Complex sentence: Since we all have head jitter all the time, the VOR is very important for stabilizing vision: patients whose VOR is impaired cannot read, because they cannot stabilize the eyes during small head tremors.
Split into simpler sentences: Since we all have head jitter all the time, the VOR is very important for stabilizing vision. Patients whose VOR is impaired cannot read, because they cannot stabilize the eyes during small head tremors.