV+. She spent several weeks in isolation getting antibiotic ointment in the eye twice/day, which was quite a task with just me doing it.

When I lived in California, the city animal shelter would do neuter and vaccinations for a low fee, on condition that the cats be ear-tipped (which makes it harder to get them adopted). We did about a dozen that visited us that way.