Complex sentence: The surgery did restore some of Shirl Jenning's vision, however he was overwhelmed with visual sensory data and was unable to connect what he was seeing with his visual memory, which had all but disappeared.
Split into simpler sentences: The surgery did restore some of Shirl Jenning's vision. However, he was overwhelmed with visual sensory data and was unable to connect what he was seeing with his visual memory, which had all but disappeared.