"My slim PS3 stopped playing bluray movies but still played games, it played DVDs fine due to it having a second eye for playing DVDs and CDs. The last versions of the fat PS3 and all slim and new slim models have a two eye setup, one eye to read bluray disks, the other to read DVDs and CDs to extend the life of the bluray eye. Well anyway it started to not read any games, it still played DVDs and CDs and PS1 games (its past its warranty) so I took it apart and took a q tip and dabbed it in some alcohol (doesn't require it to be drenched) and spun it lightly on both eyes and took the dry end to wipe off and remove any excess dirt and alcohol. I then took a can of compressed air and blew into the laser eyes and a clump of dust blew out. Assembled the unit and now it instantly sees all disks and plays all games and bluray movies.
Searched online about the issue and apparently the boot file in the system that enables it to read blu ray format can become corrupted causing the unit to not read blu rays. So you have to do a full system restore (11+ hours) that will replace the corrupted file with a new one.
If you replaced the eye with a new one, maybe the replacement is faulty, or one of the data connections isn't making a proper connection (like dust or hair fell into the connector). How about blowing out the old eye and cleaning the two eyes with alcohol and a q tip and reinstall that back into the unit and see if that works.