Figure 1. Comparison of the high resolution SD-OCT and standard TD-OCT.

Figure 1 shows high resolution SD-OCT scans (left column) and standard TD-OCT scans (right column) of 2 MS patients. Patient 1, 34 year old female, RRMS, disease duration 15years, prior ON (left eye, 2 years after disease onset). Patient 2, SPMS, 47 year old male, SPMS, disease duration 20 years, no prior ON. Measurements of RNFL were comparable in patient 1 but differed about 5.3 µm (OD, right eye) and 9.8 µm (OS, left eye) in patient 2 (red arrows, lower row). Baseline/reference scans of standard TD-OCT are averaged out of 3 sequential scans (asterisks) with partly substantial differences of each single scan. Low scanning speed and prolonged examination time of standard TD-OCT can often not compensate low image resolution despite good centering around the optic nerve as a result of poor fixation and motion artefacts. In contrast, with high resolution SD-OCT reliable and properly centered baseline and follow up scans can be achieved with ultrahigh speed scanning and an eye tracking mode. Moreover, with high resolution SD-OCT previous scan locations can be identified and guide the laser beam to identical scan positions repeatedly.