Sentence:  Using the spherical lenses, <WSD>unfog</WSD> the patient as above. When this is completed, rotate the cylinder cell 90° and, using the cylinder lenses this time, <WSD>unfog</WSD> the patient again till best acuity is reached. 
Meaning of the word marked with <WSD> tags:  To adjust the lenses a patient looks through in order to clarify their vision.