I returned to the Southpoint location today and continued to shadow Dr. Besharat. There were a lot of patients who came in for contact lenses today. Through shadowing I got learn about the distinct differences between using glasses and contact lenses. Glasses are usually more effective than contacts for two reasons. The first is that a contact lens makes contact with the surface of the eye which can lead to dryness and irritation on the eye. Dryness and irritation ultimately lead to a compromise of a patients vision. If not managed correctly dryness can lead to clouded vision and ultimately the contact lenses cannot be used again and the patient will have to go back to glasses. The second reason for the change in disparity is because of astigmatism. Astigmatism is irregularity in he curverture of the surface of the eye. Instead of being one smooth curve, the eye has varying areas of sloping. These variances lead to light entering the eye in irregular way and vision to be compromised. Glasses can be custom made to a persons eye so a correction for astigmatism can be added. The shape of a contact lens is standard and there are limitations to the amount if astigmatism correction that can be added to the prescription. In general a contact lens and glasses have different prescription because the lens sits on the surface of the eye whereas glasses sit on the ridge of the nose so there is a gap between the correction and the eyes. The below photos are of the machinery used to read the glasses,  evaluate and rectify the prescription, and also of a case with lenses in them that can be used to mimic the effect of a contact lens: