What effect did Theodora, wife of Emperor Justinian, have on the Byzantine Empire?

It depends on who you read of the various croniclers
Theodora married Justinian in 523AD, before his access to the Imperial Throne.
Of humble origin, some say she was a courtesan, she was certainly more sensitive to the royal fast and pump than her husband, and sternly stood by the throne when Justinian prepared to flee Byzantium before a riotous populace in 532.
The Empress Theodora in San Vitale
She regularly attended the Imperial Council and presided over it whenever her husband was away.
Indirect traces of her influence on Byzantine policies are found in the “Corpus Juris Civilis” the new legal platform promulgated during Justinian reign.
She protected women in general, and prostitutes in particular, for whom she edified houses and set a fund for their assistance and redemption.
She is disparaged by some Byzantine chroniclers (Procopius in particular) and celebrated by others. She was worshipped in Ravenna, the Italian Byzantine capital where the mosaics of the church of Saint Vitale represent her in her full garb and dignity