Soviet leader Mikhail S. Gorbachev has not been seen in public since Aug. 7 because his wife, Raisa, became seriously ill following an appendectomy, the Swedish newspaper Expressen reported. The paper said Mrs. Gorbachev, 53, suffered from complications in connection with the operation. It said she had been seriously ill for 14 days and that Gorbachev decided to prolong his vacation on the Black Sea to stay with her. It said Soviet eye surgeon Svyatolslav Fyodorov made the revelation to Mikael Lonn, a Swedish colleague visiting Moscow. There was no indication that Raisa Gorbachev's purported ailment had anything to do with the eyes, however. The report did not give any details about her present physical condition.