Complex sentence: In severe cases of keratoconjunctivitis sicca, tarsorrhaphy may be preformed where the eyelids are partially sewn together, ideally leading to a reduction in tear evaporation.
Split into simpler sentences: In severe cases of keratoconjunctivitis sicca, tarsorrhaphy may be preformed where the eyelids are partially sewn together. This reduces the palpebral fissure (eyelid separation), ideally leading to a reduction in tear evaporation.