Complex sentence: One of the primary facial features often closely associated with the epicanthic fold is the nasal bridge; all else equal, a lower-rooted nose bridge is more likely to cause epicanthic folds, and a higher-rooted nose bridge is less likely to do so.
Split into simpler sentences: One of the primary facial features that is often closely associated with the epicanthic fold is elevation of the nasal bridge. All else equal, a lower-rooted nasal bridge is more likely to cause epicanthic folds, and a higher-rooted nose bridge is less likely to do so.