A comparative study on the measurement of pupillary offset by Pentacam anterior segment analyzer and Keratron Scout corneal topographer

Abstract:

AIM: To evaluate the difference and consistency of pupillary offset measured by the Pentacam anterior segment analyzer and Keratron Scout corneal topographer.

METHODS: Three hundred and eleven patients(604 eyes)who underwent excimer laser in situ keratomileusis from November 2017 to February 2018 were randomly selected. Before surgery, the pupillary offset values were measured by Pentacam and Keratron, and the differences and consistency of the values between the two instruments were compared.

RESULTS: The pupillary offset values of the right eyes, left eyes, and both eyes between Pentacam and Keratron were statistically different(P<0.05). There were no significant statistical differences in the offset orientations of right eyes, left eyes and both eyes between the two instruments(P>0.05). The 95% consistent line(LoA)of offset value and offset orientation in the right eyes, left eyes and both eyes between the two instruments were -0.11-0.19mm and -157.01°-135.35°, -0.12-0.18mm and -150.16°-158.22°, -0.11-0.19mm and -154.30°-147.10°, respectively.

CONCLUSION: The pupillary offset measured by the Pentacam was smaller than that measured by the Keratron, but the difference was within the clinically acceptable range. The accurate pupillary offset can be obtained, and be the mutual reference, correction and supplement in the both instruments.

Key words:Pentacam anterior segment analyzer; Keratron Scout corneal topographer; pupillary offset; pupil size; offset value; offset axial