The study was done to determine the correlation and relative contribution of preoperative anterior corneal Zernike coefficients to higher order aberration ablation depth (HOA-AD) with topography-guided excimer laser correction.

Retrospective study was done about 46,271 consecutive preoperative virgin eyes. Anterior corneal Zernike coefficients (C6 to C27) and HOA-AD data on a 6.5-mm optical zone were analyzed from the Contoura (Alcon Laboratories, Inc) treatment software.

A strong direct relationship was found between the total root mean square (RMS) anterior corneal HOA and HOA-AD (R = 0.84; P < .001). The 3rd order HOAs (C6 to C9) accounted for most of the HOA-AD (R = 0.83; P < .001). Zernike orders 4, 5, and 6 had significantly weaker correlations (4th order: R = 0.30; 5th order: R = 0.38; 6th order: R = 0.29). Vertical coma was the individual HOA with the highest correlation (R = 0.59; P < .001). Combining vertical and horizontal coma as total RMS coma increased the correlation significantly (R = 0.76; P < .001). The average HOA-AD increased by 1.5 µm for each additional 0.1-µm increment of total RMS coma.

The study concluded that anterior corneal Zernike coefficients directly and strongly correlate to the HOA-AD, with anterior corneal coma having the greatest contribution to HOA-AD.

Reference: https://doi.org/10.3928/1081597X-20200611-02